Bio-reduction of Co and Ni bearing Manganese Minerals

红土和锰结核是潜在的钴的新来源，可以通过微生物过程提取。开发这些资源和优化加工途径的关键是了解微生物-Fe和Mn矿物界面的氧化还原反应。确定微生物与含钴铁锰羟基氧化物相之间相互作用的机制对于理解钴的自然地球化学循环以及生物加工过程中这种技术上重要的金属从潜在矿石中的释放至关重要。这些通常结晶不良的含铁浓缩物的Fe和Mn矿物学包括铁和锰的羟基氧化物，其中钴以Co（II）和Co（III）的形式存在。异化Fe（III）和Mn（IV）的还原微生物提供了一个途径，以提取钴从这些来源中的电子转移过程中的关键微生物-矿物相互作用的Mn的控制是不太为人所知的比铁，钴和镍的研究很少。细胞外聚合物（包括脂多糖）在微生物-矿物质相互作用中具有不同的重要性，细胞色素、皮利和分泌的黄素可能在电子传递中起关键作用[1，2]。学生将通过研究锗物种与Mn和Mn/Fe羟基氧化物之间的相互作用，阐明微生物还原Mn羟基氧化物在控制Co命运中的作用;红土中的Co和Mn呈正相关，而锰结核中的Mn氢氧化物中的Ni与MnO 2呈正相关。将使用一系列最先进的微生物和地球化学技术研究一套含有潜在矿石的微观世界。同步辐射是至关重要的，通过确定所涉及的氧化还原过程和有机和无机成分之间的空间关系，揭示这些过渡金属的行为机制。特别是，扫描透射X射线显微镜（光束线I 08，DLS）提供，在40纳米的尺度，元素分布，金属氧化态和结构信息。测量C K边和Mn L2.3、Co L2.3和Fe L2.3边将确定微生物物种与不同微观世界的产物的氧化态之间的关系[3，4]。这将有助于更好地了解钴在环境中的循环方式，并有助于优化浸出工艺和选矿规模化发展。

Laterites and Mn-nodules are potential new sources of Co that can be extracted by microbial processes. The key to exploiting these resources and optimising processing pathways is an understanding of the redox reactions at the microbial-Fe and Mn mineral interfaces. Determining the mechanisms of the interaction between microbes and Co-bearing Fe and Mn hydroxyoxide phases is critical to understanding the natural biogeochemical cycling of cobalt, and also the release of this technologically important metal from potential ores during bioprocessing. The Fe and Mn mineralogy of these, often poorly crystalline, ferruginous concentrations comprises the ferri- and mangano-hydroxyoxides with cobalt present as both Co(II) and Co(III). Dissimilatory Fe(III) and Mn(IV) reduction by microorganisms provides a pathway to extract Co from these sources; the controls on the electron transfer processes in the key microbial-mineral interactions of Mn is less well known than Fe, and that of Co and Ni are little studied. Extracellular polymeric substances including lipopolysaccharides are thought to have varying importance in microbial-mineral interactions, and cytochromes, pili and secreted flavins may play a key role in electron transfer [1,2].The student will elucidate the role of microbial reduction of Mn hydroxyoxides in controlling Co fate by examining the interaction between Geobacter species and Mn and Mn/Fe oxyhydroxides; Co and Mn are positively correlated in laterites while Ni correlates with MnO2 in Mn-hydroxides in Mn-nodules. A suite of microcosms containing potential ores will be studied using a range of state of the art microbial and geochemical techniques. Synchrotron radiation is crucial to exposing the mechanisms of behaviour of these transition metals by determining the redox process involved and the spatial relationship between the organic and inorganic components. In particular, scanning transmission X-ray microscopy (beamline I08, DLS) provides, at a scale of 40nm, elemental distributions, metal oxidation states and structural information. Measurement the C K-edge and Mn L2.3, Co L2.3 and Fe L2,3 edge will identify the relationship between microbial species and the oxidation states of the products of different microcosms [3,4]. This will lead to a better understanding of how Co is cycled in the environment, and also help optimise the leaching processes and mineral processing scale-up development.