Radiochemistry of Titanium

NAs-Ns-3034(Revm)

R OF TITANIUM

NUCLEAR SCIENCE SERIES National Academy of Sciences/National Research Council

Published by U. S. Atomic Energy Commission COMMITTEE ON NUCLEAR SCIENCE

D. A. Bromley, Chairman Robley D. Evans, Vice Chairman Yale University MassachusettsInstitute of Technology

C. K. Reed, Executive Secretary National Academy of Sciences

Martin J. Berger Herman Feshbach National Bureau of Standards Massachusettsinstitute of Technology

Victor P. Bond F. S. Goulding Brookhaven National Laboratory Lawrence Radiation Laboratory

Gregory R. Choppin Bernd Kahn Florida State University National Center for Radiological Health

Members-at-Large

W. A. Fowler George Wetherill California Instituta of Technology University of California

G. C. Phillips Alexander Zucker Rice University Oak Ridge National Laboratory

LiaisonMembers

George A. Kolstad Walter S. Rodney U. S. Atomic Energy Commission National Science Foundation

John McElhinney Lewis Slack Naval Research Laboratory American Institute of Physics

Subcommitteeon Radiochemistry

Gregory R. Choppin, Chairman John A. Miskal Florida State University Lawrence Radiation Laboratory

Herbart M. Clark Julian M. Nielsen RensselaerPolytechnic Institute Pacific Northwest Laboratory

Raymond Davis, Jr. G. D. O’Kelley Brookhaven National Laboratory Oak Ridge National Laboratory

Bruce Dropesky Andrew F. Stehney Los Alamos Scientific Laboratory Argonne National Laboratory

Rolfe Herbar John W. Winchester Rutgers University University of Michigan AE C Category UC-4 NAS-NS-3034(Rev.)

Radiochernistry of ‘Titanium

by Vincent J. Landis

San DiegoState University San Diego, California

and

James H. Kaye

Battelle-Northwest Richland, Washington

Revised Edition

Issuance Date: January 1971

Subcommittee on Radiochemistry National Academy of Sciences-National Research Council Price $3.00, which is the minimum order price for either one, two, or three randomly selected publications in the NAS-NS series. Additional individual copies will be sold in increments of three for $3.00. Available from:

National Technical Information Service U. S. Department of Commerce Springfield, Virginia 22151

Printed in the United States of Anwrics

USAEC Division of Technical Information Extansion, Oak Ridge, Tennassas 1971 Foreword

The Subcommittee on Radiochemistry is one of a number of subcommittees working under the Committee on Nuclear Science within the National Academy of Sciences-National Research Council. Its members represent government, industrial, and university laboratories in the areas of nuclear chemistry and analytical chemistry. The Subcommittee has concerned itself with those areas of nuclear science which involve the chemist, such as the collection and distribution of’ radiochemical procedures, the radiochemical purity of reagents, the place of radiochemistry in college end university programs, and radiochemistry in environmental science, This series of monographs has grown out of the need for compilations of radiochemical information, procedures, and techniques. The Subcommittee has endeavored to present a series that wilf be of maximum use to the working scientist. Each monograph presents pertinent information required for radiochemical work with an individual element or with a specialized technique, Experts in the particular radiochemical technique have written the monographs. The Atomic Energy Commission has sponsored the printing of the series. The Subcommittee is confident these publications will be useful not only to radiochemists but also to research workers in other fields such as physics, biochemistry, or medicine who wish to use radiochemical techniques to solve specific problems.

GregoryR. Choppin,Chairman Subcommittee on Radiochemistry

... Ill Contents

1. General Reviews of the Inorganicand Analytical Chemistry of Titanium 1

11. General Reviews of the Radiochemistryof Titanium 3

III. Isotopesof Titanium 3

Iv. The InorganicChemistry of Titanium 3 1. TitaniumMetal and Alloys 8 Oxides of Titanium 9 ;: OxidationStates of Titanium 11 4. Solution Chemistry of Titanium(IV) 12 A. Simple Aqueous Solutions 12 B. HydrochloricAcid Solutions 13 c. $+ikhxeic Acid Solutions 13 5. InorganicSalts 14 A. Soluble Compounds 14 B. InsolubleCompounds 14 c. Volatile TitaniumCompounds 15 6. Complexes of Titanium 16 A. MonodentateLigands 16 B. Chelate Complexes 19 7. PrincipalMethods of Determinationof Titanium 22 A. GravimetricMethods 25 B. ‘TitrimetricDeterminations 25 c. SpectrophotometricMethods 26 8. SeparationMethods 27 A. PrecipitationSeparations 27 B. Solvent ExtractionSeparations 28 co Ion Exchange Separations 38 D. Paper ChromatographySeparations 47 9. Dissolutionof Titanium-ContainingMaterials 51 A. TitaniumMetal and Alloys B. TitaniumDioxide g c. Salts 52 D. Ores 52 E. BiologicalSamples 53

v. Hazards and Precautionsin Handling Titanium- ContainingMaterials 53 Ccmrnnts (Continued)

VI. Counthg Techniques 54 1. mtaniuln-w+ 54 A. Gamma Spectrmnetry 54 B. Beta Counttig 60 c. Other MethodE 60 TfWuIu-45 ti ;: Titeaiunl-51 61

VII. RadlochemicalSeparationProcedures 66 Frocecure 1 67 Procedure 2 70 Procedure3 n Procedure 4 72 Procedure 5 procedure 6 ?, Procedure 7 procedure 8 ;: Procedure 9 79 Procedure 10 80 Procetire Ii 8~ procedure 12 ‘,:” procedure 13

Blbllography 84

vi Radiochemistry of Titanium

by Vincent J. Landis San DiegoStateUniversity San Diego, California

and ., James H. Kaye Battelle–Northwast Richland,Washington

1. General Reviews of the Inorganic and Analytical Chemistry of Titanium

Titanium, Its Occurrence,Chemistry,and Technology,2nd / Barksdale,J., 7. edition , (The Ronald Pre=Co., New York, 1966). —

Brophy, C. A., Archer, B. J., Gibson, R. W., ——et al., TitaniumBibliography 1900-1951, (BattelleMemorial Institute,Columbus,Ohio, 1952).

Chariot,G. and Bezier, D., translatedby MurraY, 1?.C., Quantitative InorganicAnalysis, (JohnWiley and Sons, Inc., New York, 1957).

Codell,M., AnalyticalChemistryof TitaniumMetals and Compounds, / (IntersciencePublishers,Inc., N&York, 195r —

Duval, C., InorganicThermogravimetricAnalysis,2nd edition, (Elsevier PublishingCo., Amsterdam,1965).

Fresenius,R. and Jander, G., Ed., Handbuch—der AnalytischenChemie, (SpringerVerlag, Berlin, 1948).

Furman, N. H., Ed., Scott’s Standard Methods of ChemicalAnalysis,6th edition, (D. Van Nostrand Co., New Yo-2~

Gmelin’sHandbuch der AnorganischenChemie, 8th edition, System No. 41, (VerlagChemie, G.=. h., Berlin, 19=

7> Hampel, C., Rare Metals Handbook,2nd edition, (ReinholdPublishingCorp., New York, 19W

1 Hil.lebrand,W. F., LundeU, G. E. F., Bright, H. A. and Hoffman, J. I., Applied .InorganicAnalysis,2nd Wiley and Sons, New York, ~

Holness, H., Advanced InorganicQualitativeAnalysis, (Pitmanand Sons, IOndon, 1957).

Ho~kins. B. S.. Chanters—-in the Chemistm of the Less FamiliarElements, (S~ipes’Publisl&g;o., Champaign,Illi~oiZ~9~

Kelley, M. T., Ed., Progress in Nuclear Energy, Series~, Analytical Chemistry,Vol. 3, (~n=e-ndon, 1959r

Kirk, R. E. and Othmer, D. F., Eds., Encyclopediaof Chemical Technology,(The InterscienceEncyclopedia,Inc., iEw-~1.956).

Kodama, K., Methods ~ QuantitativeInorganicAnalysis, (Inter- scienceFubl- Inc., New York, ~

,’ Kolthoff,I. M. and Elving, P. J., Eds., Treatise on Analytical i..- Chemistry,(The IhterscienceEncyclopedia,Inc., N~Yo~k, 1959). Part II, Vol. 5, PP. 1-56.

Latimer,W. M. and Hildebrand,J. H., Reference—.Book of Inorganic 7L Chemistry,3rd Edition, (The mcmi.llan Co., New york, 1~~

Lundel.1,G. E. F. and Hoff?nan,J. I., Outlines of Methods of Chemical Analysis, (John Wiley and Sons, Inc., New York,q9~—

Meites, L., ~a., Randbook~ AnalyticalChemistry,(McGraw Hill Book co., New York, 19~

Mellor, J. w., ~ ComprehensiveTreatise on Inorganicana Theoretical ‘“Chemistry,(Longmans,Green and Co., Inc~ New York, ~7].

Morrison,G. H. and Freiser, H., Solvent Extractionin Analytical Chemistry,(John Wiley and Sons, Inc., Ne~5~, p. 240.

Noyes, A. A. and Bray, W. C., Qualitative Analysis ———for the Rare Elementsj (The Macmillan Co., New York, 19~

Remy, H., Treatise on Inorganic Chemistry,translatedby J. S. Anderson,~-r—~lishing Co., Amsterdam,1956). Vol. 11, pp. 44-64.

Redden, C. J., AnalyticalChemistryof the ManhattanProject, (McGraw Hill Book Co., New York, 195~.—

Samuelson,O., Ion-ExchangersQI AnalyticalChemistry,2nd Edition, (John Wiley and Sons, Inc., New York, 1963).

Sandell,E. B., ColorimetrlcDeterminationof Traces of Metals, Yrd Edition, (IntersciencePublishers,New~r~9~

Scott, W. W., Standard Methods of ChemicalAnalysis, Vol. 1, (D. Van Nostrand Co., &=~wYork, l$?~

Sidgwick,N. V., The Chemical.Elements and Their Compounds, (OxfordUniversit~?-d~)- —

2 ~ Skinner,G., Johnston,H. L. and Beckett, C., Titanium and its Compounds,(HerrickL. Johnston Enterprises,Columbus,~o~954).

Thorne, P. C. L. and Roberts, E. R., Fritz Ephraim InorganicChem- istry, 6th Edition, Revised, (NordemsnPublishingCo., Inc., = York, 1954). Thornton,W. M., Titanium, (The ChemicalCatalog Co., Inc., 1927’). I(-’ > Treadwell,F. P. and Hall, W. T., AnalyticalChemistry,9th Edition, (John Wiley and Sons, Inc., New York, 1937). Principlesana Methods of ChemicalAnalysis, (k~n%~kFiz Inc., New Y=,~— — willara, H. H. and Diehl, H., Advanced QuantitativeAnalysis, (D. Van Nostrand Co., New York~ Wilson, C. L. and Wilson, D. W., Eds., ComprehensiveAnalytical Chemistry,(ElsevierPublishingCO., Amsterdam,1960).

Yoe, J. H. and Koch, H. J., Jr., Eds., .—Trace Analysis, (John Wiley and Sona, New York, 1957).

11.General Reviews of the Radiochemistry of Titanium

Kim, C. K., —The Radiochemistry.—of Titanium, (I?AS-NS3034, 1961).

Redden, C. J., AnalyticalChemistry——of the ManhattanProject, NationalNuclear Energy Series, Vol. 1, Div~~McGraw Hill Book Company, 1950).

U1.isotopes of Titanium Table I (see page 4) is a list of the isotopes of titanium.

lV. The inorganic Chemistry of Titanium A. General Chemistry

Excellent and current reviews of the general chemistryof titanium are

listed in the “GeneralReviews” section. Although titanium is one of the most

abundant and ubiquitouselements, it has traditionallybeen treated as a rare ele-

ment because of the difficultyof reducingthe ores. It has been found in almost

all crystallinerocks, sands, and soils, as well as in vegetation,natural waters,

(3) meteorites, stars, &m& deep sea dredgings . Titanium is estimatedto constitute

0.6 percent Of the lithosphere,making it the ninth most abundantelement and the (4)6 fourthmost plentifulstructuralmetal Ferrotitsnium,titanium dioxide and

titanium tetrachloridehave been widely used for many years, but the metal has

been produced on a commercialscale only since 1948(3,5) . Table 11 shows some

propertiesof titanium of interest to the chemist.

‘3 TABIEI Table of Isotopesof Titmium (2)*

Thermal Attic kSS Natural MXie Euer~ of Neutron Isotope Abundance,$ (C+ Scale) Life of Dec~ Radiation,M3V U, barns

~i41 40.9841 .Ogoa P+ 42 Ti 41.9’775 .25s (~+& E.C.) 6.0 *

Ti43 42.g707 0.56-0.58s p+ p+ 5.8 ~i44 ~1 0.068 ( ~) 43.96234 46-48yr E.C. ~20.078 ( 9%) Ti45 44.950998 3;05-3.10h ~+, E.G. p+ 1.04 46 Ti 7.95-7.93 45.B58@ 0.63 ~47 7.75-7.32 46.9550’73 1.7 Ti48 73.45-73.99 47.g51517 8.0

Ti49 5.5L5.46 48.!351442 1.9

Ti50 5.3k-5.25 49.9W569 0.14 ~i51 50.95026 5.79-5.&hl p- p- 2.14 ~ 0.320 ( 95%) 0.605 (1.5%) 0.928 ( u%)

.*All data from reference(2J except Titanium@ data from reference(144). FIGURE I

Chart of the Nuclidesin the Titanim Region.Reference1,

— 25 “~= B+ — — — . ,4,7E.W .1.38

,$4:7 ;,? “33 ,+CL?=

Cr 3.1 . . . . . “’k%’ E2.5 E16

,55+

22 m

NOTES: This chart may be obtainedfrom BattelleNorthwestLaboratories,Richland,Washington99352. The GeneralElectricChart of the Nuclides (to December1968)is availablefrom Educational Relations,The GeneralElectricCompany,Schenectady,New York. The Karlsruhe Chart (1968)may be obtainedfrom Gersbachand Sohn Verlag, Munchen34, Barer Strasse32, Germany. FIGURE II

Decw schemes of TkLtaniumRadioisotopes(2)

~41 (0.090 s)

[ p+] 6.51 SC 12.7 est. 5.68

5.30

4.85

4.21

3.48

~c41 40 ca #

!ci43 (0.56 S) )

(Continued) FIGURE II (Continued)

~i44 (48 yr) Tln70.1463 F ~c44

(3. 92 h)

O“”F 2.66 i 2.28 ~+ 94$ l’i4’(3.09 h) EC 5% 1.88 ‘O.ogo

TF? = 1.663 P“ ‘ 0.27$ L 408 L --0.05% 1.238 d QEC 2.059 Cd-C. EC .l_~+ o.3~0 0.718 A

=~+ @+% [EC 15%1 F r-l’SC!45

~i51 (5.8 m) \ P- ‘i3- 2.46

‘4%~kti ~51 I 1, TABLE II

Propertiesof Titanium

Refemzmce klsity 4.54 g’/cc 3

Melting Point 1668°C 3

Boiling Point 3260”c 3

Electrcm Gound State [ml 3d2 hsi 4

Oxidatia Statea 4+ Mcst stale 4

3+ Stabl$ in water; odd by sir 4

* Oxid by dr/vatsr; useful in fused salts 4

o Metal or LEL(dipy)3 only 4

-1 Tl(dipY)3 only 4

Ialc Radius 0.681 (+4) 6

Covalent Radius 1.32 i 6

Imiz&zcm Potintial

1st 6.83 e.v. 6

2ud 13.57 e.v. 6

3rd 28.14 e.v. 6

4tb 48.24 e.v. 7

Oxi’datfcm Potentials:

mo.~2++2=- E“ $ ca. 1.63 V.

Ti” + H20 = T102+ +2H++ he- E“ M ca. 0.88 V.

Ti”+2H@ =Til+-~20+4ti +4 S!- E“ = 1.69 v.

No + 6 F- = TIF62- + he- E“ = 1.19 V.

Ti.2+= Ti!+ + e- E“ = ca. 0.37 V.

Ti3+ + E2Q = .T@+ + ~+ E“ = ca. -0.1 V.

1. TI!I!AHIUMMETAL AED ALLOYS

Most ccamnercialproducticm of titanium is baaed upm formaticmof the volatile tetrachlofideby chlorinaticmof the ore aud subsequentmducticm of the vapor with

8 molten magnesium(’). The reductionof titaniumtetrachlorideby sodium is used to a lesser extent. High purity titaniumhas been produced by the iodide refine- (8) nent process of van Arkel and tleBoerfor many years on a laboratoryscale . A recent developmentin refining titaniumis the electrolysisof titanium or titsnium(III)salts in a fused alkali halide solution. Table 111 shows the rela- tive purity of titaniummetal as produced or refinedby these processes. Further purificationof iodide metal as indicatedby lower stress values has been reported(g). Typical alloying constituentsfor industrialtitanium are 4-8% aluminqmtogetherwith lesser percentagesof vanadium,zirconium,molybdenum, amd/or chromium.

As a first approximation,titaniummetal is very similar to zirconiumor stainlesssteel in appearanceand in physical and chemicalproperties. At room temperature,massive titanium is reiuistsntto all common gases, salts, alkalies, (lo) mineral acids (exceptHF) sad most liquid metals. . Hydrofluoricacid and fluorboricacids react vigorouslywith titaniummetal, even when hot nitric acid forms an oxide film on titanium end fails to dissolvethe metal. Refluxingwith

1:1 HCL in the absence of &r will dissolve chips of titanium in 8 to 10 hours forminga purple titsnium(III)solution,but in the presence of air some dioxide precipitates. Similar treatmentwith dilute sulfuric acid dissolvessome of the metal but also forms a blue-graybtiihkyprecipitatewhich covers and protects the remainingmetal.

At elevated temperature,titaniumwill burn in many gasea. Reaction takes place at 150°C in fluorine(u), 3500C in chlorine,3600C in bromine, 4000C in iodine, 6100C in oxygen, 8000C in nitrogen, 700 to 8000C in steam and QOO°C in #3)” . Heating in an open flame causes a blue film to form on the surface of a piece of metal. Techniques for dissolutionof titaniummetal and alloys are given later.

