Abstract

Chromium sulphate is used extensively in Sudanese tanneries, however its exhaustion in processing is limited and a considerable quantity is passed as waste to the drain with consequent risk of pollution and environmental hazard. In this investigation spent chromium liquor was concentrated by evaporation in a triple-effect evaporator. The concentrated liquor was blended with fresh make-up chromium and re-used in tannage. The advantage of this process, in addition to its economical and environmental benefits is the continuous recovery with closed-loop recycling without loss of chromium to the drain. A complete control system is recommended.