Issue 9, 2021 - Fluorine/phosphorus chemical green development new process successfully developed

Recently, the production process of fluorosilicic acid to anhydrous hydrofluoric acid co-produced silica independently developed by Polyfluoride Chemical Co.
, Ltd.
was selected into the "Petrochemical Green Process Directory (2020 Edition)"
.
The process uses fluorosilicic acid, a by-product of the phosphate fertilizer industry, as raw material to prepare anhydrous hydrofluoric acid, which greatly improves the utilization rate of fluorine elements and reduces the cost of raw materials, which is of great significance
for protecting fluorite resources and promoting the sustainable development of fluorine chemical and phosphorus chemical industries.

The process uses ammonium fluoride and sodium fluoride reaction to prepare sodium hydrogen fluoride, and then calcines sodium hydrogen fluoride at high temperature to prepare hydrofluoric acid, and anhydrous hydrofluoric acid
is prepared after rectification and impurities.
The final product index is better than the relevant national standards, the purity reaches 99.
99%, and the obtained anhydrous hydrofluoric acid product has less impurity content and stable
product quality.

In the process, ammonia water reacts with fluorosilicic acid to prepare ammonium fluoride, and the ammonia generated by the reaction is reused by absorption during the preparation of sodium hydrogen fluoride, and the ammonia recovery rate is greater than 96%; The remaining sodium fluoride after the decomposition of sodium hydrogen fluoride to prepare hydrofluoric acid is recycled for the synthesis of sodium hydrogen fluoride, and the loss rate is less than 1%; Fluorine element is converted by fluorosilicic acid-ammonium fluoride-sodium hydrogen fluoride-hydrofluoric acid, and the utilization rate of fluorine element is also greatly improved
.

The process can also produce anhydrous hydrofluoric acid while directly using silicon in fluorosilicic acid to produce higher quality silica
.
At present, the production process of anhydrous hydrofluoric acid co-production silica from fluorosilicic acid has reached a scale of
5,000 tons / year.