Process Development to Recover Rare Earth Metals from Selected Primary Ores: A Review

Abstract

Rare earth elements (REEs) have become an integral part of modern-day technology. REEs such as light rare earth elements (LREEs) are from lanthanum to europium and heavy rare earth elements (HREEs) from gadolinium to lutetium. Rare earth metals are becoming a significant part of modern-day technology and material industry because of their applications in various fields such as hydrogen storage, alloys, batteries, bio-analysis, and nuclear technologies. Due to its multitudinous devotions in various fields, its demand is increasing day by day. This urge leads scientists to work tirelessly to discover novel methods and technologies that are beneficial in the modern era. China has considered a global leader in REE production, and its technological takeover is due to REE reserves. China has limited the supply of REE to other countries. Therefore, scientists are trying to discover low-cost and effective ways of its extraction from primary and secondary sources. Therefore, this is the need of the hour to unearth ores that contain REE and extract them by using a sustainable approach. Factors affecting leaching efficiency are the concentration of lixiviant, temperature, contact time, pulp density, and agitation have also been discussed in detail. This review highlights the leaching mechanism involved in REE extraction from primary sources. The lixiviant used has been discussed in detail. Prospects of the process have also been discussed. This tutorial-based review would be really helpful for the researchers.

Spatial Variation of Rare Earth Elements (REEs) in Agricultural Soils Collected from Different Geographical Regions in Vietnam

“…The total content of REEs in the soil depends on the type and composition of the parent rock, e.g., clay content [7], acidity or basicity (pH change) [3], carbonate (CO 3 2-) [8], total organic carbon (TOC) [9], Al, Fe, Mn, and redox potential [10] which affects the physicochemical properties of the soils. The distribution of REEs is uneven among regions in the world, mainly in China, Vietnam, the United States [11], etc., although the REEs are quite high content.…”