Study On Characters And Structure Of Coal For Injection In Blast Furnace Of Chongqing I & S Co.

The metallurgic, physical and chemical theories and methods have been used to study on the physical and chemical characteristic of the pulverized coal on blast furnace of Chongqing I&S Co., behavior of unburned coal existed in the BF. The requirement of coal powder and the blast furnace theory combustion temperature effect caused by PCI was researched theoretically. In the present refining conditions, the appropriate coal structure and pulverized rate is given, and practical experience was analyzed on No.5 BF of Chongqing I&S Co.Determination of physical chemical characters of bituminite and anthracite, the result indicate that the volatile fraction in the bituminite was more than the anthracite; the H value is increased as the volatile fraction grows. Ash composition result indicates that the SiO2 value and Al2O3 value in slag is high, increase of PCI rate which will effect formation of slag system.The grind ability of different coal and different proportion mixed coal was researched experimentally. The mass proportion of coal less than 74μm grows as the increased. Power manufacturing technology, combustion of different grain size and economic benefits considered, and the appropriate grain size (less than 200 sieve numbers) for Chongqing I&S Co. is 75%.The combustion of bituminite, anthracite and mixed coal, and the characteristics of thermal decomposition and reactivity in different temperature were researched experimentally. The result indicated that the combustion rate of bituminite is higher than anthracite .The combustion rate of mixed coal is increased as the bituminite proportion increased. Bituminite has a better reactivity than the anthracite, and the index will be increased as the proportion of bituminite grows. The result of thermal analysis is that the bituminite have a lower temperature for weight-loss than the anthracite, because the coalification degree is different. Some organic macromolecule only could be decomposed in high temperature. The suggested structure of coal for Chongqing I&S Co. is: bituminite 40-45% and the anthracite is 55-60%.The microstructure of coal was analyzed theoretically. The vitrinite and half-vitrinite are active component, and the inertinite is not that active. There is a great deal of half-vitrinite and fusinoid group in the unburned coal. The relationship of unburned coal and the PCI rate, behavior of unburned coal and effect on the character of slag. The unburned coal influence the viscosity of slag deeply, however, has little effect on the melting point. When the PCI rate is 120kg/t.Fe, there are less unburned coal, and will have little affected on the blast furnace, under the present conditions of No.5 BF of Chongqing I&S Co..