Oct 7, 1941-‘ J. ROBERTSON Ei- AL 2,257,978 EXTRACTION OF VANADIUM VALiIES FV‘ROM VANADIUM-BEARING MATERIAL Filed Feb. 25, 1940 s She'ets-Sheét 2.

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Patented Oct. 7, 1941 22,257,978

UNITED STATES PATENT o-FFiicE

EXTRACTION OF VANADIUM VALUES FROM VANADIUM-BEARING MATERIAL . John Robertson, Ricran, Peru,_'Holber't Earl Dunn, Grafton, Pa., and Archibald Alexander ‘Sproul, Rye, N. Y., assignors to Vanadium‘ Corporation of America, Bridgevill e, Pa., a corporation of Delaware Application February .23, 1940, Serial‘No. 320,458 16 Claims. (01.23-18) This invention relates to a process for recover adding transposing agents, provided that the ing vanadium values from ores and other vana roast is carried out at the proper temperature dium-bearing materials. The term vanadium and 'using the proper temperature-time cycle values is used as a. generic expression to include both for the heating and cooling operation. In the vanadium recovered whether as vanadium or respect to ‘the latter, a further, condition is that as a. compound existing in the ore or as a com the roasted ore must be cooled at a su?liciently pound synthesized from the ore. rapid rate, in order not to permit the soluble cal This application is a continuation-in-part of cium vanadate formed during the roasting to be our co-pending application, Serial No. 221,610, converted to any appreciable extent into apwater ?led July 2'7, 1938,'which application is a contin insoluble form. We have found that different uation-in-part .of our application, Serial No. vanadium ores behave diiferently in these roast’ 87,784, ?led June 27, 1936. ing and cooling operations and that ‘there exists The present invention provides a process for not only an optimumtemperature ‘and time cycle . recovering vanadium, values from ores or other during the heating or roasting stage but also a vanadium-bearing materials which is less costly critical cooling rate in the ?nal cooling stage, and in which the recovery is more nearly com which critical cooling 'rate must be exceeded, in plete than in the methods heretofore employed. order to prevent retransformation of the soluble It eliminates the use of ?uxing or transposing vanadate to an insoluble vanadate. agents during the roast-and the roast is so car We have found that when an ore containing ried out that a large proportion'of the vanadium - compounds of vanadium and calcium is roasted content is rendered water soluble, thus ‘enabling at different temperatures, a series of calcium the use of ‘a water quench in place of an acid or vanadates are formed, some of which are water alkaline leach. The water quench is, however, insoluble'and others of which are water soluble. followed by an acid leach to extract further por Thus, at a roasting temperature between about tions of vanadium. 1000° F. and l200° F. the water insoluble calcium In the accompanying drawings: ortho-vanadate is formed. Therefore, if such Fig. 1 is a ?ow sheet illustrating the preferred roasting temperatures are employed, it is neces manner of carrying out the process; sary to ‘employ a transposihg agent such as so Fig. 2 is a chart illustrating the solubility se-V dium chloride, sodium-sulphate or sodium car-" cured by quenching at the roasting temperature; bonate'in the roast, in order to Tender the'roast and water soluble. ' Fig. 3 is arsimilar chart illustrating the solu 'It is well -recogni'ze'd'by those skilled in the bilities when the ore is allowed to ?rst cool in art of “extracting metals from ores that within air before quenching. a given type the Iche‘micalcomposition, particu The most common method of recovering vana 35 larly with respect to major vconstituents (the dium value from its ores consists essentially of metals that it is desired to extract) may be roasting the ore with a suitable fluxing or trans substantially uniform from lot to lot. Yet the‘ posing agent or agents which convert the vana minor constituents (principally gangue mate dium content into soluble form. Such transpos rials) may vary widely without appearing. to al ing agents may be salt or soda ash, or both, ‘or ter the general characteristics of the ore; never other suitable material. The roasted ore is there thele‘ss, there is often apparent failure of a par after leached with water. The vanadium-bear ticular procedure to extract theabove mentioned ing liquor is ?ltered off and the vanadium con major constituentsuntil.some disturbingv feature tent is precipitated from this liquor by the addi-~ which may be a differenceprincipally of physical tion of the required amount of sulphuric acid. character has been vbrought ‘under control. In The cost of the transposing agent addedto the line with this generally accepted phenomena, we roast constitutes a large item of expense which is have found in studying vanadium ores that in the eliminated in our process. Furthermore, in our formation during roasting of the maximum process the amount of acid required is consider amount of soluble calcium vanadate the optimum ably reduced. temperature-time cycle varies somewhat with the We have found that normally water insoluble particular type‘of ore and the particular lot v‘of