The synthetic slag composed of CaO, SiO2 and Al2O3, was mixed with magnetite as well as graphite powder to prepare carbon bearing pellets, in which amount and composition of the synthetic slag as well as carbon content were changed to examine the variation of carburizing content in molten iron, and the molten carburizing behavior as well as mechanism in carbon bearing pellets were discussed. The molten carburizing process proceeds into two stages：smelting- reduction and molten iron drops polymerization. There is a dynamic balance between Fe2+ content in molten slag and carburizing content of molten iron during the first stage, which is influenced by chemical composition of the molten slag. The second carburizing stage determines the physical carburization limit of iron, which is related to the contact condition between iron and carbon particles in pellets. Moreover, the reduction limit of Fe2+ in molten slag is influenced by basicity and SiO2 absolute content. The molten carburizing content of iron in the present work reached about 4%, which meets the requirement of separation between iron and matte melt.
Key words
carbon bearing pellet /
molten carburizing process /
reduction limit /
carburizing limit
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Footnotes
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Funding
National Natural Science Foundation of China
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