Stabilization of high mercury contaminated brine purification sludge.

The highly leachable mercury contaminants of brine purification sludge (BPS) generated from the Hg-cell electrolysis process in chlorine production can be stabilized in the treatment procedure employing ferric-lignin derivatives (FLD) (Ligmet binder) and Portland cement (PC). The stabilization effectiveness has been examined by time-based multiple toxicity characteristic leaching procedure (TCLP) tests and sequential TCLP tests. In a period of 50 days, the multiple TCLP tests showed a variation of less than 90 microg l(-1) for the leachable mercury level, and the sequential TCLP tests for the same sample displayed a declining TCLP mercury level. Based on this study, the stabilization of approximately 2000 t of brine purification sludge has been successfully processed with the ferric-lignin derivatives treatment.