| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a slightly soluble structural material from waste gypsum scrap and waste gypsum mold unnecessary in the ceramic production industry by mixing waste gypsum obtained from waste gypsum scrap and waste gypsum mold with a raw material of ceramic powder, clay and Portland cement or waste cement and heat-treating the mixture in a fixed temperature range. SOLUTION: A raw material in a mixing ratio of 30 wt.% of waste gypsum, 46 wt.% of ceramic powder, 12 wt.% of kibushi-clay and 12 wt.% of Portland cement is heat-treated at 1,150-1,200 deg.C as a fixed temperature range. A waste cement comprises Portland cement obtained by removing aggregates such as sand, gravel, etc., and water from sludge recovered from a cement mixer. The waste gypsum is changed from gypsum dihydrate through gypsum hemihydrate to anhydrous gypsum by the heat treatment. The ceramic powder, the clay, etc., are changed into slightly water-soluble substances by heating, a microstructure in which waste gypsum particles changed from gypsum dihydrate into anhydrous gypsum are surrounded by the substances are formed and the water dissolution of anhydrous gypsum is suppressed to the minimum and the waste gypsum is made slightly soluble.</p> |
