Crystallization method of ammonium fluoride or ammonium bifluoride

Abstract

The invention belongs to the technical field of compound production, and particularly relates to a crystallization method of ammonium fluoride or ammonium bifluoride. The method adopts an air-cooled spray cooling tower to crystallize, takes anhydrous hydrogen fluoride and liquid ammonia as raw materials, performs reaction in batches, monitors a reaction endpoint through a rapid acid-base titration method; and reacted materials are pumped to the top of a spray tower, fall from the top of the spray tower through a distributor, sequentially pass through two layers of demisters in opposite directions, reenter a circulating tank, are then cooled, and finally fed to a crystal growing tank for culturing, and separation is carried out to obtain a finished crystal product; and meanwhile, mother liquor is recycled after being subjected to solid-liquid separation, and tail gas is emptied after passing through the three-stage spray tower and the mother liquor. According to the invention, the air-cooled spray cooling tower is adopted for crystallization, a cooling speed is high, the yield of the finished product is high, and obtained crystal particles are uniform, compact and stable and meet the requirements of national standard first-grade products; and meanwhile, liquid and tail gas obtained in a production process are uniformly and intensively recovered and recycled, no waste liquid or waste residue is generated, and zero-emission production is basically achieved.

Description

technical field [0001] The invention belongs to the technical field of compound production, and in particular relates to a crystallization method of ammonium fluoride or ammonium bifluoride. Background technique [0002] Ammonium fluoride is a white needle-like crystal, easy to absorb moisture, soluble in cold water, slightly soluble in ethanol, decomposed into ammonia and hydrogen fluoride when heated, and decomposed into ammonia and ammonium bifluoride in hot water. Its aqueous solution is acidic and can corrode glass. Relative density 1.015, toxic, median lethal dose (rat, abdominal cavity) 32mg / kg, corrosive, can be used as chemical reagent, glass etchant (participating in hydrofluoric acid), disinfectant and preservative in fermentation industry, by oxidation Solvent for beryllium metal beryllium and surface treatment agent for silicon steel plates. It is also used in the manufacture of ceramics, magnesium alloys, cleaning and descaling of boiler feed water systems and ...

AI Technical Summary

Problems solved by technology

However, natural cooling crystallization takes a long time for crystallization, serious air pollution in open type, slow heat dissipation in closed type, and longer crystallization cycle. At the same time, the particle size of crystal particles formed by natural cooling crystallization is uneven and has large deviation

[0004] Simultaneously, ammonium bifluoride has stronger corrosivity, uses the crystallizer of conventional metal material, and equipment corrosion is serious, adopts I pass plastic material, and plastic thermal conductivity is poor, and heat transfer efficiency is low

In the patent CN201510159229.4, a pressurized atomizing spray tower is used to cool with air, but the material spray enters the top of the tower, and the air outlet is also located at the top of the tower, and the atomized small droplets are easily taken out of the spray tower by the air flow. Enter the exhaust system, reduce the yield of finished products

Even the material droplets carried out crystallize in the exhaust gas pipeline, which will cause pipeline blockage as the production batch increases

Images