2500m~3 Blast Furnace Iron-Making Practice By Using Coke With High CRI And Low CSR In Bayi Steel

With chronological order, the actual production of 2500m3 blast furnace in Bayi Steel Complex can be divided into three stages. The first stage from opening in 2008 to the end of 2010 is the period to explore the operation for the blast furnace upscale. The second stage from the beginning of 2011 to April, 2013 is the period for the fluctuant in operation for the scaling expansion. The third stage from May, 2013 to present is the period of balance and stabilization for the operation system. The reasons for fluctuations of blast furnace operation can be analyzed and summarized as two. Firstly, facing that the three large-scale blast furnaces were put into operation in succession, the operators were learned and explored to the operation of large-scale blast furnaces. Secondly, the insufficient supply of raw materials as well as low temperature in the winters resulted in a passive situation of production. From 2008 to 2014, both cold and thermal properties of coke used had being been studied. During the period, the cold property indexes, such as M40(M25) and M10 had being been improved.for example, the M10 had been dropped from about 10.0% in 2008 to about 6.0% in 2014. The thermal properties of coke used, so called Coke reaction index(CRI for short) and Coke strength after reaction(CSR for short) had fluctuated largely. In 2008, The ranges of CRI is from 26.60% to 53.75% and that of CSR is from 16.30% to 60.50% respectively. Then the situation changed, up to 2014, the CRI and CSR were stabilized form 30% to 40% and from 40% to 50% respectively by continuous optimization.It is found that the the blast furnace operation situation did not corresponded with the coke' CSR while analyzing the intrinsic link of coke thermal property indexes with blast furnace operation indexes. It indicates that the coke behavior in blast furnace being simulated by CSR is inadequate. In view of this and referenced with the newly progress of relevant studies, the reasons for coke with high CRI and low CSR being used in blast furnace were adopted. In order to increase the proportion of local coal produced in Bayi Steel and reduce the costs further, a new coal blending scheme is proposed by summarizing coal blending research at the end of 2008 and the end of 2013. The new measures to reduce costs are put forward from the production process combined with the actual production of coking production line.