Abstract:Pyro-metallurgical process is usually applied to recover iron from copper slag beneficiation. According to thermodynamic principle analysis, the dominating compounds in beneficiation slag, i.e. fayalite and quartz, will react with NaOH spontaneously under given temperature and pressure when it is treated by hydrometallurgical process with alkaline solution. Sodium silicate solution and hematite can be generated from the reactions. Fe2O3 content in the residue is 71.54% and leaching rate of silicon is 76.22% under the optimum conditions including Na2O concentration of 200 g/L, temperature of 140 ℃, and reacting time of 2 h. The research results have formed the prototype of copper slag tailing separation and other metallurgical slag comprehensive utilization technology with similar composition.