| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide easily-producible portland cement wherein the amount of water-soluble Cr (IV) is small even if the whole amount of Cr is large, and the utilization rate of waste can be maintained. <P>SOLUTION: In this portland cement containing a portland cement clinker ground product and gypsum, the content rate of SO<SB POS="POST">3</SB>(excluding SO<SB POS="POST">3</SB>originated in gypsum) is 0.25-1.5 mass%, the content rate of K<SB POS="POST">2</SB>O is 0.3-0.55 mass%, and the whole amount of Cr is 70-150 mg/kg-cement. <P>COPYRIGHT: (C)2013,JPO&INPIT |
