Dec. 5, 1961 J. O. GEBSON 3,011,866 SEPARATION OF COLUMBIUM AND TANTALUM Filed Jan. 10, 1958

-2OO MESH ORE CARBON

HEAT 5OOOC WOATE Cb Cls l To Cls OTHER CHLORDES

DISTILLATION 2

WOLATLE COLUMBUM

NON- VOLATLE TANTALUM SOLUBLE IMPURITIES

H2O INSOLUBLE Ta2Ox HO

5 SOLUBLE IMPURTIES

ORE CONCENTRATE IS CARBONS

H2O HO SOLUBLE IMPURITIES-le-FILTER FILTER-e-SOLUBLE EMPURITIES Toa x HO c. x HO sTE GNITE To2O co,

E if g . - 2 INVENTOR. Jannes O. Gibson 22%2-2-24 ATTORNEYs 3,011,866 United States Patent Office Patented Dec. 5, 1961. 2 3,0866 FIG. 1 is a schematic flow sheet illustrating process SEPARATION OF Coifyisit M AND TANTALUM of the invention for separating columbium and tantalum ames C. Gibson, Littletoa, Coio. from a concentrate of their ores, and (58 Whitman Drive, New Providence, N.J.) FIG. 2 is a cross sectional view of a simplified batch Filed Jaa.. i0, 1958, Ser. No. 708,307 process for carrying out the method of the invention, and 7 Clairas. (C. 23-17) includes a simplified flow sheet of the method for re covering and separating columbium and tantalun. This invention relates to a commercial process for the separation of columbian, otherwise known as niobium, Example I and tantalun froin ores containing the elements. O In carrying out the process of the invention an ore Columbium, or niobium, is almost always found asso concentrate containing columbium and taintalum ground ciated with tantalun in ores, and in the United States and to about 200 mesh is mixed with carbon. The mixture the Western Hemisphere the metals have always been of concentrate and carbon was heated to about 500 C. found associated together in relatively low grade deposits. and during the heating chlorine gas was passed through As the uses of columbium and tantalum have expanded, 5 the mixture. A simplified batch process is illustrated in the low grade ores become a commercial source of the FIG. 2 where a mixture of five grams of columbium pent metals. Chemically columbium and tantalum are very oxide and five grams of tantalum pentoxide are mixed similar, making their separation very difficult. The With 1.1 grams of carbon and placed in a four foot known commercial processes for the separation of the length of one inch diameter Pyrex tubing 8. The mix two metals, which also includes the separation of the 20 ture of the ore and carbon is placed between glass wool metals from a large number of other metals associated plugs iii, and a stopper 2 containing two inlets is placed with them in ore which includes tungsten, molybdenum, in the end of the tube adjacent the ore-carbon mixture. iron, zircon, titanium, sodium potassium, calcium, etc., The ore and carbon mixture is heated to 500 C. by a includes a fractional crystallization and a liquid-liquid burner, and chlorine gas is introduced into the mixture eXtraction process. In each of these two known proc 25 through inlet 14 during the heating. This treatment con esses, however, the ore concentrates containing the metals verts the columbium and tantalum from the pentoxide are fused with sodium hydroxide, and the resultant prod form to the pentachloride form. The materials are sub ucts are leached with water and then with acid. The solu lined and pass through the plug and condense at about tions of the metals are then subjected to the separation positions i5 in the tube. When the conversion of the processes. 30 pentoxides to the pentachlorides is complete, the chlorine According to the present invention provide a novel gas was ceased and carbon dioxide was introduced through process for the separation of columbium from tantalum inlet 16. The material Sublimes in the presence of car and for the separation of the two metals from other bon monoxide (C-CO2--heat=2CO) then condenses metals associated with them in an ore or an ore con along the tube. The heat is applied at . The material centrate. The process includes an initial separation of 35 remaining at position 5 (the material which did not columbium and tantalun and some of the other metals Sublime) is dissolved in water, and after filtering, the un in a concentrate containing columbium, tantalum, and dissolved residue (by analysis) contains 89 plus percent other metals, by heating oxides of the metals in the of