METHOD OF SULPHATE-ION ABSORPTION IN METAL CHLORIDE AQUEOUS SOLUTIONS Russian patent published in 2008 - IPC C01D3/16 C01F11/46 

FIELD: chemistry.

SUBSTANCE: method of sulphate-ion absorption in metal chloride aqueous solutions by reaction of sulphate-ions with calcium chloride at higher temperature with following precipitation and removal of solid calcium sulphate. Calcium chloride source is production residue of calcium chloride, containing calcium chloride within 15-38 mass % and water-insoluble substances within 2-55% of residue weight. Production residue of calcium chloride is coagulated sludge chloride calcium suspension of mass fraction of calcium chloride within 25-38% and mass fraction of water-insoluble substances within 2-14 % or filter cake, produced by filtering of sludge chloride calcium suspension and containing calcium chloride within 15-30 mass % and water-insoluble substances within 20-55 mass %, or mixed specified sludge suspensions and specified filter cake.

EFFECT: invention allows for widening of process raw materials sources and for elimination of gypsum precipitation on process equipment.

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