vanadium compounds in ores or other material any type being treated. There is, therefore, a which contain vanadium and compounds of cal necessary range ofgoperating conditions required cium or other alkaline earthmetals may be to satisfactorily ‘carry out our process with the rendered water soluble Without the necessity of '55 various ores to which it is applicable, in order to 2,257,978 . ._ .. _ _ , 2. - - . secure maximum extraction. In every case, how tals are believed to be calcium deuterotetra ever, the treatment involved is a roasting to con vanadate. vert vanadium present in the ore into soluble cal— If the roast is carried out at too low a tem cium or alkaline earth metal vanadate and then perature, or at too high a temperature, and is by cooling more quickly than the afore-mentioned immediately quenched in water, the water solu critical rate to effectively preserve the water sol ble calcium vanadate is not formed. If a roast uble vanadate and prevent its transformation ing temperature above 2000° F. is employed on into the insoluble calcium vanadate stable at the ore previously described, and the roasted room temperature that would result from slow ore is then immediately quenched in water and cooling. The soluble calcium vanadate is there 10 the quench liquor is concentrated so as to form after extracted with water and any remaining va crystals, we obtain green crystals which analyze: nadium is extracted by acid leaching, thus re Percent sulting as heretofore noted in a considerable V205 ______59.30 saving in acid consumption, Water cooling ap CaO ______17.69 pears to be more rapid for all ores than this 15 H2O (Loss on ignition) ______23.35 critical cooling rate and hence two operations may be combined by quenching in water as here which correspond to the formula after described. 7 The initial stage of the roasting operation pref erably is carried out at some temperature above 20 CaVzOaAI-IzO 12000 F. This temperature is generally between and are practically insoluble in water, requiring 1400° F. and 1800° F., preferably about 1600° F., 35% or stronger sulphuric acid to dissolve them. but may go up as high as 20000 F. or‘ even higher, Upon reroasting the crystals at 1600° F. and if the maximum temperature and time cycle are quenching, they readily dissolve in water. not su?icient to cause appreciable sintering of 2.3 The process according to the present inven the material. Subsequent to the initial heating, the temperature may be lowered slowly or rapidly tion, may be carried out as follows: The ore crushed or comminuted to the desired ?neness, to some temperature not below about 1000” F. say 20 mesh, is roasted in a suitable furnace at before the rapid cooling at a rate greater than the the desired temperature, usually between about above noted critical cooling rate needs to be car 30 ried out. The temperature-time cycle produc 1400° F. and 1700" F., depending upon the type of ore or other material which is being treated.’ tive of maximum water extraction or maximum The roasted ore while being maintained at or total extraction by leaching in water and sub sequent leaching in acid will vary with different near the temperature of the roast is quenched ores and the process envisages the adjustment 3:3 in water. The quenched ore is then ground to of this temperature-time cycle in accordance with the desired degree of ?neness with the water. The ground material is ?ltered yielding a ?ltrate the needs of each case. containing a large proportion of the vanadium As an example, a characteristic ore treated in accordance with the present invention had the originally contained in the ore, hereafter called following composition: 40 “quench liquor,” and a residue hereafter called Percent “quench residue.” A leach of the quench resi due is then made with a dilute sulphuric acid V ______3.54 solution, say a 4% solution, and the leached ma CaO ______15.53 terial is ?ltered yielding a ?ltrate hereafter S03 ______25.91 - called “acid liquor” containing an additional A1203 ______11.18 proportion of the vanadium contained in the SiOz ______24.44 ore, and a ?nal residue or tailing. The quench F6203 ______1.95 liquor and acid liquor are then mixed and on be Such an ore may be roasted at a temperature of ing heated by suitable means and stirred mean about 1650° F. and immediately quenched in wa 50 while, a precipitate forms, usually considered to ter, or it may be roasted at a higher temperature be V205. This precipitate is then ?ltered and but short of sintering and allowed to cool quickly washed according to common practice. ' ' or slowly to about 1650° F. and then immediately The amount and condition of the calcium quenched in water. If the water quench liquors. compounds present in the ore are important are allowed to slowly concentrate at a tempera 55 considerations in connection with the applica ture slightly above room temperature, orange tion of this process. It is mentioned above that red crystals of about 1/2 inch size separate from minor differences even between different lots of the supernatant liquor. These crystals when ore from the same ‘deposit may create differences‘ analyzed have been found to have the following in behavior during