2. OXIDES OF TITANIUM

There are three well-definedoxides of titanium,TiO, Ti203$ and Ti02, (14) which correspondto the positive oxidationstates of titanium . The first

9 TABLE III

!&piCal Analyses of TitauiumMetal

Mg Reduced Iodide Cmm?rcial Refined Electrolytic ~ercent(’) Percent(’) Percent(U)

Iron 0.2-0.03 0.025-0.00’5 a.oo5

Chronliwnl <0.005

~esium 0.U-O.04 0.002-0.0015 0.002

sodium

Silica <0.01 ~o.o’ 0.01

Mauganese 0.06-0.03 0.013-0.005 0.03

Copper <0.03 0.002-0.0015 @. 006

Aluminun <0.005 0.05-o.o13 co. 04

Hitrogen 0.05-0.01 o.ooLomool 0.002

Hydrogen 0.008

Ww o.15-o.oo5 0.01-0.005 0.002-0.025

Carbm 0.0’-0.01 0.0>0.01 0.08

Valadium <0.005

chlorine 0.10

Molybdenm 0.0015

Nickel 0.003

Tin <0.03 <0.01

two are readily subJect to cddatlti tot,he extnnely steble dicdde. “llt~um(II) reduceswater but titauium(III)and titanium are meadilypmacipltat&dae hydroue oxides from aqueoue solutims. me p~be titenium(III)@tiOU8 oxide precipitatedby base fran water Is a very strag reducing agent. Titanium hydrous oaide is Btable and mqy be Ignited to the dicdde. Freshlyprecipitated hydroue dioxide cem be dissolvedin strong acid or alkall but the product of

10 aging, ignlticm,or precipitaticmfrms hot solutlms requireshot cacentrabed

sulfuric acid, p= ferably cmtdning anmmium sulfate, or al.kdi fusion, to effect

spee* 1301uticm(6).

Several solid per@iteniun(IV) ccqounds of somwhat uncerteAn ccuspceition m(15) @ structuream often included in the group of “titaniumaides. .

Peroxytitenium(IV) species are of greet importanceto the eolution chemiEItV of

tit&uium. Their color is the bsaie for the ccmmcm spectrophotcmetricmethod

of analysie,they are used to prevent hydrolysis,and can serve as a ‘holdbackn

to prevent preclpitaticmW In the presence of Perdde, titenlum(IV) can be

dissolvedin string alkali(17), but mprecipitates deccmlpozitionof the

perofids?.

3. OXIDATIONSTATES OF TTTAEIUM

As cau be deduced frmu Tehle II, tbe radiochemistis likely to be ccncerned

only with titanium mtal and with titauium(IV) cqomds. Oxidatim potentlala

alone do not rerkct the titenim redox picture completelyfor seve,ralresscms.

Titmium(IV) and, to a Maser extent, titauium(III) require Eev6ral molar acid

or, altemativew, cmqd.em-fomd.ng reagentsto prevent hydrolysis. As a result,

the eXSCt Sp+?deS or the i=ic strengthiS in Sufficient-t tO cause Bi@fl-

cant pmmibillty for error in the mssumd potentials.

Anhydrom titanium w be purchased es the hydride, halide or ofide (lb) ead methods for analysishkve been devised . Theee ccmrpoundsmsact wlti water to form hyti”~n and tltauium(III ). Aqueous tit smium( III) solutims must be pro-

tected frms air or evan mild cAdizing ~nts. Titanium(III) salta end Soluticam

of the chloride can be obtdned cammrcielly. Titauium(III) sblfate in acid

8Olutim Blowly produces noticeableamounts of H2S end titauiwm(III)ie one of

(18) * wry few im.s kn~ to reduce perchlomte in aqumue solutim . The ccomnm

volmmtfic eualysis for titsmlum is baaed upaI the reducticmof acidic titsmium(TV)

Oolutims by dadhium or zinc amalgam, or by aluminums.etal,follmed by titratim (14) of *e resultingtitanium{III) with a staudard axidizingagent . Since

titanim, unlike Irca, is not reducedby a silvefiszlverchloride reductor.

11 titanium and iron can be co-determinatedby redox methods(19). Solutionsof titanium(III) are used to some extent as reducingagentsboth in analysisand in kinetic studies. Referencesto the preparationand uses of such solutionsare

(20)● given in the Meites “Handbookof AnalyticalChemistry

4. SOLUTION CHEMISTRYOF TITANIUM(IV)

A. Simple Aqueous Solutions

Extreme susceptibilityto hydrolysisrequiresthat solutionsof titanium salts in non-completingmedia be maintainedat high aciditywith low titanium concentration. The ionic species of titanium in such aqueous ~+ became eti~nce for either a solutionshss long been designatedas TiO hydrated tetrapositiveion or hydrolyticpolymers has been lacking(7) . The predominatetruly hydrolyticspecies in nitric and perchloricacid solutions

has been the subject of considerablestudy(21-26).

Liberti, Chiantellaand Corgliano(26), the most recent authors,‘navestudiedthe

partitionof titanium(ill)between aqueous solutionand 8-hydroxyquinol.inein chloroform

and T3-Ain benzene. They propose the following species and equilibriumconstants:

% = [Ti(OH)22+][H+] / [TiOH3+] pK = 1.80

K ~ [Ti(OH)3+][H+]* / [TiOH3+] pK= 4.2o

K E [Ti(OH)4][H+]3 / [TiOH3+] PK = 6.3

TM&’data indicatethe followingformulationof the volubilityproduct.

Ksp ~ [7!iOH3+][OH-]3 pK = 39.4

Iiabivsnets(22)reported the followingvolubilityproducts.

Ksp E [Ti02+] [OH-]2 pK = 29

KSP ~ [TiO(OH)+][OH-] pK= 16.5

Nabivanets?sets of values do not disagree greatlywith the constantsfor simi-

lar expressionsderived from Liberti~sresults. The appezentdisagreementcon-

*To avoid possibilityof ambiguityread “K s“ as “the equilibriumconstant expressiondefined as ... v!

12 terns which ❑pc.le.eerlst in m3&rately acid aolutims. These results stmas

further the.practicalnecest3ityof using approxhnatelyme mOlJX solutimz of nltticor perchloticacid to prevent hydrolyticprecipitatim in aolutLms of titaniti.at mom -rat-. About 5 M acid cmcentratim is requiredto pn?- vent precipltatim In ziuchsolutim upca boiling.

Polarogra@ic revereibili~ cud chauges in half-warnpotential,es well

sa chmgea in l@rolysis characteristics,indicatethat weak cwuplexesare form?dby titti,wm(IV)in ‘hydrochloric,suM%ric, and phmphoric acid solutime (27) .

Such camplexesretmd hydrolysis s~hat, but it,is advisehleto use the above acidltiea es a guide for the pmp”exatim of stabk carrier solutims in most

acids.

“Aging” effects of titauiumsolutims were studiedby Babko(21). HiE results

cm finmd the pmvloue indicatlms(23) that, uuUke ziroonlwm,tit-i-( IV) dces

not form short-chainp~ric species by l@rOWSts. All ‘a@ng” effects, such

as slow la-exchange adsorptia end a slow color reactl& with hydrogen per-de, were fownd to coinciu with the TgndalJ effect indicatingcolloidalaggre~ticms.

B. ~&OchlOfiC Acid soluti-

In electrondgraticmstudies of hydrochloricacid solutims” of (22) titanlutn(IV) lV&ivenete has found that a dispmitive species predominates

frwI pH 1.3 to b M EC1, a neutral specie’s (’l!iOCIZ) predmlnates fran 4M to 10M,

end an anlmic pmdondnatea in greatirthem 10M HC1. The latter finding cmflrm (28). k results of ion exchauge 8tudiesby Krawe

c. Sdf’uric Acid SOhtiCZM

Several indicatims am availablethat sulfuric acid solutims of

titanium cmtdn suJYate and/or bisulfate [email protected], and that these ccmplexes

m strmgar than the chltide species. Eebivauets(=) obtained the foU.owing equilibria cmetsnte .

K1 z [!H02T] [S042-] / [Nmoq] , pK = 2.40 at 18°C

K2 z [mlso~l [SOQ2-1/ [Tlo(sob)zz-1 @f = 1.2o at 18°C

13 The work of Beukenkamp and Herrington(23), on the other hand, was interpretedto indicate bisulfate complexationin sulfuric acid solutionsend the following constantswere derived.

K1 E [Ti(O?3)z2+]/ [Ti(OH)~+][H+] KI = 2.0

K2 z [Ti(OH)3HS04] / [Ti(OH)3+][HS04-]. K2 =llto12

K3 s [Ti(OH)2HSO~+] / [Ti(OH)22+][HS04-] K3 = 0.64

There is general agreementthat a neutral complexpredominatesat a sulfuric acid concentrationof about 0.5 molar, but in more acidic solutions a neutral species is indicatedby Beukemkamp and a negative speciesby Nabivenets.

5. INORGANICSALTS

A. Soluble Compounds

Aa discussedin the previous section, there are really no water-soluble simple salts of titanium. Titanium(III),much like iron(III),must be maintained at low pH, and titanium solutions require an acid concentrationof several molar to prevent hydrolytic“aging” or precipitation. On the other hand, most simple salts, other than ignited dioxide,are readily soluble in acid solution, or in the presence of a completingagent such as citrate or tartrate. solu- bilities recorded for some commerciallyavailablecomplex salts at room temperatureare: Na2TiFh - 65 g/8, (NH~)2TiFh- 250 g/!2,and K2TiFh - 12 g/#9). (29) However Ginsberg reportedhydrolysis difficultiesin conjunctionwith these studies. Almost any titanium compound or mineral can be dissolvedin either hydrofluoric-sulfuricacid mixtures or by fusion in ammoniumor potassium bisulfate.

B. Insoluble C~ounds

From the standpointof quantitativeor semiquamtitativeprecipitation, the most commonlyutilized insolubleinorganiccompoundof titanium is the hydrated dioxide. Other precipitant include the acid phosphate(17),arsenate, ferrocymide(5*14), ferricyaide(14), andpotxsiw io&te(5). Thehydrous oxide tends to be very gelatinousand to occlude other substances,so a good deal of effort hss gone into the developmentof methods for producinga more crystalline

14 and pure product. Alkali hydroxide causes “non-quantitativeprecipitationdue to amphoterism(in very strong base) or the formationof colloidal.suspensions.

The addition of iron(III),zirconium,or other carryingarzentis helpful.

Procedures for carefullyadjustingthe pH have been describedusing ammonia (lT), (3.6,17) pyridine(”) , barium carbonate , thiosuLfcrbe(16’17), acetic acid(14$16’32), (5,33) hexameihykmine(”) , guenidinecarbonate ,andbenzoic acid(l’). Precipi- tation by boiling in acid solution is an effec~ivepreliminaryseparationfrom many elements end is a classicalmethod for separationfrom aluminum,chromium~

etc.(17). Zirconium,phosphate,and completingreagentsinterfere.

Under most of the conditionsabove, a fairly gelatinoushydrous oxide or basic salt is formed. It is probably safe, therefore,to assume that titanium would serve es a carrier for most other transitionmetal ions and vice versa.

The most similar reagent to titanium under most circumstancesis zirconium.

Duval(34)has reported on thermogravimetricstudies of titanium dioxide

formedwith various reagents. The followingtemperatures,are necessary for i=ition of these Precipitatesto stoichiometricTi02: aqueous ammonia (3500),

guaqidiniumcarbonate (550”C),tannin (6000C),selenite (880°C),peroxide end oxalate (320°C),cupferron (643°C),8-hydroxyquinol.ine(718°C),5,7-dibromooxine

(480°c). Several of the organic titanium compounds have a definite composition at a lower temperatureend are discussedUmder the topics ‘rChelates”or “Methods

of Determination.”

c. Volatile Titsaium compounds

The volatile tetrachlorideof titaniumhas traditionallyfound application as a purificationmethod for titanium and has been used.in radiochemical separationof titanium from other t&nsition metals(35)0 The tetrachlorideis prepared commerciallyby chlorinaticmof titanium ores. On a laboratoryscale it may be preparedby heating Ti02 with carbon blacks and then reactingwith chlorine at 550”C or above(36’37). Other methods involve heating Ti02 with (38) CC14, CHC13, phosgene, or CO and C12 . The tetrachlorideis a light yellow liquid,with a melting point of -30°C, a boiling point of 136.h°C, and a density

15 of 1.?26. Chloddes with lwer boiling points include: SiC~ (5~C),

SnC~ (lJ3°C),AsC13 (122”C), GeClq “~84°C).Volatile chlorideB with higher boillng points include VC14 (164°C), NbC15 (243”C),TaCls (234”c),FeCls (319”C).

Copper VOO1 ~ be added before diBtillatim to react with vsnadium.

6. COMPIFJES OF TITANIUM

Considerationin th~B secticm is given aly to titanium complexesvhich are formed in, or etiractablefrom, aqueousudia. For tme vho uishem to study air-oxidizabletitenium(III)[email protected], and the ertremelyhydrolysis-sensitive titanium cauplexes,starting sourcesmay be found in reviews end articles by .orgensen(3’), Stiikra(ti), aud RiveBt(41S42). Meat of the kuwn cmBtents are given in the ChemicalSocie~’ B Special Pfiliuaticn #17(39).

Ccmplexesof both titenium(III) aud (IV) are sfistituticmlabile eud their chemiBtzyis free from the disadvantages,end occaaicmaladventages,associated (44) vith inert canplexessuch as thcae of chranium(III)end [email protected](III) .

Because titanium has not been found as a simple hexaaqueion, it maybe ccasideredto alwsya efiat in aqueous Bolution aa OXO-, hydroxc-, or other c- plexed s~cies. Titanium(IV)exhibits a strong “preference”for oxygen as a dcnor atcm with fluorideas the cmly mcuodentatetiallenger. Moat strcmg chelating LLgends for titaniumhave at least cme ~gen donor atom, but nitrogen or sulfur cau fozm the seccmd bad without losing effectiveness.

A. MonodentateIdgands

Hydr~en Peroxide

The yellm to orauge color formedby titenium solutims upm additicm of hydrogen percuide is the moat canmon m?ans of detectia end determinaticmof titanium. This ccsqhx is not strong enough to forestallhydrolysisso quantitative interpretatim of the results is difficult. Frau ccmsidereblesolid end (45) solutia studies,Patel sad Jere cmcluded that the peroxide anicm usually acts “eaa bidentate Ugand. Uninhibitedby the facts, ve have ch~en to fohm the ccmventimel wlsdcm by includingthis discussia with sin@e cmplexes rather than chelates.

16 (L5) Patel and Jere have studied the titsnium(IV)-peroxidesystem in perchloric and sulfuricacid solutions,and also in the presence of chelatingligands. The summary of their resultsbelow shows the dependenceof the titenium(IV)-peroxide equilibriumupon other coordinatedgroups.

K z [TiOX] [H202] / [TiX02]

x= oxalate, pK = 6.10

x= maleate, pK = 4.72

x = malonate, pK = 4.55

x = sulfate, pK = 4.19 (inO.75 MH2S04)

(46) Without committinghimself as to the exact species involved,,Babko cal- culated the followingequilibriumconstant for the ions in which the Ti(IV):peroxide ratio is 1:1.

K = [Ti(IV)] [H202] / [Ti(IV)H202] pK= 3.05 (in HC1)

Mori(47) and cc-workersstudied the titanium(IV)-hydrogenperoxide system in aqueous sulfuric acid and concludedthat the speciesbelow were appropriate.

pHoto2 [Ti(OH)2(H20)(H202)]2+or [Ti02]~”

pH3t06 [Ti(OH)3(H202)]+

pH7t09 [Ti(OH)s(H02)] or [Til

pH 10 to 13 [Ti(OH)2(02)212-

Fluoride

The fluoride complexesof titanium(III)snd (IV) are widely utilized in preventinghydrolysis and in the dissolutionof titanium containingmetals and minerals. Kleiner(48)studied the aqueous system Ti(IV) - H202 - F- and calculatedthe followingconstent for a 0.1 M nitric acid medium.

K s [Ti02+][F-]/ [TiOF+]= 3.6 x 10-7 pK= 6.44

Since K2TiF6 can be prepared from acidic ~ueous solution,it is reasonableto assume that negative fluoride complexesare formed in solution. cotton(k)

17 states that TiOF42- is the predominatespecies in HF solutions and that TiOF+$

TiOF2 and TiOF3- also exist.

‘lMocyanate

The thiocyanatecomplex of titanium has been investigatedby spectro- (24,25) photmmetxy and extractionby Eelefosse who calculatedthe following equilibriumconstant for the complexin lltperchloric acid.

K a [Ti(OH)(SCN)2+]/ [TiOH3+] [SCI?-]PK = -1.7

She found the higher complexesto be extremelysensitiveto hydrolysis. A

titwium(IV) thiocyanatecaplex which is somewhat stihle in acetonehas been

used to extract titanium from aqueous solution and to determinetitanium

spectrophotrxnetrically(4’).

MonodentateOrganic Ligtuvia

Color chauges and changes in volubilityindickte complex formationbetween

titeniuxa(IV)and a number of organic compoundswhich are presumed to serve as

monodentateliganda. Such compoundshave only one functionalgroup or else have multiple functionalgroups so located that steric consideraticmsrender (50) their serving as chelatesimprobable. Welcher lists those used for (51) titaaium analysis up to about 1946, Sommer includes several.in his review (52) of calorimetricreagents for titanium. Caulfieldsnd Robinson studied

the color forming reactionsof titanium with 2? phenols, many of which must

serve as monodentateligands. The brief listing below is intendedto give a

feeling for the variety of such reagentsknown.

TABLE IV

Some MonodentateColor Reagents for Titanium(IV)

_@phenylphen01 1-S or 2-napthol

hydroquinone _waminobenzoicacid

thyslol quinoline

_@(?), =-, & &-aminoPhenol resorcinol

p-hydroxybenzoicacid ~-chlorophenol B. Chelati Cmplexea

!Che general rule that chelatee am mom stable thao auelogcnmmae titate cmplsxes Is folllmedby tit~um( IV). Tbis added ~tabilityis exceptitm~ pez%inent fOr titeniuub0@8U8e so few monodentateligemdspmsment hydrolysisin neutral to beslc molutim , ad few fom aniaic Bpecies.

Analyticalchemistshave laig Inveetigatidtltmtlum chelates for gravind.ric, colorlnk?tric,end electrochendcaldetecti~ =d debnalnati~ of the element.