tantalum pentoxide and less than about 5% of colum presence of carbon and chlorine to produce a volatile bium oxide. The material that sublimes is condensed on and a non-volatile fraction. The volatile fraction in 4. the cool part of the tube i7 near the outer end thereof. cludes a major portion of the metals which are sepa rated by condensation to produce a fraction containing This condensed material is dissolved in water to hydrolyze a major portion of the tantaium and columbium. The the same. The aqueous mixture is filtered to remove the columbium and tantalum values which are chlorides, Soluble impurities, and the residue by assaying was shown resulting from the condensation are heated in the presence 45 to contain 75 plus percent of columbium oxide and less of carbon monoxide to provide separation of the colum than about 23% tantalum oxide. As illustrated in the bium from the tantalum. One method is to heat the partial fioW sheet, the non-soluble material from portion mixture in the presence of carbon while carbon dioxide 15 of the tube after being hydrolyzed and filtered pro gas is passing over the heated mixture. The carbon di duced a material containing water (tantalic acid oxide reacts with carbon to produce carbon monoxide. SO H2Ta2O6), which after being ignited was recovered as The carbon monoxide reacts with the metal chlorides to tantalum pentoxide. The same is true with the colum produce a volatile columbium and a non-volatile tantalum bium which is recovered as a material having X waters fraction. By hydrating separately the two fractions sub of hydration (columbic acid-HCbOs) and on igniting stantially pure columbium may be obtained from the the same is reduced to columbium pentoxide. volatile fraction while substantially pure tantalun oxide 55 gmay be recovered from the non-volatile fraction. Example II included among the cbjects and advantages of the present invention is to provide a simplified and highly A flotation concentrate (the mineral pyrochlore) from efficient method for the separation of columbium and the Oka deposit in Quebec Province of Canada was treat tantalum from a concentrate of the natural ores of the O ed in a manner similar to that described in the figure Sane, and to separate the columbium and tantalum from for Example I. The concentrate analysis is as follows: metals which are associated with them in the ore. The invention, also, includes an economical and highly efficient Kennecott Copper analysis: Percent volatilization and distiliation of compounds of columbium Cb2O5 ------10.6 65 and tantalum and other metals associated with them in Ta2O5 as we sar erro um mom mass at an as swas a sea a law ...... 0.4 the ores, and thereby provide an effective separation of FeO3 x - was a as rv ruro was rom a ua was was a a 12.7 the metals. The process of the invention provides a non CaO ------18.2 aqueous method of separating columbium and tantalum. SiO2 ------19. These and other objects and advantages of the present MgO ------6.5 invention may be readily ascertained by referring to the TiO2 ------3.7 following description and appended illustrations in which: Paos ------0.5 3,011,866 3 4 X-ray analysis (Merlyne Salmon): Percent ties, while the insoluble columbium is recovered as the Ce ------1.4 oxide. La ------0.4 In commercial practice it may be found advantageous Y ------0.03 after fractionating the titanium chloride away from the Zr ------0.4 5 columbium chloride, tantalum chloride, iron chloride, Sr. ------0.3 etc. to place the columbium chloride, tantalum chlo U ------0.14 ride, etc. in a separate reaction vessel-add or pressurize Th ------0.09 in the stoichiometric amount of carbon monoxide (CO) Zn ------0.02 and then distill the columbium chloride away from the Cb ------10.00 non-volatile fraction, thereby making more efficient use Ta ------0.5 of chemicals (CO, COa) and getting quantitative sepa Fe ------14.0 ration of the columbium and tantalum. Min ------1.3 Also, carbon monoxide gas is the chemical of choice Nd ------0.4 and is readily metered as a fairly pure gas, rather than Ti------3.0 15 carbon dioxide gas. On a small scale it is convenient to generate it in the reaction equipment by passing car The concentrate was chlorinated by heating a 200 bon