Recovery of bismuth from chloride process solutions.
Flynn-CM Jr.; Carnahan-TG; Lindstrom-RE
U S Pat 4 285 912 1981 Aug; :
Bismuth is recovered from a complex chloride leach solution by adding a stoichiometric amount of a precipitating agent such as hexammine cobalt(III) salts or hexammine chromium(III) salts to precipitate bismuth as a hexammine cobalt(III) bismuth salt or a hexammine chromium(III) bismuth salt. The precipitate is separated from the solution. Thus, 1 l of chloride leach solution containing Cu 25, Fe 90, Zn 2, Pb 0.6, and Bi 0.37 G/l at ph 2 and 20 deg C was treated with 0.55 G Co(NH3)6Cl3 in 15 ml H2O. The precipitated Co(NH3)6BiCl6 was flocculated, centrifuged, washed with 3-pct HCl, slurried with water, and treated with CaO to ph 10-11. The resulting mixture was centrifuged to recover Bi2O3 and CO(NH3)6Cl3- CaCl2 solution. Bismuth recovery was 90 pct and that of the cobaltammine was 85 pct. Copper precipitation was 0.03 g Cu/g Bi.
U.S. Pat. 4,285,912, Aug. 25, 1981; Chem. Abstr. 96:38,813N