In general, greater et.Sbllity Is fownd with chelatingreagentshaving ~gen dmor atoms separatedby two or Vmee c-cm at- such that a 5 or 6 membemd ring my be fonsed in ccsqplexfomatia. ~ secmd ~gen ~ often be replacedby a nitrogen or sulfur atcm without greatIy diminishingthe stebiu~. Sme such reagents are quite senaitivu for titanium but nae seamto have a high degn?e of selectivity.

Citrate, oxalate,tsutrate,sti cylate, lactata, 8scorbate,and et~iene- diawinetetraecetateare examples of readily availablematerielawhich are used to prevent hydrolysis,to prevent precipitati= or to prcnnotepolarographic rever~ibllity. UnLIJsemany transitionmetals, TitertLum(IV)does not tend to

COInbi~we~ with beteAjJsetones(~l].

Cupferra, 8-hyd.roxyquinolineend its derivatives,end taunin era amag the chalating-agents ccmmonlyutillzed for gravtmetricdetenninatim of titanium. A very large number of other organicprecipitautsau’sknown which probably chelatewith titanium but which have not been as widely studied.

‘lheunending ee=ch for e@ectrophotometricreagentswith a high degree of sensitivitysod eelsctivityhas led to the stu~ of a very “lar5 nwnber of chel.ate-fontdngreagentswhich develop a color or chsnge color in.the presence of tit~um(IV] . Tircm ( disodium 1,2-dihydroxybenzene-3, 5-sulfaate) and chrcraotrbplc acid (1,&dihydFoxynaphthalane-3,6-distifmic acid) are cmumon examples of the _@diphenol end ~-diphenol classes of col.grimetricreagent for titanium. Both of theee reagents ccmtdn sulfmic acid grows to inc=aee solubilitg,aud both are capable of chelate cmqlex fonnati~ with tit~ivm(IV)

In sciti”csolutim. The latter characteristicdecreasesthe number of int.e~

19 fering caticms. The stablli~ and Sensitivityof the colo~forming complemng reagents generalJy follows the order ped-diphenols, D _*dlphenole,

> _*&nolcarboxyllc acids , > @iimola(53). In Eknmuertssurvey paper(23) and Welcher’s(50) .~atise ae ~ fiQd 75 to 100 color-formingchelate reagents.

?xalate

The oxalate coqlexes of titanium mW be used to prevent hydrolytic (54) precipitatingat pH1s greater then 5.0 ● This allows the separatim of aluminum from tltauiumby &hydroxyqtinoline, end d.da in the separatim of (55) titanium frm nicbium aud tautalum . The electrochemical=veraibili@ of (56), the titauim(III)-(IV) couple is improvedin oxalate ccmtdning solutias

Pece*(’7) shoued polarographicaUy that the mmmoxalato ccmplexesof titaulum(III) and tit-ium(IV) were of similxm stahili~.

13abko(5’)used spectrophot~tzy end ebctrauigratlm to stu~ the titaniu( IV) oxalate cmnplexesad calculatedthe cmstants belcnr.

K1 k [Ti02+] [C2042-1 / [!HOQ041 pK 6.60

K2 E [TiOC204] [C2042-] / [TiO(C20q )22-] PK 3.30

A genenil mvlew of the metal oxalato cmplexes has been written by Krishuam*

sad Harris.

Ethylenediaminetetr-etlc acid

Ethylenediamlnetetraaceticacid Is usually referredto as ELYI?A,but me also

finds its sodium salta desi~ated as Vezmine or ccmplsxae[III]. The meet useful proper@ of the titanium(IV) - EIYTAsystem 5s that the canplex formed is not ea strcmg as that of =t tmsusitia mtals. This proper@ allows other metals to be “held back” whih tit=lun is precipitatedor extracted. For example,many nmtals will not precipitate- anmmiacal solutim in tie presence of EDTAO but tituLm(IV) will. !l?hlseffect is also used in the deteminatia of titsnlumwith oupferr-. EDTA in used to p=vent the copreclpltatiw of unst

other =tal cupferrates(59)0

20 Cupferrm

Cupferrcm,the aummium salt of nit?csophenylhydroxylemdme,is perhaps the meat useful reagent in the separatismof titsmium(IV) because few cupferrates fonm in several molsu mineral acid soluticm. Its use 8s a pmsclpltatlng reagentis discused in the e.ectim a gravimetricdeterndmatims, end its use in solvent extracti= ie discussedin that sectim.

Chr~ot rcmiC Acid

Qmanotropic acid (1,&dihy~nc@thalene-3 ,6-dieulfc@c acid) is me

of the more cerefullystudied colorl-tric re~nte aud has been used for the (60) deterluhatia of titemium ebce shout lgOO . Because It Is cme of the better

reagents for debrminatim of titanium , aud it is also a representative e==Q~ of a Wge group of CUIIPOUUdS,it till be discussedin som detdl. The colored titenium(IV)-chrcmntropatecmplex is formed in solutime uhich

m over 75% in sulfuric acid. The interference of a large number of =tal lam (61) .--..-—. -—.. —. ,-s4----- .%- -A -L—-- la eliminatedat this addity . ~p~~rw-k- MY MAUSJiSWU UA~ ~Uuu=u=

Of CQIS~S u’ith1:1, 1:2. smd l:a metal to Ilgaud ratios. Houever,because

semrel formulaeq be used to representthe metal central la -d tie Chr--

tropic acid may lcee up to four of its hydrogen icne, the unemhiguoueinterpns-

taticn of the s@cies involved is Impcesibleat present. Electrophoreeis

indicatesthat positive species such 8s TIHH3* and/or TIORH3+ pn?dmintie in

solutionsu@= acidic then pH 0.1 end that negative species predominateIf the (62) pll is greater then 0.4 .

The colorluetric deteminatia was stated to be most selective at pH 2 where a complexha-g a tit=dum to I.igaudratio 01’ 1:2 predc?ninates.If

several of the cmnnm InterferingIUM exe previwly reducedwith ascorbic

acid, niobium cm.stltutesthe m~ serious metal la Interfemsnce accordingto

S-r(62). Methods of detemuiningtitsmiumwith chr~ropic acid have been (66). publishedby S~r(63,64) , Stener(65), eud by Saarni

21 Ortim-Diphenola

Catechol,firm, prokocatechuic acid, aud 2,3-dil@ro~aphthalen*6- sulfcmic acid representthe _@diphenol class of colorimtric reagents for titdum(,v)(’’’”j. Catecholis more properly nwd as lB2-dihydroxybenzene.

Since it has tvo potential.tidisplaceablehydrogen atana, it ~ be caneniently representedes FfH2. ‘llrm Is the disodium~alt of 1,2-dihy&~benzene-3,> disulfooicacid aud its parent acid mI?Wbe representedas FUi4. Protocatechulc acid is 3,&dihydroWbenzoic acid end m= be repmssentedas RH3. In spite of the rather gmeat differencesin substitnnts to the fm&mental @@henol groqing, the constautsmmt chuacteristic of chelateb=d fomati cm mary (’9)0 surptisiingly little The fact that charge differencesdu to the id zati~ (70) of sulfmic acid groups 18 signiflcautvss demonstratedby Behko who found the Ti(RE)2 type of complex to be etiractableinto orgenic solvents for

1,8-dibydroxgnaphthalenebut not for its disulfcmatidderivative,chranotroplc acid.

In situdiem simil- to thcee discussedfor chrcanotroplcacid, S~r considered this ~erles of ligfmds(’7,68).His electrophoresisstudies shou that a negative species predmninatesat pH greater thau 1.5 and 1.7 for the catechol end tira ccmplexes,=d that in both sye.temapositive e.peclespredcminst.ein

Solutima mm acidic than @i 1.1. He has also used catecholtogetheruith variouE quatezn~ bases to extract Fe(III), Mo(VI), Mb(V), V(IV), U(VI) aud (71)0 W(VI) into chloroformas a means of calorimetricanalyticaldetenninatim

7. PRINCXPAL METHOIE OF DETERMINATIONOF TITAEI~

.Cauprehensivecollectlms of methcda for the datexndnaticmof titauiumin a range of materials are @van by Claesen(72), COdeu(73) , Kodama(i4), and

Sche*fer(14). In adiliticm,Bacbmau aud Baoks have written a criticalreview of the snal@ical mthods for the tltauium,venadiwn end chrcmiumgroups(a).

!lhese=alyses imchde gravimtri c, titrimettic,apectrophotmtri c, el.ectrc- chemical, aud spectrographicMtboda, each with its areas of Spplicabiuty.

Several.of the more useful methods are given belcw.

22 A. Gravimtric M?thoda

Hydrous Oti*

The moat simple method for the detirminatim of titanium is to pre.

cipitate &d * tie hydrous oxide. Other metals vhicb would be coprecipitated

end 8Ub8tMlCeBwhich would cmplex titauiummust be absent. The use of en (1,18) aumanim acetate-aceticacid buffer ayetem ia mcammmied . lhe diluted

neutral aolutia is boiled d.goroualyfor 3 minutes, filtered,washed end

dried. The i~itia requires a temperatw of 350°C but temperature up to

950”C _ accep@ble(34).

CSIPferrcn

Since 8t&le aoluticm of tit=ium, in the absence of ccmplexingagents,

till usually be several molar in acid, cupferrai w often be added di=ctly as

B 6% aqueous eolution. !Lheprecipitatemsy be filtered end washed repeatedly . with 1:10 hydrochloricacid. ‘he usual analyticalprocedure c- for adding

fresh cupferra eoluti= SIWIY to a chilled titaulum solutia which hae been

made about ~ in sulfuric or hydrochloricacid(’ks”). The precipitatemust

be igpited to TIOZ at over 6500C because the cupferrate formed caunot be dried (34) to a depanddle canpositicm .

This sinpls -thcd guentitativelyprecipitatesnot al.y lY, but also Zr,

Hf, V, llb,Ta, MOO W. Fe, Pd, Ga, Sn, Sb, Bi, snd Po, Elemsnte parti- (75) precipitatedare Cu, Tl, !Fh,Pa, Ac and the rare eutha . The interfemsnce

of ircm ~ be preventedby ~ding S02. The mcmt specific gravi=tric use of

cupferra seems to be the additia of a 10 to 15 fold excese of EIYTAprior to

precipitation,fouwed by adjuatnentto a PH of h.5 with emmtim acetate, (59), end then pmecipitaticmwith cupferrcmas .sibove !lhisnthod prevents

interferenceby Sr. V, Mo, W, Fe, Sn, Sb, Bi, As (III) or (V), borate, alka~

metala, and, presumably,S- of the untested ccugeneraof these elenmnts.

Oxime or UIydro Wclulnoline

This reagent is conmcmlyused for the graviuetric&termination of titanium.

Wekher(76) gives the follwing procedure:

23 ‘To 150 ml. of solutirn ccmtainhg 0.1 g. of titauiumvadd 1 g.

of tartsulc acid and .0.5g. of sodium acetate. Add anmumilunhydroxide’

until the s“olution Is neutral to phsnolphthaleinand them add 1.5 - of

glacial acetic acid. Heat to 60°C, stir well, and add an excem of 2

percent alcoholic &hydroxyqulnollne reagent. Boil the mixture for 10

mlnutea, filter,wash vith hot water, -d dry at lJ.O°C.Weigh aa

!l’i@~H@i)2. The factor for titaniunis 0.1361.”

~is si@e procedure at PH 5-8 sepaAtes tit.auiumfran Mg, M, Fe, Cr, l%, h, V, (14) U, Mo, Nb, Tao Zr, or Hf as well as the alkall metals and alk.sMneearths .

The mo= acidic end of the pE ranga gives better separatismfrom other -tale.

Several workera have later indicatedthat the ~hydr~quinoline ccmrpound caumot be dried to dependablecompceitim, so the precipitateis usually either ignited to the dioxide et shout 700°C or determinedby a branide-brcsnate titmtim(’4).

Hi@er molecularweight precipitateswhich can be oven dried are given by (34) 5,7-dichlor*8-hyd.raxyqidnoUneand 5,i’-dibr~&hy&oxyquinoline . The

(77) IIEthodof Freseniua is to heat the titanium soluticm,which is 0.2 in acid, to 50°C. A cme to two percent eoluticm of the reagent in acetae added in excess. The solutim is heated to bolMng for five minutes smd filteredwhile hot. After waahing with 25 percent acetcme ccmtalningO.Ob mineral acid, and then with hot water, the precipitate1.sdried to ccmstantwei@t at 150°C.

Par&lwdr- w-tiC Acid

The use of the sodium salt of p-hydroxyphenyl~ mic acid to precipitate (78) tltauiumwas developedby Sinpeon md Chandlee and has been rated as the meat specific gravimetricreagent for titaulum(IV)(72). The usual procedureie to precipitate20 to 100 mg of titenium frcm 100 ml of soluticmwhich is 0.9 to

2.5 H in HC1 or H@04. One gram of lTH@CN is added to hold back ircm(III), aud sodium Pd@iroayphenyl-cmate (4 to 10 p“ercent)is added. The mifiure is boiled 15 minutes, filtered,and washed with 0.25 M HC1 cattining 0.5 percent

24 end, Lf.”irm 18 present, 2 percent emluonblnflthiocyauati.

A final wash with 2 percent ammcmiumnitrate yields a precipitatewhich is i~ited to Ti02 because k originalprecipitant@drns not have a depenihiblecmpcaitia (34). and ceunot be dried to auhydrouztitani~ phenyl~aate Cerium(IV), zircmium, thorium, tin(IV), and hydrogen peroxide Interi?ere.Zircmdum may be ueed 8s a nm-iaotuplc c~er, or it M be remove~by B pre~minary precipitstia fran a 2.5 to 3.0 E HC1 solutia cmtdnlng hydrogen peroxide. Several other mmic acids are also falklg specific for group IV tetravalentcixbi me,but they sue better suited for separatim of”airccmiinn,tin, or thorium than titanium.

B. l’ittimatricDetexminatims’

A very carom nmthd of titanium anaiyaisdepenti cm the stoichi-tric oridatia of titanium(III)to titeuium(IV). A cadmium or zinc awd.gam ( Jmes ) reductor or alwdnum ~tal may be used to red- acid.ic titsnium(IV) crntalnlng sOlutia . Because the resultingtitanium(III)Is rapidly air oxidized,the reduced solutiaamust be either mdntdned In au inert atau%phen, or &dized

~diately up= fomatim. Staudar&zed cerium(IV),permaugsnate,dichrazate, ircm(III)aud other.ccmmm oddizing agentswill qqentitativelyoxidize the titeniw( III).

Ue have fcnmd it cmvenient to maceiva the tltauium(III) Oi=ctly into aliquota of stmdardized cerium(IV) sulfat.asolutia. These solutime are stable =d the e=ess cefium(IV)can be titrated at leisurewith irm(II)

~iun sulfati soluticm to a :ei’rein(IMu(II)-(111) Phen=hhro-) en~~nt t receivingthe titenium(III) in ira(III ) solutla aud then ti.tratlng the ircn( II ) formal with P ~ate has also been recamnended(72,74)0

Another cavenient mathod of reducingtiteoium(?V)is givem by Scheffer(14).

A ❑olutia catalning sultic md hydrochloricacids to a total of 5 H ie put into m erlenmyer flask. For 75 to 100 mg of titdum( IV), me grsm of aluulnum foil iS added. A glass t- is nm i’rm the etopper of the flssk to a beaker of satureted Sodi= bicarb-ate solutim. In this w= &r is excluded and, upm cooling,the bicdxxuzte siphms into the acid, furnishing8 cerbcm diaxlde

25 atmmphere. br the aludnum dlasolvm, the solutim is boiled 3 to 5 minutes eud cooled. TVO mllXliters of 25$ ammium tbiocyauatein water in added ae an iniicator, cud the titauium(III)is titratedwith steaderd iEm(III) ammaIium aliJi%teSolutial. Metala which am reducedby aluminumend retidized by i?m(III ) interfere. ‘l!heaeinclude vbzmdium,ni~ium, auti~, aud chrmium.

c. spectrophotmtrlc Methods m~ Perodde

The yellw color fo-d with hy~n pertuide is the baeis of the claaaical mthod for detixdning titau.1= A solutlca catdning O.l”to 5 mg of titmium

IS made dbout 3 K in ~drochloric or a~c acid EUd 0.$ to o.45 percent ti hydr0g6n perodde. me ebnorbmme at h20 mI iB then canp-d with that of rnt-- abtiime treated in a similI?ummner.

Scheffer(l’)sped”ffcalJyrnc~nde fusim of paper,rubbeE, oxides, or

UIUCE- mlnemalE with 8 g. of sdi= carbaate h a platlnm crucible. The

.-sul~ c- la dissolvedin b ml. of water end 70 ml. of cacemtratid

4dkochloMc add. !l!heproduct is evqorated to 75 ml., flltemd If necesmry, and trm#femrd to a 100 ml. Volutfic flask. The dditim of 15 ml. of 3%

W- P--** mi~, and diltii= to volum caapletethe preparationfor

Spectrophotatric mm~t .

He rec~de maMr@ Stendardeby dissol~ O.1oo g* of N*B.S. titmium dldde h 8 g. of mmlum BuJfwte aud 20 ml. of cumentrated sulfuric acid.

He rec~nde adding 90 ml. of vuter, filteringinto a 200 ml. volmmtric flask, cooling, md diluting. AHquote of this aolutiaImake the stsm-de vhen trme- femed to 100 ml. volmtric flasks to which 20 ml. of 1:1 SU.lfuKtCacid aud

I-5ml. of ~ hYdrc@n percdde me added Befons dilutia and meae~mnt at

&o roll.

Plmsphate~ be added to prevent interferenceof the color of irm( III). huy other colored ima alao tend to Interfere md fluorlde fame a etrmg c~lex with titmi=(IV) =d therebybleacbes the demired color.

26 8-Eydro~quinollne aud EDTA

The &hydroxyquinolateprovidem me of the mat specific spectrophotaretrlc methods for the deteminatim of titanium. T*1O$79) found that cmly

copper end uranium interfere if titanic iE extracted twice at pE 8 to 9

fran 100 ml. of 0.001 H ED’EAsolutiti Into lo d,. of U &hyd.raxyquinollnein

chloroform,sad the adeorbsnceis ~’saured at 400 mu. A more detailedprocedure

may abo be found in Morrism and Frei.ser(m). .

