Thermodynamics study of sodium hydroxide roasting in a poly-metallic gold mine

Roasting is an effective pre-treatment technology to improve gold and silver recovery rate for poly-metallic gold mine. ΔG_T⁰-T function of the main chemical reaction during NaOH roasting process in the poly-metallic gold mine by thermodynamic calculations. ΔG_T⁰-T is drawn accordingly. Thermodynamics calculation results show that NaOH roasting lowers the generating chances of copper ferrite, zinc ferrite, zinc silicate and lead silicate, whose binding forces to Au and Ag decreases accordingly. The appropriate temperature of roasting sodium hydroxide is higher than 834.33 K.