Abstract: Furnace accretions are inevitably formed in the separation of smelting slag and matte, which are produced in the copper smelting by fire, when their melt is settling in the electric furnace. All existing methods of eliminating furnace accretions as well as the advantages and disadvantages of these methods are summarized and a new method of using Fe-S alloy prepared by Fe₂O₃, pyrite (main component FeS₂) and coke to eliminate furnace accretions is also included in this paper. The phase diagram of Fe-S binary system is used to analyze the properties of Fe-S alloy. The effects of preparation temperature, holding time and sulfur content on the density of Fe-S alloy are investigated. The results show that when the sulfur content is 35%(atom percentage, the same below), the best preparation temperature is 1 350 ℃ and the best holding time is 30 min; Under the best preparation temperature and holding time, if the sulfur content is between 32% and 41%, then the prepared Fe-S alloy can effectively eliminate furnace accretions.