Formation of CaCl₂ and CaF₂ from CaSO₄ and Plastics Containing Halogen Element

Abstract

Waste gypsum from construction materials have to be recycled legally in Japan.
Combustion of plastics containing halogen may generate halide gas. Stabilization treatment of halogen element should be done. In the present study, the reaction between the plastics and gypsum generating calcium halide such as CaCl₂ or CaF₂ had been investigated. Reaction condition was evaluated thermodynamically, and experiment for generating CaCl₂ and CaF₂ was conducted. CaCl₂ was formed from CaSO₄ and chloroethylene at 1273K. CaF₂ was formed over 1173K. Crystal water of CaSO₄ accelerates the reaction forming CaF₂.