Rare earth elements (REEs) and critical elements (CEs) have been in the spotlight recently due to their vital role in high-tech applications and green energy initiatives. Due to the scarcity of mineral resources for the majority of these elements, there has been significant interest in the recovery of these elements from secondary resources. Among the secondary resources, acid mine drainage (AMD) and associated sludge materials have been found to be viable sources of multiple critical elements, including REEs, Al, Co, and Mn. AMD and sludge samples from 3 AMD treatment sites in Pennsylvania were characterized for elemental content and contained value evaluation. A novel purification process based on a previously developed 3-stage AMD treatment process was designed to recover high-grade Al, REE, Co, and Mn products from the sludge materials through aqueous processing with multiple cleaner steps and precise control of the process parameters. The final products of the three stages of this purification process are boehmite and dawsonite in Stage I, adamsite-(REE) in Stage II, and cobalt oxide and ramsdellite in Stage III. Recoveries of > 99 % for the target elements were achieved with the design of a recycling load. Through the proposed purification process, 92.8 % aluminum minerals in Stage I, 88.5 % mixed-REE-carbonate in Stage II, 68 % ramsdellite, and 6.9 % cobalt oxide in Stage III were produced.

稀土元素 (REE) 和关键元素 (CE) 由于在高科技应用和绿色能源计划中的重要作用，最近备受关注。由于大多数这些元素的矿产资源稀缺，人们对从二次资源中回收这些元素产生了浓厚的兴趣。在二次资源中，酸性矿山排水 (AMD) 和相关的污泥材料已被发现是多种关键元素的可行来源，包括 REE、Al、Co 和 Mn。来自宾夕法尼亚州 3 个 AMD 处理点的 AMD 和污泥样品进行了元素含量的表征和价值评估。基于先前开发的 3 阶段 AMD 处理工艺的新型纯化工艺旨在回收高品位的铝、稀土、钴、污泥材料中的锰产品，经过水处理，具有多个清洁步骤和精确控制工艺参数。该提纯过程的三个阶段的最终产品是第一阶段的勃姆石和片钠铝石，第二阶段的亚当石-（REE）以及第三阶段的氧化钴和斜方锰矿。通过设计回收负载，目标元素的回收率 > 99%。通过提议的提纯工艺，在第一阶段生产了 92.8% 的铝矿物，在第二阶段生产了 88.5% 的混合稀土碳酸盐，在第三阶段生产了 68% 的斜方锰矿和 6.9% 的氧化钴。第三阶段的氧化钴和斜方锰矿。通过设计回收负载，目标元素的回收率 > 99%。通过提议的提纯工艺，在第一阶段生产了 92.8% 的铝矿物，在第二阶段生产了 88.5% 的混合稀土碳酸盐，在第三阶段生产了 68% 的斜方锰矿和 6.9% 的氧化钴。第三阶段的氧化钴和斜方锰矿。通过设计回收负载，目标元素的回收率 > 99%。通过提议的提纯工艺，在第一阶段生产了 92.8% 的铝矿物，在第二阶段生产了 88.5% 的混合稀土碳酸盐，在第三阶段生产了 68% 的斜方锰矿和 6.9% 的氧化钴。