Tiron, chromotropicacid, thymol, sul.fosalicyllcacid, end many other

reagentswhich form colors with titahium(IV) are used in other spectrophoto-

uetric method8. Details of these methoti ~ be found In the Freseniue

h=dbocic(72), Smdellls book(6’), and other sources. The method involving

ether extractionof a thiocyauatecQkX is’discussedin the solvent extrac-

ticm section.

8. SEPARATICllMWISIOM

Meet of tbe procedures for ~timtric analysis -, of course, also

proceduresfor separatim of titanium from other elements. In additla,

solvent extractlm, ia exchauge, distillatim, aud electrolysisare each

applicableto sep=atlcme of titanium from other elements. There have not

been very many studiee of radiochemlcalsepmatias of titanium,but a great

desJ of work has been dme by enal.@ical chemistsbecause of the ubiquitous

nature of titanium.canpounde.

A. Precipitati~ sep-tiau:

In the classicalhydrogen sulflde scheme for qualitativeeaalysis,

titanium will pnscipitateea the hy&o~de in the ammoniumsulfide group

of elements. It is often useful, hmever, to add 1% tartmntc acid PrlOr to

-g the solutia basic, thus preventingthe preclpitatia of titspium(IV)

with this group of ele-te. me lattermodiflcatia seines to separate irm

and mamy of the other tmsitta etits - the titmxlum(IV). If this

procedure is follaredby a Cupferra p~clpitati=, titaulwm and zlrcaium (16) ti mcovmred quautltatlvelywith thori-, cefium end rare earth cfntaminaticm .

27 The detailedproceduretaand interferencesfor the quantitativemsparatime

of titmium with cqpferrcm,8-hydroxyqtinolinedefivqtives, emd p-h@roxy-

phenyltu%ddc acid have been di~cuasedae grwimetfic determinative. A (72) Emmry of precipitation.aeparatime ae presentedby Claesen in shown in

T~k V. For tbe detalle of ~ of these rm?tlmde,me Ie refereed to the ‘

originalwork.

B. solvent litrtractionsqmratione

The eolvent ertmction of titanim has been investigatedpri~-

U ee an analyticaltool. The fact that titenilnnis not en Important

flesion product, end the fact that suitableIeotopeehave not been

availablefor comprehensiveextraction8t@lee until relntlvely recently,have contributedto a lack of study by radiochemigta.

However, several Byetenm of interesthave been studied.

F’luoride-Nher

Titanium(IV)is extractedlees than 0.05~ from 1 M @ ~.M ~ into an equal volumk of et@l ether.(al) ~ fdlm of tikum to extract ~ be ueeful in the ee~tlm of titanium from Hb(V),

!Ih(V),end Re(VII) which - over ~ extractedfrom 20 M SF. Sn(II),

Sri(N), As(III), As(V), @e(IV), P(V), Se(IV), V(III), V(V), M(W),

and Sb(~I) - er’cractedfrom 5$ to ~.

Chloride-TBPor Ether

Titadum( rq does not appear to be extractedby ether or other qen comteiningaolventefrm acidicchloride media. Under proper

Condition s-b(v), As(III), Ga(III), Ge(IV), Au(I~), Fe(III), Bg(II),

Mo(VI),Rb(V), Pt(V), Pa(V), SC(III), or Tl(III) ehould be extractable from titanium(IV) in acidic chloride aolutione. Extraction of scandium 44 fran 8 M RC1 into tribu@l phoepheteuw ueed to separateSc from the pment !J!IU.(82)

28 TAB.LEv PRECIPITATIONSEPARATIONS’72) ? TitaniumPrecipitnted From Reagetis ! .— —-— Fe Al HI co Un zn Be” Cr Zr’ m m Sn v Mo w u Others

Anmmnia $ + ●’‘+ * ●2 $ * + ● Cn Group, Mg HHLOH & StifO%Sl{Cyl~C + + + + +’ +3 + CT!3%iE—— + + + Ca Group, m Hexametl@enetetramine + + + + chloride&b romate + + + + + + Ca Group, m Guanidine carbonate + +2 + + + Cupferron @ i- + + + + + + + Ca. MQ. ce p-mm enylarsonate + + + + +4 + + +5 +5 + + + + + C@. !4$?.C.T1e Tannin & acetic acid + + + + + l%nnln & antipyridine + + + + + + + Tanuin & oxalic acid + + + + + + + >,7-~brcmm-U-OB-quinollne + + + + + + + + C@, M —— N scdiunhydroxide + + + +2 + + + + + 1 tD

PrecipitatedFrom !Citanlum Fe m Ni co M Zn Be Cr Zr m Cu Sn v MO w u others ,.: ~, ~&~a;eor . + + + + + + Electrolysis(into F@) + + + * + + + “+ +

+ + + + + sio2, Po;- ‘a2c03 ‘ion “ h

+ Satisfactoryseparation. * Separationincanpleteor only under specialconditions. 3) Both Cr(III)and CT(VI). 1) Only as dlvalentiron. 4) Both~(II) ~~~1). 2) Onlyas chromte. 5) In Hydrogenperoxi!e containingsolutions.

From A. C1.aassen,in Hsndbuchder”Anal@ische Chcmie,W. Freseniusand G. Jander (Eds.,),Part III, Section IV b, Springer-Verlag,Berlin, 1950; reprintedby permission. Thiocyanate-ether

Titanium(IV)is rather poorly extractedbythiocyanate into ether; however, this system is of interest for several.reasons.

Scandium is 8% extractedfrom a 7 M ammoniumthiocyanatesolution which is also 0.5 M in HC1, while titanium is only 13% extracted (84) under the same conditions. Titanium(III),on the other hand, is

84$ extractedfrom 3 Mammonium thiocyanate,which is 0.5 M in HC1.

These facts render probable a separationbased upon extractionof many elements from titanium followedby a reductionof the titanium to titanium(III)and extractionof this from many of the remainingelements.

An analyticallyspecific spectrophotometricextractionprocedure(85) is to add 1 g. of citric acid, 1 ml of thioglycolicacid, and 3 g. of ammonium thiocyanateto 25 ml of titanium solutionwhich has been made 6 M in hydrochloricacid. This is extractedwith 15 ml of 0.01 M tri-n-octylphosphineoxide (TIYO) in hexane for five minutes. The organic phase containingthe titanium is washed with

6 M sulfuricacid for 1 minute. For analysis,the organic phase is centrifugedand the absorbancemeasured. Mb, Ta, W, and &lointerfere.

Large excesses ofY, Fe(III), CU(II), Zr, Cr(VI), Co(II),IVi,Mn(II),

V(V), Mn(VII) Pb, Dy, Tb, Ho, Yb, K, Be, Al, Ca, Sn(II), Cd, Mg, Si,

Ba, B or, Li do not interferewith calorimetricdetermination. Ti,

V, Nb, Ta, Mo, W. U, Re, Fe, Ru, 0s, Co, Rh, E, Ni, Cu, and Bi are (6I.) listed by Sandell as forming colored thiocyanates.

8-~droxyquinoline-C~oroform

8-hydroxyquinoline(8-q,tinolinol,oxine) is one of the most studied extractingreagentsfor many metals. Taylor’s 1954 Ph.D. thesis was devoted primarilyto the extractionof behavior of Al,

Ti(IV), V(V), Mn(II), Fe(III), Co(II), Ni(II), CU(II), Mo(VI), w(vI), and U(VI) into chloroformby 8-hydroxyquinoline.(79) His

30 emphasiswas upon evolving analyticalmethods rather than separation

——per se. His principal contributionto titanium chemistrywas the previouslydescribedcalorimetricdeterminationusing EUTA to hold back other metals. Under his conditions,titanium was over 95$

extractedin the pH range of 8-9 while Mo(VI), w(VI), and V(V) were not extractedat all above pH 8.2.

staxyJ’6) tn 1963, publishedthe results of a more exhaustive

study of 8-hydrcxyquinolineextractionsinto chloroform. He used

oxalic acid, tartaric acid, nitrilotriaceticacid (NTA), and :L,2-

diaminocyclohexanetetraaceticacid (DCTA),in addition to ethylene-

diaminetetraaceticacid (EDTA) as competingcompletingagents.

Appropriateequilibriumconstantswere derived when possible. The

results of this work are summarized in Table VI. We have listed the

pH at which 50$ of the metal is extractedat 20°C by equal volumes

of 0.1 M oxine in chloroform. Except where noted otherwisethe pH

vs percent extractedcurve is a steep, fairly symmetrical“S” shape

which goes from 0$ extractedto 10C@ extractedin about 2 pH units.

The results for titanium are shown in more detail in figure III.

QuatiernaryAmmoniumSalts--Hydrocarbons

Although quaternaryammoniumsalts may be found useful in the extraction

of several elements from titsniumOthey do not appear to be useful in the

extractionof titsmium from alueous solution. Maeck(”) reviewedextractions by quaternaryammonium salts from 1-5 M sodium hydroxide,nitric acid,

sulfuric acid, hydrofluoricacid and hydrochloricacid solutions. No extraction of titanium or its neighborswas found, except that of vanadium(V)from

dilute hydrofluoricacid.

TetraphenylarsoniumChloride-Chloroform S-er(88) found that polyphenol complexesof titanium, such as

discussedunder chelates,were quantitativelyextractedinto chloroformby

31 Table VI

Extractionof Metals into Chloroformby 8-Eydro~quinoline pH at which the extractioncoefficientis unity z Ion O.10 M O.o1o M O.010 M 0.010 M O.010 M O.010 M Oxine Oxallc Tartaric N’TA ED!lY IXTA

4 Be(II) a 5.81 7.0 6.3 7.0 8.5 8.9 12 I@(II) 8.57b 8.1 C 7.8 c --- [No Extinction] 13 Al(III) 2.87c 6.9 c 5.6 c 8.1 8C 9.7 c 10 c 20 Ca(II) 10.38 Pp’t. 9.5 c --- [No Extraction]

21 SC(III) 3.57 7.1 6.3 10.8 ab 10.8 ab 11.4 ab 22 Ti(rv) 1.45 2.8 a 1.5 1.9 ab 7.0 ab 8.o ab 23 v(v) 0.88 por extr. poor poor extr. 24 Cr(III) [Extractablecomplex formed only on heating 1

25 Mn(II) b 5.66 6.4 6.1 6.8a ~ 12 26 Fe(III) 1.00 c 5.3 c 1.7 ac 3.2 ac 9.5 c 11 ac 27 Co(II) 3.21 4.2 3.2 5.2 a 10.1 11 c 28 NI(II) 2.38b 5.0 c 3.2 C, --- 11.5 c ~2.5 bc

Cu(II) 1.37 c 3.6c --- 3.8 c 9.0 ac 10.2 c ‘ Zn(n) 3.30 ab ;:[:;) 1.07 4.4C --- 5.5 ac 9.9 c 10.8 C 12.06 ppt. 10,4 c [No IXraction]

40 Zr(rv) 1.01 4.7 3.0 a .*, 41 m(v) [Quantitative excess mine P;92.8-10.5T 42 Mo(VI) [QuantitativepHl to 4, NO E!xtractldnpH> 8] 46 Pd(II) Ob b b b

47 Ag(I) 6.51n 6.5n 6.5= [15~~r. PH>5 ] 48 Cd(II) 4.65 C 5.5 4.9 10a [No Extraction] 49 In(III) 1.54”c 4.3 c 2.2 c 8.5 c 10,2 c 10.9 ac 56 Ba(II) 11 P@. ------[No Extraction]

La(III) 6.46 8.4 11 c W(VI) b [pmanx] [QWtitat~ecpH 2.5~~.5~S1 @(II) [Partial~on ] [Not=racted ...... ] T1(III) 2,0 c . 2.0 c 9.0 bc 11.3 bc 12 bc

82 Pb(II) 5.04 :.: 5.5 9.5 [No Hxkaction ] 83 Bi(111) 2.13 . 3.2 a 7.8a 10 11 a 90 Th(rv) 2.91 6.2 >7 >7 * gi U(VI) 2.60 a ;:: 6.7 5.4 a 6.1 a 4.7 a

Notes: a. Curve of extractionvs. pH was pot ided”in mme manner. b. Requires special handling. See originalpaper for details. c. Data from other than 0.10 or 0.010 M solutions.

32 FIGURE III

EFFECT OF pH ON THE EXTRACTION OF !M (IV) by 8-HYDROXYQUINOLINE. Reference 86. From J. Stary, Anal. Ch@. Acts, 28: 132 (1963); reprintedby Petission.

*A / AA o d-l 0123 45 6 7 8 9 10 11 12 pH

1. No added reagent.

2. 0.010 M Tartarlc acid.

3. 0.010 M Nitrilotriacetic acid.

4. 0.010 M Oxalic acid.

5. 0.010 PI Ethylenediaminetetraacetate.

6. 0.010 M 1,2-diamlnocyclohexanetetraacet5-cacid.

tetraphenylarsoniumchloride. Sommer used a chloroaceticac:idbuffer to maintain the pH of the squeousphase at 2.7, added 1% aqueous polyphenol solution and solid tetraphenylarsoniumchloride. He reportedno analytical interferencefrom Ni(II), Co(II), Mn(II), Zn, Cd, MgO Sr, Ca, Ba, Al, Th$ or tungstate. Zirconiumprecipitated.eFe(III) extractedsomewhat except with

~,3-dihydroxynaPhthalene,U(VI) andNb extracted,Ta, molybdate, andV(V) interfered.

Other Solvent ExtractionSystems

In the book “SolventExtractionof Metal Chelates,”Stary reviews the literaturesnd gives a systematicpresentationof several extraction

33 FIGURE IV

pH DEPENDENCE OF THE SOLVENT EXTRACTION OF TITANIUM AND NEIGIi130RINGELEMENTS. Reference89

From J. Stary, The Solvent Extractionof Metal Chelates,F’ergamonPress, Inc,, New York, 1964; reprintedby permission.

0.1 M Acetylacetone in Benzene 100

@ Fe $ ~ 50 -

z &- o- 01 23 4 5 6 7 8 91011 12 pH

0.1 M Benzoylacetone in Benzene 100

ba j 50

i w= o 0 1234 5 6 7 8 9 1011 12 pH

0.1 M Dibenzoylmethane in Benzene 100

d j 50 - : G w o 01 23 4 5 6 7 89 1011 12 PH

34 Figure IV continued

0.005 M Cupferron In Chloroform 100=

d ; 50 -

,ti * Mn o 1, n 01234 !36’7 8910 1112 pH systems.(w) Figure IV shows the behatior of titanium snd its neighboringelements in these systems.

Another systematicrevlev of solvent extractionsyeteme rmy be fourd in the 1962 report, JAERI 1047, edited by IshimOri.(9)

ES shows the behavior of about 60 eleuents In phosphorousderivativeex- hction system d also in s- amine eml arsonium systems.

Figures V end VI are reproducedfrm this tiew and denmnstrates the behavior of tl~um(m) and Its neighboringelemntg in representative~teme. The dbrevlatlone used are: TBP - tri-n- btiyl@osphate, TBKl - !kl-n-butylphosphlnecdde, TWO - Tri-n- oetylphosphineoxide, HDEHP - his-2-(etl@hql)phosphate,

TIOA - tri-iso-octylamine.

Thh 14er Chromtogra*

In wr?dng on his doctorate layer chronutographyvitb liquid don exchange~ adsorbed on silica, gal and muted on mlcroacopP slides es a means of conveniently determiningtk amine extractionbehavior of mmy elements. He selectedPrlmmle JM -T, AmberllteLA-I, and Alawine 336 as representing m- to atro~ adsorbingeUSdMS ~SpeCti~. ~chloric acid

COtlC~f4tiOnS Of 1 to 12 molar served es solvent. AlthoughUIQst elements showed thin 1- ~tograpbic behavior Similarto their

35 FIGURE V

Acid Dependence of Solvent Extraction of Tltanlum(IV) and Adjacent Elementa Ref’erence 90 FromT. Ishimori,JapaneeeAtomic EnergyResearch InstituteReBearch Report No. JAERI-1047,1963; reprintedby penoission.

Kd HC1 -- loo# TBP ld IF ELEMENT Ca TI v Id ‘o oxlDATlaA STATE ti HCi 154 r a4 81JJIZ El DEl Fe I Zr H.f .-

/ (II) r!extractablen) El

Kd HNosl -- loqz TBP I ELEMENT 1 Ca Sc ‘m v AND 1 OXllMT1ffl STATE / ‘0 N HNOg /’ 369121s oElUn El Cr Zr,

u D(III) Elo

36 Figure V - Continued

@ TB~ (Tolume) -- HC1 /02 ELEMENT AND Ca Sc T1 10” OXIDATION STATE /0+

/09 N HC1 L12468101Z DElEl Cr Fe Zr D El(III) El

tetrabutylmAzhylenediphosphonate (Xylene) -- F!l’JOg Kd 1, ELEMENT Id AND OXIOATION /0’ STATE /0 / N HNO 5 [0 ElDDBD

Cr Mn Fe Zr Il. DElEl(III) BEl

(Figure conttiueson the next page.)

37 extractionbehavior,titanium always chromatographedas though

it were on the silica gel with no exchangeradded. This behavior

was distinctly different from the neighboringelements,and may offer

a means of separationfor titanium. c. Ion Exchange Separations

The ion exchangebehavior of titanium follows rather directly

from its general chemistry. Completingand hydrolysisvary the ionic

charge on the titanium species and hydrolyticprecipitationcan cause

severe difficultiesin the elution of titaniws(IV).

Cation Exchangers

The cation exchangebehavior of titanium species has been well

reviewedby both Samuelson’92) andstrelow.(93)(94)(95) s~~e.lowhas

stuaiea the adsorptionof titanium and 42 to 48 other cations on

purifiedDO- 50 cation resin (AG 50-w-x8)from HC1,(93) HN03J95) and

I$Sok.(95) Tables VII, VIII, and IX show selectedvalues of weight dis-

38 FIGURE VI

Acid Dependence of Solvent Extraction of Titanium and Adjacent Elements Refererice 90.

From T. Ishimori,Japanese Atomic Energy Research InstituteResearch Report No. JAERI-1047,1963; reprintedby permission.

50% HDEHP (Toluene)-- HC:L

5% TIOA (Xylene)-. HC1 Kd

ELEME#T /02 ,.+AND Ca Sc Ti . ) o“ OXIDATIW STATE I 02

I 64 N HC1 4 8 12 DKEY Dau BCr laMn HFe DHf

(Figure continueson the next page.)

