| 摘要 |
Metals with a specific gravity greater than 4 are recovered from solutions, in which the metal is present as a cation, by contacting with a cation exchange resin having a cross-linked matrix and having bonded to said matrix acid groups as cation exchanging groups, said matrix being obtained by copolymerizing (1) a monoethylenically unsaturated monomer and (2) a polyethylenically unsaturated cross-linking agent which is copolymerizable with said monoethylenically unsaturated monomer, the copolymerization being conducted in solution in from 10 to 300%, based on the total weight of said polymer and said cross-linking agent, of an inert organic liquid which will dissolve the monomers but will not dissolve linear polymers of the monoethylenically unsaturated monomer, to produce a solid cross-linked non-proliferous copolymer linked by small veins, which veins have inert organic liquid occluded therein, and removing the occluded liquid from the polymer. Such resins are described and claimed in Specification 894,391. The resin may have as cation exchanging groups carboxylic acid, phosphonic acid, or phosphinic acid groups. The resin may be regenerated by the use of dilute solutions of mineral acids or of organic acids, for example acetic acid. Metals which may be recovered by the present process include Cu, Ag, Au, Zn, Ni, Co, Cr, U, Th, and the rare earths. The solutions employed contain these metals as cations or cationic complexes, preferably at a concentration of normal or below. The anions may be organic or inorganic acids, for example HCl, HBr, HF, H2SO4, H2SO3, HNO3, HCN, thiano-acetic, propionic, benzoic, citric or tartaric acid. Suitable complex formers include ammonia and amines, for example ethylene diamine, diethylene triamine, and propylene diamine. The pH of the solution is preferably at least 4, especially in the range 5-12. In examples, copper is recovered from a solution of cuprous chloride in ammonia and ammonium acetate, employing acetic acid for regeneration, from a Cu11 solution in ammonia, employing H2SO4 for regeneration, and Ni and U were recovered from acetate solutions, employing acetic acid for regeneration. Specifications 789,952 and 794,793 also are referred to. |
