| In this paper, firstly, the common ore used in Baogang and purchased Mongolian ore were used as research objects to study the basic sintering characteristics of their own and their mixture. According to the experimental result, the content of Mongolian ore and basicity and the content of MgO were chosen as factors to do the sintering Cup experiments which adopted the orthogonal method of three factors and three levels. The physical, chemical and metallurgical properties of sinter were tested to guide optimization industrial test. Secondly, the grain sizes of Mongolia and Baogang iron ore were measured. The pelleting ability and crystal stock strength basic property were studied. The optimum spheric agglomeration scheme of ore blending was gained. In order to reduce the pellet swelling rate, the optimization of process tests was executed with four factors and three levels. The optimal technological system of pellet was obtained.The assimilation characteristic, liquid phase fluidity, self-intensity of bonding phase and generation characteristic of SFCA of Barun ore, Mongolian ore, Australian ore and self-producing ore were systemically studied by mini-sintering test device. The result showed that Mongolian ore has good assimilation characteristic, liquid fluidity and generation characteristic of SFCA, because it contains high contents of SiO2, K and Na compared with the rest ore.On the basis of sintering basic characteristics of single ore, according to the principle of uniform design and the complementary characteristics of high temperature of ore, the ore matching scheme was designed to analyze the basic sintering characteristics of designed scheme. The ore matching scheme showed good sintering characteristics when the ore proportioning of Mongolian ore, Australian ore, self-producing ore and Barun ore are56%,0%,17%,27%;58%,10%,13%,19%; and60%,20%,20%,0%.According to the selected ore matching schemes, the sintering cup orthogonal experiment with the factors of the content of Mongolian ore, basicity and the content of MgO was designed. The sintering cup experiment result showed that, when the content of Mongolian ore, Australian ore, self-producing ore and Barun ore is56%,0%,17%,27%, basicity is1.8and the content of MgO is2.12%, the tumbler strength of sinter ore is83.7%. This is because the sinter of high basicity is helpful to generating the liquid phase of the SFC A, and then the sinter has good tumbler strength with basicity improved. When the content of Mongolian ore, Australian ore, self-producing ore and Barun ore is56%,0%,17%,27%, basicity is2.0and the content of MgO is2.32%, the low temperature reduction disintegration index reaches the lowest level, that is3.77%. And the low temperature reduction desintegration index tends to increase with the increase of the content of Mongolian ore and the decrease of basicity, which is because the increase of the content of Mongolian ore and the decrease of basicity lead to the reduction of the content of the SFC A.Under the experimental conditions of raw materials, the tumbler strength of sinter ore is82.5%, and the low temperature reduction desintegration index is5.53%, the reduction degree is77.55%, the generation content of SFCA is36.2%, the microstructure of sinter ore is relatively uniformed. When the appropriate content of Mongolian ore, Australian ore, self-producing ore and Barun ore is56%,0%,17%,27%, basicity is1.8and the content of MgO is2.12%.Mongolia concentrate is not suitable for pellet production alone. Because of its fine particle size, uneven distribution and poor crystal strength, sphericity index is0.35, which is lower than ordinary level. Adding Mongolia ore had little effect on the anti-press strength and the decrepitation temperature of green-balls, which, in the range of experiment, can basically meet the requirements of the production.The pellets strength would decrease when adding Mongolia ore in pellets. When the adding amount is45%-70%, the pellets strength is more than2000N that could meet the strength require.The pellet expansion rate of Mongolia ore adding2.3%bentonite and Baiyun ore were21.79%and28.29%. These are are not suitable if used alone. Adding45%to70%Mongolia ore into pellets, the pellet expansion rate first decreased and then increased. When the adding amount is55%, the pellet expansion rate is17.03%that is the lowest. This can meet the requirements of blast furnace.Adding2.3%bentonite and55%Mongolia ore under the current process, the green ball compression strength is8.6N, and the falling strength is3.33times, the finished pellets compression strength is2466.6N, the pellet expansion rate is17.03%that can meet the requirements of blast furnace. When the bentonite ratio is3.3%, the pellet was preheated14min under700℃, and roasted under1280℃, the pellet rate is13.41%that is optimum. |
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