Abstract
Leaching test of the electronic arc furnace slag was carried out on the basis of JIS K 0058-1 (2005) to study the dissolution behavior of the environmentally controlled elements and the main elements of which the slag was composed. The used slag was the oxidizing slag that was discharged in the smelting of normal steel. The leaching test was performed changing the initial hydrogen ion exponent (pH) of fresh and sea water and the size of slag. During the test, the concentrations of dissolved elements were measured by ICP-AES. The pH of the solution was also measured.
The concentrations of the environmentally controlled substances were below the environmental quality standards for soil and sea water. Generally, the dissolution behavior of Mg and Ca in the slag was expressed by the parabolic law, and that of Si was expressed by the linear law. The elution of those elements was estimated to be controlled be the diffusion through the surface layer of the slag. In the case that the initial pH was below 8, the pH of the solution increased up to approximately 9.5 in the early stage of the dissolution. Subsequently, it decreased to approximately 8.5. In the case that the initial pH was 10, the pH decreased to approximately 8.5. Hence the slag itself showed buffering action. The solubility of each main element of the slag was calculated from the Debye–Hückel theory. The ions in the solution and the solid phases during the elution and the precipitation were discussed from the solubility.
