硫酸カルシウムの還元熱分解による硫化カルシウム生成特性 [in Japanese] Formation Characteristic of Calcium Sulfide by Reductive Decomposition of Calcium Sulfate [in Japanese]
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For the purpose of waste gypsum board recycling and selective generation of CaS, reductive decomposition behavior of CaSO<SUB>4</SUB>.2H<SUB>2</SUB>O under CO-CO<SUB>2</SUB>-N<SUB>2</SUB> atmosphere was investigated by using a thermogravimetric analyzer.<BR>As a result, it was found that the reductive decomposition of CaSO<SUB>4</SUB>·2H<SUB>2</SUB>O to CaS in the presence of CO started at temperatures above 1023 K. However, at a temperature above 1173 K, CaS oxidation to CaO was observed and the oxidation was considered to proceed either by reaction of CaSO<SUB>4</SUB> with CaS yielding CaO or by reaction of CaS with CO<SUB>2</SUB> yielding CaO. Hence, to avoid the CaS oxidation, it was considered that the decomposition temperature should be kept below 1173 K. Furthermore, it was found that CaS generation increased with an increase in CO gas concentrations and the conversion of CaSO<SUB>4</SUB>.2H<SUB>2</SUB>O to CaS greater than 90% was obtained at a temperature of 1073 K, under CO : 10% and N<SUB>2</SUB> : 90% atmosphere.
- Inorganic Materials
Inorganic Materials 14(329), 214-220, 2007-07-01
The Society of Inorganic Materials, Japan