Method for producing magnesium arsenate by using arsenic-containing waste liquid

Abstract

The invention relates to a method for producing magnesium arsenate by using arsenic-containing waste liquid. The arsenic-containing waste liquid produced in the acid-making process of non-ferrous metal smelting enterprises by adopting a 'pyrogenic-process smelting-smoke acid-making system' process is used as a raw material to produce the magnesium arsenate. Firstly, iron, zinc and copper are removed in sequence, then As<3+> in the liquid is oxidized into As<5+> and Mg<2+>, full compounding is performed to produce a Mg3(AsO4)2 crude product, and finally the Mg3(AsO4)2 crude product is purified to produce a magnesium arsenate product. The arsenic-containing waste liquid is treated while high-purity magnesium arsenate is produced, and the effects of saving energy, reducing emissions and recycling resources are achieved.

Description

technical field [0001] The invention relates to a method for producing magnesium arsenate from arsenic-containing waste liquid. Specifically, in the non-ferrous metal smelting industry, smelting enterprises adopt the "pyrometallurgical flue gas acid production system" to desulfurize and dearsenide the concentrate powder, and use the generated flue gas to produce sulfuric acid. In the flue gas scrubbing process, an acidic liquid containing arsenic is formed, and the invention relates to a method for producing magnesium arsenate by using such acidic liquid containing arsenic. Background technique [0002] Most of arsenic and its compounds are highly toxic substances and are easy to cause cancer. They are harmful to the human body and the environment, and belong to the first class of pollutants stipulated by the state. At present, non-ferrous metal smelting enterprises produce a large amount of arsenic-containing waste liquid in the production process. Lime is mainly used to n...

AI Technical Summary

Problems solved by technology

However, this method has the following defects: first, the neutralized slag produced during the disposal process is a hazardous waste; second, the Ca in the neutralized slag 3 (AsO 4 ) 2 Under certain conditions, anti-dissolution will occur, causing secondary pollution and requiring secondary treatment; the third is to build a special storage site for stacking hazardous waste, which requires a large amount of investment and occupies land resources; the fourth is the useful substances contained in the waste liquid be disposed together, resulting in waste of resources

But this method has the following major defects: the one, the reaction process is difficult to control, can not meet the production needs; the two, can not effectively remove the Mg(OH) contained in the product 2 Composition, Mg in the product 3 (AsO 4 ) 2 The content is low, generally lower than 60%; the third is that the synthesis time of magnesium arsenate is long and the production efficiency is low; the fourth is that a one-step method of removing impurities is adopted, and the element mixture such as Fe, Zn and Cu recovered by this method is not easy to purify