Disposal of heavy metal bearing hazardous waste using chemical fixation and solidification

The Chemical Fixation and Solidification (CFS) process has been successfully applied to flyash from a glass-manufacturer and to arsenic trioxide wastes from roasting auriferous pyrite concentrates. Both wastetypes have been solidified with or without chemical fixation by addition of various amounts of Portland Cement. Leachability and unconfined compressive strength of the produced solidified waste were used as parameters to assess the efficacy of the CFS process. Leachability data for the solidified wastes was obtained by conducting standard leaching tests such as the Toxicity Characteristic Leaching Procedure (TCLP) and the Dynamic Leach Test (DLT). For the arsenic trioxide waste the leachability data was used to model long term leachability. This paper outlines the results from the application of the CFS process to industrial flyash and of arsenic trioxide waste and discuss the long term leaching models developed to predict leaching from arsenic trioxide waste