Method for removing cadmium and ferrum from crude antimony by using metaphosphoric acid

Abstract

The invention discloses a method for removing cadmium and ferrum from crude antimony by using metaphosphoric acid. The method is carried out according to the following steps that: the metaphosphoric acid is added into a metallurgical furnace containing crude antimony liquid, and the furnace is continuously heated to melt the metaphosphoric acid, so that the metaphosphoric acid can cover on the surface of the antimony liquid; then, a blowing pipe is inserted into the antimony liquid to blow, the cadmium in the antimony liquid is oxidized into cadmium oxide, the temperature of the furnace is maintained, the continuous blowing is carried out, the cadmium oxide and the ferrum in the antimony liquid react with the metaphosphoric acid covering on the surface of the antimony liquid to produce cadmium metaphophate and ferrum metaphophate respectively, and the cadmium metaphophate and the ferrum metaphophate scarify with the metaphosphoric acid and float on the surface of the antimony liquid so as to realize the separation of the cadmium and the ferrum from antimony; and finally, the scum floating on the surface of the antimony liquid is removed. The method for removing the cadmium and the ferrum from the crude antimony, disclosed by the invention, belongs to an originate at home and abroad, the effect of cadmium and ferrum removal is good, the process flow is simple, the operation is convenient, the production cost is low, the pollution of environment cannot be generated, the production practicality is strong, considerable economic benefits are produced, and meanwhile, excellent environmental benefits are also brought.

Description

technical field [0001] The invention relates to the field of antimony pyrometallurgy, in particular to a method for removing cadmium and iron in crude antimony with metaphosphoric acid. Background technique [0002] my country is a big country producing antimony, and the output of refined antimony accounts for more than 60% of the world. Refined antimony is refined from crude antimony. For the refining of crude antimony, it has been used at home and abroad. In the 1930s, Professor Zhao Tiancong, an expert in antimony metallurgy in my country, The invented soda blowing oxidation refining method (hereinafter referred to as alkali method). Crude antimony can remove arsenic, selenium, sulfur, iron and other impurity elements through alkaline refining, making it a qualified refined antimony product, but it cannot remove cadmium in crude antimony. The difficulty in removing cadmium in crude antimony by pyrometallurgy lies in: cadmium In antimony liquid, it dissolves with antimony...

AI Technical Summary

Problems solved by technology

[0003] Cadmium is a harmful element in refined antimony products. Although the antimony standard promulgated by the state in 2001 has no quantitative regulations on cadmium, it has become an unwritten rule that the cadmium content in refined antimony should not exceed 0.002% in antimony trade at home and abroad. According to regulations, some antimony raw materials with high cadmium content cannot be used and stockpiled, which brings great harm to environmental protection, and makes it impossible to refine crude antimony with excessive cadmium content into qualified refined antimony products

Many antimony metallurgists have done a lot of research work on the removal of cadmium from crude antimony, and some people have tried to use wet methods to separate cadmium and antimony, but they have not been applied due to high production costs and poor separation effects.

Alkali refining has a good effect in removing iron in crude antimony, but the key points of operation are difficult to grasp. It is often necessary to use the method of cooling and removing iron to make the iron content in crude antimony reach the standard. It takes 4-5 hours to complete this process

Images