Jun MIKAMI

Clarification of the Heavy Metal Leaching Characteristic of Recycled Materials and Selection of the Optimal Effective Use Method of Incineration Ashes Reproduction Materials

Toshiya KOMATSU, Shoichi FUJITA, Shuji HIMENO


The basic law for establishing the recycling-based society was enacted, and the importance of recycling has become more widely recognized. However, environmental pollution from toxic substance in recycled incineration ash materials is a concern that prevents some recycling. Therefore there is a need for monitoring the environmental safety of heavy metals for the recycled materials suitably. In this study, Japanese leaching test (JLT-46), pH4 dependent test and diffusion test were performed to better understand heavy metal leaching characteristic and the environmental safety of sludge and concrete blocks, etc. The influence of solvent pH and the influence by the granular size of samples were studied. From the results, if can be concluded that use of only JLT-46 is inadequate and leaching test based on acid conditions and various utilization conditions are essential. Also whether or not incineration ash can be used as primary materials was investigated, using the environmental safety management of soil. Out of the 20 samples of incineration ashes reproduction materials, 9types had met the criteria of the environmental safety management of soil and can be used as primary materials. The remaining 11 types did not meet the criteria but it can be suggested to be used as secondary materials. Due to the evaluation inadequacy of JLT-46, there is a need to evaluate the leaching influence of these secondary materials, using the diffusion test.