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The interaction of rare earth bearing (La, Nd, Dy) aqueous solutions with calcite crystals at ambient and hydrothermal conditions (25–220 °C) results in the solvent-mediated surface precipitation a...

Critical to the functionality of energy efficient lighting, off-shore wind turbines, and electric vehicles are rare earth (RE)-containing phosphors and magnets. With an increase in the market penetration of these clean energy technologies, demand for RE-containing components is expected to grow. However, the production of rare earth elements (REEs) has an adverse impact on the environment. Existing literature provides some information on the environmental impacts but often fails to give a detailed production pathway that can be modeled without preexisting knowledge of life cycle analysis (LCA) or a dedicated LCA software. In this study, life cycle inventories were compiled based on representative production pathways in China using facility-level energy/material data. Phosphors and magnets using REEs from monazite/bastnasite deposits in Bayan Obo as well as ion-adsorption clays from China’s southern provinces are covered. Analysis of inventory data shows that electricity requirements and emissions to water...

Bastnasite is a fluoro-carbonate mineral that is the largest source of rare earth elements (REEs) such as Y, La, and Ce. With increasing demand for REE in many emerging technologies, there is an urgent need for improving the efficiency of ore beneficiation by froth flotation. To design improved flotation agents that can selectively bind to the mineral surface, a fundamental understanding of the bulk and surface properties of bastnasite is essential. Unexpectedly, density functional theory (DFT) calculations using the PBEsol exchange correlation functional and the DFT-D3 dispersion correction reveal that the most stable form of La-bastnasite is isomorphic to the structure of Ce-bastnasite belonging to the P62c space group, whereas the common structure listed in the Inorganic Crystal Structure Database structure belonging to the P62m space group is ca. 11.3 kJ/mol higher in energy per LaFCO3 formula unit. We report powder X-ray diffraction measurements on synthetic La-bastnasite to support these theoretic...

In this work, studies were carried out on the extraction properties of Mn(II) and MnO4- in sulfuric acid medium using Cyanex 923. Effects of different variables on the extraction of Mn(II) and MnO4-, such as the concentrations of acid, the extractant, and the temperature, were investigated. Results indicated that Mn(II) was extracted weakly by Cyanex 923; however, MnO4- could be strongly extracted into the organic phase. The extraction mechanism of MnO4- was proposed, and the influence of MnO4- on the extraction of cerium was identified when KMnO4 as oxidizer added into the bastnasite sulfuric acid leaching liquor. As MnO4- was easier to be extracted into the organic phase than Ce(IV) and then lost its ability for oxidization, a new device was designed to realize sufficient oxidization of cerium from III to IV, and which has been applied to industrialization.