Method for sanitary production of sodium fluosilicate

Abstract

The invention discloses a method for sanitary production of sodium fluosilicate. Mirabilite is adopted by the method as raw materials to react with fluosilicic acid to form the sodium fluosilicate and dilute sulphuric acid. The dilute sulphuric acid is used as wet process phosphoric acid to filter dilute acid to digest. In the process of combination, firstly, water and the dilute sulphuric acid are added to the mirabilite, and then the mirabilite is put into a salt melting groove to dissolve, and after dissolving, the mirabilite contains sodium sulfate solutions ranging from 5% to 40%, and the mirabilite is put in a salt water groove to keep warm through steam to be used. Fluosilicic acid is added to a crystallization groove, and then sodium sulfate salt solutions are added to the crystallization groove, and so that sodium fluosilicate and the dilute sulphuric acid are prepared. After being filtered, the sodium fluosilicate and the dilute sulphuric acid are dried to prepare a sodium fluosilicate end product. The dilute sulphuric acid returns to a wet process phosphoric acid device to be used as washing water. The method for sanitary production of the sodium fluosilicate uses mother liquor which is generated in the production of the sodium fluosilicate as wet process phosphoric acid washing water, so that in the production of the sodium fluosilicate, pollution and sewage processing cost is not only reduced, but also in the process of extraction of the wet process phosphoric acid, consumption of sulfuric acid is simultaneously reduced. Therefore, production cost of the sodium fluosilicate and the wet process phosphoric acid is reduced.

Description

technical field [0001] The invention relates to compounds containing silicon, fluorine and other elements, in particular to a method for producing sodium fluorosilicate. Background technique [0002] A large amount of fluorine-containing gas is produced in the process of producing phosphoric acid from phosphate rock. At present, fluorosilicic acid is produced by absorbing it with water, and then processed into other products to recover fluorine resources from phosphate rock. Due to the reliable process and advanced equipment, the large-scale wet-process phosphoric acid plant can recover high-end fluorine chemical products such as anhydrous hydrogen fluoride and aluminum fluoride with a concentration of 18-20% of recovered fluosilicic acid. Most small and medium-sized wet-process phosphoric acid plants recover fluosilicic acid with a low concentration of only 8-12%, which cannot meet the raw material requirements of high-end fluorine chemical products. They are often directly...

AI Technical Summary

Problems solved by technology

Most small and medium-sized wet-process phosphoric acid plants recover fluosilicic acid with a low concentration of only 8-12%, which cannot meet the raw material requirements of high-end fluorine chemical products. They are often directly discharged to sewage treatment or used to produce sodium fluosilicate and other products, which causes resources Waste and increase the cost of sewage treatment

The traditional method of producing sodium fluorosilicate uses NaCl and fluorosilicic acid to generate sodium fluorosilicate and low-concentration hydrochloric acid. At present, there is no good way to use low-concentration hydrochloric acid, and it is often directly discharged to sewage treatment