| In recent years, with the expansion of steel industry production capacity in our country, the discharge amount of the metallurgical dust was more and more. The recycling of the metallurgical dust has become widespread existent common problems. At present, the metallurgical dust has been used directly for sintering by most iron and steel companies. But it was easy to cause fluctuations to the production process. For the shortcoming problem of stable production process and quality of product resulted from adding the dust directly to the sintering in Shuicheng Iron and Steel Co., Ltd. in order to recycle it, the MPS process has been used to make experimental investigation on the dust for reaching the purpose of reasonable recycling.Through confirming appropriate parameters and selecting reasonable binders of making pellet, an experimental investigation had been made to study the pelletizability and the quality of dust mini-pellet in laboratory condition. And then, with the resource condition, sintering experiment of different proportioning rates and different layer height was carried out on having made mini-pellet. The sintering performance and sinter quality of dust mini-pellet adding to sintering mixed material was analyzed and investigated. The conclusion was come to from the experiment and it would offer theoretical direction for the industrial production of following stage.The experimental results of pelletizing showed that the lime is a more reasonable binder for dust mini-pelletizing. It not only could better improve the pelletizability of dust, but also wouldn't bring in detrimental impurity at the follow-up process. And at the same time, a variety of dust making into a mixed type dust to mini-pelletize could complement each other's advantages. In this experiment, the optimum pelletizing parameters using dust was pelletizing time of 12min, disc pelletizer speed of 26r/min and moisture content of mini-pellet controlling in about 11%. When the grain diameter of dust mini-pellet was 3~8mm, its average green impact strength was >3times/0.5m and the burst temperature of mini-pellet was reaching 600℃. The strength index of green and dry pellet fully satisfied the requirements of mini-pellet adding to sintering.The experimental investigation of sintering showed that dust mini-pelletizing adding to sintering could play a dual role of making full use of secondary resources and as a core material of pelletizing. It not only could improve the permeability of layer, but also could stabilize water and carbon and prevent composition fluctuating of sintering. At the same time, there was no negative influence on the natural degradation of sintering. When the layer height was 500mm, 620mm and 720mm, and the corresponding dosage of dust and mini-pellet was 4%, 6% and 8% in the experiment, the vertical sintering speed, yield and tumbler index improved 7.5%, 12.3%, 25.7%, 0.94%, 5.4, 7.2%, 3.12%, 4.37% and 12.67%, and the coal consumption reduced 5.9%, 13.2% and 17.6%, respectively, by adding the mini-pellet compared with adding the dust. The experimental results also showed that the optimum ore matching scheme was Australian ore of 17.1%, yangchun ore concentrate of 7%, Brazil ore of 34.8%, India ore of 7%, roasting ore of 3%, coking coal of 6.4%, limestone of 7.1%, lime of 6.4%, dolomite of 5% and mini-pellet of 6% to 8% in the existing raw materials condition of Shuicheng Iron and Steel Co., Ltd., when the layer height was 600mm to 700mm.The final experimental investigation showed that the dust mini-pelletizing adding to sintering was feasible, the pelletizability and the sintering index of which could satisfy the production requirement. This was a new way of recycling the secondary resources. It would yield significant results for improving economy and society effect of enterprise and have good spread meaning. |
PDF Full Text Request