Abstract: The paper describes the current development of pyrite slag utilization technology and the characteristics of roasted pyrite slag. The optimal process conditions for pyrite slag treatment by chemical method were determined by experiments, including using aqua regia as the leaching agent at a 5% dosage and a 50 g/L concentration, a 70 ℃reaction temperature and a 2 h leaching time. The iron concentrate obtained by the experiment had a 60.70% iron grade, 98.50% recovery, 62.10％ desulfurization rate and a 0.27%sulfur content. Based on the experiments, the pyrite slag leaching mechanism is analyzed. It is concluded that the leaching agent can promote the dissolution of CaSO₄, oxidation dissolution of metal sulphides and dissolution of basic oxides, and that water rinsing is also the key in the process of treating pyrite slag by chemical method, which can promote the dissolution of soluble substances and also clear off their attachment.

Key words: Pyrite slag, Iron concentrate, Desulfurization rate, Leaching mechanism