| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a coal ash granulated sand production method by which hexavalent chromium eluted from a coal ash itself is restrained to≤0.05 mg/l being a soil environmental reference value even in the case of using the coal ash of high hexavalent chromium content for a civil engineering material as a raw material. <P>SOLUTION: The coal ash is mixed with a minute amount of a hexavalent chromium elution depressant (calcium polysulfide and/or sodium thiosulfate) and water and then the mixture is granulated to a definite particle size in a process for processing to the coal ash granulated sand. Thereby, it is found that the coal ash granulated sand can be easily blended with the coal ash with ease and hexavalent chromium elution can be restrained below landfill criteria even in the case of granule of the coal ash of high hexavalent chromium content, and the above-mentioned problem has been solved. <P>COPYRIGHT: (C)2004,JPO</p> |
