Process for treating hydroxide sludge residues containing nonferrous metals

摘要

A method for processing a hydroxide sludge residue to separate and recover the nonferrous metal values therefrom including the steps of (1) concentrating the residue and acidifying and heating the concentrated residue to produce a solution containing the nonferrous metal values; (2) removing the copper from the solution by liquid-liquid extraction; (3) separating the chromium, aluminum, residual portions of iron, as well as the remaining calcium from the copper-free solution by high temperature pressure hydrolysis to obtain the metals as the hydrated oxides or basic sulfates; (4) removing zinc and nickel from the remaining solution by liquid-liquid extraction; (5) processing the individual nonferrous metal fractions to isolate and recover the metal values in a conventional manner. By using this process, the nonferrous metal values can be easily separated in a relatively high state of purity from the hydroxide sludge wastes.