Investigation On Sintering Basic Characteristic Of Iron Ore In Brazil

At latest year, the development of iron and steel industry more and more depends on imported iron ores in our country, and it results in the large fluctuation in the raw material. So further researches on the basic characteristic of imported iron ores provide powerful basis on judging its granulation and sintering properties, selecting feasible processing parameter, steel corporation buying iron ores and optimizing the ore matching, and guiding sintering yield. Also it has important and realistic significance in the promotion of the iron and steel industry in our country.By the way of briquette------roasting in the tube furnance------microc-examination, the paper researches the formed characteristic of calsium ferrite. Different experimental methods, such as cylinder granulation, measurement of air permeability properties, water sieve, and so on, are adopted in the experiments of granulation poperties and the creation of granulation model. Combining the experiments in the sintering plot, the paper creates the relation of the formed characteristic of calsium ferrite and the tumbler strength of sinter, and the relation of the granulometry of sinter mix material and the speed of sintering.The experiment results of the formed characteristic of calcium ferrite show: along with the change of fuel, roasting temperature, time of high temperature, the quantity of calsium ferrite which yieided by iron ores and calcium oxide changes parabolically. If the quantity of silica in the iron ores is more, the large-grained iron ores yield more quantity of calsium ferrite, but the fine-grained iron ores yield less quantity of calsium ferrite.The experiment results of granulation test show: the structure model of granulating pellet with high ratio concentrate is: 20%～40% itself size class and 80%～60% quasi granule. The quasi granule of granulating mixed material focus on 3～8mm. The nucleus granule is 1～5mm, distributing dynamically. The adhesive granule is -0.5mm. The proportion of nucleus granule and adhesive granule in the granulating pellet with 5～8mm is higher than its in other size class.If the proportion of nucleus granule and adhesive granule is higher, the content of size class +5mm is more, and the content of size class 1～5mm is less. If the content of adhesive granule in granulating pellet is more, the water absorbed at granulation is more. Along with the ratio of concentrate increasing, the water used to granulation increases, and the average granularity has trend to increase. The air permeability of mixed material with high ratio concentrate is better than it of mixed material with high ratio fine ore. But the time of singtering is long, and the sintering velocity is slow, because the water is more, and the capability of concentrate yielding calcium ferrite is not better. When the average granularity of mixed material after granulation is in 4～4.5mm, the air permeability of mixed material is best, and sintering index is also better. At this time, the proportion of nucleus granule and adhesive granule at about 0.7 is best.