PROCESS OF PREPARING LOW-IRON AMMONIUM ALUM

摘要

A process is disclosed for preparing low-iron ammonium alum from an aqueous ammonium alum solution which contains Fe3+ ions. This aqueous ammonium alum solution which has a pH not in excess of 5, is passed through at least one electrolytic cell to reduce at least one half of the Fe3+ ions in the solution to Fe2+ ions. The solution is cooled and ammonium alum is crystallized whereas the Fe2+ ions remain in the liquid phase.