Recovering rare earth elements from svanbergite ores by roasting and phosphoric acid leaching
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1
Collage of Mining, Guizhou University
2
Engineering Research Center for Silicate Solid Waste Resource Utilization of Hebei Province, HeBei GEO University
3
North Engineering Design and Research Institute Co., Ltd.
4
Guizhou Tianbao Mineral Resources Consulting Service Co., Ltd.
Publication date: 2024-09-17
Corresponding author
Jie Zhang
Collage of Mining, Guizhou University
Physicochem. Probl. Miner. Process. 2024;60(5):193459
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ABSTRACT
Rare earth elements (REEs) are regarded as key global strategic metals, and recovering REEs from phosphate ores might constitute an alternative method of acquiring rare earth resources. Svanbergite ores in Sichuan are particular phosphates rocks that contain abundant REEs, which are valuable resources that have not been fully developed and utilized. Consequently, the development of crucial technologies for extracting REEs from svanbergite ores hold strategic and scientific significance. This study employed roasting and phosphoric acid leaching processes to recover REEs from svanbergite ores. Response surface methodology (RSM) was applied to optimize the hydrometallurgical process parameters. This study found that the optimal conditions for REEs recovery were: a roasting temperature 600℃, a roasting time of 38.72 min, a phosphoric acid concentration of 40%, a leaching liquid/solid mass ratio of 10, a leaching temperature of 75℃ and a leaching time of 70 min, resulting in a maximum predicted REE recovery rate of 83.57%. The experimental values exhibited a high degree of proximity to the predicted values, thereby substantiating the accuracy of the model and validating the plausibility of the optimized solution. Mechanistic analysis revealed that after the roasting process, the crandallite formed new acid-soluble new phases. Following the phosphoric acid leaching process, REEs were present predominantly in the form of REE3+ in the leaching solution, consequently separating the REEs from the svanbergite ores. This study provides a valuable reference for the recovery of REEs from associated rare earth phosphate ores.