Process for removing arsenic in process of preparing anhydrous hydrogen fluoride by fluosilicic acid method

Abstract

The invention relates to the technical field of arsenic removal of anhydrous hydrogen fluoride, in particular to a process for removing arsenic in the process of preparing anhydrous hydrogen fluorideby a fluosilicic acid method, which comprises the following steps of: 1, pre-purifying fluosilicic acid; 2, pre-oxidizing trivalent arsenic in fluosilicic acid; 3, carrying out further catalytic oxidation on trivalent arsenic by using microporous filtration II hydrogen peroxide; 4, treating the materials with a concentration and reaction system; 5, screening silicon dioxide; 6, gasifying and decomposing the material; 7, treating the material through a hydrogen fluoride reboiling system and a drying separation system. The method has the beneficial effects that hydrogen peroxide and manganese dioxide can be added as catalysts under the conditions of normal temperature and acidity to oxidize arsenic in fluosilicic acid into pentavalent arsenic; since a small amount of trivalent arsenic cannotreact with hydrogen fluoride to generate arsenic trifluoride difficult to separate under the condition that the boiling point of arsenate is 160 DEG C, the oxidation operation and cost are low, large-batch production is facilitated, and the obtained anhydrous hydrogen fluoride is high in purity and small in harm.

Description

technical field [0001] The invention relates to the technical field of arsenic removal of anhydrous hydrogen fluoride, in particular to a process for removing arsenic in the process of preparing anhydrous hydrogen fluoride by a fluorosilicic acid method. Background technique [0002] At present, the products obtained from the production of anhydrous hydrogen fluoride from fluosilicic acid all have high impurity content. There are some research reports on the removal of impurities, but there are few cases of industrial removal. Wengfu Lantian Company is the exclusive unit to realize the industrial application of fluosilicic acid to anhydrous hydrogen fluoride technology. Impurities will affect product quality and are not conducive to the use of products in various downstream industries of hydrogen fluoride. Removing impurities from anhydrous hydrogen fluoride is a common problem in the industry. The use of hydrogen fluoride to produce other fluorine salts and fluorine-contain...

AI Technical Summary

Problems solved by technology

[0003] The arsenic content of the raw material fluorosilicate currently supplied is relatively high, and can contain more than 50ppm when it is high. 3 form exists

Arsenic in anhydrous hydrogen fluoride generally exists in the form of trivalent ions, while AsF 3 It is very close to the boiling point of hydrofluoric acid, which is 57.8°C under normal pressure. After the arsenic compound enters the rectification, it is difficult to effectively separate it only by rectification, resulting in a high content of As in the product.

Images