EXPERIMENTAL-STUDY OF THE WASTE BINDER ANHYDRITE IN THE SOLIDIFICATION STABILIZATION PROCESS OF HEAVY-METAL SLUDGES/

An experimental study of the use of an industrial byproduct, anhydrite (CaSO4), as inorganic binder in the solidification/stabilization (S/S ) process of heavy metal sludges has been performed. The influence of the variables: binder:waste ratio, anhydrite particle size and water a mount on the S/S process of a synthetic sludge containing Cd, Cr and P b has been studied. Leaching of stabilized products using the Toxicity Characterization Leaching procedure was used to evaluate the behaviou r of heavy metals after treatment with anhydrite. Significant reductio ns of leached metal concentrations were achieved depending on the expe rimental variables. Therefore, it has been shown the possibility to us e anhydrite as binder in S/S processes of wastes containing heavy meta ls and the influence of the main variables in the S/S process, in orde r to satisfy landfill disposal regulations. (C) 1998 Elsevier Science B.V.