| With the rapid development of the iron and steel industry,iron ore agglomeration meets the problems of high-grade ore depletion,raw materials diversification,the imbalance of acid and alkali furnace charge,etc.In line with addressing these challenges,Central South University developed the composite agglomeration process（CAP）–an innovative technology for preparing blast furnace burdens.The CAP method consists of a pellet part,matrix materials,and a transition zone.Amongst these,the quality of the pellet part is highly essential for the improvement of the CAP products.Hence,it is vital to prepare qualified green pellets to ensure an efficient production process and create conditions for achieving high quality,low fuel consumption,and high yield of CAP products.In this paper,magnetite concentrate from Liberia was used as raw material,the green pellet preparation process was optimized,the influence of alkalinity on the properties of CAP products was found out,and the phase transformation of pellets under controlled atmosphere roasting was studied.The main innovations and conclusions are as follows:（1）Optimization of CAP parameters of Liberian magnetite concentrate:under the optimal condition of comprehensive material alkalinity R=1.3,fuel dosage of 4.5%,pellet dosage of 40%,pellet size of 8～10mm,the yield of composite sinters was73%～76%,and tumble index was 72～76%,productivity was 1.40 t·（m2·h）-1,solid fuel dosage was 52～53 kg·t-1.The production and quality index of CAP was significantly better than TSP.（2）The internal consolidation mechanism of pellet was investigated.Thermodynamic calculation and simulated roasting test showed that Fe O in pellet was difficult to be oxidized.The olivine liquid phases were easily formed,which may improve the strength of pellets.The addition of Ca O in pellet can effectively avoid the binding of Si O2 and iron oxide,and promote the formation of SFCA liquid phase containing Fe O.33 Figures,32 Tables,and 114 References... |
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