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The effect of three major influence process parameters, carbon addition ratio, ore particle size, and coal particle size on the compressive strength of high-alumina iron ore-coal composite hot briquette (Al-CCB) with the application of response surface methodology is investigated in this paper. The results show that, with using multiple regression analysis, the experimental data can be fitted into a quadratic polynomial model. Based on the coefficient of determination ( R2 = 0.9883) and the analysis of variance (ANOVA), the model shows good agreement with the experimental data. The effect on the compressive strength of Al-CCB from big to small is carbon addition ratio, ore particle size, and coal particle size. In order to obtain the Al-CCB with 600 N of compressive strength, the optimal experiment conditions are found to be the coal addition ratio of 16.44%, ore particle size of −100 mesh and coal particle size of −100 mesh, resulting in an actual compressive strength of 613 N, as compared to the model prediction of 600 N. This paper can provide guidance for the optimization on preparation of Al-CCB. Also, it can offer reference for the process improvement of other ore-coal composite agglomerates. [ABSTRACT FROM AUTHOR]

Carbon composite iron ore hot briquette (CCB) is the product of fine iron ore and fine coal by hot briquetting process, which attracts more and more attention as a new type of ironmaking raw materials aiming to improve the operation efficiency and reduce the coke consumption of blast furnace. This paper is devoted to experimental study on metallurgical properties of CCB and numerical simulation of the BF operation with CCB charging. At first, the metallurgical properties of CCB, including cold crushing strength, RDI, RSI, reducibility, high temperature strength, and softening and dripping are experimentally tested and compared with the common burdens, which revealed that the CCB possesses the required metallurgical properties and is suitable to use as the blast furnace burden. Then, the effects of charging CCB on the dripping properties of comprehensive burdens are elucidated based on the experiments under simulated blast furnace conditions. The results showed that the maximum charging ratio of CCB in the iron burdens is 40%-50% for achieving appropriate dripping properties of the mixed burdens. Finally, a multi-fluid blast furnace model is used to simulate BF operation with CCB charging. According to model simulations, charging CCB will cause the temperature level to decreases in the furnace and the location of the cohesive zone shifts downward. On the other hand, the productivity tends to increase while coke rate and total reducing agent rate decrease, the heat efficiency improves remarkably and the operation performance of BF is effectively enhanced. [ABSTRACT FROM AUTHOR]