关键词: 铜渣, 转底炉, 直接还原, 金属铁粉

Abstract: In order to solve the problem of development and utilization of a copper slag in China， the recovery of valuable element iron and zinc， and as well as the removal of impurity sulfur were studied by direct reduction-grinding magnetic separation process in simulated rotary hearth furnace with semi-coke as reducing agent and dolomite as additive. The results showed that the removal rate of zinc in direct reduction process was 99.14%， the ZnO content was 79.59% in zinc oxide powder under the conditions of 25% semi-coke， 10% dolomite， 1 300 ℃ reduction temperature and 35 minutes reduction time， and the metallic iron powder with 92.79% iron grade and 0.08% sulfur content was obtained with an iron recovery of 88.12% by grinding and magnetic separation from metallized pellets. The mechanism analysis showed that most of the iron-bearing minerals in copper slag had been transformed into metallic iron phases， which presented obvious aggregation and growth. The maximum metal iron particles could reach more than 100 microns， and there was a clear edge between the iron and gangue minerals， which would be propitious to obtain high-grade metallic iron powder by subsequent grinding and magnetic separation processes.

Key words: Copper slag, Rotary hearth furnace, Direct reduction, Metallic iron powder