Oxygen pressure acid leaching of artificial sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation

Fe^3+/Fe^2+自沉淀催化人工闪锌矿的氧压酸浸

The mechanism of oxygen pressure acid leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation was investigated in this study.Artificial sphalerite was fabricated with varying amounts of iron content via the sintering of ZnS and FeS and used for the pressure acid leaching experiment.The variations in the potential of the pressure leaching system were investigated by using a self-designed potential autoclave.The results showed that compared to the non-iron sphalerite,there was a violent redox reaction between the 25.70%Fe-artificial sphalerite and dissolved oxygen during the process of pressure leaching;and the catalytic mechanism was attributed to the redox couple Fe^3+/Fe^2+,where Fe3+oxidizes the H2S gas film and the reduced Fe2+state is subsequently oxidized by the dissolved oxygen.Furthermore,the effect of temperature,H2SO4 concentration,and oxygen partial pressure on the artificial sphalerite with different iron contents was studied.The sphalerite samples with iron content were observed to dissolve more easily in sulfuric acid compared to the non-iron samples.Moreover,the activation energy of artificial sphalerite was observed to be lower in the sample with 25.70%iron content(22.26 kJ/mol)compared to that with no iron(32.31 kJ/mol);and the apparent reaction orders were obtained with respect to H2SO4 concentration(1.10 and 1.36)and oxygen partial pressure(1.29 and 1.41),respectively.A comprehensive kinetic model was developed on the basis of the experimental data and the fitted leaching ratio plot;and the kinetic equations for the leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation were determined.

本文研究了Fe^3+/Fe^2+自沉淀催化闪锌矿氧压酸浸的机理。利用ZnS和FeS烧结制备了具有不同铁含量的人造闪锌矿,并将其用于加压酸浸实验。利用自行设计的电位高压釜,研究了压力浸出系统的电势变化。结果表明,与不含铁闪锌矿相比,加压浸出过程中含25.70%铁的人造闪锌矿与溶解氧之间发生剧烈的氧化还原反应。催化机理归因于氧化还原对Fe^3+/Fe^2+,其中Fe3+氧化H2S气膜,还原的Fe2+随后被溶解氧氧化。此外,研究了温度、H2SO4浓度和氧分压对不同铁含量的人造闪锌矿的影响。与不含铁的样品相比,含铁的闪锌矿样品更容易溶于硫酸。铁含量为25.70%(22.26k J/mol)的人工闪锌矿的活化能比不含铁样品的活化能低(32.31k J/mol),并分别得到H2SO4浓度(1.10和1.36)和氧分压(1.29和1.41)的表观反应级数。根据实验数据和拟合的动力学图谱,建立了相关的动力学模型,并得到了Fe^3+/Fe^2+自沉淀催化闪锌矿浸出的动力学方程。