Central South University, Changsha, Hunan, China; Key Lab of Biohydrometallurgy of Ministry of Education, Changsha, Hunan, China.
Central South University, Changsha, Hunan, China; Key Lab of Biohydrometallurgy of Ministry of Education, Changsha, Hunan, China.
J Environ Manage. 2024 Sep;368:122184. doi: 10.1016/j.jenvman.2024.122184. Epub 2024 Aug 11.
Ion adsorption rare earth ore nearly satisfy global market demand for heavy rare earth elements (HREEs). Bio-leaching has important potential for the clean and efficient extraction of ion-adsorption rare earth ore. However, the complexities of in-situ mining restrict the use of contact/direct bio-leaching, and non-contact/indirect bio-leaching would be the best choice. This study explore the potential of fermentation broths prepared by Yarrowia lipolytica (ATCC 30162) for the bio-leaching of ion-adsorption rare earth ore, and three typical metabolites (potassium citrate (KCit), sodium citrate (NaCit) and ammonium citrate ((NH)Cit) of Yarrowia lipolytica were further evaluated in simulated bioleaching (non-contact bioleaching) of ion-adsorption rare earth ore, including leaching behavior, seepage rule and rare earth elements (REEs) morphological transformation. The column leaching experiments shown that direct leaching of REEs using fermentation broths results in incomplete leaching of REEs due to the influence of impurities. Using the purified and prepared metabolites as lixiviant, REEs can be effectively extracted (leaching efficiency >90%) at cation concentration was only 10 % of the commonly used ammonium sulfate concentration (45 mM). Cation type had less effect on leaching efficiency. During the ion-adsorption rare earth ore leaching process, rare earth ions form a variety of complex chelates with citrate, thus transferring rare earth elements from the mineral surface to the leachate. Experimental results showed that pH and concentration together determined the type and form of rare earth chelates, which in turn affect the leaching behavior of REEs and solution seepage rule. This study helps to provide a theoretical basis for the regulation and enhancement of ion-adsorption rare earth ore non-contact bioleaching process.
离子吸附型稀土矿几乎可以满足全球对重稀土元素（HREEs）的需求。生物浸出在清洁、高效提取离子吸附型稀土矿方面具有重要潜力。然而，原地开采的复杂性限制了接触/直接生物浸出的应用，非接触/间接生物浸出将是最佳选择。本研究探讨了利用解脂耶氏酵母（ATCC 30162）发酵液在离子吸附型稀土矿生物浸出中的应用潜力，并进一步评估了解脂耶氏酵母的三种典型代谢产物（柠檬酸钾（KCit）、柠檬酸钠（NaCit）和柠檬酸铵（（NH）Cit）在离子吸附型稀土矿的模拟生物浸出（非接触生物浸出）中的作用，包括浸出行为、渗流规律和稀土元素（REEs）形态转化。柱浸实验表明，由于杂质的影响，直接使用发酵液浸出 REEs 会导致 REEs 浸出不完全。使用纯化和制备的代谢产物作为浸出剂，在阳离子浓度仅为常用硫酸铵浓度（45mM）的 10%时，REEs 可以得到有效提取（浸出率>90%）。阳离子类型对浸出效率的影响较小。在离子吸附型稀土矿浸出过程中，稀土离子与柠檬酸形成各种复杂的配合物，从而将稀土元素从矿物表面转移到浸出液中。实验结果表明，pH 值和浓度共同决定了稀土配合物的类型和形式，进而影响 REEs 的浸出行为和溶液渗流规律。本研究有助于为离子吸附型稀土矿非接触生物浸出过程的调控和强化提供理论依据。
