Bio-detoxification of chromite ore processing residue by column leaching

Column leaching detoxification experiments of chromite ore processing residue (COPR) with Leucobacter sp. Ch-1 were carried out based on the contamination circumstances of Changsha chromate factory and characteristics of COPR. The results indicate that before experiment COPR should be made into particles, and the optimal conditions are particle size of 4-8 mm, pH value of 10.0, and temperature of 30 ℃. Under the optimum conditions, the concentration of Cr(Ⅵ) in the leachate changes from 250.6 mg/L down to 0 mg/L after detoxification, which reaches national discharge standard of waste water, and the leaching toxicity of detoxified COPR with the value of 0.4 mg/L was also lower than the national standard of solid waste.