No.1-21 Development method in suppressing the leaching of trace erements from coal fly ash

Abstract

The leaching of trace elements in coal fly ash such as As, Se, and B is desired to be controlled. Development of suppression the leaching of the trace elements has been studied using paper sludge ash (PS) containing the high calcium content. When the high cacium content paper sludge ash (PS#3) was mixed to a coal fly ash by weight percentages of 20−25%, the leaching ratios of As, Se, and B was strongly decreased than the environmental regulation. To find a dominant chemical compound for the suppression of trace elements, effect of CaO and Ca(OH)₂ were examined. Both calsium compound have effectively decreased the leaching of As, Se, and B. It found that PS#3 contained 8.2% CaO and 1.0% Ca(OH)₂, which were the dominant compound for the suppression of trace elements.