Study On The Formation Of Complex Calcium Ferrite Of Baiyunebo Iron Ore During Sintering Process

In this paper, the influence of the main sintering factors on the formation of complexcalcium ferrite by Baiyunebo iron ore was studied using mini-sintering test device, opticalmicroscope （OM） and SEMEDAX which based on the condition of self-producedBaiyunebo iron ore concentrate by Baotou Steel Company. It enriches and develops thespecial ore sintering theory, and also it plays a key role on the utilization of Baiyunebo ironore more effectively, quality and quantity.The Australian ore was used as the main ferrous material. The tests were carried byadjusting the compound silicate gangue potash feldspar, aegirine, CaO, SiO₂and MgOaccording to the chemical composition of self-produced Baiyunebo iron ore concentrate byBaotou Steel Company. The main sintering factors designed include the content of F, K andNa, sintering temperature, sample’s basicity and Al₂O₃/SiO₂ratio. The result shows that F, Kand Na in Baiyunebo iron concentrate has a strongly inhibiting effect on the formation ofSFCA and it promotes fine acicular and columnar grains to agglomerate into coarse grains sothe adhesion of SFCA to iron oxides decreases. With the increasing of sintering temperature,the amount of calcium ferrite increases firstly and then decreases. In this experimentalconditions, the proper sintering temperature should be controlled between1240℃and1280℃。The sinter basicity makes a positive contribution to the growth of SFCA. However,a higher basicity may result in the generation of columnar shape SFCA, so the basicity ofsinter produced by Baiyunebo iron ore should be around2.0. As the A/S ratio rises in sinter,it has the detrimental effect to form SFCA, and the morphology of SFCA changes fromacicular, columnar to tabular. It is disadvantageous to improve sintering strength andmetallurgical performance, so it should minimize the A/S ratio during sintering process.Under this experimental condition, the appropriate A/S ratio is0.3.In this paper the influence of main sinter factors during sintering process on theformation of SFCA were studied. Its results have great significance to optimize sinteringprocess, improve strength and metallurgical properties of sinter.