Gold leaching experiments were carried out on the left sulfur concentrate which was obtained by flotation in a lead and zinc mine of Hunan. The best condition of roasting oxidizing on refractory gold-bearing sulfur concentrate was studied with synchronous thermal analyzer. Besides,the surface morphology and the changes of main elements in raw ore and roasted ore were analyzed by scanning electron microscopy and energy spectrometer analysis. Effects of initial iodine content,iodine and iodide mol ratio,reaction time and liquid-solid ratio on lea...