Research on the Main Factors Influencing Leaching from Fly Ash

摘要

The leaching of pollutants into groundwater is important issue when evaluating the risk of a solid waste on human health and the environment. In this paper, the millipore rotary agitator was used for leaching experiment, and 28 different leaching tests were grouped and investigated to study the factors influencing on leaching. The main conclusions were drawn as follows: The arsenic content of extraction fluids was far below the concentrations specified in 40CRF 261.24, so no obtained evidence revealed that the fly ash was hazardous. The fly ash with small particle size was with more specific surface area and higher content of Arsenic, which may lead to more Arsenic leached from solid into solution. Arsenic was leached into the extraction solution for TCLP #1 and #2 instead of SPLP and DWLP. The greater L/S ratio leaded to more dilution of fly ash so as to have lower contents of arsenic in extraction fluids. The release of arsenic from fly ash depended on the extraction time, the longer time, the higher content the extraction fluid obtained. The extracted Arsenic contents were influenced with pH. Lower result was obtained from neutral solutions, when increased with the acidity or alkalinity of the solutions, higher content of Arsenic from extraction was obtained.