Separation and refining method of arsenic trioxide

Abstract

The invention relates to a separation and refining method of arsenic trioxide. According to the method, a arsenic trioxide crude product is used as raw material and undergoes the following steps: (1) esterification reaction; (2) solid-liquid separation; (3) adsorption and impurity removal; (4) solid-liquid separation; (5) rectification and impurity removal; (6) hydrolysis-crystallization; (7) solid-liquid separation; (8) washing; (9) dehydration; and (10) drying. Thus, high-purity arsenic trioxide is obtained. The separation and refining method has the following advantages: process flow is short; the separation and refining method is simple; product purity is high; quality is stable; the process is safe and reliable; energy consumption is low; the amount of ''three wastes (waste gas, waste water and industrial residue)'' is small; and the separation and refining method is a clean production method which is adopted for the preparation of high-purity arsenic trioxide and accords with development requirements of the green chemical industry.

Description

technical field [0001] The invention relates to a method for separating and refining diarsenic trioxide, in particular to a method for obtaining a high-purity arsenic trioxide product by separating and refining crude diarsenic trioxide as a raw material through esterification-rectification-hydrolysis-crystallization coupling technology, belonging to the technical field of fine chemicals. Background technique [0002] 1.1 Properties and uses of arsenic trioxide [0003] Arsenic trioxide, commonly known as arsenic, also known as anhydrous arsenic acid, arsenic, white arsenic, arsenous anhydride; English name is arsenic trioxide; arsenous acid anhydride; molecular formula As 2 o 3 , white powder or crystal. There are three crystal forms: monoclinic crystal with a relative density of 4.15 and sublimation at 193°C; cubic crystal with a relative density of 3.865; amorphous body with a relative density of 3.738 and a melting point of 312.3°C. Arsenic trioxide is slightly soluble...

AI Technical Summary

Problems solved by technology

[0016] (1) High impurity content and unstable product quality: the material processed by sublimation method in the whole production process is solid phase or gas-solid material, and the obtained arsenic trioxide product usually has high impurity content and unstable product quality

[0017] (2) Low production efficiency: the sublimation method utilizes the easy sublimation characteristics of solid diarsenic trioxide to remove impurities in diarsenic trioxide

Affected by the sublimation area, the heat and mass transfer rate of solid phase materials or gas-solid phase materials is small, so the production efficiency is low

[0018] (3) Large energy consumption: In the separation and refining process of the sublimation method, in order to increase the sublimation rate, it needs to be carried out at a high temperature, and the gas phase material after sublimation must be cooled to increase the yield of the product, so the material must be heated and must be heated. Cool down, resulting in large energy consumption and low energy utilization

[0019] (4) Large amount of waste gas treatment: In the separation and refining process of the sublimation method, in order to increase the sublimation rate and protect the product, it is usually necessary to complete the sublimation and sublimation material collection process under certain atmospheric conditions, and a large amount of waste gas must be treated for recycling. or standard discharge

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