CALCIUM FLUORIDE SYNTHESIS METHOD AND DEVICE FOR REALISING SAID METHOD Russian patent published in 2010 - IPC C01F11/22 

FIELD: chemistry.

SUBSTANCE: invention can be used in metallurgy and in making protective coatings of welding electrodes. The calcium fluoride synthesis method involves reaction of a solution of hydrofluosilicic acid with a calcium carbonate suspension, holding the reaction mixture, separation of calcium fluoride suspension and drying the product. Calcium carbonate is first mixed with water. Hydrofluosilicic acid is added and a calcium fluoride suspension is obtained. Part of the obtained suspension is separated and added to calcium carbonate suspension as a nucleating agent, and the remaining part of the suspension is filtered and calcium fluoride residue is separated. The calcium carbonate suspension is then mixed with the calcium fluoride nucleating agent and treated with hydrofluosilicic acid. Further, the calcium fluoride nucleating agent and calcium fluoride residue are separated. The nucleating agent is taken in amount of 15-30% of the output of the end product. Final pH of the reaction mixture before separating the calcium fluoride residue must be equal to 5-7. The calcium carbonate suspension is prepared while maintaining the ratio of solid to liquid in the range 1:(2-4.5) based on part of the clear solution obtained during separation of calcium fluoride residue, and the rest of the clear solution is taken for hydrofluosilicic acid synthesis. A calcium fluoride synthesis device is proposed.

EFFECT: invention enables to obtain calcium fluoride with minimal content of impurities, which contains not less than 98 wt % of basic material and increase environmental safety of production.

13 cl, 4 dwg, 2 ex