| To determine the mechanism by which zinc ferrite forms when ferrous zinc sulphide ore is roasted, the experiment has been carried out under given conditions by sufficiently mixing zinc oxide with ferric oxide in a stoichiometric way. The results obtained from this experiment are summarized as follows: 1) Formation of zinc ferrite was confirmed by x-ray diffraction analysis in formed compound at alternation of various mole ratio and temperatures. 2) Zinc ferrite was obtained by stoichiometric ratio without any effect of mixed mole ratio i.e., zinc ferrite was not confirmed at temperature less than 700℃, but was found at above 700℃. 3) Zinc leaching rate of synthetic zinc ferrite on sulphuric acid solution or ammonium salt solution was similar at low temperatures (below 680℃), but decreased at above 700℃. For ammonium salt solution (ZnO: Fe₂O₃＝1 : 1), the zinc leaching rate was found to be 9.07% at 1000℃ and 49.97% at 700℃, respectively. This zinc leaching rate for sulphuric solid solution (ZnO: Fe₂O₃＝1 : 1), however, showed 25.03% at 1000℃ and 95.79% at a temperature 700℃. Therefore, zinc leaching rate of zinc ferrite on sulphuric acid solution was found to be more than twice as much as for ammonium salt solution. 4) Zinc ferrite was found to from at 1000℃ even under conditions of changing mole ratio. For ZnO: Fe₂O₃= 1:1, however, the formation of zinc ferrite only was confirmed. When values of the ratio of ZnO to Fe₂O₃were 1 to 1 and 5 to 1, both zinc ferrite and free zinc oxide were obtained, where when its value was 1 to 2 the formation of zinc ferrite and free Fe₂O₃was determined. |
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