A process for softening water and removing iron and manganese therefrom by a base-interchange and a process for preparing the requisite agent therefor

摘要

286,307. Rosenheim, A. March 4, 1927, [Convention date]. Purifying liquids.-Water is treated to soften it and to remove iron and manganese by base exchange with silicic acid gel or a gel of a metal oxide such as stannic acid, titanic acid, alumina, chromic oxide, or ferrous or ferric oxide in which has been incorporated alkali or ammonium either by treatment with aqueous solutions of caustic alkalies or ammonia or of alkaline-reacting alkali metal or ammonium compounds, or by treatment with aqueous solutions of other bases such as lime, baryta, or strontia followed by treatment with a solution of an alkali metal compound such as common salt. As alkaline-reacting compounds, carbonates, borates, phosphates, cyanides, silicates, aluminates, stannates, and titanates are referred to. Impregnation with alkali may alternatively be effected with the sols from which the gels are to be formed. Aluminates, stannates or titanates may be added to the solutions prior to sol formation; and sols or gels to be treated may be mixed with an aqueous salt solution of a trivalent metal, for instance with ferric, chromic, or aluminium chloride, sulphate, or acetate, and a mixed gel be then obtained by treatment with sufficient alkali &c. Treatment of gels may be effected before or after drying. Specifications 26842/09, 9755/13, 100,638, 110,363, 142,974, 159,196; and 203,158, 206,267 and 263,198, [all in Class 2 (iii), Dyes &c.], are referred to. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the following subject-matter :-Untreated gels may be used directly to soften water in the presence of bases; and the impregnation thereof with alkali may take place at increased or reduced pressure. This subject-matter does not appear in the Specification as accepted.