the process, unless means analysis: for handling these differences are thoroughly, » Percent itmderstood. This applied to the calcium con V205 ______68.92 ent. These conditions are observed most par-' CaO ______10.62 ticularly in vanadium ores of the roscoelite type. H2O ______20.46 Occasionally a roscoelite or will be found which, although it contains calcium ‘compounds in more which corresponds to the formula than su?icient proportion to form- the desired CaO.2V205.6I-I2O Water soluble calcium vanadate (CaO.2V2O5) does not perform in the desired manner unless or special precautions are taken. This appears to CaV4O11.6H2O 70 be due to the fact that calcium is present largely ’ These ‘crystals were readily dissolved in water in the form of calcium carbonate. In some and their vanadium contact precipitated as cases, it may be present in amount sufficient to Vanadium pentoXide by addition of a suitable provide much more calcium than is necessary amount of the acid leach liquor as hereinafter for the formation of normal water insoluble cal- ' described in our preferred process. These crys 75 cium vanadate (3CaO.VzO5); it will be observed 3. that v‘the'perc'zentages of calcium infthis ilatter‘ " To further illustrate the process, the follow compound is much greater than in the water ing example isgiven: 'Tlle'ore containing 3.01% soluble ‘compound. v'We ‘have found that ‘where vanadium, was ground to all pass a 20 mesh calcium 'is'presentTin the form of ~minerals which screen. It was then roasted for 105 minutes will-yield'when ‘subjected to our roasting pro at ‘1650° F., and while at this temperature was cedure free lime or lime in‘ such ‘form as to 'be quenched in water. The-quenched material‘was‘ reactable with vanadium compound-s, conversion then ground to 95% through 200 mesh and ?l of the vanadium content to the water insoluble tered. The?ltratewas found to contain approx calcium vanadate increases as the amount of imately 62% of the vanadium originally con this-available free lime approaches the 'stoichio tained in the ore. The quench residue was metric proportions necessary-to form the ‘normal leached with a 7.0% by weight solution of sul water insoluble calcium 'vanadate. In other phuric ‘acid, the acid contained in the solution words, the presence :of free lime tends to pro amounting to 96 pounds of acid per ton of ore mote the formation at high temperature of the in' the feed. The leached material was then ?l insoluble calcium vanadate. We have found 15 tered, and the acidjliquor was found to con that if excess calcium exists, for example, in the tain approximately 27% of the-vanadium-origi form of calcium sulphate this is not true, and nally contained in the ore, thus giving a-total the soluble calcium vanadate forms under our extraction of approximately 89%. Acid liquor roasting conditions very readily. Thus in the was then addedto‘the quench ‘liquor until the case of those ores which contain:calcium com mixture was slightly acid, thusprecipitating ap pounds but do not under our described roasting proximately'28 pounds of calcium sulphate per conditions p-roducelarge amounts of water-solu ton'of original feed. This calcium sulphate was ble calcium vanadate, they can be caused to do then ?ltered off, and to the I?ltrate was added so by the addition of pyrite, elemental sulphur the remainder-of the acid liquor. The mixture or other sulphurizing means which presumably 2. was then heated to approximately 180° ‘F. and convert the free lime 'into calcium sulphate. maintained at that temperature for‘two hours, Likewise ores not containing calcium may be stirring ‘meanwhile, thus precipitating the va-v caused to react on roasting with the production nadium contained in-the liquors. ‘The e?iciency of water-soluble calcium vanadates by the addi of precipitation was approximately 92%, thus tion of’lime and sulphur containing compounds. 30 giving an overall recovery of’approxi'mately 82% Further in the application of our process to of the vanadium contained in the ore. The pre roscoelite ores it was found in one case that cipitate was then washed and ‘dried. an ore containing only ‘50% as much lime as Fig. 2 illustrates the ‘effect upon the solubility was necessary to form the water-soluble van of the vanadium values of roasting at different adate and which netted a total recovery ofonly temperatures and quenching in water at the 32% of its vanadium content could be mixed roasting temperature. The curve “dissolved in inlequal part with an-ore ‘containing su?icient water” shows the percentage of the total initial lime to form at least 2CaO.V2O5 and originally vanadium content of the ore which is dissolved yielding only 56% of its vanadium in soluble by the water in which ‘the roasted ‘ore is form and when the mixture was-treated by the quenched, ground'and leached. The curve “dis standard procedure of our invention a combined solved in 4% "H2SO4” shows the percentage of recovery of 78% ‘of all of the vanadium was ob the vanadium contentdissolved bythe sulphuric tained. ' ' acid leach calculated as apercentage of the total In order to form the water soluble calcium initial vvanadium content of the ore. The curve deuterotetra-vanadate, it