Method for refining bismuth from bismuth oxide slag

Abstract

The invention discloses a method for refining bismuth from bismuth oxide slags. The bismuth oxide slags and reduction agents are subjected to reduction smelting, liquation decoppering, primary lead removal through chlorine, vacuum distillation for silver removal, secondary lead removal through chlorine, high-temperature refining for dechloridation, and caustic soda flakes adding for tellurium removal, and finally refined bismuth is obtained. Alloy containing silver, copper, bismuth, lead and the like directly enters the decoppering procedure, wet pretreatment is omitted, the decoppering procedure is simplified, copper matte and silver-zinc crusts are prevented from being generated, the usage amount of nitric acid in a wet section is reduced, emission of nitric oxide in the nitric acid dissolving process is reduced, and pollution to the environment is reduced; after a zinc adding and silver removal technique is changed into the vacuum distillation for physical silver removal technique, the silver-zinc crusts which are difficult to treat are eradicated, physical separation of silver and bismuth is achieved to the maximum extent, and the recovery rate of silver is increased; and the usage amount of coal gas and auxiliary materials is reduced, the labor intensity of workers is relieved, the production period of the refined bismuth is shortened, the production cost of the refined bismuth is reduced, and the direct recovery rate and the recovery rate of the refined bismuth are increased.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, in particular to a method for refining bismuth from bismuth oxide slag. Background technique [0002] Smelters use bismuth oxide slag as raw material to produce refined bismuth. At present, there are two common production processes, one is the smelting process of wet method first and then pyromethod, and the other is pyrometallurgical smelting process. [0003] The smelting process of wet method first and fire method uses bismuth oxide slag as raw material. After ball milling, hydrochloric acid is added for leaching. The leaching slag is returned to the anode slime smelting system for silver recovery. The leaching solution is neutralized to obtain bismuth oxychloride and after neutralization Liquid, bismuth oxychloride is put into the converter to be reduced and smelted, press-filtered, and dried to become coarse bismuth. Chlorine gas removes lead and zinc, and refined bismuth is obtained aft...

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