MELTING AND STONE PRODUCTION USING MSW INCINERATED ASH

摘要

Most of the municipal solid waste in Japan is incinerated and the generated-ash is landfilled. However, environmentalrnpollution problems have increased and Japan has decreasing final disposal sites for landfills.rnWith the application of the melting system, the volume of incinerated ash can be reduced and the effective usernof melted slag is being developed for use in civil engineering works. However, the low strength of melted slag as arnvitreous structure has limited its effective use that requires higher strength. As a solution for this deficiency, a technologyrnto crystallize melted slag into produced-stones was developed.rnWith the joint cooperation of Chiba Prefecture and Kamagaya City, a demonstration plant for melting &rnstone-production with a capacity of 4.8 tons of incinerated ash per day was constructed. The demonstration testrnwas conducted from May 1998 to June 1999 with satisfactory results stated below. Long-term stable operation andrnperformance of the plant have been confirmed and effective applications of produced-stones have been demonstratedrnon a commercial scale. The results are:rn1. A stable, continuous operation and good quality produced-stones have been confirmed by treatingrnmore than 750 tons of MSW incinerated ash.rn2. More than 99.9% of dioxins contained in the incinerated ash were decomposed, and the concentrationrnof dioxins in produced-stones were less than the detection limit set by Japanese environmental standards.rn3. Leaching values of hazardous heavy metals of produced-stones sufficiently meet the environmentalrnstandard on soil pollution of the Environment Agency with superior leaching behavior for the vitreousrnslag, thus confirming their safe applications.rn4. The effective application of produced-stones for aggregate was tested based on Japanese IndustrialrnStandards and every figure of test results met the Japanese standard values. The use of producedstonesrnas raw materials for permeable-pavement blocks has been confirmed in commercial constructionrnfor a park in Chiba Prefecture. Asphalt use was also confirmed by paving a commercial roadwayrnin Kamagaya City.