Abstract The abundance of limonitic laterite ores in tropical and sub-tropical areas represents a large, and mostly unexploited, cobalt resource. Bioprocessing oxidised ores, and also waste materials such as tailings and processing residues, using acidophilic microorganisms to catalyse the reductive dissolution of iron and manganese minerals, is an environmentally benign alternative approach of extracting valuable base metals associated with these deposits. This work describes results from laboratory-scale experiments in which five cobalt-bearing materials, three primary limonitic laterite ores and two processing residues (filter dust and slag), all sourced from mines and a processing plant in Greece, were bioleached under reducing conditions by a consortium of acidophilic bacteria (using elemental sulfur as electron donor) in stirred tank bioreactors at pH 1.5 and 35 °C. Whilst the target metal, cobalt, was successfully bioleached from all five materials (40–50% within 30 days) the extraction of some other metals was more variable (e.g. between 2 and 48% of iron). Concentrations of soluble cobalt were highly correlated, in most cases, with those of manganese, in agreement with the finding that cobalt was primarily deported in manganese (IV) minerals. Acid consumption also differed greatly between mineral samples, ranging between 3 and 67 moles H2SO4 g−1 cobalt extracted. Comprehensive mineralogical analysis of the three limonitic samples before and after bioprocessing revealed significant variations between the ores, and demonstrated that elemental and mineralogical variabilities can greatly impact their amenability for reductive bioleaching.

中文翻译：

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用于贱金属回收的含钴材料的硫增强还原生物处理

摘要 热带和亚热带地区蕴藏着丰富的褐铁矿红土矿，代表了大量且大部分未开发的钴资源。生物处理氧化矿石以及尾矿和加工残渣等废料，使用嗜酸微生物催化铁和锰矿物的还原溶解，是一种环境友好的替代方法，可提取与这些矿床相关的有价值的贱金属。这项工作描述了实验室规模实验的结果，其中五种含钴材料、三种初级褐铁矿红土矿石和两种加工残留物（过滤粉尘和矿渣）均来自希腊的矿山和加工厂，在 pH 1.5 和 35 °C 的搅拌罐生物反应器中，由嗜酸细菌聚生体（使用元素硫作为电子供体）在还原条件下进行生物浸出。虽然目标金属钴已从所有五种材料中成功生物浸出（30 天内 40-50%），但其他一些金属的提取变化更大（例如，铁的 2% 至 48%）。在大多数情况下，可溶性钴的浓度与锰的浓度高度相关，这与钴主要在锰 (IV) 矿物中被驱逐出境的发现一致。矿物样品之间的酸消耗量也有很大差异，提取的钴在 3 到 67 摩尔 H2SO4 g-1 之间。生物处理前后三个褐铁矿样品的综合矿物学分析显示矿石之间存在显着差异，