Sustainable Mining and Metallurgy

A large amount of gypsum produced during the waste acid treatment of a copper smelter is disposed as for sale, producing minimal benefit. In this paper, the production process of gypsum during acid making process was introduced; based on the property of gypsum that CaSO4 as its main composition is decomposed into CaO, SO2 and O2, and combining the high temperature conditions of flash converting furnace, the comprehensive utilization of gypsum was conducted; moreover, the influence of gypsum blending on flash furnace process, problems in gypsum recycling and corresponding optimization measures were set forth. The calcium oxide produced in the pyrolytic reaction of the blending of gypsum and pulverized coal in the flash furnace can be used to replace the quick lime required for production; the sulfur dioxide produced in the reaction is converted to sulfuric acid during the follow-up off-gas acid making process, increasing the output of sulfuric acid as a byproduct; the oxygen produced in the reaction can reduce the oxygen consumption in copper smelting. The comprehensive utilization of gypsum not only solves the environmental protection related issues of enterprises but also brings considerable economic benefits.