Amendment of multi-binders was employed for the immobilization of metal(loid)s in field-contaminated soils to reduce the leaching potential. The effect of different types of multi-binders (lime/diammonium phosphate, diammonium phosphate/ladle slag and lime/ladle slag) on the solidification/ stabilization of metal(loid)s (Pb, Zn, Cu and As) from the smelter soil and mine tailing soil were investigated. The amended soils were evaluated by measuring Toxicity Characterization Leaching Procedure (TCLP) leaching concentration of metal(loid)s. The results show that the leaching concentration of metal(loid)s decreased with the immobilization using multi-binders. In terms of TCLP extraction, the mixed binder was effective in the order of lime/ladle slag > diammonium phosphate/ladle slag > lime/diammonium phosphate. When the mixed binder amendment (0.15 g lime+0.15 g ladle slag for 1g smelter soil and 0.05 g lime+0.1 g ladle slag for 1 g mine tailing soil, respectively) was used, the leaching concentration of metal(loid)s decreased by 90%. However, As leaching concentration increased with diammonium phosphate/lime and diammonium phosphate/ladle slag amendment competitive anion exchange between arsenic ion and phosphate ion from diammonium phosphate. The Standard, Measurements and Testing programme (SM&T) analysis indicated that fraction 1 (F1, exchangeable fraction) decreased, while fraction 4 (F4, residual fraction) increased. The increased immobilization efficiency was attributed to the increase in the F4 of the SM&T extraction. From this work, it was possible to suggest that both arsenic and heavy metals can be simultaneously immobilized by the amendment of multi-binder such as lime/ladle slag.

Raw and secondary waste materials from recycling products have been used to produce cements. A total of 10 cements produced from recycling products were analyzed for chemical composition, such as Na2O, MgO, Al2O3, SiO2, SO3, Cl, K2O, CaO, TiO2, Cr2O3, MnO, Fe2O3, CuO, ZnO, and PbO, using the Korean standard leaching test. The total content of toxic substances, such as Pb, Cd, Cu, As, Hg, and Cr(VI), present in each cement was also measured. The corrosion characteristics of cement leachates were also determined by measuring their pH values using an ion selective electrode and measuring the corrosion rate of a circular steel plate in each leachate. The chemical composition of the cements was found to be 60-67% CaO, 18-23% SiO2, and 5-6% Al2O3. Based on the results of the leaching tests, the samples did not exceed the prescribed regulatory leaching levels. The total content of toxic substances in each cement did not exceed the voluntary agreement criteria of 20 mg/kg. In the case of the corrosion characteristics of the cement leachates, the pH of each leachate was greater than 12.5 and the corrosion rate of a circular steel plate in each leachate did not exceed 6.35 mm/yr. The correlation between pH and the corrosion rate of steel in the solid waste leachates was difficult to determine.