Preparation of Building Material Using Elemental Sulfur and Heavy metal Containing Slag

摘要

Elemental sulfur and volatilization kiln slag (VKS) containing heavy-metal produced by smelter factories were used to produce sulfured building material. The effects of heating mode, material proportion (M_(Sulfur): M_(VKS)), size of waste particles and ratio of aggregate to filler(A/F) on the mechanical properties and leaching toxicities of solidified stuff were investigated. The optimal conditions for the solidification are stepped heating mode, 3:7 ratio of M_(Sulfur) to M_(VKS), particle size less than 150μm and 3/17 ratio of A/F. Under the above optimal conditions, the compressive strength of solidified stuff rises to 35 MPa, and water absorption is down to 4%-6%. Furthermore, when NaOH is applied as an additive in the process of solidification, the concentrations of most heavy metals except Pb~(2+) have reached the national leaching toxicity standard. The results of X-ray diffraction reveal that sulfured solidification is caused by the physical encapsulation rather than chemical transformation.