Rare earth elements (REEs) are of great importance to modern society and their reliable supply is a major concern of many industries that utilize them in metal alloys, semiconductors, electrical equipment, and defense equipment. REEs in the coal waste have been revealed to be an alternative resource for REEs production. In this study, the extraction, recovery, and upgrading of the REEs from coal waste has been realized with the bioleaching and precipitation processes. Reliable and sustainable acid and oxidant production from the oxidation of the pyrite with Acidithiobacillus ferrooxidans to generate acid for leaching were realized in this research. The acidified bioleaching solution was used to extract REEs from coal waste, with 13–14% yields for most REE elements (~72 h of leaching). However, recovery for longer duration tests was significant higher (varies from 40–60% for individual REEs). After extraction, precipitation and separation processes were designed with the aid of Visual Minteq calculations and modeling to concentrate the REEs. With the procedures designed in this research, a final REEs precipitate product containing 36.7% REEs was produced.

中文翻译：

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从煤基资源中回收和增强稀土元素：生物浸出和沉淀

稀土元素（REE）对现代社会非常重要，其可靠的供应是许多在金属合金，半导体，电气设备和国防设备中使用稀土元素的行业的主要关注。煤炭废物中的稀土元素已被证明是稀土元素生产的替代资源。在这项研究中，已经通过生物浸出和沉淀过程实现了从煤waste石中提取，回收和提纯稀土元素。黄铁矿用酸性铁氧体氧化硫铁矿氧化产生可靠，可持续的酸和氧化剂在这项研究中实现了产生酸以进行浸出。酸化的生物浸出溶液用于从煤废料中提取稀土元素，大多数稀土元素（浸出〜72 h）的产率为13–14％。但是，持续时间更长的测试的恢复率要高得多（单个REE的变化范围为40-60％）。提取后，借助Visual Minteq计算和建模设计沉淀和分离过程，以浓缩稀土元素。通过本研究中设计的程序，最终的REEs沉淀产物产生了包含36.7％REEs的产物。