Study on recovering iron from smelting slag by carbothermic reduction

摘要

In order to recover the iron in copper smelting slag quenched with water in smelters, carbothermic reduction was adopted to reduce the iron oxide existing in different phase such as fayalite, vitreous and magnetite in the slag to metal iron. In the optimum conditions, it was demonstrated that the metallization efficiency of iron could reach more than 86.1%. Furthermore in the process the calcium carbonate is used not only as desulfurization agent，but also as accelerated gasification of solid carbon，which improved the ratio of CO among reaction atmosphere and enhanced the reduction rate of iron oxide as well as increased the metallization rate of iron．In addition this study proved that the combination ability between calcium positive ion and silicon oxygen anion is bigger than that between iron positive ion and silicon oxygen anion. As a result SiO_2 combined with CaO and FeO existed in a form of freedom state which guaranteed the reduction process went with a swing.