Abstract:Hematite is a kind of high-quality iron bearing material for the preparation of iron carbide, but there is a problem of low carburizing efficiency. In order to improve the carburizing efficiency of hematite, alkali salt were added to hematite. The mechanism of alkali salts in the carburizing process of hematite pellets was investigated using X-ray diffraction (XRD), high-frequency infrared carbon-sulfur analyzer and scanning electron microscope. The results show that the alkali salt (Na2CO3) can promote the transformation of dense iron ore particles into loose porous iron ore particles, strengthen the lattice distortion of iron ore, improve the adsorption and decomposition ability of CO on the surface of iron and iron carbide, so as to improve the reduction and carburization efficiency of hematite pellets. In addition, preheating treatment is very effective method to enhance the effect of Na2CO3 additive. Preheating treatment can not only strengthen the lattice distortion of iron ore, but also enhance the strengthening effect of Na+, which significantly improves the carburizing efficiency of hematite pellets. After preheating at 1 000 ℃ for 15 min, the carburization index of carburized pellets made from hematite containing 3%Na2CO3 increased from 13.23 to 28.99. The research results can provide reference for improving the carburizing efficiency of hematite.
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