| 摘要 |
<p><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 of adjusting a compounding ratio of the clay material and the iron material in the raw material is included so that the total chromium content in the cement clinker is 50-140 mg/kg, and the product of K<SB POS="POST">2</SB>O/Na<SB POS="POST">2</SB>O (mass ratio) and the total alkali content (mass%) in the cement clinker is not greater than 1.05. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