39 Figure VI - Continued

Kd lC@ Amberlite (Xylene) IA-1-HC1 10’ ELEMENT IF AND id OXIWTm STATE Pr

hi’ ~~~~

4.912 ElN HC1 KEY

Cr Mn Fe Zr --- “(III) /’ \ D*--- /’ DElEl

1~ Pdmene JKT (Xylem) HC1

40 Figure VI - Continued

0.1 M dimethylbenzylphe~lmotiw chloride (Chloroform)- H(;1 , Kd 10

,~2 ELEMENT

AND 100 OXIDATICN k? STAT E

,64 N HC1 D4681OL2

Cr Hf D(III) D tribution coefficients,~, from these studies. The cation equivalentsto restn equivalentsratio, q, was maintainedat 0.4 so that the coefficients reportedwere compatiblewithin, and between, the systems studied.

Table X shows selectedresults of a similar study using slightly (96) acid auusoniumsulfate solutions.

Strelow i.llustratetl the usefulness of these values with & series of separations. Columns containing20 g of resin (100 meq.) were loaded with 1 meq. of each of severalmetal ions. A solvent in which

~ for the ion to be eluted was les. than 10, and those for the Ions to be retainedwere greater than 30 was selected. Elution with 200 to 400.ml.removed the desired ion and another appropriatesolvent was used to elute each successiveion. This techniquewas applied to a separationof titanium from a mixture by adsorptionfrom 0.1-5

M H2S04 containing1$ R202.(94) Elution with 0.25 M H2SOk containing

1$ H202 removed %, V(V), Mo, Ta, anclw. An elution wii.h0.5 MH2S04

41 TABLEVII CationExchange- KD at VariousHC1Concentrations (Mwex50).Reference93. From F. W. E. StrelowjAnal.Chem.,32: 1185(1960);reprintedby Remission. Concentrationof I&drocbloricAcid I I Cation 0.1 M 0.2M 0.5M 1.OM 2.OM 3.OM 4.OM

Ca 3200 790 151 42.29 12.2 7.3 5.0

Ti(IV) >104 297 39 3J..86 3.7 !2.4 1.7. V(IV) 230 44 7.20 v(v) 13.9 7.0 5.0 1.10 0.7 0.2 0.3 Cr(III) 1130 262 73 ti.6g 7.9 4.8 2.7 Mn(II) 2230 610 84 20.17 6.0 3.9 2.5 Fe(II) 182i) 370 66 19.77 4.1 2.7 1.8 Fe(III)m 3400 225 35.45 5.2 3.6 2.0 Al 8200 lWO 318 60.8 12.5 4.7 2.8 Y >105 >104 1460 144.6 29.7 13.6 8.6 -105 Zr >105 >105 7250 48g 61 W_.---l

TABLZVIII CationExchange- Kn at VariousHNOaConcentrations (Dowe;50).Reference9$, From F. W. E. Strelow,R. Rethaneyer,and C. S. C. Bot,hma,,Anal.Cha., 37: 106(1965);reprintedby pedssion.

# CatIon O.IM O. 2M 0.5M 1.OM 2.0!4 3.OM 4.OM

Ca 1450 480 L13 35.3 9.7 4.3 1.8

Sc >10” 3300 500 116 23.3 11.6 7.6

Ti(IV) 1410 461 71 14.6 6.5 4.5 3.4 V(IV) 495 157 35.6 14.0 4.7 3.0 2.5

v(v) 20.0 10.9 4.9 2.0 1.2 0.8 0.5

Cr(III) 5100 1620 418 112 27.8 19.2 10.9

MI(II) r240 389 89 #3.4 11.4 7.1 3.0

Fe(III) >104 41OO 362 74 14.3 6.2 3.1

Al >104 390a 392 79 16.5 8.0 5.4 4 Zr >104 >104 10 6500 652 112 30.7

42 mBILEn C8tSQI m2hmnge- ~, ~able I@lb Comoentratione

(- 5oJF$efemce 95. Frm F. W. E. Strelow,R. Eethmmeyur,end C. S. C. Bothma,And. Cha., 37:1.06(1965);reprintedby penuimion.

~tition 0? ~C Acid

c.mtioll0.05H 0.1U 0.25U 0.5M 1.0K 1.5M 2.0M

00 105’0 141 34.9 8.5 4.4 3.b m(n) 395 2?5 b5.El 9.0 2.5 1.0 13.4

V(lv) 1230 490 140 46.6 U.5 2.b O.b

v(v) Z1.1 15.2 6.7 2.8 1.2 0.7 O.k

Mm) 15% 176 IA 55 18.7 0.9 0.2

mm) 159 610 165 59 17. b 8.9 5.5 Fe(n) 16m 560 139 46.0 15.3 9.8 6.6 mm) >104 m’ 255 58 1.3.5 b.6 1.8 N >lob 8YM 540 126 27.9 m.6 4.7

Zr M b7b 98 b.6 1.4 1.2 l.r)

!JmmEX

Catiom E!xckagE - ~ Wt Vuioue lm4q Cmceuhut,ime (Ibmax 50LFHeren. %. F- J. hlBi?UObi,T. Its,andR. Kuroda, J. Cbrmatogr.,39:61 (1%9);reprtitedby pemmketin.

Im 0.20M I 0.30 M 1.0M

SC 9.5 I 4.5 2.5 mm) b. 5 3.5 2.5 1.5 v(m) 18 8.2 4.0 .1.9 Q(m) ?70 77 U 0.2 Fe(m) 23 7.7 3.8 1.8 Al 85 35 8.0 2.5 <1 <1 cl P <1

43 rwmovedm(rv), n, lUldu(vI). Ga, Fe(IH), ~(1), ~ AS ~ on the Colmm. TIME use of ~02 to p-eventl@rolYsIs dld not appear to change the ditiributionof titanium appreciably. 9ev’eral authom have f- the addition of i@rogen ~fde ta be useful in the ion exchange wparatlon of tltunlum.

9trelov also developeda convenientcation exchange*hod for a~tlq acmdim and the r-e eartha frcm titanium ~ mst other (97) metal ions of the Insoluble@lmxide gmmp. Af%er bei~ loaded on to Dowex-50frcm0.1 M Hc1 solution, tltardum(IV)could be eltia vith 1.75 M M!l. Scandium and the rare eartha vere then eluted vith

3.0 M ~.

Acco_ to Fritz(m) 0.5 M BBr vIII not effect remval of tltanium(IV) frc4na Douex-~ column. Sime the neighboringelements are not remved by HRr either, this solvent till be applicableouly to the removnl of other elements fkom the fint transitionseries elmenta. Aa would be anticipated,0.1 or 1.0 M W rapidly remved titanium from the same resin(99). Co(II), &(III), Mn(II) and

V(IV) vere not eluted by 0.1 M HF. Al, Sc, Nb d Zr vere eluted with the titanium.

Table XI im a cougdlatlonof some cation exchange sepsratione

which have been reported In the literature. The referencesare

primily frm SanuelBon(*) and Strelow (1963).‘*)

Anion Exchangers In hydrocbloficacid, titanium ie a member of the group of

elemnts which are very sllghtlyadsorbedby anion exchangeresin.e (ha) from dilute acid but are mre Btronglyadsorbed from strong acid.

~lYBiB problem are reportd If the F@rochloric acid concentmtion ~ 1s less than 9 M. Sincese(m), v(w), Cr(~I), W k!ckII)m wv

ellght~ adeorbecl from Xl at enY concentrationwhile TI(IV) is

adaorbed from concentratedHCl, several sepemationschemes have

44 T4BLEm ~ of cation Rxchuoge Septmatione of Mtalllm

Resin Bqmrnt!?dFJmellt Reference From

SOlutime Dmex50 Th Ti, Zr-1$CitriCAcid (loo) Th-liH~Citrate

Solutione RO-2 Zr l’i-In ml (101) zr - 4HE1

Pol.y. Styr. Al ~iEW)- ~02 - PE 1-3 (102) Eulfonate

Ti auoya Al Ti - 0.75M ml & (103) m-a H2°2 Al- 214BC1

Solutione, AG-~ow k, m Ti -2Km (104) std.clay zr- 5 M HCl

Soltiioue KIJ-2 Fe(m) m - 0.s MH12.1 (105) Fe ..4 MHCI. (lmded _ 0.25 M HCl)

m Fe(m) Ti- 0.4M HC1 (106) Fe- 4 M EC1

Solutione Sm Cr(III) .m+Rcl (107) (5 held)

Solutiom m-l MO(n) m- 0.5H~i (108) Ti - 4blEl

n -1ZS3H u(m) -2ME1 (109) ;Iv) - lMH,#04 solutions m w

Solutione & ma v(v), MO v, h, w - PH 1 ~Ok (m) Steele n + 15 ~02

Solutiom Sm m m -o.31TH#b+ (112) 5$ citric

Solutim KO-2 R’b Rb -o.3MHcl+ (113) O.* 502

Ialmnita Poly Stm Fe Fe- 2MKCR (114) wf onnte !rl- 10%~~

Ste’elB ~50 w -(III),Si OtherE- 0.% SO (U5) Cu(n) m, la,V(IV)-11 ~+o.37’$ Cr EIj, W AmmLm citraP d II, RtI sn(IV)

Steele folmlae?lyaev(v) (u6) Reaorcinol R%: %%

Solutione ~50 v(v), v- 0.01M EIOk, (U7) Fe(III) w 502 m - 1.0M Hclq,, 1$ z#2 Fe -2ME1

45 been developedusing these facts. Vanadium(V)and chromium ~awf119) ~o, are much more stronglyadsorbed than titanium.

instance,separateda mixture on Dowex X-1 by eluting V(IV) with 12.1 M

HCI, Ti(IV) with 9.1 MHC1, and Fe(III) with 1.0 M HC1. The systematic

studies of Nelson, Rush, and ~aus, (119~1~) indicatethat the adsorption

of titanium from concentratedHC1 could be the basis for many

other se~ations.

The labile fluoride complexesof titanium are also useful in

anion exchange separations. Since fluoride is useful in the dissolving

of titanium materials,the use of this meditunis reasonablein spite

of the difficultiesincumbent in the use of plastic ware and the

extra care requiredby fluorides. Dowex-1 has been used in compre- (lZQ) hensive studies of anion exchange of metal ions from 1.0 M HF.

Figure VII shows some of the results of this work. The values given are

volume distributioncoefficients,D . . v

Nelson, Rush and ICcaus(120) also specificallyillustratedthe separation of V(IV) from Ti(IV) in HC1-HF systemsby both anion and cation exchangeto show the reciprocalrelationshipbetween these methods. Figure VIII is taken from this work.

Faris(ul) has studiedthe elution of 50 elements from Dowex-1 (X-1O) with various hydrofluoricacid concentrations. Figure IX shows the behaviour of some elements of interest expressedin terms of weight distributioncoefficients.

Other studies show that, if 0.3~ hydrogen peroxide is added to prevent hydrolysis,titanium is very slightlyadsorbed from 0.2 to 4.0 E sulflzricacid. The potentialutility of this system would be in quickly separat- ing slightly adsorbed ions like Ti(IV), V(IV), and Cr(III) from more strongly held ions suchas Zr(IV), Ta(V), Mo(VI), and Cr(VI).

In additionto these systematicstudies of anion exchangebehavior in mineral acid systems,a good deal of use has been made of titanium complexesto

46 FIGUFW VII Anion Exchange Adsorptlon of Some Element6 from Hydrochloric Acid and Hydrochloric Acid-Hydrofluorlc Acid Mixtures.Reference 120. FromF. Nelson, R. M. Rush, andK. A. Kraus, J. Amer. Ch~. SOC., 82: 339 (1960); reprtitedby permission.

26 F&ent j4 —&md-j- Oxidattin ‘2 . ‘State 3 ~o a Go 48u2 !! MolerityHC1 MmM~

Adsorption of some elements frcm HC1 and HC1-HF solutions (0.1 < M HC1 < 12): —, dimtrlbu- tlon coeff’lclen~s-inab=ence of HF; distribution coefficients in HC1-HF mixtures ‘ (usually lMRFexce t Zr(IV), I-If(IV),Nb(V) ahd Ta(V), when–g = 0.51’.

effect anion exchange separationsfor enal.@icalpa$poaes. In mBt of the analyticalseparations,the only tidicatlonof pity is the ~ of interferences with a calorimetrictent. Some of these reparationprocedures-e outlined in

Table ~1. Again, most of the referencesare taken frau Samelnon (9) ~~

D. Paper Chromatogmphy 8eparaticnm

Althou@ usually conaidsredas 61.ou,paper chrmuatographycan offer

a reasmably rapid aud cmwunient =IUM3 of Eiep-stingmetal icm.e. This Mthod hae been used to sepmte flssicmproducts,aud titanium has been w?pxmted

fra Q, Fe, Zr,,and other elementsby using such varied solvent syetmm -

47 TABLE XII

A Summary of Anion Exchange Separationsof Titanium

Ori~n Resin SeparatedEluent Reference. From

Solutions Dowex 1 V(IV) V - u.l MHcl (119) Fe(III) Ti - 9.1 MHC1 Fe - 1.0 MHC1

Minerals ntA 400 Fe ~1) Fe .. ~A6corbtc acid (123) Cr[III) PH 4;Ti - 1 N H2SOA Hi, CO(II)

Fe Alloys Dowex-1 MO, v m- O.llfH,,04+ (124) Zr 3$ E#2

Natural DoveX-l Ca, Fig, Many- 1$ Ascorbic PH4-5 (125) Water (aacorbate) Fe(lII), MeI!v- 0.1 N H,,Ok + 0.25 MMF etc. Ti- 0.1 N H.$04 + 3$ K202

Silicate DowEx-1 R.E.,K)f- Others - O.lN 4,s04+ (126) Rocks Fe,Al,Be 0.25 MNaF Group 11, Ti - 0.1 N H2S04 + 3$ H202 w, Zr Zr -4MHC1

Minerals Dowex-1 GrOUP II (in HF) Zr,Be,Fe Ni,co,zn, Mn,Th,,V,W l.@,U,Sn,Sb

Ti Target Dowex-1 Se, V(IV) Sc- 0.1 Moxalic, (1’28) 0.1 14El v- 0.1 Moxella, 0.4 MHC1 Ti- 0.1 0.1 MHC1 (CarrlerIYeeSc& V)

HI Temp Dowex-1 Mc,w, m Ti - a) 25$ HC1, 5$ HF (la) Alloys or b) 5@HCl, 1O$ KF

steelB IRA 400 Fe,Cr,Ni V(V), Fe - 0.12 M Hcl +. (130) v, w, co 0.4 M HF m, w, Rb TI -3MHC1 (No interference~02 Color)

HF EDE-1OP RbTaFe Fe Hb(.9) -lkfml, (131) Solutione 0.05 MHF Titi(.1) Te(.06) - 3MHC1 Ta(.9k) - 9MHC1, 0.05 MHF”

High Tamp Dowex-1 Rb!ram TI Zr - 5* HC1,”1O$HF (132) Woys Sn Fe FeMSn- ~RHkcl, 12.5$ HC1J *HF (Followed cupferronpptn.) .

48 TABLE XII (continued)

Origin Resin Separated Eluent Reference From

Steels Dowex-1 NbTaw V Ti Zr - 1.5 MHC1, (133) Mo 0.5 MOxalic Nb - Same later Ta-3 M HC1, 0.5 MOxalic w -4 MHC1, 0.1 M Citric Ma- 1.9 M?u?4cl,o.44M ammoniumcitrate

Ti Target Dowex-1 V(IV), Se v- 0,5 to 2.5 Mm? (134) Sc - 15MHF (bothcarrierfree)

Alloys IRA-400 Ta Nb Ti - 2@HF, 4@HCl (135) Nb- 5$ RF, 25? HC1 Ta - 75$ HI’,25$ HCI

Solutlons An-pF Mn(II) Mn-8MKCl (136) Ti adsorbed (1:1 should elute)”

Alloys Dowex-1 Zr Hf Mo Ti - 6$ H2SOL, 0.025 {137) M Oxalic Zr Hf - 1% ~pso$ ;oo;50:&~ic Nb - 20$ H2S04, . Mo - 2@ H2S04

Silicate Dowex-1 Fe Mn Ca Others - 3.5$ Sulfosali- (138) rocks Mg Others cylic acid Fe - Cone. IK21 Ti - 1:1 HC1

pentanol-benzene-HCl;butanol-HCl;methyl acetate-HN03-water;and ether- xnethano&HCl(20).

Qureshi and co-workershave developeda method for quantitativelyseparat- ing titanium from syntheticmixtures of over 17 cations includingFe(III),

Cr(III),Al, V(IV), and U022+(139’140). About onelambda samples of O.l M metal ion solutionsin 4 M HC1 were put on 15 x 3 Cn striPs of No. 1 PaPer and hung in glass jars. About one hour was required for the solvent to travel their usual 12.5 cm distance. Their most versatilesolvent system was formic acid-HCl-acetone,3:5:2. Citrate and tartrate did not interferebecause of the high hydrochloricacid concentration. Aqueous 5% chromotropicacid was used to establishthe location of the titanium.

49 FIGURE VIII

Ion Ekchange Separation of Titanium and Vanadium.Refe=nce 120.

Frm F. Nelson, R. M. Rush, and K. A. Kraue, J. Amer. Chem. Sot., 82: 339 (1960);reprintedby permission.

2 — V(rv) . n —

f a I I 1 2 3 4 5 B 1.5 ~ HC1 >

TI(IV)

0 I I D 1- 2 3 4 5 Column volumes of effluent

Separation of TI(IV) and V(IV): A, anion exchange; B, cation exchange.

50 FIGURE IX AnIon Exohange Adsorption frcm Hydrofluoric Acid.Referenceml. Anal. Ch~ ., 32: 520 (1960);reprhted by pemi.eaion.

Ti v, C5 II

v . VI EiIllMv“ FE”;\ III IM

VII Ma. LLz Kwi!lIII Roman numerals refer to oxidation atate. No Ada. - No adsorption from 1 M - 2’4M HF.

