Method for preparing arsenic trioxide by utilizing arsenic sulfide residues

Abstract

The invention discloses a method for preparing arsenic trioxide by utilizing arsenic sulfide residues. The method comprises the following steps: oxidizing arsenic sulfide residues with hydrogen peroxide under atmospheric conditions, filtering and collecting the filtrate; oxidizing the arsenic sulfide residues with the filtrate, and filtering and collecting the filtrate; evaporating and concentrating, cooling and crystallizing, thereby obtaining the arsenic trioxide. According to the method disclosed by the invention, the arsenic sulfide residues are oxidized with the hydrogen peroxide, the operation is rapid and efficient, the arsenic sulfide residues are oxidized with the product, heat produced by the oxidization process of the hydrogen peroxide is favorable for latter reactions, any newimpurity is not introduced in the whole process, and the purity of the obtained arsenic trioxide is higher than 99%. The filtrate containing pentavalent arsenic doped with specific residual hydrogen peroxide is oxidized again, and the reaction temperature and the concentration of arsenic sulfide in the reaction system are controlled, so that the oxidizing reaction efficiency can be effectively improved, and the recycling rate of the arsenic sulfide can be effectively improved by controlling the content of SO4<2-> in the recycled arsenic sulfide residues; secondary pollution in the process is avoided, high-pressure equipment is not needed, the cost is reduced, the conditions are simple and mild, and the application prospects are excellent.

Description

technical field [0001] The invention belongs to the technical field of resource waste recycling, and relates to the recycling technology of arsenic sulfide slag, in particular to a method for preparing arsenic trioxide by using arsenic sulfide slag. Background technique [0002] Non-ferrous metal smelting ores are mainly sulfide ores. During pyro-smelting (including drying, sintering, roasting, smelting, blowing, fuming, volatilization, casting, etc.), a large amount of flue gas containing sulfur dioxide will be produced. The smelting flue gas is mainly It is used to prepare sulfuric acid; at the same time, smoke is also carried in the flue gas. In order to ensure the quality of sulfuric acid, impurities such as smoke and dust must be removed from the flue gas. Flue gas is usually treated by a combination of dry and wet methods. Wet dust collection makes the dust and water fully contact, and impurities such as arsenic dust, sulfur trioxide, fluorine, and chlorine in the flue...

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Problems solved by technology

[0004] At present, there are two main methods for preparing arsenic trioxide from arsenic sulfide slag: (1) fire treatment such as redox roasting to recover arsenic in the form of arsenic trioxide, which has the advantages of mature technology and short process, but there is environmental pollution Serious, high investment costs and other shortcomings have been basically eliminated; 2) wet treatment, wet treatment in the prior art mainly includes copper sulfate replacement method, oxygen pressure leaching method, alkali leaching method and high iron sulfate method, etc., but these There are still many shortcomings in the method, such as the consumption of copper powder in the copper sulfate replacement method is large, the copper recovery is difficult, and the cost is high

[0005] The arsenic sulfide slag is leached by oxygen pressure leaching, and then passed through a reducing agent such as SO 2 Preparation of arsenic trioxide by reduction, but the oxidation efficiency is low, and the high-salt process requires high equipment, and new impurities need to be introduced, which will affect the quality of arsenic trioxide, and further purification is required

Alkaline leaching method is incomplete and the consumption and price of sodium hydroxide are high. The process of ferric sulfate method is complicated and costly. The iron in the prepared arsenic trioxide is easy to exceed the standard, which makes the purity and whiteness difficult to meet the requirements.

[0006] The Chinese invention patent application with the application number 201710203220.8 discloses a process for extracting arsenic from arsenic sulfide waste residue by an all-wet method. Specifically, oxygen is used to perform high-pressure leaching of arsenic filter cake, and then the arsenic filter cake is used to reduce the oxygen pressure leaching solution to prepare arsenic trioxide. However, there are also high oxygen pressure leaching temperatures, low leaching efficiency, and the need to use high-pressure equipment, which requires high equipment investment.

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