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Comparison of Three Approaches for Bioleaching of Rare Earth Elements from Bauxite
Minerals ( IF 2.5 ) Pub Date : 2020-07-22 , DOI: 10.3390/min10080649 Megan J. Barnett , Barbara Palumbo-Roe , Eimear A. Deady , Simon P. Gregory
Minerals ( IF 2.5 ) Pub Date : 2020-07-22 , DOI: 10.3390/min10080649 Megan J. Barnett , Barbara Palumbo-Roe , Eimear A. Deady , Simon P. Gregory
Approximately 300 million tonnes of bauxite are processed annually, primarily to extract alumina, and can contain moderate rare earth element (REE) concentrations, which are critical to a green energy future. Three bioleaching techniques (organic acid, reductive and oxidative) were tested on three karst bauxites using either Aspergillus sp. (organic acid bioleaching) or Acidithiobacillus ferrooxidans (reductive and oxidative bioleaching). Recovery was highest in relation to middle REE (generally Nd to Gd), with maximum recovery of individual REE between 26.2% and 62.8%, depending on the bauxite sample. REE recovery occurred at low pH (generally < 3), as a result of organic acids produced by Aspergillus sp. or sulphuric acid present in A. ferrooxidans growth media. Acid production was seen when A. ferrooxidans was present. However, a clear increase in REE recovery in the presence of A. ferrooxidans (compared to the control) was only seen with one bauxite sample (clay-rich) and only under oxidative conditions. The complex and varied nature of REE-bearing minerals in bauxite provides multiple targets for bioleaching, and although the majority of recoverable REE can be leached by organic and inorganic acids, there is potential for enhanced recovery by bioleaching.
中文翻译:
三种铝土矿中稀土元素生物浸提方法的比较
每年大约加工3亿吨铝土矿,主要用于提取氧化铝,并且可以包含适度的稀土元素(REE)浓度,这对于绿色能源的未来至关重要。使用曲霉菌属的一种,在三种岩溶铝土矿上测试了三种生物浸出技术(有机酸,还原性和氧化性)。(有机酸生物浸出)或酸性硫氧亚铁氧化亚铁(还原和氧化生物浸出)。相对于中等稀土元素(通常从Nd到Gd),回收率最高,根据铝土矿样品,单个REE的最大回收率在26.2%至62.8%之间。由于Aspergillus sp。产生的有机酸,在低pH(通常<3)下发生REE回收。或存在于硫酸中A.氧化铁生长培养基。当存在A.ferrooxidans时,会产生酸。但是,仅在一种铝土矿样品(富含粘土)且仅在氧化条件下,观察到在存在铁氧农杆菌(与对照相比)的情况下,REE回收率明显增加。铝土矿中含REE矿物的复杂性和多样性为生物浸出提供了多个目标,尽管大多数可回收的REE可以被有机和无机酸浸出,但仍有可能通过生物浸出提高回收率。
更新日期:2020-07-22
中文翻译:
三种铝土矿中稀土元素生物浸提方法的比较
每年大约加工3亿吨铝土矿,主要用于提取氧化铝,并且可以包含适度的稀土元素(REE)浓度,这对于绿色能源的未来至关重要。使用曲霉菌属的一种,在三种岩溶铝土矿上测试了三种生物浸出技术(有机酸,还原性和氧化性)。(有机酸生物浸出)或酸性硫氧亚铁氧化亚铁(还原和氧化生物浸出)。相对于中等稀土元素(通常从Nd到Gd),回收率最高,根据铝土矿样品,单个REE的最大回收率在26.2%至62.8%之间。由于Aspergillus sp。产生的有机酸,在低pH(通常<3)下发生REE回收。或存在于硫酸中A.氧化铁生长培养基。当存在A.ferrooxidans时,会产生酸。但是,仅在一种铝土矿样品(富含粘土)且仅在氧化条件下,观察到在存在铁氧农杆菌(与对照相比)的情况下,REE回收率明显增加。铝土矿中含REE矿物的复杂性和多样性为生物浸出提供了多个目标,尽管大多数可回收的REE可以被有机和无机酸浸出,但仍有可能通过生物浸出提高回收率。