is necessary that cal “total dissolved” shows the combined recovery cium sulphate or its equivalent be present in of the water leach ‘and the acid leach of the the rcastto .theextent of about lie of the vana original vanadium content of the ore. It will dium content. Usually it is present in a much be seen that at ‘a roasting temperature of 12000 greater amount. In the characteristic ore, an , F., only 12.5% of the vanadium content is-solu-, analysis "of which has 'been'given previously, the ble in water, whereas at 1400" F., 45% of the 15.53% calcium oxide corresponds to‘ 37.75% cal vanadium content is soluble. Beginning at about cium sulphate, vwhile only 1% of 8.54% or 2.5% 1400” F., and extending up'to 1600° F. the solu of CaSO4 is necessary‘for‘the-formationof the bility of the vanadium content inwater increases soluble calcium vanadate. ’ . . , rapidly and thereafter decreases until a temper Certain of the ores‘contain a'large amount of ature‘o'f about ‘1700" F. is reached, after which calcium sulphate beyond that necessary to form it decreases even more rapidly. The amount of the water soluble calcium deuterotetra-vanadate the vanadium content remaining in the. quench and it has been found that this has a tendency residue after the water quench which‘is dissolved to go into solution with the vanadium and pre therefrom by a 4% sulphuric ‘acid solution cipitate with it ‘to a certain extent, thus lower reaches a minimum at about 1600917‘. roasting ing the grade of the product. .In treatingsuch temperature and thereafter increases rapidly as ores,‘ it has been found desirable to precipitate the amount of vanadium which'has been dis part of .the dissolved calcium sulphate from the solvediin water decreases. ' . quench .li'quor prior to precipitating the vanadi The total recovery for the particular ore was um. This step has been illustrated in Fig. 1 65 at a maximum at about 1700°’F. roasting tem birthday be omitted where the amountv ofcal-i perature. The curves illustrate the critical na cium compound present in the ore is not too ture of the roasting‘and quenching tempera great. The elimination of excess calcium can, be tures, ‘the abrupt ‘changes in the slopes of the dcneby adding acid liquor to the quench liquor curves being-due, it is believed, :to the forma untilrthe mixture is slightly :acid, :as ‘ determined 70 tion of the various calcium compounds at-the by; arsuitable indicator, whereupon a large .pro different ‘temperatures. :For the particular ore portion of the calcium sulphate ‘is precipitated, on which the chart of Fig. 2 is based, it is evi This .is‘thenw?lteredo? and the vanadium pre dentthat; a roasting temperature of .1600" F. cipitated by-iaddinga further; quantity ‘of the; acid . will produce the-maximum recoveryiin the wa-l liquor to the ?ltrate, heating and stirring. ter quench and leach, although at 1700° F., the 4 2,257,978 total recovery is somewhat more, since the vanadium which is not overcome by the subse amount dissolved in the sulphuric acid is some quent acid leach. , what greater than at 1600° F. When the proper roasting temperatures are It will be apparent that a great economy is employed in accordance with the present inven effected, since a large part, if not the greater tion, in order to form the Water-soluble deutero part, of the vanadium can be dissolved by a cheap tetra-vanadate, it is found that quenching in wa solvent, water, and that acid need be used only ter is even superior to quenching in dilute sul to dissolve the residuum of the vanadium con phuric acid. This is shown by the following ta tent remaining in the quench residue. ble, in which three roasts were conducted under The desirability of quenching the roasted ore carefully controlled conditions at 1650“ F. to in water while the ore is within the critical 1700° F. for 1112 hours and the roast instantly temperature range at which the water-soluble quenched in the respective solutions. calcium vanadate exists rather than allowing TABLE II the roasted ore to cool slowly below this range before quenching in water is illustrated by a Per cent total V soluble in comparison of Figs. 2 and 3. In Fig. 2, the Test No. Procedure ———_--—-—-— roasted ore was immediately quenched in water Quench Acid leach Total from the temperature of the roast. In Fig. 3, the roasted ore was allowed to cool in a mass in S—807-... Water quench, leach resi- 64. 45 23. 48 87. 93 air for ?ve minutes before quenching in water. due in 2% acid. The curve “dissolved in water” shows the per S—8ll.... Quench in 2% acid ______.. 17.40 17. 40 centage of the total initial vanadium content S-8l2. . .. Quench in 4% acid ______.. 50. 92 50. 