Process for removing iron(III) from acid zinc salt solutions by solvent extraction

摘要

Iron(III)-containing acid zinc liquors are, to separate the iron(III) ions from aqueous acid zinc liquors, treated with primary aliphatic amines and an organophosphonic monoester which functions as extraction agent. The solvent loaded with iron(III) ions is subsequently freed of accompanying metallic impurities and of iron(III) ions in two re-extraction steps by treatment with mineral acids or with aqueous solutions of the salts of such mineral acids. The organic phase purified of iron(III) ions is then again used for extraction. From the iron(III)-enriched re-extraction solution, an iron(III) compound can be obtained by a drying process or hydrolysis reaction, with the solution freed of the iron(III) compound being regenerated for multiple use in the re-extraction.