Chemistry of inorganic compounds – Treating mixture to obtain metal containing compound – Group vib metal
Patent
1980-04-15
1981-11-03
Carter, Herbert T.
Chemistry of inorganic compounds
Treating mixture to obtain metal containing compound
Group vib metal
423 61, 423 65, 423 68, 423 55, 423 23, 423 27, 423138, 423150, 423 53, C01G 3100, C01G 3700, C01G 3900, C01G 4100
Patent
active
042985811
ABSTRACT:
Disclosed is a process for recovering chromium, vanadium, molybdenum, and tungsten from secondary resources such as alloy scrap comprising a refractory metal and base metals such as cobalt, nickel, iron, and copper. The scrap is calcined with sodium carbonate in air to convert the refractory metal values to MoO.sub.4.sup.=, VO.sub.4.sup..ident., WO.sub.4.sup.=, and CrO.sub.4.sup.= and the base metals to water insoluble oxides. A leach of the calcined materials produces a pregnant liquor rich in refractory metals which, after separation of the vanadium, molybdenum and tungsten values, is treated with CO, CHOO.sup.- CH.sub.3 OH, or HCHO to reduce Cr.sup.+6 to CR.sup.+3. The carbonate and bicarbonate salts produced as a byproduct of the reduction are recycled to the calcination stage.
As a result of the V, W, and Mo partition, a mixed solid comprising CaO.nV.sub.2 O.sub.5, CaMoO.sub.4, and CaWO.sub.4 is produced. This is treated with carbonated water or formic acid to selectively dissolve vanadium values which are subsequently recovered by precipitation or extraction. The remaining mixed CaWO.sub.4 and CaMoO.sub.4 solid is treated with H.sub.2 O.sub.2 and sulfuric acid to reject a Mo and W-free CaSO.sub.4 precipitate, and to produce a concentrated solution of tungsten and molybdenum. The W values are selectively precipitated from this solution by decomposing the peroxy complexes. The process has the advantages that a wide variety of different feed materials can be treated, no energy intensive pyrometallurgy is involved, reagent comsumption is minimized, and no aqueous effluents are produced.
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Douglas Donald A.
Menashi Jameel
Rappas Alkis S.
Cabot Corporation
Carter Herbert T.
Dropkin Robert F.
Schuman Jack
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