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...

AI Technical Summary

Problems solved by technology

[0005] The above two processes for producing refined bismuth with bismuth oxide slag as raw materials have the following disadvantages: 1. long production cycle, complex procedures, high labor intensity, and low direct yield of bismuth, generally below 70%; 2. bismuth refining process The output rate of various slags is high, and there are many re-invested materials; ③Copper is enriched in the form of matte, and the content of silver and bismuth in matte is relatively high, generally silver 5-10Kg / ton, bismuth 10-20%, silver The separation of copper and bismuth is not complete, and wet processing is still required; ④ The cost of smelting is relatively high. Generally, the processing fee for refined bismuth is more than 20,000 yuan. The benefit drops significantly; ⑤ When refining and removing silver, zinc ingots need to be consumed, generally 100 kg / ton of refined bismuth, and silver-zinc shells are produced after adding zinc ingots. Zinc cannot be recycled and reused, resulting in waste of resources. Chlorine gas removes zinc to form zinc chloride, which is difficult to recycle; nitrogen oxides that are difficult to handle are produced in the process of adding nitric acid to dissolve the alloy, and there is a certain pollution to the environment after discharge; Increased occupancy and inconvenient recycling

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