92 of the ore which was dissolved by the water in In the specific illustrations of the process thus which the ore was quenched. The curve “dis far referred to, the ore was quenched in water solved in 4% H2304” shows the percentage of 25' vanadium content dissolved by the sulphuric from a temperature at or near the temperature of the roast, in order to trap or retain the water acid leach calculated to percentage of the total soluble calcium vanadate. However, the process initial vanadium content of the ore. The curve may be carried out in other ways. The ore may “total dissolved” shows the combined recovery of be roasted at a temperature higher than that at the water leach and the acid leach of the origi 30 which it is to be quenched in water and the nal vanadium content of the ore. roasted ore may be cooled either quickly or slowly It will be seen from a comparison of these Figs. 2 and 3 that in Fig. 3 not only did the down to the quenching temperature and then greater part of the vanadium content require quenched. The important considerations in car rying out the process are that the ore is roasted the more expensive solvent acid, to recover it, 35 at a temperature high enough to form the water but that the total recovery was less than when soluble calcium vanadate and that it be cooled the ore was roasted to the proper temperature rapidly enough from a temperature at which the and immediately quenched in water, as shown water-soluble calcium vanadate still exists, so in Fig. 2. as to retain the water-soluble calcium vanadate. The comparative data illustrated by Figs. 2 The following table illustrates several modi?ca and 3 is set forth in the following table. These tions of the procedure which may be utilized: results were obtained in the following manner: An ore containing 3.54% vanadium was ground TABLE III to 20 mesh and roasted for a period of 90 min Tests on a Peruvian ore utes at various temperatures. At the comple tion of the roasting period, a portion of the dis Extraction charged material was instantly quenched in cold [11:19“ Roasting conditions, °F. water, and the remainder of the material was 0- Water Acid T t 1 allowed to cool in air for a period of 5 minutes quench leach o a before quenching in water. 1312.--. 1600" F. (held 60 min.) quenched 64. 42 19. 12 33. 54 TABLE I in water. 1271...... do ...... 57. 97 21. 86 81.83 H13 1800° F. (60 m.), cool to 1600° F. 45. 83 35. 19 81.02 in 25 min., quench in Water. . Roast cooled in air 5 1289.--. 18000 F. (90 m.), cool to 1600° F. 62. 94 31. 13 94.07 Roast instantaneously min before quench K in 60 min., quench in water. quenched, per cent of in e t f t t 1 total V soluble g’ p r cen o o a 1314.... 1800° F. (60 111.), Cool to 1400° F. 57. 94 33. 96 91.90 Roasting V soluble ‘ in 70 min., quench in water. 1315.... 1800° F. (60 m.), cool to 1200° F. 27.60 63. 26 90.86 temp., r’F. in 130 min, quench in water. . In In In In 1281.... 1900° F. (90 m.), cool to 1600‘ F. 12.40 55.20 67. 60 quench 4% Total quench 4% Total in 60 min., quench in water. water acid water acid 60 1316-... 1900° F. (20 m.), cool to 1600° F. 33. 78 54.03 87.81 in 42 min., quench in water.

______-- 0.5 68.5 69.0 ______-. 0.6 63.7 65.0 In tests Nos._1312 and 1271, the ore was roasted 36. 32 48. 83 1. 78 40. 69 42. 47 24. 51 52. 50 6. 45 31.88 38.33 at 1600° F. for 60 minutes and then quenched in 23. 72 68. 48 10. 11 36. 32 46. 43 water from this temperature. In the remaining 27. 78 80. 93 15. 61 43. 75 59. 36 65 22. 90 85. 64 6. 98 57. 55 64. 53 tests, the ores were heated to 1800 or 1900° F. as 33. 55 90. 65 6. 54 64. 99 71. 53 indicated and were then cooled} to diiTerent tem 59. 71 88. 60 8. 27 54. 37 62. 64 peratures at di?erent rates and were then quenched in water. ' , Even a delay of 5 minutes under conditions 70 In general, the ‘preferred initial heating is in which allow the retransformation of the water the range of 1600 to 1800° F. and the preferred soluble calcium vanadate into the water insoluble range from which rapid cooling takes place is calcium vanadate before quenching, as shown by in the range'of 1400 to 1600° F. With some ores; this table and the charts of Figs. 2 and 3, causes the process works more satisfactorily with con a marked decrease in water solubility in the 75 tinued heating at 1600° F. for a suitable time. 2,257,978 5 followed; by rapid cooling. However, heating may earth-metals, such as magnesium, barium, stron be as high as 2000° F; or somewhat higher and, tium, and". beryllium. ‘ * althoug'l'r the rapid cooling is usually 'from some We have illustrated? and described‘ the pre temperature more than 1200° F., it may take ferred manner of carrying out theprocess. Some placeifizomatemperature as low aslOOO" F. Even of5the steps may be omitted‘ under certain cir though a. particular ore may require a roasting cumstances. Thus the grinding 10f the ore sub temperature of 1200D F; in. order to vform the sequent. to‘ the roast.v and‘ water quench is not water-soluble calcium. vanadate, the soluble ‘absolutely essential for: the success or the proc vanadate. when once: formedmay be retained at ess but gives superior‘ results and‘ is‘ preferred. a. temperature somewhat lower‘ than that re Wherethe ore does not'contain toolarge amounts quired for its formation. of calcium‘, itsprecipitation and removal may be T'As. noted. above, the preferred procedure is omitted.v The invention is not limited to the ‘heating. for a sui?cient length of time at about preferred procedure but‘may' be practiced within 1'600" F‘.- to causev the vanadium. to be converted the scope of‘ the'followin'g claims;v ' into. the water solublecalcium vanadate. and then 15 We claim: ' ' ' ' I to quench. from. at or near the. temperature of 1~.