硫酸介质中载金黄铁矿的氧化动力学

Oxidation Kinetics Reaction of Gold-Bearing Pyrite in Sulphuric Acid

利用自制反应器研究了黄铁矿的化学氧化溶解动力学过程,对氧化产物进行分析。结果显示:在温度为45～90℃内,黄铁矿的活化能为37.00 kJ·mol-1,结合黄铁矿的浸出率不受搅拌速度影响,认为黄铁矿的浸出过程受化学控制;溶液中Fe3+浓度与酸度影响黄铁矿的浸出;S物相分析与EDS图谱结果显示黄铁矿中的硫经过一系列中间形态,最终氧化成SO24-,并且有部分单质硫生成。由于S2O23-为中间关键的转化步骤,结合XPS图谱分析,认为S2O23-为中间过程的氧化机制。

Oxidation of pyrite in ferric sulfate solutions was studied using short-term batch experiments. The studies included analy- ses of sulfite, thiosulfate, polythionates and sulfate. The results of pyrite oxidation showed that the leaching rate of pyrite linearly in- creased with temperature increase, an apparent activation energy for pyrite oxidation was 37.00 kJ ·mol^-1 （45 - 90 ℃ ）. The magnitude of the activation energy and the speed with no effect suggested that the process of pyrite dissolution was controlled by reaction, and not by diffusion ; leaching rates was dependent on initial concentration of ferric iron and the acidity ; from analyses of phase, EDS and XPS, it was proposed that the formation of S2O3^2- in the intermediate stage was a crucial step for sulphide oxidation to eventually oxidize to sulphate and elemental sulphur during the oxidation process.