闪锌矿-MnO_2同时发电浸出过程的动力学

Dynamics in simultaneous electrogenerative-leaching for sphalerite-MnO_2

将发电浸出技术用于闪锌矿-MnO2的同时浸出,建立了生物发电浸出的原电池体系,分别研究不同粒度、不同温度时,有菌和无菌条件对闪锌矿发电浸出的影响。采用未反应核模型来研究有菌和无菌发电浸出过程中化学反应和扩散现象、采用SEM研究同时发电浸出中A.f菌对闪锌矿表面的作用,结果表明:有菌时,闪锌矿粒度为16.6μm时,12 h Zn2+浸出率达到32.01%,而达到同样的浸出率采用常规生物浸出时需要10 d;发电浸出过程的控制步骤是扩散;在阳极液中有菌时,发电浸出体系的活化能为11.97 kJ/mol,而无菌时的活化能为14.39 kJ/mol,这表明A.f菌能降低发电浸出反应的活化能。发电浸出进行24 h后,A.f菌能氧化发电浸出产生的硫。

The principle for the electro-generative leaching was applied to simultaneous leaching of sphalerite-MnO2. A galvanic system for the bio-electro-generative leaching was set up. The effects of grain size and temperature on rate of zinc extraction from sphalerite in the of presence and absence of A. ferrooxidans were studied, respectively. The unreacted shrinking core model was used for describing the reaction-relative and diffusion-relative phenomena presented in the process of the electro-generative leaching with and without bacteria, which is considered to be diffusion control. SEM was used to study the effect of A. ferrooxidans on the ores in the electro-generative simultaneous leaching. The results show that with bacteria, the maximum extraction of zinc from the ores with grain size of 16.6μm can reach 32,01% for 12 h, while to obtain the same extraction ratio in the traditional bio-leaching route （i.e. not electro-generative one） takes ten days to ore granules with the same size. The activation energies of the anodic reaction for leaching system in the presence and in the absence of bacteria are calculated to be I 1.97 and 14.39 kJ/mol, respectively, indicating that they can be decreased by A. ferrooxidans. The produced sulfur on the surface of the sulfides can be oxidized by A. ferrooxidans after bio-electro-generative leaching for 24 h.