- In a process for recovering‘ vanadium values the. roast into water.' However, the roast. need from materials containing‘ vanadium. and cal not: beimmediately' quenched from at or. near cium compounds, the steps comprising‘ roasting the temperature of the roast but may be cooled the materials without essential‘ additions of al'-“ quickly or slowly down. to any temperature at kali-metal c‘ompoundsiwhich'l would combine with which. a considerable proportion of the vanadii the vanadium content tolform water-‘soluble al um; is still retained in the water-soluble form kali-metal vanadates and at a temperature above and the. product may then be quenched from this that at‘which, upon heating, Water'insoluble cal lower temperature. The step of' quenching in cium vanadates are‘ transformed into" Water water is actually two steps in one, these being 25 soluble calcium vanadates butv at a temperature the quenchingrand the leaching with water. The below‘that at which there is appreciable sinter quenching may involve cooling in any medium ing of the material, then quenching the roast in at ‘any. rate which in a given ore is‘su?iciently a medium which does not contain essential quan rapid to retain after' the cooling a large‘ pro tities of acid or alkali vanadiuml-solubilizing re portion of the vanadium inthe ‘form of the wa 308 agents’ and'at a- temperature: at which a large ter-soluble calcium vanadate. For example, the proportion of. the ‘water-soluble calciumv van ore‘may be discharged at. the ?nal temperature adates are still retained in water-soluble form of.‘ the roast‘ into a streamof. cool‘ air and if the and‘ dissolving the quenchedivmaterial in water ore islso discharged in a stream su?iciently divid which ,doesv not contain essential quantities of ed, cooling" at thev desired ratewill take place. acid or alkaline vanadium-solubilizing' reagents, The ore can.‘ be subsequently leached in water and: separating the soluble calcium vanadates and yield. a large proportion of its vanadium to from the residue. " " ' the- water used for dissolving. Actually ‘it is 2. In a’ process‘ for‘ recovering vanadium values found. in practice that this method is'not' as‘ from materials‘ containing vanadium and‘ al-_ desirable as quenching directly into water, ‘?rst " kaline earth metal-‘compounds, the steps com because of the likelihood of lossesb'y'. dusting and prising. roastingl the: materials without essential second because it‘ is‘unnecessary to have the two additions.‘ or"v alkali-metal compounds‘ which steps independent‘ of each other. would“ combine with the ‘vanadium content to . "The present process eliminates the necessity form. water-soluble. alkali-metal vanadates and offlemploying alkaline 'fluxes during the roasting a at" a'temperature abovev that at which, upon or: leaching steps. As previously pointed out, heating, water‘insoluble alkaline earth metal only’96 pounds of sulphuric acid‘ are required per vanadates aretransformediinto water-soluble al ton‘of ore treated, or' less than 5% of the weight‘ kaline earth metalvanadatesibut at‘ a'tempe'ra-. of. the ore. 'I'hislow amount of acid is made‘ ture below. that at‘? which there is appreciable possible. because of the high percentage of ;" ~ sinter'ing. of: the material, then quenching the‘ vanadium which is extracted in thewater quench. roast‘ in a medium- which does not contain-es In this manner, we are able'to'reduce the nor sential quantities of acid'ior: alkaline fvanadium mal acid‘ consumption by 60%, whether used‘, as solubilizing reagents and: atf~ a temperature at a leaching agent or as a Subsequent precipitant; which a large proportion of‘. the Water-soluble Vanadium ores. averaging 4.33% in vanadium ;; ‘ alkaline earth m'etalvanadates' are still retained content. have been treated‘ in. accordance with in water-soluble form and dissolving the quenched the present invention, with. an: average extrac material. in- water which does‘ not contain‘ essen—' tion inthe Water quench of "55% vanadium and tial quantities of: acid 'or‘alk'alineevanadium solu in the acidileach of: 3.83%, or a total extraction bilizing reagents, and" separating the soluble a1‘ of 931.3% of. the vanadium content. Precipitation 50' kaline' earth metal vanadates from the residue.’ of thisvanadiurn has been accomplished by com . 3.v In aprocess for recovering'vanadium values bining the quen'chliquor-and‘the acid liquor at from materials ‘containing vanadium and‘ calcium‘ a- precipitation e?iciency of 98% to produce compounds, the‘ steps" comprising roasting the vanadium pentoxide' analyzing 35%‘ to 50% V materials without essential additions of alkali as desired, depending upon the extent‘) to which if metali'compounds which would combine with the the precipitated calciumv sulphate is removed in vanadium content’ to form water-soluble alkali advance. metal'vanadates andat atemperature of‘ at'least Acids other than sulphuric acid may be em 1200° F., in order to form waterhsoluble' calcium ployed to dissolve the vanadium content of the‘ vanadates, vthenquenching the roast in a medi quenchzresidue and to precipitate vanadium pent‘- ‘ umwhich does not'contain essential quantities oxide from the quench liquor. While the proc of acid or alkaline