Method for producing anhydrous hydrogen fluoride and coproducing silica white from low-grade fluorine resources

Abstract

The invention discloses a method for producing anhydrous hydrogen fluoride and coproducing silica white from low-grade fluorine resources, which comprises the following steps: carrying out ammonolysis on a phosphate fertilizer byproduct fluosilicic acid solution to obtain an ammonium fluoride solution and silicon dioxide, washing the filter cake, and drying to obtain the silica white product, wherein the filtrate ammonium fluoride solution is used for the next production step; concentrating the ammonium fluoride solution, and carrying out pyrolysis to obtain an ammonium bifluoride solution and ammonia gas, wherein the ammonium bifluoride solution is used for the next production step, and the ammonia gas is used for ammonolysis of the fluosilicic acid solution; reacting the ammonium bifluoride solution and sodium fluoride to generate a sodium bifluoride slurry, and drying the filter cake to obtain sodium bifluoride, wherein the filtrate ammonium fluoride solution can be recycled; and carrying out pyrolysis on the sodium bifluoride to obtain crude anhydrous hydrogen fluoride and sodium fluoride, and purifying the anhydrous hydrogen fluoride to obtain the anhydrous hydrogen fluoride product, wherein the sodium fluoride can be recycled. The method disclosed by the invention has the advantages of accessible raw materials, low price, simple production technique and lower cost for the anhydrous hydrogen fluoride product, solves the bottleneck of environmental protection in the development of low-grade fluorine resource industry, and does not generate secondary pollution in the production process.

Description

technical field [0001] The invention relates to the technical field of production of inorganic chemical products, in particular to a method for producing anhydrous hydrogen fluoride and co-producing white carbon black by using low-grade fluorine resources. Background technique [0002] As a basic fluorine chemical product, hydrogen fluoride is mainly used in the production of refrigerants, fluorine resins, fluoride salts, fluorine rubber, fluorine-containing intermediates and fine chemicals, with broad market prospects. At present, the production methods of hydrogen fluoride in the world are almost all fluorite-sulfuric acid method. As a strategic resource, fluorspar has limited reserves and is a non-renewable natural mineral resource. It cannot be replaced or completely replaced in most application fields. According to statistics, in the next 20 years, the domestic demand for fluorspar will be about 37 million tons, while the current domestic reserves of fluorspar rich in ...

AI Technical Summary

Problems solved by technology

However, the disadvantages of the current method of producing hydrogen fluoride with fluorosilicic acid solution are: first, the conversion is incomplete, and the main content of hydrogen fluoride is low; second, the problem of equipment corrosion has not been fundamentally solved; third, the energy consumption is relatively high, and industrialization is uneconomical ; Four, secondary pollution is likely to occur in the production process

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