There are 17 rare earth elements, namely lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, ymium, erbium, thulium, ytterbium, lutetium, scandium and yttrium. Rare earth elements have optical, electromagnetic and other physical characteristics. When rare earth elements are added into other materials, the quality and performance of products can be greatly improved, and the effect of "the Midas touch turns to gold" is known as the "vitamin" of modern industry. A common metaphor is that if oil is the blood of industry, rare earths are its vitamins. Rare earth minerals can be widely used in atomic energy, glass, petroleum, textile, boot leather, dyeing, petrochemical, optics, laser, hydrogen storage, display panel, magnetic materials and other industries. Nowadays the global demand for rare earth resources is huge for military, science, technology and people's livelihood.
The mineral composition of rare earth ores is complex and contains many minerals and gangue minerals, so it is not easy to separate rare earth ores. The appropriate beneficiation process can be selected based on the different physical and chemical properties of their minerals and associated gangue. Prominer also has a close relation with state-owned laboratories and industrial companies that have rich experience in rare earth beneficiation and concentration so we can provide professional services on rare earth beneficiation technology studies and concentration plant EPC services. The common rare earth beneficiation technology is as below:
Gravity separation of rare earth minerals is carried out by using the density difference between rare earth minerals and gangue minerals. For example, coastal placer mineral containing rare earth often adopt gravity separation and rare earth vein ore always use gravity separation for pre-concentration.
The flotation of rare earth ores is one of the main methods for the separation of rare earth ores. It uses the difference of physical and chemical properties between the surface of rare earth minerals and associated minerals to separate them from associated gangue and other minerals to obtain effective rare earth concentrates. For example, in Baotou Bayan Obo ore, because the density and magnetism of fluorocarbon holmium ore and monazite are basically the same, flotation process is adopted, or after gravity separation in seashore placer, rare earth concentrate is often obtained from heavy sand by flotation.
Rare earth mineral magnetic separation aims at some rare earth minerals with weak magnetism or rare earth minerals accompanied with magnetite. The magnetic separator with different magnetic field intensity is used to separate rare earth minerals according to the different specific magnetization coefficients of rare earth minerals with associated gangue and other minerals. For example, weak magnetic separation is used to separate ilmenite from monazite in seashore placer, or high magnetic separation is used to separate monazite from zircon, quartz and other minerals. In flotation of rare earth ores, in order to simplify flotation process and save flotation reagents, high intensity magnetic separation technology is sometimes used to pre-enrich rare earth ores.
Rare earth ore electroseparation is mainly due to the fact that rare earth ore belongs to non-good conductor. Therefore, it can be separated from good conductive minerals by using its different conductivity from associated minerals. Generally, electrostatic separation is mostly used in the heavy sand concentrating operation after gravity separation of seashore placer.
Chemical beneficiation of rare earth ores is mostly used in rare earth deposits which are adhering to kaolin or clay in ionic form. The chemical beneficiation method of leaching first and then precipitating is adopted because of the solubility of rare earth ions in sodium chloride or ammonium sulfate solution. Or for soluble acid or fluorocarbonate rare earth ores which are prone to phase change at high temperature, flotation can be carried out first, enrichment can be carried out, and then purification by chemical mineral processing.