9. mssawmon OF TIWIUN—cammrm mTHUAIS

A. Tit@iun Metal - ~oys

~tti= ~ win di6sdvc in ncul-oxidisiq lJCifh, euch ee

~fl~ic, s~ic, t@kOChltiC, or fluoroboric. Addition of l@ragen permide or nitric acid will tkn ~ odd8tion to (14) Ti(IV). ~fltiC meld reacta [email protected],ed Scheffer ree~ mddlng RF elowly and dropuise to a e8mple of titanium

- or UOy Whiah IS coveredVith Vater. Ulmelly hydrofluoric acid IS wed in ccm$xoctionwith dilute eulfuricecid, although titaniumwill dismlve in ~iC acid alo?M if the mixture is healed to _ of S03, yieldiw Ti(SOh)2 and s02. The reactionwith fhlOkiC meld 18 COMKU* -= in cold FJolutlon,end 18 mmidmmy leas tiolent tkwl with ~-iC ecid. mChlOriC acid will

51 dissolve the metal at a mderate rate Vith heatiag. Titanilm tri- chloride 18 forma if the Solution IB protected fromaddation.

Dilute tidizing acids usually attack the Im4alvery Elovly to fona an Insolubleodle, or acid film.

steels Contdrlingtitaniummy be dimolved in 1:1 ‘EC1and the residuetreatedwith one of the fOllOvfn&BF euulmlo4, 55$ =104, HH03,aquaregia,Ec!l,mo3 W H.#04. Alumhum metalmay be treated with MSOH, then with BW03 and H#04.

B. Tltanium Dioxide

scheffer(14)suggestsa satisfactorymdium for dimolutlon of

0.5 g of titanium oxide as 8 g of ammuium sulfate and 20 ml of concentratedsulfuricacid. Sodiumor ptaesium sulfatesare somewhat less satisfactory.Sulfuricacidalonereactstoo slowlyto be useful. Hot hydrd’luoric acid reacts SIWIY with titanium cddes and more BF must be added during dissolution. Scheffer recommmda addition of 10 ml concentratedsulfuricacid per gram of titaniunditide when dissoltiw the oxides vith BF.

W tide may also be fused with potassiumpymaulfate in a pr- celain crucible at 800” C. ~ion tith sodium carbonateskuld be follomd by dissolutionin hot 6M IK!l. c. salts

The halldes of titaniun are soluble in water, though hydrolysis

Umy occur. Wat double salts and titanates-e soluble in hydrochloric acid, The sulfate Ti(SO~)~ is soluble in cold, dilute sulfuricacid but at lW acidity @’drolyseato en insolublebasic sulfate or -ted -de.

D. Ores

ores such as llmenitej rutdle, or others containingmainly iron, 6ilicon, calcium, magneslm and aluminum my be treated with 3:1 mlfuric acidand an equalvolumeof I@rofluoricacidin a

52 phtimnn dish or Teflon beaker. Alttitively, fusion with potaasitm

PYTOSUlfate my be used. Depending on the nature of the ore, fuelon with NaOH, lVaOHend Ha2C03, Ha202, 10:1 N~C03-~03, KHF2, 116 w-Ha~207,

or borax may be effective(74) Iron ores can be dl~solvedin HCl and

H.j304 end the residue treated with HF and H#Ok or the mmple mm be

treated with ~04 and l$FOk.(74)

E. BlolcgicalSamples

The sample may be treated with concentratedsulfuricand nitric

acids ani heated. S- alwuntB of ammnium persulfatemy be added

if necessaryto speed up oxidation. If diSsOIUtim of tltunim has not (14) occurred, amumlum sulfate ~ be added and the solutionboiled.

Many organic eemples can be brought Into solutionby burning in air or

~ge% fonm by treat~t of the resultingash by the emmnium

sulfate-sulfuricmethod describedfor titaniumdioxide, or by fusion

of the ash with potassium~omilfate. For smaU samples,direct fusion

of the sample with potassiumpyros~ate in a platinum crucibleis

satisfactory,followedby dissolutionin sulfuric acid. Organic

samples may also souetimesbe dissolvedin concentratedtitric acid

folloued by careful additionof 7* ~chloric acid.(141)

V. Hazards and Precautions in Handling Titanium-Containing Materials

lVelther the metal mr most compomda of titenium -e toxic or

explosive. The metal Is ratad as p~iolcgically Inert - the dlodde

is considered as a “tisance” O’nlY(142). TitaDlum metal * strong

oxidizingCondltioneIs pymphorlc . It is, in fact, the only element

which will burn In nitrcgen.(5) The tetrachlorideof titanium evolves

copiouswhite ftnnesof titanium hydrous oxide and l@rochloric acid

on exposure to moisture. For this reason, titanium tetrachlorldeis

53 listed to the skin. Dissolutionof titanim metal In hydrofluorlcacid~ become violent, as msnticmed earlier.

V1. Counting Techniques

The titanim isotopesof interestfor radlochemlstryare Tl”, ti’?, and T151. !l!itanium-4-4IM3aall of the attributesof an

-celled tracer, nwmdy, it has a long half-l~fe (48 y], in relatively easy to detect, and is camnercidly avall~le (w, a cyclotron--ad radionuclide). Titanium-45(3.1 hour) also ~ have s- use as a tracer for applicatlonareqpirlnga shorter half-life. Titanium-51 hae a U-life of mly 5.80 ndmrtes, and is of in-eat ckdefly because it is produced ficenneutron capt- by titanium-50(5.34$ abundance),and as such la useful for determlnatiionof titaniumby activmtlonmnalyais. The half-lim Of the othm titanium iS~S me too short to be of general interest. Titanium-tihas bean receutly mrt~ aS hating a half-~fe of 0.25 + 0.04 sec and decays to the (144) 6~. 5 keV state of scamllmu-h2.

1. ~44

Titan.lum-44decays by electron capture to Sc”, accompanied by the emissionof 68 end 78 km _ v. scandiudd+In turndec~s

44 beta COUUt~ Of SC .

A. Gaama mctrmetry 44 The detection of Ti will be dlscuasedin scme detail because ~u-sc44 ~ its i~e - a tracer a the fati ttit is a useful source for energy calibrationof HaI(Tl) detectors. Titanium-44W9y be deterndneddirectly ulth a mill HaI(l!l)detector by measuringthe 65 and 78 kev a- raym. The advantageof thistechuiqueis thata

54 relativelyinexpensiveN31(Tl)crystal 1s adequate; a thiclmessof (145) 0.22 cm should abaorb 90$ of the radiation at the8e energies.

Although the backgromd in crystalsof this thickness is generalJy low, a further reduction can be obtainedby countingthe samplebetween two such crystals,requiringg~-gamm coincidence. An even greater hprmemerrt in sensitivity“isobtainableby two-dimensionalspectrometry.

In the presence of gamma radiation of higher energies,tt ❑ay be preferable 44 to measure the gamma radiationfrcsnSC . This consists of 0.51 MeV gamma rays from positron annihilation,together with a 1.16 WJ gamma ray. Aa seen ilra

Figure X, the spectrumtaken with a 3“ WI (Tl) detector consists- of the

0.51 MeV and 1.16 MeV peaks, the 1.67 MeV sum peak, aud the lower ener~ Ti44 peaks. Use of a well crystal,ks in Figure ~, ati one to also measure the sum peaks at 1.02 and 2.18 MeV. 44 Detection of Ti - SC44 with a Ge(Li) diode proves to be a very selective method, as can be seen fian Figure ~IA.A diode with 3 kev resolutioncan easily 44 resolve the Ti p peaks at 68 and 78 kev. Ge(Li) - IfaI(Tl) coincidence 44 techniquescald be used to resolve Ti - SC44 frcm interferingradionuc~des.

Scme of the diodes commerciallyavailable for lov-energy (< lCQ kev) measure- 44 ments would be suitsble for detectingthe 68 and 78 kev !!3 _ raw. In Table ~IX, the detection capabi=ties of a number of counting systems 44 for Ti - SC44 have been compared. For pupses of this table, counting efficiency “Efiis consideredas the net countingrate ‘E” under the peak(s) of interestdivided by the disintegrationrate of the scwrce. Bsck@ound “B” iS the bacl@uund counting rate in cm under the same peak(s). The midnmm detect- able activlty “D” is given by the expresslca:

D=~~ E ~T where “Cn is the coefficientof variation (C = u/’N),and “T” iS the total (146) counting the, sample plus bac~ound. L. Currie has recentlypresented another informativediscussionof r.miiochemicalstatistics.(143)

55 9 8 FIGURE X 7

6 Spectrum of 5 48-year Tf44 4 3“ x 4“ NaI Source Distance 0.5 cm 3 Eme~y Scale 10 KeV/PHU

2 ““l”

. - 1 M‘

7 ! I I 6+-H+ 5- 1 I k I I

9 8 In 1

7 ““ \

6 “ ~ -, 1 5“ I I I I I \ m “1 1 , I 1 I 1 4 I I h I II I I

1 I , I 1 1 1 4I

nuse Height I u I o 50 100 150 200

56 .-. 11 1-1,”: 1.,1’-’. In’ . . a ,.,’ I II 1 I n 1 I I 1 1,

$ 1 Y 5 c s s

o 50 100 .150 200 250

57 . 0 4’ =J-

& %wm ‘ ‘++’%+w.+kfi :!...=.. J. .:.,:,.,...:ZII 10 . .*”.:.>:y .““--YW.“1,’”.s. ; . ;.‘ ..- ...... -.”.,.. .“...... -...... -...... --- w-- ...... ------I 1 , , 0 200 400 600 800 1000 1200 1400 1600 1800 Channel Number 30 cm3 Ge (Ll) Diode (coaxial) Sample 5 ml aqueous solution 9-16-69 FIGURE XII A Energy Scale 1.0 kev\channel Ge(Li) DIODE SPECTRUM OF 44Ti-%c Table X111

Detection Sensltivltyfor Titanium-44by Gamma Spectrometry

Detector Mode Peek (MeV) Detector E!ackgroundD lm NeI(Tl) Efficiency CPM

2hcL/32° .069,.078 .2’53 4.22 .367 2“xl/32” (2) Multipxmmeter .147sum .0338 .005 .P46

3“X4” .069, .078 .373 21.7 1.1’2 .147sum .145 25.0 3.16 .51 .E18 21,8 1.93 1.16 .0462 7.74 5.42 1.67 sum .0188 2.74 7.98 3“X4” (2) summed .147sum .404 54.8 1.64 1.02 Bum .0794 11.4 3.83 1.16 .mo 18.4 5.02 1.67 awn .034 6.05” 7.54 2.18 mm .0172 3:61 10.0

Coincidence .147mm .2W .240 .227 1.02 mm .0823 1.17 1.20 1.67 SUM .0213 .860 3.99 2.18 Blll!l .0175 .730 4.48

5“x6” (2) Summed 1.02, 1.16 .0899 18.0 4.25

Coincidence 2.18EI~ .0872 1.16 1.13

Multiparameter 2.18eum .0719 .218 .609

5“X5” well .147 sm, .681 65.4 1.07 1.02 Bum .=6 13.9 2,88 1.67 BWI .0959 8.74 2.79 2.18 SUUl .101 5.13 2.04

11’’x6° (2) Sunnled 1.02, 1.16 .403 487 4.90

Coincidence 2.18 Bum .402 12.0 .776

~tiperameter 2.18 sum .’244 .990 .373

59 For low-levelcounting,sample and backgroundcountingperiods should be equal, so for a 1000 minute sample count, with a 2a detection limit “D” becomes:

1+-B ~w Dlooo = 500E

For further informationon gamma spectrometrytechniquesthe reader is referred to O’Kel.ley,(147)~iegb~,(148) and Watt and

Ramsden!lw)

B. Beta Counting

The 1.47,1.37,and O.% MeV positronsresultingfromdecayof 44 the Sc daughterin 93’/Jof the transitionsprovidea sensitivemeans for the detectionof small’qwutitiesof titanium-h4.The samplemust be free of beta contamination,whichusuallyinvolvesperforming specifictitaniumseparationand purificationchemistry.Afterallowing 4.4 sufficient time for growth of the 4.0 hour Sc daughter followingfinal purification,the sample is counted tith a geiger or proportional counter. Detection limits are determinedby the amount’ofsample, counterbackground,length of counting time, anticounter sensitivity, as well as the contaminationlimits determinedby the analyst for blanks. A low-levelbeta system employingcostic-rayguard detectors, mercury and lead shielding,and a small geiger counter (5 cmp sample 44 area) can yield a background of 0.2 cpm, and a 2 sigma Sc detection limit of 0.105 dpn for 1000 minutes of counting.

A method which is less dependenton low blanks involvesmillktmg 44 44 Sc fromthe parent Ti after establishingequilibrium,end following the 4.0 hour decay.

C. Other Methods

A 3.03keV X-rayresults frcm the electron capture decay of titanium-k4; however, the low energy and low fluorescenceyield of this X-ray make detection difficult. Therefore,countingmethods based on X-ray detectionwould seem of little practical importance.

60 More exotic systems for titanium-44mea6urementinclude beta-gamm or beta-

@nma- gamma coincidencetechniques,and multiparemeteranalyaiswith, ar without,

beta coincidencegating. Figure IUXB shows & aailtlparameteranticoincidence

spectrum of the 2.18 14sVSUM peak of titanium-~ and scandium-~ using a liaI(Tl) detector.

2. TI~45

Since titanium-45decaya to the grmnd state of stable scandium-45,only the positron annihilationgame rays, shown in Figure XIII, are detectablein a lVaX(Tl)detector. Discriminationfrom interferingradionuclidesdep?ndsupon resoltingthe 3.08 hour half-,llfeccmponentat 0.51 or 1.02 MN. The 1.02 MeV positronmay alao be detectedwith a gei~r or proportionalcuter. Figure XCV

showsthe titanium-45spectrumas meaaured with a (38(Li) detector system.(149)

Titanium-45for tracer applicationscan be “madefrrmIa (d, 2n) reaction on a

scandiumtarget. Titanium contsdningtitanium-45can also be produced by the

titanium-k6 (n,2n) reaction,and after ~rification of titanium and decay of

titanium-51the sample should give a relativelyclean spectmm of titanium-45.

3. TITARIUM-51

!lltanium-51is most eaaily identifiedby a 0.323 MeV gamma ray

resulting from the decay to stable vanadium-51. The 0.323 MeV gains

ie in coincidencewith a 0.61 WV gamma during 1.~ of the tranei-

tiont3!2)A 0.93 MeV game, althoughof 10V Intenslm (4.8$of decay

events), mW help to identify ti~um-51 in the Pres-ce of inter- feringganKoaeBt lower wgiea . A titaniun-51spectrum taken with a ~m(141) 3“ dia. x 3“ thick NaI(!lEL)detector la shown in F’IgureXV ..

reprted a counting efficiencyof 20-i@ for 10 ml of sample in a 3/4”

x 611teat tube in a e.t~ 1-3/4” x 2“ acintillatm well crystal.

The beta rays of ~itaDi@91(2.1 MeV, *.%; 1.5 MeV, 4.%) can %e

counted In a Geiger or ~rtional counter, and the rel.qtively high

energy beta ray at 2.1 MsV minimizes self-absorptionproblems. A

61 FIWRE XIIB Spectnm of 48 Year TL44 + SC44 2- 6“ x 5“ Nal With Ne-102 Antlcoincidence Annulus 2 Parameter Analysis: 2.15 < E <“2.25 MeV sum

‘. ::. . :. . . .-: :.;;: .. -: . ,.

4— a—

‘2—

m I 1111 J1 I 11:1”11 I II t

31.1’ I I II I I I

,,, . .,: 11’1” i I ill 0.2 0.4 0.6 0.8 1.0 Gamma Energy MeV

62 FIGURE XIII

spectrum or 3.08 hr. T145 3“ x 3“ NaI (Tl) AbBorber 1.18 g@2 Be + 200 mg Cu Sandwich Source Dlat. 10 cm Energy Scale 1 keV/PHU

o 200 400 600 800 1000

63 ,.6

I 308-hr TiM 2,5 cm2 Aroa M 4mm Go [LO I ASSORBER CL5W%I+ POly SOURCE DISTI 3cm {d ~ERGY SCAJ_EI L043 hWCbmmd

= j+d

T 1 1 ,, 1 1 ~ ,

,.2

fo , I

.11 1 1 1 1 1 1 1 [ I I I I I I ) 1 1 1 I I 0 50 100 !50 ’200 230 300 350 4go 450 500 550 600 H“no 730 800850 900 930 4000 C4mnnal Numbnr

FIGURE XIV

Diode Spectrum of Titanium-45. ReferenceU9. FIGURE XV Gamma Ray Spectrum of Ti51.Reference 141.

1 [ I ‘~OOOF==—T=.323 ~_ I 1

5.8-MINUTE Tisl t 3“X 3“ NaI

SOURCE DISTANCE 0.5cm J--ENERGY SCALE = I KEV/’PHU I

I I I I

100

10 200 400 600 800 1000 I photopeakefficiencyof 23$ wouldbe expected for the 0.323 MeV gamna from a point source at a distance of 0.6 cmfroma 3“ x 3“ NaI(TI)

Crystal!’S”)

!/11.Radiochemical Separation Procedures

The first five proceduresare applicableto the five-minute isotope titanium-51and the three-hourisotope titanium-45. The next two proceduresare quite time consuming,and may be applicable to titanium-44studies in geochemicals~mples and meteorites. Procedures

8 and 9 are included as means of milking the scandia-44 da~hter from the parent titanium-44.

The scarcityof radiochemicalproceduresfor titaniumhas been mainly due to the lack of a suitableisotope for tracer studiesuntil recently,and the fact that titanium isotopes are not importantin fission of uranium and plutonium. It is encouragingthat high energy nuclear physics and spsllationstudies are contributingto this subject.

Preparationof TitaniumCarrier

(1) ‘2TiF6”H20‘ethod Weigh approximate~ 13.5 g of K2TiF6”H20,transferto a Pt

dish, and treat with 50 ml 1:1 H2SOk. Evaporate to fUIS@Sof

SO , cool, add 10 ml H 0, evaporateagain to fumes of SO . 3 2 3 Cool, dilute to 250 ml. Remove aliquots for analysis.

(2) TiC\ Method

Transfer 40 ml reagent grade TiC13 (2@) to a beaker. Add a

few ml.lM HC1 and sufficientH202 to give an orange color.

Boil until orange color disappears,then dilute to 250 ml

with 1 M HC1. Remove ali~ots for analysis.

(3) Ti02Method

Place 1.0 g analyticalgrade Ti02 in a crucible. Add about 8

grams ammoniumbisulfate,mix, then cover the ton of the mixture

66 with ammoniumbisulfate. Partiallycover the crucibleand heat

gently to avoid spatteringuntil the mixture is molten. Swirl

mixture, and heat until all Ti02 is dissolvedin the

melt. cool> and dissolvemelt in 1 MHC1 (or H2SOh). Filter

any residue. Dilute filtrateto 250 ml with 1 M HC1 and remove

aliquots for analysis.

