| 摘要 |
PROBLEM TO BE SOLVED: To provide a cement composition where a rate of a selenium elution amount to selenium content is small and where the elution amount of selenium can be suppressed, and to provide a cement-based solidifying material. SOLUTION: The cement composition contains cement clinker, plaster and a rinsed residue of an extracted clinker. The selenium content in the cement composition is 15.5 mg/kg or less and the amount of C<SB>3</SB>S is 60-80 mass% according to calculation by Bogue's equations. The cement-based solidifying material using the composition is also provided. Selenium in the cement composition is reduced by extracting a part of a selenium-containing exhaust gas from a suspension preheater part in a cement firing apparatus to a rotary kiln hood inlet and by using the rinsed residue of the extracted dust. COPYRIGHT: (C)2009,JPO&INPIT
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