Original scientific paper

Aqueous Leachate from Electric Furnace Slag

Alenka Rastovčan-Mioč ; Faculty of Metallurgy, University of Zagreb, Aleja narodnih heroja 3, 44000 Sisak, Croatia
Štefica Cerjan-Stefanović ; Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 19, 10000 Zagreb, Croatia
Lidija Ćurković ; Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 19, 10000 Zagreb, Croatia

Abstract

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 in 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 was determined in order to define the influence of such material on the environment. The phase composition of slag was determined by the X-ray diffraction method. Eluated anions (F-, Cl-, NO₂-, Br-, NO₃- and SO₄2-) were determined by ion-chromatographic analysis. Eluated cations (Na+, K+, Ca2+ and Mg2+) were established by spectrometric atom absorption.
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 paying special attention on its potential impact on the environment.

Keywords

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

Hrčak ID:

132076

URI

https://hrcak.srce.hr/132076

Publication date:

5.6.2000.

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