Elution of Metals from Fused Slags Produced from General Garbage

Many industrial products that would traditionally be disposed of are now being recycled to reduce environmental pollution and conserve resources. Various techniques for the recovery, processing, and reuse of materials have been developed. Recently, the safety of reusing such materials has been investigated. Waste materials such as city garbage are generated in great quantities. In Japan, most garbage is incinerated and the residue (incineration ash) is reclaimed. The residual capacities of disposal plants are gradually decreasing annually. Control of the amount of city garbage generated and recycling of incineration ash are necessary for environmental protection. Fused slags can be produced from incineration ashes, and such slags can be used to produce construction materials such as slabs for sidewalks [1]. These products are now being used in various practical applications, therefore it is necessary to better understand their safety. There are various types of melting furnaces and materials, e.g., sewage sludge, therefore the properties of the slags produced vary greatly depending on the location and season. Most investigations to date have focused on the physical aspects of their use, e.g., the density and durability of concrete products prepared from slag for use as building materials [2]. There are few reports on the chemical components of slag aggregates. The inorganic materials in slags are important. They do not decompose during fusion and remain largely intact in the end product. This is particularly important because metals can have toxic effects [3]. In this study, we investigated the safety of reusing fused slags as building materials. Elution tests were performed on ten fused slags, with different sampling points and produced using different methods, and their metal contents were determined.