Research On Improving The Property Of Anti-pulverization In Low-temperature Reduction Of Low Silicon Sinter

In order to enhance the productivity of blast furnace and reduce the coke rate, the effective means is smelting with the low-silica sinter. However, the homogenization of low silicon sinter decreases with the decrease of SiO2 , the intensity becomes low and the property of anti-pulverization in low-temperature reduction process is poor.This test studied the reducibility of the sinter and the property of anti-pulverization in low-temperature reduction process, and the sinter is offered by one iron and steel corporation.The result showes that the reducibility of sinter is well,and the average value of RI is 77.85 percent. However, the property of anti-pulverization in low-temperature reduction process is bad.The average value of RDI+3.5 is 56 percent, and the lowest value is 40 percent. The property of anti-pulverization improved effectively with the addition of CaCl2, and the value of RDI+3.15 increased by 10 percent.However, no significant decrease was found for the the leveal of RDI-0.5.In order to improve the property of anti-pulverization in low-temperature reduction process, sintering cup test was proceed to study the microstructure of low-silica sinter with the help of mineragraphy microscope. The effect of the content of sinter and sintering process on the property of anti-pulverization in low-temperature reduction process were studied.The results are as follows:The main structure of low-silica sinter is charactered by (interlace solution), the property of anti-pulverization in low-temperature reduction process improves with the increase of the content of Fe3O4 and calcium ferrite in the sinter, while silicate glass and hematite distributing intensively in the sinter do harm to the property of anti-pulverization, especially the skeleton crystal hematite.With the Al2O3/SiO2 increase, SFCA formed and the properaty of sinter is improved. However, more cavity also formed at an excessively high leveal of Al2O3/SiO2, and the optimum level of Al2O3/SiO2 in the present study is 0.31.The content of MgO has a double impact on the property of anti-pulverization in low-temperature reduction process and the optimum level of MgO is 2.02 percent.For the present sinter and sintering process, the decrease of Australian ore proportion will improve the property of anti-pulverization and the optimum ratio of Australian ore is 9 percent.The increase of fuel matching is in favor of the rate of finished products, rotating drum exponent and the property of anti-pulverization in low-temperature reduction process.But an excessive level of fuel matching will make the microstructure worse, the optimum level of fuel matching is 5.0 percent for the present sinter.With the increase of basicity, the structure of sinter transformed into cementation phase which is riched in calcium ferrite. The microstructure is improved and the pulverization in low-temperature reduction process is restrained effectively. The optimum leveal of basicity identified as 2.3 based on the test. Low-temperature sintering will proceed more easily when the thickness of the bed of material increases.But an excessive tinckness will lead to the transformation of sinter phase and the property of anti-pulverization in low-temperature reduction process becomes worse. The optimum level of thickness was identified as 515mm in this study.