Development of Bioreactors for Leaching of Sulfide Minerals

这份报告描述了一种生物工程方法，在以各种模式运行的搅拌槽反应器中，利用嗜酸性硫氧化细菌对硫化物矿物进行生物浸出。使用我们先前提出的间歇生物浸出动力学模型，对氧化亚铁硫杆菌-元素硫系统收集的速率数据进行了分析，以评估微生物动力学和化学计量参数。元素硫的这些关键参数与黄铁矿(FeS_2)和闪锌矿(ZnS)等金属硫化物的关键参数的大小相似。此外，在黄铁矿的浸出过程中，嗜热菌的比生长速率约为中嗜性氧化亚铁杆菌的4倍，说明嗜热菌比中嗜热菌对黄铁矿的浸出效果更好。采用重复间歇操作(部分置换溶液)和半间歇操作(溶液连续进入…)，大大加快了黄铁矿的生物浸出更多的ND从反应器中移除，但黄铁矿颗粒仍留在反应器中)。为了预测半间歇和重复间歇反应器中的生物浸出动力学，对间歇模型进行了修正，考虑了反应器中游离细胞的去除。模型预测结果与观察到的生物浸出速率基本一致。当生物反应器同时对液体和黄铁矿颗粒进行连续观察时，随着稀释率的增加，平均浸出分数和游离细胞浓度迅速下降。浸出率对稀释率有一个极大值，浸出率与料液装料量不成正比。将间歇模型扩展到连续流反应器中模拟生物浸出过程。在较宽的稀释率和进料固体浓度范围内，连续模型对实验数据进行了较好的预测，为矿产资源生物浸出搅拌槽式反应器的合理设计和运行提供了有用的信息。较少

This report describes a biochemical engineering approach to the bioleaching of sulfide minerals by acidophilic sulfur-oxidizing bacteria in stirred tank reactors operated in a variety of modes.1. Rate data collected for the T.ferrooxidans-elemental sulfur system were analyzed to evaluate the microbial kinetic and stoichiometric parameters, using our kinetic model previously proposed for batch bioleaching. These key parameters for elemental sulfur were similar magnitude to those for metal sulfides such as pyrite (FeS_2) and sphalerite (ZnS). In the leaching of pyrite, moreover, the thermophile A.brierleyi had about four times the specific growth rate of the mesophile T.ferrooxidans, demonstrating that the thermophile is more effective than the mesophile for the pyrite leaching.2. The bioleaching of pyrite was observed to be greatly accelerated by adopting the repeated batch operation (partial replacement of solution) and the semi-batch operation (the solution was continuously fed into a … More nd removed from the reactor, but the pyrite particles stayd in the reactor). To predict the bioleaching kinetics in the semi-batch and repeated batch reactors, the batch model was modified to take into account the removal of free cells from the reactor. The model predictions were consistent with the observed bioleaching rates.3. When the bioreactor was oberated continuously with respect to both liquid and pyrite particles, the mean leaching fraction and the free cell concentration decreased repidly with increasing the dilution rate. There was a sharp maximum in the leaching rate with respect to the dilution rate, and the leaching rate was not directly proportional to the solid-liquid loading ratio in the feed. The batch model was extended to simulate the bioleaching in a continuous flow reactor. The experimental data were predicted well by the continuous model over a wide range of dilution rates and feed solid concentrations.The above-mentioned results provide useful information concerning reasonable design and operation of stirred tank reactors for bioleaching processes of mineral resources. Less