METHOD OF CONCENTRATING EXTRACTION PHOSPHORIC ACID WITH SIMULTANEOUS OBTAINIG OF HYDROFLUOROSILICIC ACID Russian patent published in 2008 - IPC C01B25/00 C01B33/10 

FIELD: chemistry.

SUBSTANCE: invention pertains to concentration of extraction phosphoric acid through its evaporation, which can then later be used in the production of compound fertilisers, feed phosphates and phosphorous salts. The method allows for obtaining productional hydrofluorosilicic acid, which can be used in the production of different fluoric salts (aluminium fluoride, cryolite, silicon fluorides of sodium, potassium etc.). The method of concentrating phosphoric acid with simultaneous obtaining of hydrofluorosilicic acid involves vacuum evaporation and absorption of fluorine from juice vapour of a solution of hydrofluorosilicic acid while supplying it to the low phase contact zone with output of productional hydrofluorosilicic acid. At the absorption stage, the juice vapour is supplied at a speed of 65-200 m/s, and its speed in the phase contact zone is maintained at 35-110 m/s.

EFFECT: considerable lowering of power consumption of the process; increased degree of absorption of vapour with simultaneous increase in output of the process and concentration of hydrofluorosilicic acid.

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