Study On Leaching Of Zinc From Two Sulfur Oxygen Mixed Zinc Ore

Zinc is mainly used for galvanizing protection and battery manufacturing industry, its production mainly using zinc sulfide as the raw materials. As zinc sulphide resource are increasingly drying up, more attention has been paid to the development and utilization of zinc oxide ore. However acidic solvent processing zinc oxide ore make a large number of alkaline gangue and silicate by dissolution, not only the great amount of acid consumption, and pulp of liquid-solid separation difficult, and the ammonia kind of solvent can avoid alkaline gangus and leaching of silicate. With the application of ammonia process in nonferrous metals, ammonia leaching has been paid attention to in the process of Zinc Oxide mine. In this paper with hemimorphite, sphalerite and mixed ore as raw material, respectively adopt ammonia solution as leaching agent of hemimorphite and weak acid solution with ultrasonic as of sphalerite. The effects of temperature, concentration, stirring rate, leaching time, liquid to solid ratio, etc, on the leaching rate of zinc were investigated., and experimental study and analysis on kinetics of ammonia leaching. By using X ray diffraction, scanning electron microscope test of hemimorphite, sphalerite and leaching slag,come to the following conclusion:(1)NH3-(NH4)2SO4 is adopted to leach of hemimorphite, through the single factor experiment to obtained the optimal technological conditions:the whole ammonia concentration 8.5 mol/L, [NH3]/[NH4+] concentration ratio 1-1, liquid-solid ratio 20 " 1, stirring speed 300 r/min, leaching temperature 45℃,11 mL ethylenediamine as extractratio per 100mL leaching agent, leaching time 1 h, hemimorphite leaching rate can reach 97.7%.(2)In pH=4 sulfuric acid solution, with hydrogen peroxide leaching of sphalerite,the experimental conditions are:initial liquid-solid ratio between sulfuric acid solution and ore is 10:1, with hydrogen peroxide, stirring speed 300 r/min, total leaching time 4h, leaching temperature 45℃, ultrasonic frequency 53Hz, the total ultrasonic time 40min in 4 times, sphalerite leaching rate can reach 56%.(3) The mixed ore has been processed by ultrasonic assisted extraction first and then ammonia leaching. The experimental conditions of ultrasonic assisted extraction are:initial liquid-solid ratio between sulfuric acid solution and mixed ore is 10: 1, with hydrogen peroxide, stirring speed 300 r/min, total leaching time 4h, leaching temperature 45℃, ultrasonic frequency 53Hz, the total ultrasonic time 40min in 4times. The experimental conditions of ammonia leaching are:the whole ammonia concentration 8.5 mol/L, [NH3]/ [NH4+] concentration ratio 1:1, liquid-solid ratio 20:1, stirring speed 300 r/min, leaching temperature 45℃,11 mL ethylenediamine as extractratio per 100mL leaching agent, leaching time 1 h. Mixed ore leaching rate can reach 91%.(4) This process of hemimorphite leaching in NH3-(NH4)2SO4 follows the shrinking unreacted core model, and follows the rules of solid product layer diffusion control, The activation energy of the stage is calculated to be 16.25 kJ/molo The process of mixed ore leaching in NH3-(NH4)2SO4 follows the shrinking unreacted core model, and follows the rules of solid product layer diffusion control, The activation energy of the stage is calculated to be 19.1kJ/mol.