Chromium (VI) Inhibition of Low pH Bioleaching of Limonitic Nickel-Cobalt Ore.
Chromium (VI) Inhibition of Low pH Bioleaching of Limonitic Nickel-Cobalt Ore.
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DOI：
10.3389/fmicb.2021.802991
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发表时间：
2021
影响因子：
5.2
通讯作者：
Johnson DB
中科院分区：
文献类型：
--
作者：
Santos AL;Dybowska A;Schofield PF;Herrington RJ;Cibin G;Johnson DB
风化层的褐铁矿通常作为废物储存在红土矿山中，通常含有大量有价值的贱金属，如镍、钴和锰。目前对这些过渡金属有相当大的需求，预计在今后几十年将继续增加（连同它们的商品价值），这主要是由于它们在电池和可再生技术中的使用。褐铁矿生物处理是一项新兴技术，通常利用嗜酸原核生物催化零价硫氧化，偶联Fe （III）和Mn （IV）矿物的还原，从而释放出目标金属。含铬矿物，如铬铁矿，其金属以Cr （III）的形式存在，广泛存在于红土矿床中。然而，也有报道称，这种金属的氧化程度更高、生物毒性更强的形式[Cr (VI)]可能存在于某些褐铁矿中，这是由锰（IV）氧化物氧化Cr （III）形成的。利用新喀里多尼亚红土矿的褐铁矿在实验室规模的反应器中进行的生物浸出实验发现，固体密度为~ 10% w/v时，亲酸剂完全抑制了铁的还原，这是还原溶解过程中的一个关键反应。进一步的调查发现，这是由于酸性液体中释放的铬（VI）所致。对所用褐铁矿的x射线吸收近边结构（XANES）光谱分析发现，实验所用的三种褐铁矿样品中总铬的3.1 ~ 8.0%以Cr （VI）的形式存在于原料中。通过增加褐铁矿或添加亚铁，可以消除Cr （VI）对微生物的抑制作用，亚铁将Cr （VI）还原为毒性较小的Cr (III)，从而使钴（实验中的主要目标金属）的提取率达到90%。
Limonitic layers of the regolith, which are often stockpiled as waste materials at laterite mines, commonly contain significant concentrations of valuable base metals, such as nickel, cobalt, and manganese. There is currently considerable demand for these transition metals, and this is projected to continue to increase (alongside their commodity values) during the next few decades, due in the most part to their use in battery and renewable technologies. Limonite bioprocessing is an emerging technology that often uses acidophilic prokaryotes to catalyse the oxidation of zero-valent sulphur coupled to the reduction of Fe (III) and Mn (IV) minerals, resulting in the release of target metals. Chromium-bearing minerals, such as chromite, where the metal is present as Cr (III), are widespread in laterite deposits. However, there are also reports that the more oxidised and more biotoxic form of this metal [Cr (VI)] may be present in some limonites, formed by the oxidation of Cr (III) by manganese (IV) oxides. Bioleaching experiments carried out in laboratory-scale reactors using limonites from a laterite mine in New Caledonia found that solid densities of ∼10% w/v resulted in complete inhibition of iron reduction by acidophiles, which is a critical reaction in the reductive dissolution process. Further investigations found this to be due to the release of Cr (VI) in the acidic liquors. X-ray absorption near edge structure (XANES) spectroscopy analysis of the limonites used found that between 3.1 and 8.0% of the total chromium in the three limonite samples used in experiments was present in the raw materials as Cr (VI). Microbial inhibition due to Cr (VI) could be eliminated either by adding limonite incrementally or by the addition of ferrous iron, which reduces Cr (VI) to less toxic Cr (III), resulting in rates of extraction of cobalt (the main target metal in the experiments) of >90%.
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影响因子：
5.2
作者：
Dopson M;Ossandon FJ;Lövgren L;Holmes DS
通讯作者：
Holmes DS
影响因子：
11.4
作者：
Marrero, J.;Coto, O.;Schippers, A.
通讯作者：
Schippers, A.
影响因子：
2.5
作者：
Ravel, B;Newville, M
通讯作者：
Newville, M
影响因子：
5.2
作者：
Johnson DB;Smith SL;Santos AL
通讯作者：
Santos AL
影响因子：
15
作者：
PFLAUM, RT;HOWICK, LC
通讯作者：
HOWICK, LC