vanadium-solubilizing reagents ess has been described and'developed with espe and ‘at a temperature ofat least 1000° F., in orderv cial‘reference to the most commonly occurring to'retainia substantial proportion of the water alkaline earth metal, calcium, the process may soluble calcium vi'lanadates in‘ Water soluble‘ form be applied; to ores. containing other alkaline 1'1 and dissolving‘ the quenched‘ materiali in water' 6 2,257,978 which does not contain essential quantities of tween 1400" F. and 1800" F. at which the calcium acid or alkaline vanadium solubilizing reagents, and vanadium compounds react to form water and separating the soluble calcium vanadates soluble calcium vanadates, then quenching the from the residue. roast at or near the temperature of the roast in 4. In a process for recovering vanadium values water which does not contain essential quan from materials containing vanadium and cal tities of acid or alkaline vanadium-solubilizing cium compounds, the steps comprising adding reagents, and separating the soluble ‘calcium material containing sulphur to the vanadium vanadates from the residue. containing material, roasting said materials 9. In a process for recovering vanadium values without essential additions of alkali-metal com 10 from materials containing vanadium and calcium pounds which would combine with the vanadium compounds, the steps comprising roasting the content to form water-soluble alkali-metal van materials without essential additions of alkali adates and at a temperature above that at which, metal compounds which would combine with the upon heating, water insoluble calcium vanadates vanadium content to form Water-soluble alkali are transformed into water-soluble calcium van 15 metal vanadates, then quenching the roast at a adates but at a temperature below that at which temperature of at least 1000° F. in water which there is appreciable sintering of the material, then does not contain essential quantities of acid or quenching the roast at a temperature at which alkaline vanadium-solubilizing reagents, sepa~ a substantial proportion of the water-soluble rating the quench residue from the quench liquor, calcium vanadates are still retained in water 20 leaching the quench residue with acid, separat soluble form and dissolving the quenched mate ing the acid liquor from the quench residue, and rial in water which does not contain essential mixing the acid liquor and quench liquor and quantities of acid or alkaline vanadium-solubiliz heating them to precipitate vanadium oxide. ing reagents, and separating the soluble calcium 10. In a process for recovering vanadium values vanadates from the residue. 25 from materials containing vanadium and alka 5. In a ‘process for recovering vanadium values line-earth-metal compounds, the steps compris from materials containing vanadium and calcium ing roasting the materials without essential compounds, the steps comprising roasting the additions of alkali-metal compounds which would materials without essential additions of alkali combine with the vanadium content to form metal compounds which would combine with the 30 water-soluble alkali-metal vanadates and at a vanadium content to form water-soluble alkali temperature at which the alkaline-earth metal metal vanadates and at a temperature at which and vanadium compounds react to form water the calcium and vanadium compounds react to soluble alkaline-earth metal vanadates, then form water-soluble calcium vanadates, then quenching the roast in water which does not con quenching the roast in water which does not 35 tain essential quantities of acid or alkaline van contain essential quantities of acid or alkaline adium-solubilizing reagents and at a tempera vanadium-solubilizing reagents and at a tem ture at which a large proportion of the water perature at which a large proportion of the 'soluble alkaline-earth metal vanadates are still water-soluble calcium vanadates are still retained retained in water-soluble form, and separating in water-soluble form, and separating the water 40 the water-soluble alkaline-earth metal vanadates soluble calcium vanadates from the residue. from the residue. 6. In a process for recovering vanadium values 11. In a process for recovering vanadium values from materials containing vanadium and cal from materials containing vanadium and alka cium compounds, the steps comprising roasting line-earth metal compounds, the steps comprising the materials without essential additions of al 45 roasting the materials without essential addi kali-metal compounds which would combine with tions of alkali-metal compounds which would the vanadium content to form Water-soluble al combine with the vanadium content to form kali-metal vanadates, then quenching the roast water-soluble alkali-metal vanadates, then at a temperature of at least 1000° F. in water quenching the roast at a temperature of at least which does not contain essential quantities of 50 1000° F. in water which does not contain essen acid or alkaline vanadium-solubilizing reagents, tial quantities of acid or alkaline vanadium and separating the water-soluble calcium vana solubilizing reagents, and separating the water dates from the