The Smelting Of Low Silicon Pig Iron And The Research Of Influence Of The MgO Content In Slag

With the development of the iron and steel industry, especially the development of the clean-steel production technology, the production of iron-making and steel-making increase the requirements on the silicon content in pig iron. It is one of the effective ways of smelting the low silicon pig iron to increase the cleanliness degree of steel and to decrease the cost of iron and steal. There are a lot of factors affecting the silicon content in pig iron in the blast furnace production, and increasing the MgO content in the slag is one of the effective methods. This essay has a theoretical analysis on the mechanism of smelting low silicon content pig iron in the blast furnace and the relationship between the MgO content in slag and the silicon content in pig iron, and the author has experimental research on the relationship between the MgO content in slag and the slag nature. The essay puts forward the guiding suggestions of the production operation on the smelting of low silicon content pig iron in the end.The essay first analyses in detail the performance of silicon in the blast furnace, and the author finds that there are many factors affecting the silicon content in pig iron. Increasing the MgO content in slag will have great influence on the decreasing of silicon content in pig iron.The reason that increasing appropriately the MgO content in slag can decrease the silicon content in pig iron lies in the improvement of the nature of slag, which is mainly shown as follows: 1) decrease the activityof SiO2 in slag; 2) increase the softening temperature of slag; 3) decrease the viscosity of slag; 4) increase the stability of slag; 5) decrease the reaction surface between slag and coke; 6) the reduction gasification of MgO in slag contributes to the decrease of silicon content in pig iron.Based on the theoretical research, the author has experimental analysis on the relationship between the MgO content in slag and the slag nature. The result of the experiments shows: the appropriate increase of MgO content in slag course the decrease of slag viscosity, the decrease of flowing temperature and the increase of certainty , that improve the slag nature.In the end, based on the research results of this essay, the author puts forward operation guidance suggestions on how to increase MgO content in slag. The suggestions are as follows: 1) use the beneficiated burden for blast furnace to increase MgO content in sinter and pellet, which is a direct way to increase MgO content in slag of blast furnace; 2) decrease the coke rate and then increase comparatively MgO content in slag, which includes: first, adopt the intensification of smelting process to decrease coke rate such as using beneficiated burden, high hot-blast temperature, oxygen-enriched blast, high top pressure operation and fuel injection etc; second, combine the upper and lower conditioning to improve the utility of gas to decrease the coke rate.