A method for preparing high-purity potassium fluoride and co-producing white carbon black with potassium fluorosilicate

Abstract

The invention relates to a method for preparing high-purity potassium fluoride and co-producing white carbon black by adopting potassium fluosilicate by adopting potassium fluosilicate. The method provided by the invention comprises the following steps of: firstly carrying out an ammonolysis reaction on ammonia water and potassium fluosilicate to obtain mixed slurry of ammonium fluoride, potassium fluoride and silicon dioxide solid; filtering the mixed slurry, washing a filter cake, and then drying to obtain the white carbon black; adding potassium hydroxide into filtrate to carry out an alkaline hydrolysis reaction, so as to obtain a potassium fluoride solution, and absorbing ammonia gas discharged by a reaction and recycling the absorbed ammonia gas; and standing and settling the potassium fluoride solution, taking supernatant liquor and carrying out induced crystallization on the supernatant liquor, and filtering, washing and drying to obtain the potassium fluoride finished product. The method provided by the invention is low in cost, can effectively solve the problems of development and utilization of crude potassium fluosilicate and environmental protection and has good economic benefit and social benefit; the prepared potassium fluoride is high in purity, and the ammonia water is recycled in the whole reaction process, utilization rate of raw materials is high; and the method provided by the invention is simple in processing steps, no product harmful to the environment is produced, and production environment is friendly.

Description

technical field [0001] The invention relates to a method for preparing high-purity potassium fluoride and co-producing white carbon black by using potassium fluorosilicate, belonging to the technical field of inorganic chemical production. Background technique [0002] Potassium fluoride is an important inorganic compound, which is widely used in glass engraving, food antiseptic, electroplating and preparation of potassium hydrogen fluoride, etc.; in the field of welding, it is mainly used as a flux for various alloys or metal welding, and in the field of organic compound generation. As a fluorinating agent, it can also be used as an absorbent for absorbing hydrogen fluoride and water. In the field of pesticides, it is used to produce sodium fluoroacetate and ammonium fluoroacetate pesticides. In the field of medicine, it is used to prepare norfloxacin. Potassium fluoride is traditionally used The production method is to react hydrofluoric acid with potassium hydroxide as ra...

AI Technical Summary

Problems solved by technology

White carbon black, the scientific name of light silica, is mainly used as a dispersant for pesticides and firefighting, as a reinforcing agent for rubber and plastics; the traditional production method of white carbon black is the acid hydrolysis of water glass, but there are complex silicon dioxide in this method. Impurities such as acid polymers affect the quality of silica

[0003] Chinese patent document CN101049946 (application number: 200710065874.5) discloses a preparation method of high-purity potassium fluoride. The reaction solution is settled to induce crystallization to obtain the product potassium fluoride, but this method uses hydrogen fluoride gas and potassium hydroxide as raw materials, not only the production cost is high, but also the obtained potassium fluoride product has complicated post-processing procedures, low yield and low raw material utilization rate. Gao; Chinese patent document CN101376509 (application number: 200710055077.9) discloses a method for preparing potassium fluoride by using ammonium fluoride and potassium hydroxide as raw materials, but this method also has high production costs and is not suitable for wide application

Chinese patent document CN101134583A (application number: 200610106981.3) discloses a method for preparing potassium fluoride using fluosilicic acid and potassium hydroxide as raw materials, although the method uses fluosilicic acid as one of the raw materials to reduce production costs to a certain extent , but this method uses potassium hydroxide to react with fluosilicic acid to prepare potassium fluosilicate, and then decomposes fluosilicic acid at 300-800°C, not only reacting potassium hydroxide as one of the main raw materials, but the cost is high, Moreover, the reaction product potassium fluorosilicate is decomposed at a high temperature of 300-800°C to obtain potassium fluoride, which consumes a lot of energy.

[0004] The by-product crude potassium fluorosilicate in the process of defluorination and purification of wet-process phosphoric acid has low purity and contains soluble phosphorus, and its direct discharge will pollute the environment

At present, the by-product crude potassium fluorosilicate in the process of defluorination and purification of wet-process phosphoric acid has few utilization methods and has a great impact on the environment.