GB639123A - Treating magnesium bearing brines - Google Patents

Abstract

<PICT:0639123/III/1> In precipitating magnesium hydroxide from brines, by the addition of lime-bearing reactant, the magnesium ion content of the reacting solution is continuously diluted, e.g. to 0.01-0.8 grms. litre, by adding a magnesium ion-free mother liquor with precipitate resulting from a previous reaction, the amount of lime &c. added to the diluted solution being such that the indicated pH of the reacting mass is 9.6-11.5 for sea water and 9.8-12.5 for low sodium-content brines, thickening and filtering. In one method of operation, brine flows sequentially through a series of agitator tanks, slaked and classified lime or calcined dolomite being fed thereto, the feed to the first tank being optional. Part of the unseparated reaction slurry is passed from the last tank of the series to the first. The brine may be first softened with lime in an apparatus of the kind disclosed in Specification 545,913, [Group I]. Another magnesium precipitation plant comprises a tank 70 to which the (softened) brine is delivered through rotating apertured radial arms 71. The arms carry vertical V-sectioned blades 75 having interposed between them stationary V-sectioned baffles 76. The lime is supplied through pipes 85-88, and the reaction liquor is circulated by pump 81, the effluent escaping into launder 79 and through pipe 27. Reference has been directed by the Comptroller to Specification 640,348.