銑鉄中のケイ素とイオウの濃度に及ぼす高炉操業要因の影響

抄録

For the purpose of determining optimum operating conditions for the refining processes of iron and steel making, transfer reactions of silicon and sulphur into pig iron were studied from the kinetic and thermodynamic points of view, and general estimation equations were derived concerning contents of silicon and sulphur in pig iron. The results obtained were summarized as follows :
( 1 ) Simulation was carried out by making use of actual operating data of thirteen blast furnaces whose operating conditions were different with regard to inner volume, production rate, fuel rate, and so forth, and it was confirmed that the equations in the present paper agreed approximately with the actual ones.
( 2 ) It was clarified that actual contents of silicon and sulphur in pig iron were nearly the equilibrium ones on the assumption that the partial pressure of CO generated in the layers of slag and pig iron was much the same as blast pressure.
( 3 ) Main operating factors exerting influence on the silicon content in pig iron were blast pressure, pig iron temperature, slag composition (basicity, contents of MgO and Al₂O₃ ), and pig iron composition (contents of C and Mn), and the effects of these factors on the silicon content were evaluated quantitatively.
( 4 ) Kinetic analysis as to the silicon transfer from SiO gas to molten pig iron in the region of blast furnace tuyeres indicated that besides the factors described above (3), the silicon content would be influenced by production rate and the dropping distance between a tuyere level and an inner edge of a cohesive zone.
( 5 ) Main operating factors exerting influence on the sulphur content in pig iron were blast pressure, total input sulphur, pig iron temperature, slag rate, slag composition (basicity contents of MgO and Al₂O₃) and pig iron composition (contents of C and Si), and the effects of these factors on the sulphur content were evaluated quantitatively.