• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.365-369
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• 2001

EAF's dust has been treated mainly by pyrometallurgical reduction process in rotary kiln furnace to recover valuable metal elements such as Zn and to avoid the disposal of hazardous materials to waste. Recently, hydrometallurgical eletrowinning of zinc from a zinc-amino chloride solution obtained by the leaching of EAF's dust was developed to recover high grade zinc metal from EAF’s dust. But there are some disadvantages in each process such as difficulty of operation condition control and sticking problem in kiln process and low extractability and recovery of zinc owing to insoluble zinc-ferrite in electrowinning process. We propose a new combined process of pyrometallurgical one and hydrometallurgical one to treat EAF's dust efficiently and economically. In this study, ammonium chloride solution leaching of crude zinc oxide recovered from reduction of EAF's dust was carried out to find out the efficiency of zinc extraction from it and the possibility for performance of eletrowinning in the proposed process. Effects of various leaching variables ruck as leaching temperature, concentration of leaching solution and leaching time were investigated. And the leaching results of the crude zinc oxide were compared with those of EAF's dust. The extraction percents of zinc in ammonium chloride solution leaching of the crude zinc oxide recovered from reduction of EAF's dust were above 80% after 60 minutes of leaching under the leaching condition of 4M NH$_4$CI concentration and above leaching temperature of 7$0^{\circ}C$. And the concentrations of zinc in the leached solution were obtained above 50g/$\ell$. The activation energy calculated for zinc extraction in NH$_4$CI leaching was 58.1 KJ/㏖ for EAF's dust and 15.8 KJ/㏖ for the crude zinc oxide recovered from reduction of EAF's dust.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.4
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• pp.58-68
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• 1999

This experiment was to investigate decoloization characteristics of E1 effluents from the bleaching plant of pulp mill with three white-rot fungi(Trametes versicolor, Ganoderma appanatum and Pleurotus ostreatus).In addition, the effect of carbon and nitrogen resources was discussed on its decolorization. The color removal of E1 effluent during shaking and stationary cultures were 72% and 80%, respectively. Stationary culture was more effective on decolorization of E1 effluent compared to the shaking culture. The optimum inoculum weight was 1.0g based on dry weight of mycelia . The decolorization medium I showed 88% of the color removal of E1 effluent with in one day cultivation of T.versicolor and P.ostreatus . Color removal was increased from 87% to 90%. T.versicolor and P.ostreatus by the addition of 0.5% glucose. By addition of nitorgen sources(ammonium sulfate and ammonium choride), medium was much higher than that of carbon source. With 0.1% ammoniumm sulfate, P.ostreatus and T.versicolor showed 94% and 92% of the color removal within one day of cultivation , respectively. On decolorization medium II, T.versicolor and P.ostretus were 94% of oclor removal with addition of carbon source. The addition of nitrogen source was much more efficient than that of carbon source. With 0.1% amminium chloride, T.versicolor and P.ostreatus showed 95% of its color removal . The decolorization medium II was higher color removal than medium I, and also MnP and laccase were produced. However, the decolorization medium I produced a little MnP and laccase activity. It could be suggested that MnP and laccase may play an important role in decolorization of E1 effluent.