METHOD FOR SYSTEM PROCESSING OF SEA WATER Russian patent published in 1997 - IPC

FIELD: sea water utilization. SUBSTANCE: method is aimed at recovering useful mineral components and producing sweet water. Method includes filtration through natural zeolite, isolation of calcium via passing filtrate through modified artificial zeolite in Na⁺ form, and magnesium isolation stage via passing solution through carboxylate cationite in Na⁺ form, regeneration of zeolites by concentrated sodium chloride solution followed by converting regenerate into lime, regeneration of cationite with soda solution followed by isolation of magnesium carbonate from regenerate, and concentrating sea water to produce secondary brines with subsequent isolation of sodium salts therefrom. These processes are supplemented with isolation of bromine, boron, and producing sweet water. The first process is performed after calcium isolation stage using electrosorption on modified activated carbon with metal hydroxides admixed, regeneration by way of passing sweet water, and subsequent processing of regenerate into magnesium bromide concentrate. Boron is isolated via passing solution from magnesium isolation stage through low-basic anionite in carbonate form followed by regeneration by soda solution and electrolytically isolating sodium perborate from regenerate. Sweet water production is accompanied with formation of secondary brines. Zeolites are regenerated with sodium chloride solution supplemented with no more than 0.2 g-equiv/l of sodium sulfate. Regeneration of carboxylate cationite is effected at temperature not exceeding 20 C, while regenerate, prior to be reprocessed, is heated to a temperature at least 35 C. Filtrates from calcium and magnesium carbonates and sodium perborate isolation stages are returned into zeolite, cationite, and anionite regeneration stages, respectively. EFFECT: increased number of recovered substances and produced sweet water. 5 cl, 4 dwg