プラスチックを用いた石膏からのCaO及びCaSの生成 [in Japanese] Recovery of CaO and CaS from CaSO_4 using waste plastics [in Japanese]
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Waste gypsum from construction materials have to be recycled legally in Japan. The waste gypsum contains CaSO<SUB>4</SUB> and other materials such as papers. And thus it is impossible to reuse them directly as a CaSO<SUB>4</SUB> resource. A treatment at higher reaction temperature seems to be suitable for recycling a large quantity of the gypsum. However, CaSO<SUB>4</SUB> is rather stable even at high temperature, therefore cost-intensive reactants are necessary.<BR>Re-generation of CaO or CaS from CaSO<SUB>4</SUB> was investigated using waste plastics, which were considered as reduction agent. Thermodynamic simulation was employed to find optimal conditions for reduction of CaSO<SUB>4</SUB>. Reduction experiments were conducted using reagents of CaSO<SUB>4</SUB> and polyethylene. CaO was formed from CaSO<SUB>4</SUB> and polyethylene mixture over 1273K in air. Crystal water of CaSO<SUB>4</SUB> accelerates the reaction forming CaO. Plastics can be successfully used to produce CaO and CaS from CaSO<SUB>4</SUB> in controlled atmosphere.
- Journal of MMIJ
Journal of MMIJ 122(9), 456-461, 2006-10-04
The Mining and Materials Processing Institute of Japan