Chromium Recovery from Tannery Industry Wastes. Phase I

摘要

An experimental and analytical investigation is reported of the research requirements involved in developing a process to recover chromium from tannery wastes. Chromium present in such wastes is a serious problem because of its toxicity to humans and fish and its carcinogenic nature. Several tasks were performed: the potential waste resource was characterized; new and historical tannery wastes were sampled; laboratory wastes were tested to determine critical parameters necessary for developing a viable chromium recovery process; data obtained were evaluated in terms of developing an economical process; and areas requiring additional research were identified. The investigation indicates that a viable chromium recovery process can be developed based on acid leaching of waste sludges. This will require development of low cost techniques to dewater sludge prior to combustion. Key dewatering questions to be resolved include a better definition of the amounts of historical wastes associated with currently operating tanneries, determination of waste sludge rheology, determinations of the fate of trace elements in an integrated process, and development of a suitable technique to stabilize residues from the process for safe disposal.