Research On The Sintering Characteristics Of Typical Imported Iron Ores

Iron ore resources are poor in China. Large amount of low-grade iron ores, poor condition of exploitation and higher cost limit the increasement of domestic iron ores production. The development of steel industries in our country depends more heavily on the imported iron ores than before. In 2004, the proportion of imported iron ores used in the iron making surpassed 50%. Further researches on the sintering characteristic of imported iron ores have important and realistic significance in the promotion of the steel industry in China because different kinds of imported iron ores are characterized as varied sintering properties.A new method is developed to take systematical researches on the sintering characteristics of imported iron ores in this paper. This paper takes eight various kinds of imported iron ores widely used in China as the objects by using this method. They are YANDY, KP, HM, PG, HF, HIBF, EG and MAC. Different experimental methods, such as disk granulation, measurement of air permeability properties, and so on, are adopted in the experiments of granulation properties. By the way of briquette—roasting in the tube furnace, the researches on the influence of the beginning temperature of massive formation of calcium ferrite(T_10%), the maximum generation temperature of calcium ferrite(T_max), the amount of maximum calcium ferrite(Q_max), the temperature zone of massive formation for calcium ferrite(ΔT_max) on the sintering characteristics are taken; these are tested by the experiments in the sintering plot.The experimental results of granulation properties show: the granulation properties of KP are the best, and those of PG are the worse, the others are moderate; the results of the mineral izaiton properties show that: (1) the beginning temperature of massive formation of calcium ferrite, T_10%: T_10% of YANDY is the lowest, and T_10% of EG, HM, HF are between 1195 and 1205℃, and T_10% of KP, MAC, HIBF are 1205℃ or so, and then T_10% of EG is between 1205℃ ¹225℃; (2) the maximum generation temperature of calcium ferrite, T_max: T_max of EG and HIBF is 1265 ℃; and that of PG is 1245 ℃; and that of other ones is 1225 ℃. (3)the amount of maximum calcium ferrite, the high-low sequence of Qmaxis as follows: YANDY, HIBF, MAC, HF, EG, PG, KP, HM. (4) the temperature zone of massive formation for calcium ferrite, the high-low sequence of ATmax is as follows: YANDY, HF, HIBF, EG, HM, PG, MAC, KP. Combined with the results of above researches, The conclusions are drawn from the sintering experiments: (1) While the water percentage is in the suitable condition, the larger ATmax is, the less influence coke percentage has in determining the strength of sinter; otherwise, the less ATmax, the more influence; (2) In the same sintering conditions, the greater the value of Qmax is, the better the strength of sinter ores is; while the value of Qmax is nearly the same, the lower Tmax is, the better the strength of sinter ore is. (3) while the value of Qmax is nearly the same, the higher the amount of crystal water in the imported iron ores is, the worse the strength of sinter ore is . The experiments in the sinering plot show: The new method which is developed plays a more important role in the sintering practice.