2008 Volume 48 Issue 9 Pages 1311-1315
The immobilization of hexavalent chromium in wastewater using blast furnace slag as the immobilizing agent was investigated by using hydrothermal treatment. The results showed that immobilization was not attained without a hydrothermal treatment, while hexavalent chromium in solution could be immobilized through the process of hydrothermal treatment with the blast furnace slag at 250°C for 18 h. In particular, the reducing condition was attributed to the presence of sulfur in the blast furnace slag, which indicated that the sulfur could plays key role in the immobilization of hexavalent chromium in the present study. In addition, the leaching test was carried out to evaluate the level of immobilization of hexavalent chromium in the products after the hydrothermal treatment, and it was found that the degree of immobilization was very high. Based on the results obtained in the present study, the immobilization mechanism of the hydrothermal treatment of blast furnace slag in wastewater was elucidated.