Bioreductive Dissolution as a Pretreatment for Recalcitrant Rare-Earth Phosphate Minerals Associated with Lateritic Ores
Bioreductive Dissolution as a Pretreatment for Recalcitrant Rare-Earth Phosphate Minerals Associated with Lateritic Ores
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DOI：
10.3390/min9030136
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发表时间：
2019-02
期刊：
影响因子：
2.5
通讯作者：
I. Nancucheo;G. Oliveira;M. Lopes;D. Johnson
中科院分区：
文献类型：
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作者：
I. Nancucheo;G. Oliveira;M. Lopes;D. Johnson
最近的研究已经证明了生物技术方法用于使用嗜酸细菌提取贱金属的适用性，所述嗜酸细菌使用元素硫作为电子供体催化氧化矿石中的三价铁氧化物的还原溶解。在巴西，红土矿床通常与磷酸盐矿物如独居石有关，独居石是最丰富的稀土磷酸盐矿物之一。鉴于独居石是高度难熔的，稀土元素（REE）提取非常难以实现，并且常规地涉及在高温下用浓氢氧化钠和/或硫酸消化;因此，它不被认为是潜在的资源。研究了酸性硫杆菌（A.）在pH和温度控制的搅拌反应器中的物种。在好氧条件下，利用A.在极低的pH值下，氧化硫杆菌极大地增强了铁从三价铁矿物中的溶解，以及磷酸盐的溶解（约35%），这可以用作独居石溶解的指示剂。从这项研究的结果已经证明了使用生物还原矿物溶解的潜力，它可以被应用作为预处理，以去除覆盖的三价铁矿物在一个类似于生物氧化的难处理金的过程中，并扩大可以使用这种方法处理的矿物的范围。
Recent research has demonstrated the applicability of a biotechnological approach for extracting base metals using acidophilic bacteria that catalyze the reductive dissolution of ferric iron oxides from oxidized ores, using elemental sulfur as an electron donor. In Brazil, lateritic deposits are frequently associated with phosphate minerals such as monazite, which is one of the most abundant rare-earth phosphate minerals. Given the fact that monazite is highly refractory, rare earth elements (REE) extraction is very difficult to achieve and conventionally involves digesting with concentrated sodium hydroxide and/or sulfuric acid at high temperatures; therefore, it has not been considered as a potential resource. This study aimed to determine the effect of the bioreductive dissolution of ferric iron minerals associated with monazite using Acidithiobacillus (A.) species in pH- and temperature-controlled stirred reactors. Under aerobic conditions, using A. thiooxidans at extremely low pH greatly enhanced the solubilization of iron from ferric iron minerals, as well that of phosphate (about 35%), which can be used as an indicator of the dissolution of monazite. The results from this study have demonstrated the potential of using bioreductive mineral dissolution, which can be applied as pretreatment to remove coverings of ferric iron minerals in a process analogous to the bio-oxidation of refractory golds and expand the range of minerals that could be processed using this approach.