Abstract:
An improved method of (NH
4)
2SO
4 roasting followed by water leaching to utilize zinc oxidized ores was studied. The operating parameters were obtained by investigating the effects of the molar ratio of (NH
4)
2SO
4 to zinc, roasting temperature, and holding time on zinc extraction. The roasting process followed the chemical reaction control mechanism with the apparent activation energy value of 41.74 kJ·mol
−1. The transformation of mineral phases in roasting was identified by X-ray diffraction analysis combined with thermogravimetry–differential thermal analysis curves. The water leaching conditions, including the leaching temperature, leaching time, stirring velocity, and liquid-to-solid ratio, were discussed, and the leaching kinetics was studied. The reaction rate was obtained under outer diffusion without product layer control; the values of the apparent activation energy for two stages were 4.12 and 8.19 kJ·mol
−1. The maximum zinc extraction ratio reached 96% while the efficiency of iron extraction was approximately 32% under appropriate conditions. This work offers an effective method for the comprehensive use of zinc oxidized ores.