Thermal stabilization of chromium slag by sewage sludge: Effects of sludge quantity and temperature  

作　　者：Changlin Wu,Hua Zhang,Pinjing He,Liming Shao State Key Laboratory of Pollution Control and Resources Reuse,Key Laboratory of Yangtze River Water Environment,College of Environmental Science & Engineering,Tongji University,Shanghai 200092,China. 

出　　处：《Journal of Environmental Sciences》2010年第7期1110-1115,共6页环境科学学报（英文版）

基　　金：supported by the National High-Tech Research and Development Program (863) of China(No. 2007AA061300);the International Cooperation Project of Science and Technology Commission of Shanghai Municipality (No. 08230707000)

摘　　要：To investigate the feasibility of detoxifying chromium slag by sewage sludge, synthetic chromium slag containing 3% of Cr（Ⅵ） was mixed with sewage sludge followed by thermal treatment in nitrogen gas for stabilizing chromium. The effects of slag to sludge ratio （0.5, 1 and 2） and temperature （200, 300, 500, 700 and 900℃） on treatment efficiency were investigated. During the mixing process before thermal treatment, 59.8%-99.7% of Cr（Ⅵ） was reduced, but Cr could be easily leached from the reduction product. Increasing heating temperature and decreasing slag to sludge ratio strengthened the reduction and stabilization of Cr（Ⅵ）. When the slag to sludge ratio was 0.5 and thermal treatment temperature was 300℃, the total leached Cr and Cr（Ⅵ） declined to 0.55 mg/L and 0.17 mg/L respectively, and 45.5% of Cr in the thermally treated residue existed as residual fraction. A two-stage mechanism was proposed for the reduction and stabilization of Cr.To investigate the feasibility of detoxifying chromium slag by sewage sludge, synthetic chromium slag containing 3% of Cr（Ⅵ） was mixed with sewage sludge followed by thermal treatment in nitrogen gas for stabilizing chromium. The effects of slag to sludge ratio （0.5, 1 and 2） and temperature （200, 300, 500, 700 and 900℃） on treatment efficiency were investigated. During the mixing process before thermal treatment, 59.8%-99.7% of Cr（Ⅵ） was reduced, but Cr could be easily leached from the reduction product. Increasing heating temperature and decreasing slag to sludge ratio strengthened the reduction and stabilization of Cr（Ⅵ）. When the slag to sludge ratio was 0.5 and thermal treatment temperature was 300℃, the total leached Cr and Cr（Ⅵ） declined to 0.55 mg/L and 0.17 mg/L respectively, and 45.5% of Cr in the thermally treated residue existed as residual fraction. A two-stage mechanism was proposed for the reduction and stabilization of Cr.

关 键 词：chromium slag sewage sludge reduction DETOXIFICATION thermal treatment leached concentration 

分 类 号：X703[环境科学与工程—环境工程]