| Iron ore sinter is currently the main raw materials for BF(Blast Furnace) process, and thus its quality is essential for intensified smelting operation in BF. In middle 1960 s, the calcium ferrites sintering theory was proposed and gradually get advantage to the silicate sintering theory. As the former gradually get developed with practice, the high-basicity sintering process has become in dominate. The morphology and property of calcium ferrite, which is the main banding phase of high-basicity iron ore sinter, is critical to the quality of iron ore sinter. Literature research indicates that when the technological parameter was fixed, the formation of calcium ferrites and its crystallization behaviors were determined mainly by chemical composition of raw materials and operation parameters in cooling process. As the exhaustion of high quality iron ore resources forced the steel plants to use the low grade iron ore, the complexity of raw materials which cause in fluctuation of chemical composition has became a big complication for the sinter plants to maintain the quality of sinter.This research is supported by National Natural Science Foundation of China(NSFC No.51104192) and is in order to study the dissolution kinetics of Si O2 or Mg O into calcium ferrites based melts. Rotating cylinder method was used to understand the solid-liquid dissolution behavior. Thermodynamic software was used to determine the experiment temperature, composition, melt viscosity, and the kinetic parameters of the solution of the derivation. Research results were summarized as follows:① The dissolution of Si O2 into calcium ferrite melt is proportional to the experiment time, experiment temperature, rotating speed of rod sample and the Mg O mass percentage in inital slag, and it is inversely proportional to the Si O2 mass percentage and the Fe2O3/Ca O mass ratio of initial melts, which is mainly driven by solid and liquid phase concentration difference; The XRD patterns of final includes Ca2Fe2O5, Ca Fe2O4 and Ca2 Si O4 with low Si O2 mass percentage(<25%), and the XRD patterns of final includes Ca Fe2O4, Fe2O3 and Ca Si O3 with high Si O2 mass percentage(>25%), and the XRD patterns of final includes SFCAM, Mg Fe2O4 and Fe2O3 with high Mg O mass percentage(>2%); The solid-liquid interface of Si O2 dissolve into calcium ferrite melt is in crack, obvious intermediate layer are not found, the dissolution reaction is just on the surface of rod sample. = 0?(-1?62?3)[(%Solute)-(%Solute)] can describes the dissolution rate; Dissolving process is mainly driven by Si O2 concentration difference of solid-liquid interface, and the melt viscosity have great influence on the rate of dissolution; The diffusion coefficient of Si O2 in this study ranges from 1.18×10-6 to 4.01×10-6 cm2·s-1. The content of melt has great influence on the Si O2 dissolution activation energy, and it’s in the order of magnitude of 102 k J·mol-1.② The dissolution of Mg O into calcium ferrite melt is proportional to the experiment time, experiment temperature and rotating speed of rod sample, and it is inversely proportional to the Mg O mass percentage and the Fe2O3/Ca O mass ratio of initial melts, and it firstly increases and then decrease with adding Si O2, which is mainly driven by solid and liquid phase concentration difference; The XRD patterns of final includes Ca2Fe1.52Al0。48O5 and Mg Fe Al O4 with low Fe2O3/Ca O mass ratio(<2.33), and the XRD patterns of final includes Ca2Fe1.52Al0.48O5 and Mg Fe2O4 with high Fe2O3/Ca O mass ratio(>2.33), and the XRD patterns of final includes SFCAM and Mg Fe2O4 with low Si O2 mass percentage(≤2%), and the XRD patterns of final includes SFCAM and Ca2 Si O4 with low Si O2 mass percentage(>2%); The solid-liquid interface of Mg O dissolve into calcium ferrite melt is in crack, obvious intermediate layer are not found, the dissolution reaction happens into the rod sample, which is different from the result of Si O2 dissolving process. = 0?(-1?62?3)[(%Solute)-(%Solute)] can describes the dissolution rate; Dissolving process is mainly driven by Mg O concentration difference of solid-liquid interface, and the melt viscosity have great influence on the rate of dissolution; The diffusion coefficient of Mg O in this study ranges from 1.03×10-6 to 1.18×10-5 cm2·s-1. The content of melt has great influence on the Mg O dissolution activation energy, and it’s in the order of magnitude of 102 k J·mol-1, which is higher than the Si O2 dissolution activation energy however, the chemical reaction of Mg O dissolving into calcium ferrite melt melt happens into the rod sample, because The melt serious erosions into the rod sample. |
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