Analysis of Aliquots

Dilute aliquot to 100 ml, then make just basic with NH OH. 4 Boil 5 minutes, filter,and wash the precipitatewith distilled

water. Ignite in a crucibleto Ti02, cool, and weigh. Calculate

T.icontent in mg Ti per ml of carrier solution.

Note: Alternatively,Ti may be determinedin the aliquotsby

spectrophotometryof the T.i(IV)peroxo complex.

PHOCEDURE 1 (141) Source - C. K. Kim, University of Michigan

Element separated: Titanium Time for sep’n: 13 minutes

Target material: Meteorites, rocks and Equipmentrequired: 30 ml minerals, alloys,botanical and nickel cruciblewith a biologicalashes. lid, Fisher burner, centrifuge,separator funnel. Type ofbbdt: ‘eutron activation;12 15 minute irradiationat 10 n cm-2 See-l

Yield: -68$ 56 51 Degree of purification: Slight contaminationof kln and V’ .

Procedure:

(1) Heat 5 ml Ti+4 carrier (0.8 mg) in nickel crucibleto dryness; add

4 or ~ g Na202. (The amoumt of carrier added is dependentcmthe titanium content in the sample).

(2) Add- 0.1 g of irradiatedfinely ground sample and put on lid tightly

(note a); fuse for one minute; swirl melt onto side of crucible. Cool

67 crucibleand contents rapidly by dipping base of crucibleinto cold water until the contentshave solidified.

(3) Dissolve the solidifiedmelt in H20, boil, centrifugeand acidify the residue with either HC1 or H2S04.

(~) AddFe carrier and make the solution alkalinewith NHkOHto precipitate Ti02; centrifuge.

(5) Add ~OmJ- Of @H2S04 to the residue andadd~o~ of6~ aqueous +4 cupferronand 10 ml of isopropylether. Shake vigorously. Ti extracts into the organic layer. Draw off the aqueous layer (crushedice should be used to keep the liquids cool).

(6) Add crushediceto the ether solution;back wash with 20 ml of cooled 15% NaOH (Cu, V, Mo, w are eliminatedhere).

(7) Wash ether fractionwithl$ H2S04 and transfer ether to marked tube for counting.

(8) Count0.32Mev y-rayof 5.8-minuteTi51 with y-spectrometer; determine chemicalyield by measuring (after decay) the pertitanic acid (yellow)with a Beckman Spectrophotometer(420 ~).

IYotes: a) If the sample is irradiatedin a gelatin capsule and the capsule is also fused, care must be exercisedbecause the gelatin capsule is vigorouslyattackedby the peroxide. b) Depending on the type of sample, some of the steps in the separation

could be omitted. For instance,unless a large amount of vanadium is

containedin the sample, step 6 (NaOHbackwashing)is unnecessary

since most of the vanadium is eliminatedas the sodium vanadatewhich

is dissolved in water when the Na202 melt is treated with water and

centrifuged. However, if there is a large amount of vanadium in the

sample, a trace of vanadiummight come down with titanium and it

interfereswith the spectrometricaldeterminationof titanium

Although N’aOHbackwashingeliminatesvanadium very well, at the same

68 time it reduces the chemicalrecovery of titanium appreciatilyby forming a titanium oxide precipitate.

C) The temperatureshouldbe kept low (-.10” C) preceding the NaOH backwashingand the aqueous layer should be removed immediatelyafter the shaking. A filteringstep through a fine sinteredglass chimney or Whatman No. 42 filter paper is required,if a large amount of sample is fused because an insufficientfusion time rn~ result in incomplete fusion. d) Step k is not necessaryexcept if a fair amount of copper is present in the sample. Copper is a rather serious contaminationif it comes down with titanium since it has a 0.511 Mev annihilationpeak near to the

0.32 Mev titanium peak. Step 6 aI.soeliminatescopper. e) Step 7 should be done twice if possible to eliminatemechanical contaminationwhich always accompaniessolvent extraction. Care must be taken to draw the aqueous layer completelyfrom the ether layer.

Throughoutthe experiment,it is necessaryto keep the temperature rather low (- 10° C) so as not to destroy the cupferron. Often, the heat involved in the neutralizationwith NROB will cause trouble. f) If 0.3-0.4 mg of titanium is containedin the sample, either a lakge amount of Ti carrier or a small amotmt of the sample should be taken so that the calorimetricyield determinationgives reproducible values. For a large amount of titanium carrier, 500 m~ should be used instead of the normal 420 mu photometricdetermination. g) Much practice will be required for the Na202 fusion. A ring clamp for holding the nickel crucible shouldbe one inch away from the surfaces of the burner for best results. when the cruciblebecomes red, a swirlingmot~on is recommended. Air cooling from red crucible to black makes it easy to dissolvethe melt with water. h) In its simplest form of one cupferronextractionand a aouble

H2S04 wash, this procedure can be completed in 8 minutes on a sample such as aluminum alloy with a yield of around 94.

69 mCCEMIRE 2

Source - C. K. IUm, Universityof Michlga!w)

Hlement separated: Titanium Time for Eep’n: -10 min.

Target nmterial: Meteorites, rocks and Equipmwrtrequired: minerals; biological and Standw?dPlus 30 ml botanical samples nickel crucibleand sinteredglass filter Type of bbdt: Neutron activation with chimney.

Yield: -05$

Degree of purification: Good for gamma Epectroscw

AcWantagei3:Fast and elmple

Procedure: +4 (1) Heat 5 ml Ti c~ier (0.8 mg) in nickel crucibleto dryness;

add 4 or 5 g N~02. (The anmunt of cmrier added is depmdent on

the tltanlum content in the sample).

(2) Fuse .0.1 g of irradiat~ finely pound sample for one minute;

swirl melt mto side of cruc Ible. Cool crucible md contentsrapidly

by dippingbase of crucible into cold water until the contentshave ,

aolldified.

(3) Mesolve the wlt in H20 and centrifuge.

(4) Dissolve the residue in a minimum of concentratedH2S04. Dflute

this solutionto 2 N in ~~ and filter.

. (5) Am n c-ier and boil the solution. Add4~ p-hydr~he~l-

arsonic acid in moderate =Cess and stir vigorously,

(6) Digest over a hot mate.

(7) COO1moderatq d filter t_h Whatman No. 42 filter paper on the 131nteredglass’fflter.

(8) hansfer the precipitateto a teflon covered counting card and 51 count the 0.32 Mev y-ray of !tl with y-spectrometer;deterdne chemical

yield by dissoluticmand measuringpertitanlcacid (yellow)nlth

Heclman Spectropbotometer(4X) ~)(61)

70 Notes:

For a sample abundant in chromium,an anion exchange COllXIWlshould be used to adsorb chromate ions prior to step 5.

PROCEDURE 3

Source- C. K. Kim, Universityof Michigan(’41)

Element separated: Titanium Time for Sep’n: - 11 min.

Target material: Aluminun alloy Equipmentrequired:

Type ofbbdt: Neutron activation standard

Yield: 5- 85$

Degree of purification: Fairly good (Mn56 contaminated)

Advantages: Rapid separation

Procedure:

(1) Dissolve the irradiatedsample in concentratedHC1 with 5 ml of Ti carrier (- .8 mg Ti). Heat, add CU carrier and atlute with water until weakly acidic.

(2) Pass H2S gas through the solutionto precipitatethe sulfides of contaminants(particularlyCu if present);boil the solution,centrifuge and filter.

(3) AddFe carrier to the filtrate,add Na202 powder until it becomes alkaline,boil, and centrifuge. +4 (4) Dissolve residue in10$H2S04. cool. Extract Ti with 10 ml of @ cupferronin isopropylether.

(5) wash the etherextractantwith ~@$ H2S04twiceanadra.vOff the aqueouslayer.

(6) Eva&rate the ether ina150ml beaker over a hot plate. (7) Positionthe 150ml.beakerin frontof theNaI crystaland 51 countthe 0.32Mev y-rayfromTi by y-spectrometry.Determine the chemicalyield by dissolvingthe residue in the beaker and measuring pertitanicacid (yellow)with Beckman spectrophotometer(4,?0m~).(61)

71 N’ote:

The countingof the resiclueon the bottom of the beaker (step 7) increasesthe coumtingefficiencyabout three times over the counting of a liquid sample.

PROCEDURE 4

Source - C. K. Kim, Universityof Michigan(’l’)

Element separated: Titanium Time for sep’n: 12 minutes

Target material: Botanicaland Equipmentrequired: Standard biological samples

TYKE ofbbdt: Neutron activation

Yield: 9@

Degree of purification: Fairly good for y-spectrometry

Advantages: Fast and simple

Procedure:

(1) Leach the sample with concentratedHN03 and heat to dryness in.

250 ml beaker. Add 7% HC104 and ftime.

(2) Add concentratedHC1 and clarify solutionby heating.

(3) Add Fe carrier and make the solutionalkalinewith NaOH to pre- cipitateFe(OH)3 and Ti02. Centrifuge.

(4) Dissolve the residue with l@ H2S04. Cool.

(5) Extract Ti+4 with 10 ml @ cupferronin 10 ml isopropylether.

(6) Wash the ether extractantwithlO$ Hi,S04twice antidraw offt.he aqueous layer.

(7) Tr~sfer the ether l~erto a co~tiWtube and count the 0.32 51 Mev y-ray of 5.8-minuteTi by y-spectrometry. Determinethe chemical yieldby measuringpertitanicaciii(yellow)with Beckman spectrophotometer

(420 W).(61)

Notes: a) Step 3 can be eliminated if the sample does not contain a large amount of any one element. Iodine is a rather significant problem, however,

72 in handling marine organisms; Fe does not carry iodine down with the titanium. A prelinina~ CC14 extraction can be used to eliminate much of the io6ine if desired, but it must be repeated at least twice for this purpose. Fuming with concentrated H2S04 expels most of the iodine; however it.is not advisable to use this technique because active iodine might con- taminate the hood. Ka2S203 absorbs iodine upon filtering the solution but a trace amount is still retained in the solution. b) Fusion with Na2S207, NaHS03, or KHF2 in platinum crucible cam be substituted for the acid leach in step 1. The melt is then dissolved in concentrated

H2S04 and water. Silica rocks can be fused with HF plus H2S04 in a platinum crucible.‘ If a large amount of vsnadium is a contaminant in a ssmple$ 15% NaOH backwaahing should be done after the cupferron extraction in place of step 3.

PROCEDURE 5

Source - C. K. Kim, University of Michigan(’41)

Element separated: Titanium Time for seprn: 17-20 minutes

Target material: NBS Ferrochromium Equipment required: Standard alloy containing 0.03477Ti. plus 30 ml nickel crucible with lid, separator funnel.

Type of bbdt: ileutron activation

Yield: - 50%

Degree of purification: some (@l, M1154, and V52 COnt,S,MhIS,tir311.

Disadvantage: Procedure takes too long for 5.8-minute half-life.

Procedure:

(1) Fuse the irradiated sample with Na202 in a nickel crucible;

swirl the melt onto side of crucible. Cool crucible and contents rapidly by dipping base of crucibleinto cold water until contents have solidified.

(2) Dissolve the melt in water, centrifuge,and acidify with concentrated H2S04.

(3) Add NH40Hto ??recipitateTi02, centri~e and dissolve the residue in 1 N HC1.

73 (4) Add Zr carrier and precipitatethe Titanium(IV)with p-hydroxypehnylarsonic

acid; stir vigorouslyand centrifuge.

(5) Dissolve the precipitatewith15 ~ of 7MH2S04. (6) @ract Ti+4 with 4? tri-octylphosphineoxide (’TOPO)in hexane by shaking or stirringwith a glass roCimechanicallyfor 10 minutes.

(7) Draw off hexane phase and transfer extractantto countingtube 51 for counting. Count the 0.Y2 Mev y-my of 5.8-tinuteTi with

y-spectrometry.

Notes:

a) The chemicalrecovery is proportionalto the length of stirring time in the TOFO extraction. TOPO extractionfor various elementshas (151) been thoroughlystudiedby White.

b) An oxine extractioncombinedwith EiY1’A-maskingcould be used

in place of the TOPO extraction. However, oxine is selectiveonly

at a specificPH and it takes time to adjust to a pH of 5-7 (the

range in which titanium is extracted). Besides, titaniumtends to

hydrolyze at a pH of 5-7 to give a white precipitate. Therefore,

tartaric acid should be used for the separation. The separation~equires

about 15 minutes, gives poor recovery of Ti and furthermoregives

contaminationof V, Mn, and others.

(3) The cupferronextractionappears tobe much better forTi th~ the above two extractants.

PROCEDURE 6

Source - M. T. I&pschutz,Universityof Chicago

Element separated: Titanium Time for sep’n: days

Sample material: Iron meteorites 60-190 grams

Degree of purification: SeparatesTi from cosmogonicand natural radionuclidesencounteredin meteorites. 44 Advantages: Good separationof Ti for gamma coincidenceanalysis.

74 Rrocfdure:

(1) Refltm sample In cone. El+HROa. _ic F3rticles still present > in residue my be treated with ~3 end this solution la then added to +4 the main aolutlon. hill50 ~. m carrier, ad carriers for other elements of interest.

(2) convert solutionto 8 M HCl, and extract iron into isopropyl ether.

(3) l?vumrate13211-, convertta a 1 H H#Ok solutionof 1-2 litervolums.

(4) Electrolyte solution witha mercurycathodeEt 10-20ampsand

3.4 volts until 10ss of color indlcate6renmval of Iii‘2 and CO+2.

(5) Concentratesolutionto 1.8 N ~4, sd preci@tate ti-~ by addition Of ~ p—~ nykmmnic acid mlution. Ignite

~cipitate to T102 and fume to dryness with EIFsolutionto volatilize

silicon as siFb. Ignite again, and determinetit.ani=yield grati- 44 smtricalJyas T102. Mnnrt for gamm Countiq and ellov Sc to ~ow

in. Ho chemicalfield correctionis usually necessary for titanium from

iron meteorites.

PRoCIWm7

Source - P. J. cressy,G0ddm3 SPceflightCenter,Gr*elt, Maryland

J. E. ICaye,Battelle-lVortlWest,Richlend,Washington

Elemsntseparated: Titaniulll Time for aep’n: dqs

Sample material: date meteorite 150-400 grams iron meteorites 150-400 gram

Degree of purification: SeparuteaTi frcsncoemgenic and natural radiomuclidesencounteredin meteorites. 44 44 Ad-es: Ti may be edimated by genma analysiE or Sc my be milked frcnuthe purifiedTi for bets counting. Procedure includes spectrophotometricanalysis of Ti in stone udan-ites. Procedure: A. Mss.olutlonof StoneMeteoritesami s~tion of Iron

(1) Cleanqeclmm with acetone, grind In agate mrtar to powder, amlwelgh. Add400uI148$BF. Afterreactiondbe.ides,add lQO a ealc.H#04. HeatmixtureuntilOlllconIB expelMd. (2) ~fer to teflonevaporatingdish,add 200 ml cone.

H#04, and evaporateunder heat lamp until dry. Add _ ti

cone. HMO , evaporate, repeat twice. 3 (3) -f- to a 2-literPorceldn evaporatingdish,add 403

nilcone. HCl, and evaporateto dryness. Repeat twice with 200 ml

poa-kionecone. HC1. Maeolve residue in 9 M HC1.

(4) Prepare three 2-lltersepardory funnels, each containing

hOO ti isopropyl ether saturated with 9 M E.Cl.Add meteorite solutionand extractironby counter-currentmethod. Wash combln~ etherlayerstwicewith 1~ ml of 9 M El, and coniblne

vashlngBwithnmlnEl solution.skipto 13tepC5.

B. Dieaolut.ionof IronMeteoritesand Sepan?itionof Iron (1) Wash samplewith acetone,then etchwith 6 M BR03,rinse vith distilledwater,and weigh.

(2) Dscommae by additionof 8 M B?J03dmpwise (intoa reactton

vessel fitted vith tmps to capture volatile gases if c14, C136

are to be determined). After reaction S1OWI3,heat to enmre

diaaolutlon.

(3) M c~iers for ~(IV) (100 ms T102 equivalent),and other

el~nts of interest. Filter solution. Reumve Cl- If Cl36 Ie

tO be measured by adding ~ AgH03 and filteringor centrifuging

the resultingAgCl predpltate.

(4) Evaporate solution,convertto 3M HC1. Afteralloulng

solutionto stand for several hours, filter any silica pre6ent

d ~Cl if excess Ag+ was added in ❑tep 3. Evaporate flltrate,

convert to 9 M HCl, and remove iron by couuter-current solvent

76 extraction using 4-500ml portionsof isopropylether pre-equili-

brnted vith 9 M K!l. Back-washthe etherlayertwicewith9 M HCl and ccmblnewashingswithmain HCl layer.

c. sepaation and -I flcationof Titanium

(5) Heat9 M Hc1 solutionbrieflyb driveoff ether. Pass

throughan anionexchangecolumgcontainhg 250 nilwet Vollnm of

DOW=X 1 x-8 (50-100msh) resin, which ha~ been vashed with four

columm vol~ of distilledwater ‘@ of 9 M HC1. Elute

meteoritewith 9 M HC1 solutionat 2-3 nilper minute.

(6) Evaporatethe 9 Meluent to a small volume, and cool to belou

5“C. Add 30 ml”chilled6$ aqueous cupferronsolution. Extract

yenou titmxhnncu3WerroncomplexInto250 ml chloroform.

Repeat extraction2-3 times. Conbine chloroform18yerS, wash vith cold6 M HC1.

(’7) Evapo=te almst to dryness. Add coneHK13 cautiouslyand heat to destroy organic nmtter. Repeat. Add 20 IIUcone F$S04

and heat until clear or pale yellow. Dilute to 100 ti with 0.3 M

F$S04. Add ~ g of tartaric acid ami 10 mg of Cu+2 carrier.

(8) Wecipitate ~ with H>, filter and dlscwrd the Precipitate.

Boil the filtrate,then neutralizevith MHhOH. Filter any ~ecl-

pitate and discard. Evawrate filtrate,and destroy organic

mterial (cautiously! ) with cone HMO Dissolvefinalresidue 3“ In 0.3 M ~04.

