BISMUTH CLEANING METHOD Russian patent published in 2015 - IPC C22B30/06 C22B9/05 C22B9/10 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy of less-common elements, namely to a method of deep bismuth cleaning. The method of deep bismuth cleaning from impurities, namely from impurities of lead and chlorine involves chlorination of bismuth melt by bubbling with a mixture of carbon tetrachloride and inert gas at 550-600°C and flow rate of carbon tetrachloride of 2-4 ml per 1 kg of refined bismuth with inert gas consumption of 30-35 l/h. After chlorination is completed, bubbling of bismuth melt with inert gas is performed. Then, additional bubbling of the melt is performed with a mixture of ethyl alcohol and inert gas. Prior to bubbling of the melt with the mixture of inert gas and ethyl alcohol, first, refining slags are removed from the melt, and bubbling is performed at ethyl alcohol consumption of 5-8 ml per 1 kg of refined bismuth. Inert gas consumption is 30-35 l/h.

EFFECT: obtaining high-purity bismuth with reduced content of lead and chlorine.

2 cl, 2 tbl, 1 ex