Abstract Experiments were carried out to test the amenabilities of mineral deposits that contained cobalt deported in arseno-sulfide (cobaltite) and arsenide (skutterudite) minerals, to oxidative bioleaching at mesophilic temperatures and low pH. An ore sample from the Iron Mask deposit (Canada) and a mineral concentrate from a working mine (Bou Azzer, Morocco) were thoroughly characterised, both prior to and following bio-processing. A “top down” approach, using microbial consortia including (initially) 13 species of mineral-degrading acidophiles was used to bioleach the ore and concentrate in shake flasks and bioreactors. Cobalt was successfully liberated from both materials tested (up to 93% from the ore, and 49% from the concentrate), though the chemistries of the leach liquors were very different, with redox potentials being >200 mV lower, and concentrations of soluble arsenic about 7-fold greater, with the concentrate. Addition of pyrite to the arsenide concentrate was found to promote the biomineralisation of scorodite (ferric arsenate), which was detected by both XRD and SEM-EDX, but was not found in bioleached residues of the arseno-sulfide ore. A model was proposed wherein pyrite had three critical roles in facilitating the genesis of scorodite: (i) providing the catalytic surface to promote the oxidation of As (III) to As (V); (ii) acting as a putative “seed” for scorodite crystallisation; (iii) being a secondary source of iron, since the molar ratios of iron:arsenic in the concentrate itself (0.19:1) was well below that required for effective removal of soluble arsenic as scorodite (1:1). This work provided proof of concept that cobalt arseno-sulfide and arsenide ores and concentrates are amenable to bio-processing, and also that it is possible to induce concurrent solubilisation of arsenic from primary minerals and immobilisation in a secondary mineral, scorodite.

中文翻译：

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富砷钴矿产资源的生物浸出，以及方钴矿氧化生物加工过程中同时发生臭葱石生物矿化的证据

摘要 进行了实验以测试含有砷硫化物（钴矿）和砷化物（方钴矿）矿物中的钴的矿床在中温温度和低 pH 值下对氧化生物浸出的适应性。在生物处理之前和之后，对来自 Iron Mask 矿床（加拿大）的矿石样品和来自工作矿山（Bou Azzer，摩洛哥）的矿物精矿进行了彻底的表征。“自上而下”的方法，使用微生物群落，包括（最初）13 种矿物降解嗜酸菌，用于生物浸出矿石并在摇瓶和生物反应器中浓缩。尽管浸出液的化学性质非常不同，氧化还原电位低 > 200 mV，但成功地从两种测试材料中释放了钴（高达 93% 来自矿石，49% 来自精矿），可溶性砷的浓度大约是浓缩物的 7 倍。发现将黄铁矿添加到砷化物浓缩物中可促进臭葱石（砷酸铁）的生物矿化，XRD 和 SEM-EDX 均检测到这种情况，但在砷硫化物矿石的生物浸出残留物中未发现。提出了一个模型，其中黄铁矿在促进臭葱石的形成方面具有三个关键作用：(i) 提供催化表面以促进 As (III) 氧化为 As (V)；(ii) 作为臭葱石结晶的推定“种子”；(iii) 是铁的次要来源，因为精矿本身中铁与砷的摩尔比 (0.19:1) 远低于有效去除作为臭葱石的可溶性砷所需的摩尔比 (1:1)。