(9) Add 5 ml of 3@ EUTA solution,@lust to PH 5.0 vith ~OH,

~ cool to belov 5“c. Add 30 ti cold 6$ cupferron,let stand

15 minuteE in ice. Filter on Wbtm hO paper, wash with cold lx

cupferronsolution,ignite to Ti02, =i@.

44 Ibtm Sc Imsy be milked fras the purified T102,aftertiming

for growth to equilibrium,using ~edure 8.

77 D. Estimationof chemicalyieldof titanium(source:P. J. Cresay) (1) An aliquotfromthe meteoritesolutionafterdit3solution,

containing about 0.5 w titanium,is takenfor amil.ysis(stepA3). (Note:stonemeteorlteacontain.08-.15$T102by nmas). Evapo- ratevithE#04 to S03 fumes.

(2) DlsBolveresidue,in2 M E&04, diluteto 100 ml. TWO 10-ml and two ~-ml allquotsare takenfor analysis.

(3) Add ten drops30$ ~02 to one aliquotof eachVOlme, using the remainingallquotsfor reference.The absorptionspectrum

from350-650mi~imicronais takenfor eachset of aIiquots. (k) The t~mittance of”eachsampleat 420,430,~, k50,aud h60 millindcronaIs determined.The weightof titaniumcomesponding to the transmittanceat eachwavelengthis obtainedfranthe s~ extinctionplots. The fivetiues for eachset of &iquots are averaged,@ the two resultingmean titaniumcontentsare averaged. note:

The stmdard extinctionplotsare obtainedby makingup a syn- theticneteoritesolutionwithvaryingauauntsof titanium,and

maauring the transmittancevs. titanium content.

PRocnxmRE8

Source - J. E. Kaye, Battelle-Northwest,Rlchland,WaEhin@on

Element eepemtd: scam Time for s~tion: less than 4 hours

Sample Imterial: Titanium dioxide

Yield: % 44 Degreeof purification: SeparatesSc frcm any beta impurlties presentin Ti02 fromprocedure7. SC44 Advantages: nmy be determinedby followingthe 4.0 hourdec~, eitherby gsmm or beta counting.

78 Procedure: (1) FuseTi02vlth sodiumbisulfate,dissolveIn 3 M HC1. Add +3 z!omgsc carrier. Ext=t ‘1’i02into100 a cHc13using20 ml cold 6$ aqueou8cupferron,and repeat. (2) Wash aqueouelayertwicewith CHC13. Add NH40Hto precipitate

SC(OH)3. Centrifuge,washwith 20 ml distilledwater.

(3) Pass samplethrougha 10-mlDomsx50,x-8 (100-200mesh)cation exchange colmsn. vaeh vlth 25 ml 2 M HC1. Elube Sc+3 with 50 ml

6M HCl. Evaporate6 M eluart, precipitateSC(OH)3 with lKE40H.

Filter, wash with distilledwater, and ignite to SC O Weigh, mount, 2 3“ and count by followingthe 4.0 hour B+ dec~. Correct decay to time of cupferronextraction.

Note: u cosmercialSc O often contains beta impurltlee. For lov-levelSC 23 meaeuremnlm it may be helpful to purify the Sc carrierbefons adding to the sample.

~9 (152) Source: M. W. Greene* M. Hillman,lWOOkhaVt3n National Laboratories.

Isotope Separated: Scandium-u

Sample Material:Titauilml-44“cow” Yield: 60-70$

Degreeof Pmity: ca. O.@ contasdnation

MvantegeB : A cozrvenlent source of eaal~ detect~, short 11* BCtillfk&.

Procedure:

(1) A column of 10-15 ml of hwex-1, x-8 (50-100mesh) anionexchaageresin in the chlorineformwas preped. A 2 cm tube with a coarse frf.t as base ns recommendedas a column. A 0.5 Cm layer of ~erd quartzbetween two discs of filter cloth um held In place at the top of the resin bed by a split polyethylenering. This layer prevented

79 MIXIIASof the resin ami also preventeddraining of the column whleh must not became dry.

(2) The col- was rinsed free of excess chloridewith water.

(3) ~ to two ~ of 3$ ~02 = addedto eachti Of tltanimm-~

solution.The product was evaporated to dryness and then taken up in 20 ml of

0.1 M oxalic acid.

(4) The titanlura-~oxalate solutionwas loaded on the resin and washed ?ylth

4ornlof a sol.utidnwhich was 0.1 M in oxallc acid and 0.2 M in HC1.

(5) The generatoris milked by elutingwith 30 - ~ ml of the 0.1 M oxaMc -

0.2 M HCl solution.

(6) LOng lived contaminationIncreaseawith use but can be reduced again by eluting the titaniudkh frau the column with 1 M HC1. The titanium-hhis then reloaded aa in steps 3 and k.

PRomMiElo

8ource - (%ata Rudstem, Forskningsr&3ensLaboratorium,Nyk~ping,Sweden(153)

Element separated: Titanium -=: To remove other aPe.U.stion

Target Material: Cobalt prcduct s frcm Cobalt

Type of bombardment: 170-MevProtons Time forSeparation: @ min.

Yield: 10 - 5* Volumes: Less than 10 ml.

PROCEIURE: m The targets were dissolvedin dilute nitric acid containing0.2 mg of titanium carrier together with iron and vanadium carriers. (2) !lhe solution was made ammonlecal, aud the resulting precipitate was waahed twice ulth dilute emmonia. (3) The washed precipitate was boiled with 1 M NaOH containing~02. (4) The precipitatewas then dissolvedin HCl and more vanadium carrier, lkOH, and ~02 were added. The mixture waa Wiled. (5) After centrifugjn& the precipitante was waahed and then dissolvedih 6MEIC1. ” (6) AU. iron was removed frcm the resultingHCl solutionby repeat~ -ractlon with dletbyl ether.

80 (7) The aqueous @ase was made 1 M in HC1 and 1 ml of 6$ aqueous cupferron solMtion was added. The titanium cupferrateWBS extractedinto chloroform. (8) The chloroformsolutionwas washed twice with 1 M ml and then evapixatadand ignited into a @eldn crucible. (9) The Ti02 re81due was dissolvedin 1 M nitric acid which was evaporated to 0.5 mi to form the titaniumtest solution. (lo)The titanium concentrationof the test solutionwas determinedspectro- Photmnetricallyusing chrcmmtropicacid.(154)

PRocEwmla

Source: G. RudstemjP. C. Stevenson,and R. L. ,o*r(155)

Element separated: Titanium

Tar@ Material: Iron

Type of bmkwirdment: 340-Mev Protons

(1) The targets were dissolvedin E MHC1, or scsnetimes,6MHH03, containing 10mgofTi(IV). (2) Fran a 6 M HN03 solutionof the target, titanium iodate was precipitated*. (*Procedure12, Barr, suggestsusing O.5 MF105) (3) The Ti(105)4precipitateWM dissolvedin dilute HCl containingsufficient HaaSO~,or H#03,tor educethei odatetolodine. (4) Concentratedammonia, or ~ gas, waa then used to precipitateTi02. (~ es WEW preferred.) (5) The hydrous oxide was dissolvedin 10-20 ml of 0.5 MSI?03 and the solution was seerengedwith yttrium. This was done by adding 5 to 10 mg of yttrium chlorideor nitrate In very dilute acid, adding 1 or 2 ml of eaturated oxalic acid, StiRing vigorously,and digesting In a hot water bath for several❑inutes. The yttrium oxalate precipatewas discarded. (6) About 1 ml of saturatedtartaric acid was sdded to the resulting solution. The solutionwas mde ammoniacaland 5-lClmg of iron(III)and manganese chlorideswere added. Sufficienttcmtrate prevents precipitation. The solutionwas then Gubbled with ES gas and the resulting iron and manganese suldlldeswere discsxded. (7) The solution from this searengewaemade lM inHCl and about 15 ml.of cold @ aqueous cupferronwas added. Standing In an Ice bath 15 minutes completedthe precipitation. (8) This precipitatewas convertedto hydrous titanhm oaide using ammonia.

81 (9) The hydrousmide -S dissolvedin 6MHC1 and the titaniuma@in precipitatedas the iodate. (10) The titanium iodate was dissolvedin dilute HC1 and ~S03 as in step (3). (~) The fiti titaniumhydrous otide precipitatewas made by adding ammon.ia to thin solution,washing and ignitingto the weighable!lY02.

Note : This procedurewas designedta separatetitanium fras an iron target, therefore,decontaminationfrcm Zr and Hf was not determined.

PmcmuRE12

Since: Donald W. Barr(156)

Element sepszated: !lltanlum

Target material: Copper

Type of bombardment: 5.7-Bev Protons

Yield: *

Procedure: (1) The copper foils were dissolvedin a minimum of concentratedHN03 ccmtainingthe desired carriersIncluding5 mg of titanium a8 1102. (2) The solutionwas adjusted to 1 Min HC1 and the copper was precipitated with ~S . (3) Titaniumwas precipitatedas the hydrous oxide which was washed and dissolvedinHC1. (4) Tartaric acid was tided to complexthe titanium,and an iron-manganese basic tide scavengewas performed. (5) The titadum containingaolutlonwas made 1 M in HCl and @ aqueous cupferronwas added. (6) Tltanlum cupfermatewas extractedinto chlorofomnand washed with 1 M HC1. (7) The chloroformsolutionwas evaporatedover concentratedHNO to 3 elisdnateany organic material. (8) The resultingresidue was dissolvedin acid and made alkalineto precipitateTi02. (9) This precipitatewas dissolvedin 6 MH1’W33,and 0.5 MKIO= W8S aided. J (lo)The titanium iodate precipitate was dissolvedusingHCl and Ha2S03. (u) Titaniumhydroxide,precipitated&as this solution,was used for Ccunting. (E) Spectrophotometrlcanalysisof this precipitate,using the perdde method In suNuric acid, was used to calculatethe chemicalyield.

82 PKXEIWEE I-3

Source: SeymcarKatcoff, Brookhven Nationalhboratory

Element separated: Titanium Yleti: 5-W%

[email protected]$ Bllver De~ee of Hflcation: good to excellent ~ of Bombardment: High enaw protons Time for Separation: 4 hmm

Rooedum t (1) DiemolveirradiatedAg target‘in10 ml 4N I&03 containing1 ml 27 M 2F and 20-30mg Ti carrier in a plastiocen~i.fugetube (solutlonehould @ tree of SO; ions). (2) Msika1 M in HCl and centriftage off the A&l.

(3) &l& 5 mg La+3# ati~rp and centrifugeoff the LaF3. Repeat, (4) hef)ipitati-~6 m adding 5 w h aa=iw8 Z ml B8(N09 )E solution

(50 w/u@, and 1 ml 27 M W. Centrifuge and repeat3 more timm. (51 To the eupernaimadd 10 MI saturatedH3303and [email protected] preoQd.tatehydrow TiOQ. Allowto standfor 10 minutesand then centrifuge. Diaeohfe h HOII W.ute to 15 m18 [email protected]@ ~O~J umtrifugep wafih~and re-oentrifligo, (6) DlaEolvein a minimumof saturatedoxaUo aoid (- 4 ML). !hwnafarto a DOW?H-l, X6, anion emhange column~ ZOO-200 meah~ b diwa~ 16 om long. The d.umn h Wepexed by waahing with a 8du’Mcm U in ~ls 0.5 H in oxau.a add, and 0,035 M h H#g* Elute the W with this aama aolutiom (7) becipitatehydroue Ti02 by adding4 M HEOL Stiirand oentrifiw~ Diaaolve in dilute HOl, re-precipitate,aud centrifuge. (6) DiaBolve‘inIB$03and add few mg V+5 aarrlcm. l?recipitateTi(105)4 with20 ml of 0.5 ME103 In 6 N HH03. Centrifu@. Diaoolveby adding 10 ml 3 M HOl and mild Ih#i05. (9) hecipitate !EL02with NH4CUL oentrlfWe~ and dissolve in 2 ml oonoI m~. Dilute to”5 ml and preaipltateN (103)4a@n by ad~ng W ti~ of 0.5 M lUOq in 6 M HIW~. Ceddfuge. Dlaaolva aa h step 8.

(lo) RecipiWte Ti02 with HH40H,centrifu@,and disaolvain nd* 6 N EO1O Tranefer to a mall @.ane vial, diluteto a s@bnderd vohme, and oumt with a lVaIwell cryetal.

83 Bibliography

1. R&man, C. A., “The Chart of the Nuclides,” (Bsttelle Northwest

Laboratarles,Richland,Waeblngton,1969).

2. Lederer, C. M., J. M. HoUander, 1. Pearlman, ‘Table of IsotopeE!,”

6th M., John Wiley and Sons, ?Iew”York (1967).

3. Ogden, H. R., “lltanium,” in Rare Metals Handboak, 2nd Ed. (C. A. Eampel,

~.), (Reinhold~bllshing Corp..,Hew York, 1%1).

4. Wton, F. A. and F. R. S. Wilklnson,Advanced Inor-C chemist~,

2nd Ed. (Interscience PubMshers, Inc., New York, 1966) Chapter 29,

pages799-608.

5* Ho@ns, B. Smith,Chauters——in the Chemistry——.of the Less—Femdllar ~ (StipesPubliehlngCo.,Champiign,I13A.noie,1939),ChapterIl.

6. Xleinber& J., H. & hgerslnger, Jr. and E. tirlswld,Xnnrmnle ~a~

(D.C. Heathand Co., Boston, 1960), pages 491-498.

7. Latiner, W. M., ~datlon potentials,2nd El. (Prentice-Hall,Hew York 1952),p. 266.

8. vanArkel,A. E. and J. H. deBoer,Z. Ancug. Chem. l& 345 (1925).

9. Rutherford,J. L., R. L. Smith) and M. Herman, A.F.O.S.R.-TH-@-6g4

(~ n Inst. Labs. for Rese~ch and Development,Philadelphia,July

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91 ,...

NUCLEAR SCIENCE SERIES: MONOGRAPHS ON RADIOCHEMISTRY AND RADIOCHEMICAL TECHNIQUES

See the back of the title page for availability information

ELEMENTS Salanium, NAS-NS-3030 (Rev.) [lKI Silicon, NAS-NS-304B (Rev.) [lBBS] Aluminum and Gallium, NAS-NS-3032 [1%1] Silvw, NAS-NS-3047 [ 19511 Americium and Curium, NAS-NS-300B [1S60] Sodium, NAS-NS-3tX5 [19621 Antimony, NAS-NS-3033 [1*11 Sulfur, NAS-NS-3CG4 [ 1S611 Arsenic, NAS-NS-3002 (Rev.} [16661 .’ Tachnatium, NAS-NS-3021 [1960] Aatatine,NAS-NS-3012 [1 sOI Tellurium, NAS-NS-303B [19S0] Barium, Calclum, and Strontium, Thorium, NAS-NS-3004 [ 1B601 NAS-NS-301 o [1 MO] Tin, NAS-NS-3023 [19601 Ba@ium, NAS-NS-3013 [19601 Titanium, NAS-NS-3034 (Rev.) [1971] Cadmium, NAS-NS-3001 [1B501 Trarracurium Elemanta, NAS-NS3031 [19S01 Carbon, Nitr~n, and Oxy@n, Turr@tanr NAS-NS-WM2 [19S1 ] NAS-NS-3019 [ 1960] Uranium, NAS-NS-3050 [1=11 (2&urn, NAS-NS-3035 [1S61 ] Vanadium, NAS-NS-3022 [1*OI Chromium, NAS-NS-3007 (Rav.) [19531 Zinc, NAS-NS-3015 [1%01 cobalt, NAS-NS3041 [19611 Zirccmium and Hafnium,NAS-NS-3011 [1S01 Copper, NAS-N%3027 [ 19611 Fluori~, Chlarina, Bromine, and Iodina, TECHNICIUES NAS-NS-3005 [1%01 Frartcium, NAS-NS-3W3 [1950] Ahsoluta Measurement of Alpha Emkkrn 9Garmanium, NAS-NS-3CM3, [1W1 1 and Spontaneous Fitaion, NASNS-3112 Gb4d, NAS-NS-3036 [1S11 [166s1 Iridium, NAS-NS-3014 [ l$MOI Activation Analysi!r widt Clr&gad Particlus, Iridium, NAS-NS-3045 [ 1961] NAS-NS-3110 [19661 Iron, NAS-NS-3017 [1960] Applications of Computers to Nucl-r arrd Lead, NAS-NS-3040 [1=11 Radiochemistry, NAS-NS-31 07 [ 1*2] Magn~ium, NAS-NS-3024 [1B511 Application of Distillation Techniques to Manganese, NAS-NS-301B [1=0] Radkhemicel Separations, NAS-NS31OS Mercury, NAS-NS-3026 (Rev.) .[1970] [1B521 MolyMenum, NAS-NS-3009 [1 S601 Chemkal Yield Demrmirratiom in Radi- Nickel, NAS-NS-3051 [1*1 I chamistry, NAS-NS-3111 [ 19S7] Niobium and Tantalum, NA$NS-3039 [1%11 Da@ctian and Meesurament of Nuclear Osmium, NAS-NS-3046 [1B61] Radietion, NAS-NS-31= [19611 Palladium, NAS-NS-3052 [16S11 Liquid-Liquid Extmrctiorrwith High- Phc6phorus, NAS-NS-3055 [ 1952] Molwular-Weight Amines, NAS-NS-3101 Platinum, NAS-NS-3044 [ 1*1 I [1=01 Plutonium, NAS-NS-305B [1=51 Low-Level Radiochamical Separadom. Polonium, NAS-NS-3037 [1 9511 NAS-NS-3103 [19611 Potium, NAS-NS-304B [1%1 1 Papar Chromatographic and ElaXroml~ation Protactinium, NAS-NS-3016 [1969] Tachniquaa in Radiochemiatry, NAS-NS Radium, NAS-NS-3067 [1964] 31W [19621 Rare Earths-scandium, Yttrium, and Procmalng of Counting Data, NAS-NS31OB Actinium, NAS-N3-3020 [19611 [1s651 Rare Guses, NAS-NS-3025 [19601 Rapid Radimhemical Separati~, NAS-NS Rhanium, NAS-NS-3026 [1=1 ] 3104 [19511 Rhodium, NAS-NS-300B (Rev.) [1 S66] Separations by Solvent Extraction witfr Rubidium, NAS-NS-3063 [1962] Tri-n-octylphoaphina Oxide, NAS-NS-31~ Rutianium, NAS-NS-3029 [1 961] [19s1]

Current as of JanuaW 1971