METHOD FOR PROCESSING BISMUTH METAL TO OBTAIN BASIC BISMUTH OXALATE Russian patent published in 2022 - IPC C01G29/00 C22B30/06 C22B3/44 

FIELD: hydrometallurgy.

SUBSTANCE: invention relates to the hydrometallurgy of rare metals, namely, to a method for processing bismuth-containing materials to obtain bismuth oxalate of the basic composition Bi(C₂O₄)OH. Bismuth metal is dissolved in nitric acid at a concentration of 7 mol/L. Bismuth is purified from impurity metals to obtain bismuth nitrate of the main composition [Bi₆O₄(OH) ₄](NO₃)₆·H₂O by adding an aqueous solution of ammonium carbonate with a concentration of 2.5 mol/l to a solution of bismuth nitrate at a temperature of 55°C to pH 1. The mother liquor is separated from the precipitate by decantation and the precipitate is washed with a solution of nitric acid with a concentration of 0.1 mol/l at a temperature of 60°C. The precipitate of basic bismuth nitrate is mixed with water, oxalic acid is added to the mixture with stirring at a molar ratio of oxalic acid to basic bismuth nitrate equal to 6.0-6.6 and a temperature of 50-80°C. Bismuth oxalate basic is washed with water and dried.

EFFECT: method allows to reduce the volume of solutions sent for disposal by more than 3 times.

1 cl, 1 tbl, 3 ex