| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a cement composition of good quality by reducing an amount of water-soluble Cr(VI). <P>SOLUTION: The method of manufacturing a cement composition reduced in water-soluble hexavalent chromium comprises the steps of: calcining cement clinker using a raw material including limestone, silica, a clay material and an iron material; thereafter adding gypsum; and pulverizing, wherein a step for adjusting a compounding ratio of the clay material and the iron material in the raw material is included so that a K<SB POS="POST">2</SB>O amount (mass%) and a total Cr amount (mass%) in the cement clinker satisfy the relation: total Cr amount×10<SP POS="POST">4</SP>≤-222×K<SB POS="POST">2</SB>O amount+225. <P>COPYRIGHT: (C)2013,JPO&INPIT |
