| The dusts generated from electric arc furnace (EAF) offgas contain abundant metallic elements such as Fe, Zn and Pb, etc. Simply disposing or land-filling the EAF dusts could result in serious environment pollution because of leaching of the toxic elements such as Pb, Cr. During directly recycling the EAF dusts for the blast furnace (BF), the zinc enriched in the BF would shorten the lining life, and block the gas pipeline of BF. Because of the leaching of toxic elements, the land-filled of the offgas dusts in traditional simple way were forbidden since 1988 in the western countries, the dusts must be treated as no-toxic waste products before being land-filled. The treatment and utilization of EAF dusts were highly valued in the western countries, many kinds of research were carried out. However, up to now, there are no any ordinary practical processes could be established. In China, the utilization research of EAF dusts followed behind western countries, no practical processes could be employed, and the processes used in western countries wasn't suitable for local circumstance. In order to reduce the environment pollution caused by the EAF dusts, get high grade Zinc oxide powders and Semi-metallic pellets at the same time, and understand the comprehensive utilization of such dusts, pellet-containing-carbon roasting reduction method was developed to remove the zinc from the EAF dusts, according to the difference of physical-chemical property of metallic elements and the characteristic of high content Zinc of EAF dusts.Firstly, physical-chemical property of the EAF dusts was analyzed in the thesis, then the reducing thermodynamics were calculated out, and the kinetics of EAF dusts was studied. The research shown that the EAF dusts is easy reduced at high temperature, which proved that the reduction of dusts by roasting reduction method is possible in theory. In order to meet the experimental condition of carbon-containing pellets, the palletizing-property of EAF dust was researched. Experimental results shown that the EAF dusts of Nanjing steel are very fine, the sizes of all particles are less-than 5μm, which is very beneficial to be pelletized. The results also shown that performances of the pellets could meet the experimental requirements under the condition without any binder.Based on the research of thermodynamics and kinetics, the integrated utilization of the EAF dusts research was carried in the laboratory. Through studying the effects of reductant, reduction temperature, reduction time, carbon content on the process, the processing parameters were determined. The experimental results shown that coke-reductant is better than coal-reductant. With coke-reductant, the parameters of roasting reduction method are shown as follows: carbon-oxygen ratio: 0.8~0.9, reduction temperature 1150℃, reduction time 50 min. The treated pellets are semi-metallic pellets, total ferrum content in the treated pellets is about 67%, the highest content of TFe will reach up to 69.8%; metal ferrum content is about 63%, the highest value is 66.5%; the compression strength of single pellet is about 4 kN; ZnO content in the collected zinc oxide powders is about 80%, the highest value is 84.28%. Zinc oxide content of the collected powders is little lower than that we expected, because of the limit of oxidizing-room in laboratory. The industrial process could improve the grade of zinc oxide powders through improving the oxidizability of oxidizing-room.Based on the success of laboratory research, semi-industrial research was carried out,the purpose is to approve the feasibility of the equipment and heating-way which designed for the experiment. The effect of temperature, carbon-oxygen ratio on...
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