Development And Application Of Low-magnesium Compound Desulfurizer

The complexity of V-Ti magnetite gives some difficulties in desulfurizing at pangang. The titanium-vanadium magnetite contains amount of V, Ti elements, so the molten iron has higher sulfur composition, and its temperature is lower 40-50℃than common molten iron. With the low Si and low temperature and existence of Ti and V elements, it formats a considerable number of TiC, TiN,Ti (C, N) and other high melting point materials during BF ironmaking, so the fluidity of desulphurzing slag is not very good. These factors lead to low utilization rate of desulfurizers in pangang steel. Though the hot metal desulphurization gains some achievements at pangang, it has high cost of desulfurizing as the price of magnesium is become higher and higher and economic crises happens. So it is necessary to find a kind of low cost desulfurizer which is suitable to current desulfurization process as to reduce the burden of pangang steel.One kind of low cost compound desulfurizers is carried out by the orthogonal test in the laboratory which is also test by a large amount of industry-trials. From the experiments and tests,we can get the following conclusions:(1) On the conditions of the present vanadium bearing hot melal, the Mg-CaO-CaC2 compound desulfurizer can get a better desulphurization effects in theory, the final pretreatment of sulfur content in hot metal can be lowed to 10-7%, While using the CaO alone, the sulfur content in hot metal can only be lowed to 1.57x10-3%and While using the CaO alone, the sulfur content in hot metal can only be lowed to 0.66x10-4%.(2) Though the orthogonal test in the laboratory, the best ratio of the compound desulfurizer is carried out. The percentage of best compound desulfurizer is thatω(Mg):ω(Mg):ω(CaC2):ω(Na2CO3):ω(CaF2):ω(C):co(CaO)=4.6:25:6:3:2.5:58.9.(3) A large amount of contrast trial between the compound desulfurizer and AD desulfurizer showed that average desulphurization effect with the compound desulfurizer is 87.14%, which is increased by 6.03%; the average iron loss is 4.65%, which is reduced by 0.61%; the average V loss in desulfurization is 0.0086%, which is increased by 0.0001%. (4) Analyzing the large amount of production data in desulfurizing station of panzhihua steelmaking plant by the multivariant liner regression method, model of desulfurization ration by operating parameters is followed:y=0.843+0.0051nWp-1.4E-006t-1340.552ω(So)+1563.739Xs-0.0021nω(V)This model shows that the desulfurization rate increases with increasing the desulfurizer consumption; the desulfurization rate decreases with prolonging the blowing time; the initial contents of desulfurize is as low as possible; the desulfurization rate decreases with increasing the injection speed of desulfurizer. And also the model shows that the desulfurizer consumption is 8-10kg/t,the blowing time is around 23min, the desulfurization rate is 0.3-0.4 kg/min-t, all of which are the priority consideration, when the desulfuriziton process is optimized.Using this compound desulfurizers has created an enormous economic benefits, which has provides strong support for pangang to deal with the economic crisis that happened in 2008. And also this desulfurization model gives strong support for the automation of iron production and optimum of desulfurization process parameters.