A new method for the treatment of chromite ore processing residues.

Chromite ore processing residue (COPR), derived from the so-called high-lime processing of chromite ore, contains a significant fraction of a leachable Cr(VI) which is harmful to human being and other organisms. In recent years, the concern over environmental pollution from the waste residue containing Cr(VI) has become a major problem for the chromium chemical industry. The main purpose of this investigation is to evaluate a new method for remediation of Cr(VI) in COPR. COPR was mixed with reductants, sucrose, starch or flour, and was calcinated at elevated temperatures in inertial gas. Effects of temperature, dosages of reductants and time on Cr(VI) reduction were investigated. Above 500 degrees C, Cr(VI) can be completely reduced to Cr(III).