The present situation of production technology of China's crystal crystal industry

The production process of cryolite has many kinds, and the classification of fluorine source is mainly fluorite and phosphorus fertilizer.
According to the characteristics of reaction, acid method and alkali method were classified.
In addition, there are ammonium fluoaluminate, aluminum industry and electrolytic aluminum recycling, and fluorine waste gas.
Fluorite method is the main raw material of sulfuric acid and fluorite (CaF2), which can be used to synthesize hydrogen fluoride through acid solution, and then synthesize the cryolite by hydrogen fluoride.
According to the state of the use of hydrogen fluoride, which is divided into wet and dry, wet process for the traditional classic craft, mature technology, but the quality is not high, pollution is serious, mainly have a soda ash fluorine aluminate, clay a bittern a sodium sulfate, sodium aluminate, kaolin (glauber's salt), etc.;
The dry reaction conditions are high, but the product quality is high and the pollution is small.
The method of phosphate fertilizer is used to synthesize the crystal stone.
There are two broad categories: fluorosilicate and sodium fluorosilicate.
The fluorosilicic acid method can be divided into direct method and ammonia method according to the process route, and the method of sodium aluminate (also known as the yugoslav law).
Sodium fluorosilicate method can be divided into pure alkali monosodium aluminate method (also known as carbonization method), ammonia monosodium sulphate method and ammonia sodium aluminate method, HF 1 Al (OH) 3, a soda method, etc.
The ice crystals produced by the para production of phosphate fertilizer are higher than [n (NaF) : n (AlF3)], good quality, and high quality of white carbon black, and the comprehensive utilization of resources is high.
Ammonium fluoaluminate is a kind of patented technology with Chinese independent intellectual property rights.
This method is used to obtain the polymer by using the waste slag of aluminum profile industry as raw material and the caustic reaction of caustic soda.
The byproduct ammonia gas is absorbed by water or dilute hydrofluoric acid and can be used in the process of sodium fluorosilicate.
The advantages in ammonium aluminum fluoride acid instead of hydrofluoric acid and aluminum hydroxide, both to protect the limited fluorite and bauxite resources in China, and reduce the pollution of the environment, is a promising technique.
Electrolytic aluminum industry recovery method is a method to recover the crystal stone through a series of physical methods such as screening, flotation, filtration and drying.
Electrolytic aluminum industry in the process of production to produce fluoride waste residue, containing about 30% (mass fraction) of cryolite, 1% (mass fraction) of alumina and 1% (mass fraction) of calcium oxide and the rest for granular, graphite carbon, impurities such as aluminum and silicon oxide, carbide as raw materials, after the flotation cryolite recyclable parts.
The advantage of this method is that the fluorine resources are recycled and the valuable fluorite resources are saved.
The disadvantage is that after flotation, ice crystal has low content and high impurity content.