residue. soluble alkaline-earth metal vanadates from the 7. In a process for recovering vanadium values residue. from materials containing vanadium and calcium 55 12. In a process for recovering vanadium values compounds, the steps comprising roasting the from materials containing vanadium and alka materials without essential additions of alkali line-earth metal compounds, the steps comprising metal com-pounds which would combine with roasting the materials without essential addi the vanadiumv content to form water-soluble al tions of alkali-metal compounds which would kali-metal vanadates and at a temperature be 60 combine with the vanadium content to form tween 1200" F. and 2000° F. at which the calcium water-soluble alkali-metal vanadates and at a and vanadium compounds react to form water temperature at which the alkaline-earth metal soluble calcium vanadates, quenching the roast and vanadium compounds react to form water at a temperature of at least 1000° F. in water soluble alkaline-earth metal deuterotetra-vana which does not contain essential quantities of date, quenching the roast in Water which does acid or alkaline vanadium-solubilizing reagents, not contain essential quantities of acid or alka and separating the water-soluble calcium vana line vanadium-solubilizing reagents and at a dates from the residue. temperature at which a large proportion of the 8-. In a process for recovering vanadium values water-soluble alkaline-earth metal deuterotetra from materials containing vanadium and cal- *7 vanadate is still retained in water-soluble form, cium compounds, the steps comprising roasting and separating the water-soluble deuterotetra the materials without essential additions of al vanadate from the residue. kali-metal compounds which would combine with 13. In a process for recovering vanadium val the vanadium content to form water-soluble al ues from materials containing vanadium and kali-metal vanadates and. at a temperature be calcium compounds. the steps comprising roast 2,257,978 7 ing the materials without essential additions of and vanadium compounds react to form water alkali-metal compounds which would combine solulole calcium vanadates, quenching the roast with the vanadium content to form water-solu at or near the temperature of the roast in water, ble alkali-metal vanadates and at a temperature separating the quench residue from the quench above that at which, upon heating, water-in liquor, leaching the quench residue with a solu soluble calcium vanadates are transformed into tion of sulphuric acid, separating the acid liquor water-soluble calcium vanadates, then quench from the quench residue, mixing the acid liquor ing the roast in water which does not contain with the quench liquor until the mixed liquors essential quantities of acid or alkaline vanadium are slightly acid and calcium sulphate is pre solubilizing reagents and at a temperature at 10 cipitated, filtering off the calcium sulphate, and which a large proportion of the water-soluble cal mixing a further quantity of the acid liquor with cium vanadates are still retained in water-solu the ?ltrate from the calcium sulphate, and heat ble form, and separating the soluble calcium ing them to precipitate vanadium oxide. vanadates from the residue. , 16. In a process for recovering vanadium from 14. In a process for recovering vanadium val 15 material containing vanadium and alkaline ues from materials containing vanadium and earth metal compounds, the steps comprising alkaline-earth metal compounds, the steps com roasting the material at a temperature at which prising roasting the materials without essential the alkaline-earth metal and vanadium com additions of alkali-metal compounds which would pounds react to form water soluble alkaline-earth combine with the vanadium content to form metal vanadate, quenching the roast at or near water-soluble alkali-metal vanadates and at a the temperature of the roast in water, separating temperature above that at which, upon heating, the quench residue from the quench liquor water-insoluble alkaline-earth metal vanadates leaching the quench residue with a solution of are transformed into water-soluble alkaline; sulphuric acid, separating the acid liquor from earth metal vanadates, then quenching the roast 25 the quench residue, mixing the acid liquor with in water which does not contain essential quan the quench liquor until the mixed liquors are tities of acid or alkaline vanadium-solubilizing slightly acid and alkaline-earth metal sulphate reagents and at a temperature at which a large is precipitated, ?ltering 01f the alkaline-earth proportion of the water-soluble alkaline-earth metal sulphate, and mixing a further quantity of metal vanadates are still retained in water-solu 30 the acid liquor with the ?ltrate from the alkaline ble form, and separating the soluble alkaline earth metal sulphate, and heating them to pre earth metal vanadates from the residue. cipitate vanadium oxide. 15. In a process for recovering vanadium from materials containing vanadium and calcium com JOHN ROBERTSON. pounds, the steps comprising roasting the ma 35 HQLBERT EARL DUNN. terial at a temperature at which the calcium ARCHIBALD ALEXANDER SPROUL.