engleski

Aqueous Leachate from Electric Furnace Slag

In manufacturing manganese and carbon steel in the basic electric arc furnace,70 to 80 kg of slag per tonne of steel is produced, whereas the grey cast production results with 30 to 40 kg of slag per tonne of grey cast. Such large slag volumes require special care for their disposal at landfills near steel and rolling mills. It is therefore necessary to examine the chemical stability of slag under various conditions. The paper reports examinations of the chemical and phase composition of slag, as well as the number of anions and cations. The number of anions and cations in water eluates were determined in order to define the influence of such material on the environment. The phase composition of slag was determined by X-ray diffraction method. Eluated anions (F-, Cl-, NO2-, Br-, NO3- and SO4-2) were determined by ion-cromatographic analysis. Eluated cations (Na+, K+, Ca+2 and Mg+2) were established by spectrometric atom apsorption. Changes in pH, conductivity and chemical composition of water eluates were monitored for 96 hours. The results have shown that the examined slag material could, with regard to its chemical and phase composition, constitute a stable Fe-Mn-Ca silicate material. However, elution of the examined components, along with the change in conductivity and pH value, implies that slag is not chemically inert and that therefore the problem of slag disposal has to be approached with special attention on its potential impact on the environment.

electric furnace slag; slag phase composition; anions chromatographic analysis; chemical stability of slag

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