dioxide through hot carbon. mesh ground sample with chlorine gas to a temperature In the hydrolysis of sublimed anhydrous chloride ma of about 500 C. After the chlorination was completed, terials as described in the above examples, water or dilute carbon dioxide was passed through the mixture to sub- 20 acid may be used, particularly in the final washings, lime off various fractions thereof. The sublimed mate- to remove the last traces of soluble chlorides. rial was recovered, hydrolyzed in water and filtered. The While the invention has been illustrated by reference hydrated material from the sublimed portion was ignit- to specific embodiments, there is no intent to limit the ed and on analysis showed that it contained 96% colum- scope of the invention to the precise details so set forth, bium pentoxide, 3% tantalum pentoxide and 0.5% of 25 exceptinsofar as defined in the following claims. zirconium oxide. (This illustrated that carbon dioxide I claim: made no separation; Example III illustrates that carbon 1. The process of separating columbium values from monoxide was required to form a non-volatile compound.) tantalum values and from their natural ores which in cludes other metals comprising treating an intimate mix Example III 30 ture of such an ore and carbon with chlorine gas at Another sample of the Oka ore (with carbon in accord- about 500 C., condensing the columbium and tantalum pletionance with of Examplethe chlorination, I) was chlorinated carbon dioxide and after was the passed com- treatingreaction theproducts condensed of the columbia resultant andvolatile intun composition, portions through the ore with the heating being applied to the with carbon monoxide gaS at about 500. C., recovering residue to form carbon monoxide (C-CO->2CO). The 35 the resultant volatile composition thereof as a columbium sublimedhydrolysis, material filtering, was and recovered igniting by the condensation. residue therefrom After product,position asand a tantainrecovering Product. the resultant non-volatile com as before, the oxides analyzed 96.5% columbium pentox- 2. The process of separating columbium values from ide while tantalum pentoxide was not detected by the tantalum values and from their natural ores which includes analysis, (degree of detection about 0.005 to 0.01% 40 other metals comprising treating an intinate mixture of tantium entioxide) and zirconium oxide was analyzed Such an ore and carbon with chlorine gas at about 500 to be present at about 0.6%. C., condensing the columbium and tantalum reaction The flow sheet of FIGURE 1 illustrates the process, products from the resultant volatile material, treating the where a charge of minus 200 mesh ore or a concentrate condensed columbium and tantalum portions with carbon thereof is heated to about 500° C. with about 110% 45 monoxide gas at about 500 C., recovering the resultant of the theoretical amount of carbon required for oxide volatile composition thereof, hydrolyzing the resultant re reduction. Chlorine gas is passed through the heated covered volatile composition to produce a columbium charge to chlorinate the columbium, tantalum and sev- Oxide, as a precipitate, hydrolyzing the resultant non eral other metals. At about 450-500 C. columbium volatile composition thereof to produce a tantalum oxide pentachloride, tantalum pentachloride and other chlo- 50 as a precipitate. rides sublime from the charge. By distillation the other 3. The process of separating columbium values from chlorides may be effectively separated as at A, by known tantalum values and from their natural ores which includes procedures. The residue from the distillation step 2 is other metals comprising chlorinating an intimate mixture heated to about 500 C. in the presence of carbon monox- of such an ore and carbon at about 500 C., condensing ide, as at stage 3 where the volatile columbium composi- 65 the columbium and tantalum reaction products of the tion sublimes. This material is condensed and is hydro- resultant volatile product, treating the condensed colum lyzed in water and the soluble impurities are filtered bium and tantalum portions with carbon monoxide gas at from the insoluble columbium pentoxide. The non-vola- about 500 C., recovering the resultant