Makiko WATANABE

The Estimation of the Composition Range of Ash for High Quality Slag in Ash Melting Process

Shoichi FUJITA, Toshiya KOMATSU, Shuji HIMENO

It is necessary to produced high quality slag made from Municipal Solid Waste Incinerator ash to broaden its utilization. In this study, we examined the physical strength and leaching characteristic of Pb slag for model slag samples of various composition of ash, and estimated the composition range of ash for high quality slag.
The abration test which is material strength test was used. For the range of basicity 1.25-1.75, physical strength of slag was higher, due to the formation of Gehlenite crystals. The result of Japanese leaching testiJLT-46j, Pb leaching concentration fulfilled the leaching criterion for the range of basicity 1.0-2.0. For acid conditions, model slag with eutectic texture in the range of basicity 1.0-1.25, showed higher leaching ratio of Pb which were about 2-3 times higher than other composition of ash. Therefore, the adequate composition of ash for high quality slag can be said to be in the range of basicity 1.5-1.75.Moreover, it is clear that the difference of leaching mechanism in acid and alkaline conditions was seen.
The results from experimental model slag agreed with the original Municipal Solid Waste Incinerator ash.