Abstract:Spraying limestone powder into the converter for slag dephosphorization is beneficial for improving reaction efficiency, it can be slagging rapidly, at the same time can also be resourceful use of CO2. Therefore, based on thermogravimetric differential thermal analyzer and high-temperature tube furnace, the decomposition behavior of small particle limestone at steelmaking temperature was studied. The research results show that with the decrease in heating rate, the starting temperature and completion temperature of small particle limestone decomposition decrease,and the faster the rate of heating, the shorter the duration of decomposition reaction. Limestone particles with particle size of 2.5 mm or less can be decomposed quickly under 1 000 ℃, the smaller the particle size, the faster the decomposition, and the lower the completion temperature of the reaction, so it can be seen that the use of powder spraying in the converter can reduce slagging time and improve smelting efficiency. Compared to N2, air, and O2, under the pure CO2 atmosphere, the completion temperature of thermal decomposition reaction for limestone increases, but the time required for decomposition is shortened by 1/3, and with the increase in partial pressure of CO2, the completion temperature of decomposition increases while the decomposition accelerates. With the increase of calcination temperature, the time required for complete decomposition of limestone with different size is shortened to different degrees, and the larger the particle size, the more obvious shorten degree. At the same calcination temperature, the time required for complete transformation of limestone shows a trend from longer to shorter then to longer again as the limestone size goes from small to large. Only from the calcination efficiency of small particle limestone, converter blown limestone powder particle size selection of 0.13-1.5 mm is appropriate.
WU W, DAI S F, LIU Y. Dephosphorization stability of hot metal by double slag operation in basic oxygen furnace[J]. Journal of Iron and Steel Research International, 2017, 24(9):908.