Extractive Metallurgy of Rare Earths

The rare earth market is a diversified market. It is not just a product, but 15 rare earth elements, yttrium, scandium and a variety of compounds ranging from 46% pure chlorides to 99.9999% single rare earth oxides and rare earth metals. They all have a variety of uses.

1. Rare earth beneficiation

Beneficiation is the use of the difference in physical and chemical properties between the various minerals that make up the ore. Different beneficiation methods are used to gather the useful minerals in the ore, remove the harmful impurities, and separate them from gangue minerals with the help of different beneficiation technology and different beneficiation equipment.

2. Extractive metallurgy of rare earth

There are two methods of extractive metallurgy of rare earth, namely hydrometallurgy and pyrometallurgy.

The whole process of hydrometallurgy is mostly in solution and solvent. For example, the decomposition of rare earth concentrates, the separation and extraction of rare earth oxides, rare earth compounds, and single rare earth metals are chemical separation processes such as precipitation, crystallization, redox, solvent extraction, and ion exchange. Nowadays, the most common application is the organic solvent extraction method, which is a general process for industrial separation of high-purity single rare earth elements. The hydrometallurgical process is complex, the product purity is high and its finished products are widely used.

The pyrometallurgical process is simple and the productivity is high. Rare earth pyrometallurgy mainly includes the production of rare earth alloys by silicothermic reduction, the production of rare earth metals or alloys by molten salt electrolysis, and the production of rare earth alloys by metal thermal reduction. The common characteristic of pyrometallurgy is that it is produced under high-temperature conditions.

3. Classification method of rare earth products

There are many types of rare earth products. According to the processing depth, they can be divided into metallurgical products and application products. The former refers to rare earth concentrates produced by rare earth mines and smelting enterprises, single and mixed rare earth oxides, metals and their alloys, single and mixed rare earth salts, etc. There are more than 300 varieties and more than 500 specifications in total.

The latter refers to all manufactured products containing rare earth, such as rare earth permanent magnets, rare earth phosphors, rare earth polishing powders, rare earth fertilizers, rare earth laser crystals, rare earth hydrogen storage materials. At present, there is no unified classification method and no unified name, and the boundary is not clear. Everyone is familiar with the name of mineral products, primary products (or crude products) are called upstream products; deep processing products (or single products, high purity products) are called midstream products; application materials and application products (or devices) are called downstream products.

It is divided into several stages from rare earth raw materials to the final product. The closer to the final product, the higher the technical content and the higher the added value. The process from raw materials to finished products involves the process from raw materials, materials, devices to products, and each link has key technologies. The closer to the final product, the higher the technical content and the higher the added value.