Investigation of selective leaching conditions of ZnO, ZnFe2O4 and Fe2O3 in electric arc furnace dust in HNO3

Electric arc furnace dust (EAFD) includes mainly Zn, Fe, Pb, Ca and Mn-bearing compounds. Thus, EAFD is classified as a hazardous waste. The dissolution behavior of Zn-and Fe-bearing compounds in EAFD in nitric acid solutions was investigated in this work. The composition of Zn-and Fe-bearing compounds in the EAFD was determined as 28.58, 37.96 and 11.33 % for ZnO, ZnFe2O4 and Fe2O3, respectively. The effect of stirring speed, temperature and HNO3 concentration on the dissolution rate of ZnO, ZnFe2O4 and Fe2O3 were investigated and optimum leaching conditions determined. While ZnO was dis-solved rapidly, the dissolution rate of ZnFe2O4 increased with increasing tem-perature and HNO3 concentration. Fe2O3 was not soluble in 0.5 M HNO3 solut-ion at 40 degrees C, whereas it was dissolved completely in 4 M HNO3 solution at 80 degrees C.