REDUCIBLE GYPSUM COMPOSITION, METHOD OF MANUFACTURING THE SAME, CEMENT BASED SOLIDIFICATION MATERIAL AND SOLIDIFICATION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a reducible gypsum composition and a method of manufacturing the same by which the effect of suppressing the elusion of 6-valent chromium is uniformalized, the degradation of solidification strength is prevented and elusion suppressing cost is reduced and further, the cost of gypsum for solidification material is reduced and a solidification material manufacturing step is simplified. SOLUTION: The reducible gypsum composition contains calcium sulfite hemihydrate and gypsum dihydrate. The method of manufacturing the reducible gypsum composition containing calcium sulfite hemihydrate and gypsum dihydrate is carried out by mechanically dehydrating slurry containing calcium sulfite hemihydrate in a flue gas desulfurization step and slurry containing gypsum dihydrate obtained by oxidizing the slurry containing calcium sulfite hemihydrate all together or separately, adding 0.25-1.0 mol calcium oxide based treating material per 1 mol free water of the dehydrated material and drying to be powdered. COPYRIGHT: (C)2007,JPO&INPIT