Calcium Characterization in Paper Sludge Ashes as The Additives in Trace Element Leaching From Coal Fly Ash

Abstract

Abstarct

Burning coal in coal-fired electric plants produced large volume of coal fly ash that potentially hazardous to local environment. The establishment of an inexpensive leaching control method to prevent the leaching of trace elements from coal fly ash is required for the utilization of large-scale fly ash as an embaknment material. This study examined the effects of the additives on suppressing As, B and Se leaching from coal fly ash using paper sludge ashes (PS Ash XA, PS Ash XB and PS Ash Xc). PS Ash is waste generated in the papermaking and lime industry processes and contain high levels of calcium. The treated fly ash (FA H and FA C) and the resulting mixtures were subjected to a leaching test as per the Environmental Agency of Japan Notifications No.13. The result indicate that the leaching concentrations of As, B, and Se could be greatly reduced in fly ash with the highest effect given by PS Ash XC, followed by PS Ash XB and PS Ash XA. PS Ash XC greatly reduced both the leaching concentrations of As, B, and Se by about 82,10-98.90%, while PS Ash XB reduced the As, Se and B leaching concentrations by approximately 78.10%. A reason for the decrease in leaching concentrations of As, B and Se may be the precipitaion with calcium or the formation of ettingite. The presence of leached Ca are key factors affecting the decrease of As, B and Se leaching concentrations from fly ash. The utilization of paper sludge ash as inexpensive additivesnis a promising method to control the leaching of As, B, Se into the envirentment

Keywords: coal fly ash; leaching; calcium; arsenic; boron; selenium