METHOD OF BISMUTH NITRATE BASIC PRODUCING Russian patent published in 1999 - IPC

FIELD: chemical technology, rare metal hydrometallurgy. SUBSTANCE: invention relates to methods of processing bismuth-containing substances to obtain bismuth compounds. Metallic bismuth is oxidized at 320-730 C by addition of bismuth oxide (15-30 wt.%) to its melt. Then obtained bismuth oxide is dissolved in nitric acid. Then bismuth is subjected for hydrolytic treatment by addition of sodium hydroxide solution or water at pH 0.5-1.4 and at 40-90 C. Precipitate is washed out with water and dried at 80-120 C. Invention ensures to decrease nitric acid consumption by two-fold, eliminate nitrogen oxides evolving in atmosphere, decrease process time and obtain product no containing lead and iron. EFFECT: improved method of producing. 2 tbl, 3 ex