volatile composi tile residue of the third step is hydrolyzed in Water and tion thereof, hydrolyzing the resultant recovered volatile the soluble impurities filtered off leaving an insoluble 60 composition with dilute acid to produce an insoluble product of tantalum oxide. The hydrolyzing of the co- columbium oxide, and hydrolyzing the resultant non lumbium and tantalum chlorides produces a fine, diffi- volatile composition to produce an insoluble tantalum cult to filter composition and a filter aid, such as Se- oxide. paran, may be used in the filtration. Using an ore such 4. The process of separating columbium values from as the Oka ore, the non-volatile residue remaining from tantalum values and from their natural ores which in frighgating, EA"if, cludes other metals comprising chlorinating an intimate ------W. mixture of such an ore and carbon at about 500 C, con hillisIran. chloride agai Ele densing the columbium and tantalum chloride reaction columbium pentachloride, tantalum pentachloride, fer- 70 products of the resultant volatile product, treating the rous chloride, zinc chloride, titanium chloride, tin chlo- condensed columbium and tantalum portions with carbon ride, etc. The distillation step 2 removes titanium chlo- monoxide gaS at about 500 C. recovering the resultant ride, silicon chloride, etc. The volatile material leaving volatile composition, hydrolyzing the said resultant stage 3 includes the columbium, iron, aluminum, etc. volatile composition to remove soluble impurities and The iron, aluminum etc. are removed as soluble impuri- 75 recover an insoluble columbium oxide, and hydrolyzing 3,011,866 5 6 the non-volatile composition thereof to remove soluble which comprise heating a crude mixture of columbium impurities and recover an insoluble tantalum oxide. pentachloride and tantalum peatachloride along with other 5. The process of separating columbium values from metallic chlorides as impurities in the intimate presence of tantalum values and from their natural ores which in carbon monoxide at about 500 C. to form volatile and cludes other metals comprising chlorinating an intimate 5 non-volatile compositions, hydrolyzing the resultant vola mixture of such an ore with carbon at about 500 C. to tie compositions to recover insoluble columbium oxide produce a first volatile composition inclusive of colum from soluble impurities, and hydrolyzing the resultant bium and tantalum reaction products, fractionating the non-volatile composition from the heating step to re resultant first volatile composition to separate columbium cover insoluble tantalum oxide from soluble impurities. and tantalum compositions, heating the columbium and O tantallim compositions with carbon monoxide gas to References Cited in the file of this patent about 500 C. to produce a second volatile composition and a non-volatile composition, hydrolyzing the second UNITED STATES PATENTS volatile composition with dilute acid to remove soluble 1,822,266 Becket ------Sept. 9, 1931 impurities and recover an insoluble columbium oxide, and 5 2,429,671 Cuvelliez ------Oct. 28, 1947 hydrolyzing the non-volatile composition with dilute acid 2,766, 112 Schafer ------Oct. 9, 1956 to remove soluble impurities and to recover an insoluble 2,928,722 Scheller ------Mar. 15, 1960 oxide. 6. In the process of separating columbium from FOREIGN PATENTS tantalum and from mixtures containing the same, the 20 644,454 Great Britain ------Oct. 11, 1950 steps which comprise heating a said mixture and carbon 893, 197 Germany ------Oct. 15, 1954 monoxide with chlorine gas at about 500 C. to form volatile and non-volatile compositions, hydrolyzing the OTHER REFERENCES resultant volatile compositions to recover insoluble colum May et al. in Industrial and Engineering Chemistry, bium oxide therefrom, and hydrolyzing the resultant non 25 December 1954, pages 2495-2500. volatile compositions from the heating step to recover Hampel: “Rare Metals Handbook,' publ. by Reinhold insoluble tantalum oxide therefrom. Publ. Corp., N.Y., 1954, page 396. 7. In the process of separating columbium from Mellor: “Comprehensive Treatise on Inorganic and tantalum and from mixtures containing the same the steps Theoretical Chemistry,' vol. 9, 1929, page 843.