A simulation experimental study on oxidative kinetics of sphalerite under hypergene condition

• Published in: Acta geochimica 2012-12, Vol.31 (4), p.457-464
• Main Authors: Pan, Ziping, Ye, Lin, Liu, Tiegeng, Cheng, Zengtao, Gao, Wei, Yang, Yulong
• Format: Article
• Language: English
• Subjects: Chemical reactions; Dissolution; Earth and Environmental Science; Earth Sciences; Geochemistry; Ion concentration; Kinetics; Oxidants; Oxidation; Oxidation rate; Oxidizing agents; Pollution; Simulation; Sphalerite; 三价铁离子; 化学反应控制; 模拟实验; 氧化动力学; 氧化速率; 表生条件; 铁离子浓度; 闪锌矿
• ISSN: 1000-9426; 2096-0956; 1993-0364; 2365-7499
• DOI: 10.1007/s11631-012-0597-8

The sphalerite oxidative kinetics under hypergene condition was simulated and studied by means of a mixed flow reactor over a pH range of 1.0-7.8, and at dissolution temperatures from 20 to 55℃, ferric ion concen- trations from 1.0×10^-5 to 1.0×10^2mol/L, 02 flux of 0.5 L/min, and oxidants of ferric ion and 02. It is indicated that with ferric ion as oxidant, the oxidation rate of sphalerite increases with increasing ferric ion concentration, tem- perature and decreasing pH value, and under the studied conditions, the dissolution rates of Zn and Cd are approxi- mately identical, with the values of activation energy being 41.75 and 42.51 kJ.mol-~, respectively, suggesting that the oxidation rate of sphalerite is controlled by chemical reactions on mineral surface. However, with 02 as oxidant, the oxidation mechanism of sphalerite varies with pH value. Oxidation rate decreases with increasing pH value when pH is lower than 5.95, whereas the increase of pH value results in an increase in oxidation rate when pH value is higher than 7. The oxidation rate of sphalerite can be expressed as：