| The productivity and quality of sinter have direct effects on blast-furnace iron-making, while the conventional characteristics of iron ore for sintering as well as the sintering basic characteristics have fundamental effects on the metallurgical properties of sinter, and the basicity play a crucial part in the sintering process and the metallurgical properties of sinter. In order to further improve the quality of sinter, a study on the conventional characteristics of sintering iron ore and the sintering basic characteristics is required, based on which the study on the effects of basicity on sintering process as well as the metallurgical properties of sinter needs to be done on the purpose of finding out the optimal basicity suitable for the existing sintering conditions.This experiment uses the Russian vanadium titanium sinter applied in a domestic steel mill and homemade mixed powder as the object of study, and is aimed at studying the basic sintering properties of the two kinds of iron ore powder. It also examines the effects of basicity on the sintering process and the metallurgical properties of sinter.The conventional characters of Russian vanadium titanium sinter and the mixed powder are analyzed under the circumstances of the lab. Through the study the assimilation properties, the liquid liquidity, the intensity of binding phase, the crystal consolidation strength as well as the melting point and speed are examined.The result of the experiment shows that the homemade mixed powder has relatively lower assimilation temperature (1291℃), has the best liquid liquidity (with a liquidity index of4.20), a high self-intensity of binding phase (2010N/sample), and has a good quality of crystal consolidation strength (compression strength622N/sample). The Russian vanadium titanium sinter has a high assimilation temperature (1335℃), has bad liquid liquidity (with a liquidity index of1.95), a low grade of binding phase intensity (compression strength lower than450N/sample), and a bad crystal consolidation strength (compression strength 365N/sample).Under the circumstances of the lab, the particle properties and chemical compositions of Russian vanadium titanium magnetite and the homemade mixed powder are examined through experiments, and the effects of basicity on the parameters of sintering process and the effects of basicity on sintering process parameters and the cold compression strength of sinter are studied.The result of the sintering experiment shows that the homemade mixed powder has relatively large diameter, larger size of granularity, and is easier to granulate due to ribbed edges and has higher grade of iron. Russian vanadium titanium sinter, which belongs to high chromium type of titanium, has smaller diameter, smaller size of granularity, and has ordinary granulating performance. Its granulation rate can be improved by ameliorating the pelletizing process. With an basicity of1.9-2.7, and with the fixed material height, the sintering time of sample using40%of Russian vanadium titanium sinter and20%of homemade mixed powder becomes shorter, the vertical sintering velocity gets higher, the firing rate and the10mm yield gets lower, the drum index gets first lower and then higher, the abrasion resistance index constantly gets lower, the abrasion resistance improves and the utilization factor of sintering cup increases with higher basicity.According to the results listed above, and considering the existing raw materials, the fuels as well as the sintering process, the mixed sample of Russian vanadium titanium sinter and homemade mixed powder is selected for practical use. The basicity of the sample using40%of Russian vanadium titanium sinter and20%of homemade mixed powder should be increased to2.5-2.7. But with higher basicity, the full iron content of sinter will decrease. In order to guarantee the full iron grade of the furnace sinter, the basicity should not be too high. When the basicity is limited to a certain level, and when R=2.5, the sinter has the best falling strength. Therefore the basicity should be increased from the existing2.1to2.5. |
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