Study On Sintering Flue Gas Dry Desulfurization By Low Grade Manganese Ore

To solve the large SO2 emissions of China steel industry, the high operating costs, equipment corrosion, large occupation of land area, large consumption of fresh water, and formation of secondary pollutants of traditional desulfurization technology, such as lime stone/gypsum method, ammonia-ammonium sulfate method, magnesia method of wet flue gas desulfurization, a novel dry sintering flue gas desulfurization technology using low grade manganese ore was put forward. The basic principle of this technology was made the redox reaction between reducing agents manganese dioxide(Mn O2) and oxidizing agents sulfur dioxide(SO2) happened, which come from low grade manganese ore and sintering flue gas, respectively, namely the flue gas from sintering process could be desulphurization directly without further cooling or heating. Low grade manganese ore can removal SO2 of sintering flue gas to meet the stringent government regulations and achieve a goal of recovery a high value manganese-containing end-product economically. At the view of thermodynamic and macro-kinetics, the technology is entirely feasible. The mainly contents in this paper are as follows:The calculation of thermodynamic theory of dry desulfurization system was conducted according to the probable reactions occurring in the desulfurization process. The isothermal predominate diagram of Mn-S-O, Fe-S-O system were drawn by thermodynamic calculation. The thermodynamic analysis results showed that in the temperature range of sintering flue gas(120~180℃), low grade manganese ore has a great trend to generate manganese sulphate(Mn SO4), and high temperature is negative to dry desulfurization; the oxygen partial pressure is weak influence to dry desulfurization and there exist the coexistent stability region of Mn SO4 and Fe2O3 in diagram, indicating that Mn O2 can be sulfated without sulfide and sulfate of iron.In experiment applying using U-shaped glass tube as SO2-reacting apparatus, using compressed air-pure SO2 mixtures as simulated sintering flue gas, the conditions of dry desulfurization reaction rate including the temperature of sintering flue gas, the particle size of low grade manganese ore, concentration of SO2, and the rates of mixtures gas flow were addressed in detail. Results showed that the dry desulfurization rate of low grade manganese ore react with sintering flue gas temperature increases, along with pyrolusite mesh size increases, decreases with the increase of intake sulphur dioxide concentrations increased, with mixed gas flow decreases. At the appropriate condition, the removal of SO2 can reach 70%, which can meet the national pollution discharge of new iron and steel sintering machine. The paper also studied the macro-kinetics of and the experiment results concluded that the reaction rate of dry desulfurization process is limited by the outgoing quality and diffusion, and has nothing to do with interfacial chemical reaction. This conclusion is supported by reaction rate did not go up with the increases of temperature, apparent activation energy of interfacial chemical reaction and other calculation obtained from experimental data. Finally the model of macro-kinetic is established to describe the reaction rate of the dry desulfurization process: In which。The research will hopefully solve the low concentrations of sulfur pollution problems of sintering flue gas from iron-steel industry, and achieved the greatest utilization of low grade manganese ore resources, provided the basis for subsequent preparation of manganese products. In a word, it is significance for the treatment of sintering flue gas containing sulphur and the development manganese industry.