Everything You Need to Know about Rare Earth Ore Beneficiation Process
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( Rare earth ore )
Rare earth ore is an important mineral resource in the world. The development and utilization of rare earth resources have positive significance to the economic development of the whole world. In this paper, we will mainly introduce the beneficiation process of rare earth ore.
Let's start it!
01 What is Rare Earth Ore?Back
Rare earth ore, also known as rare earth element ore or rare earth metal ore, mainly exists in the earth 's crust in the form of minerals. As the basic constituent element of minerals, it occurs in the mineral lattice in the form of ionic compounds and constitutes an indispensable component of minerals.
There are 17 elements in the rare earth ore, namely lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium.
02 What are the Functions of Rare Earth Ore?Back
Rare earth elements have optical, electromagnetic and other physical properties, the addition of trace amounts of rare earth elements in other materials, can greatly improve product quality and performance, play a ' stone into gold ' role, known as the ' vitamin ' of modern industry. For example, in steel and non-ferrous metallurgy, adding a few thousandths (or ten thousandths) of the mixed rare earth as an additive, significantly eliminate the influence of harmful impurities on it, and can improve the properties of the alloy. In terms of atomic energy, rare earth minerals can be used as neutron control rods, and their isotopes can be used as ray sources in flaw detection, medicine and scientific research. In addition, rare earth minerals can also be widely used in glass, petroleum, textile, boot leather, dyeing, petrochemical, optical, laser, hydrogen storage, display panels, magnetic materials and other industries.
03 Why Rare Earth Ore is Difficult to Process?Back
#1 Complex Mineral Properties
The composition of rare earth ore is very complex, and the mineral composition is diverse. There are also many useful minerals and gangue minerals. In the process of separation, multiple combined processes are needed, and the requirements for mineral processing technology are very high.
The monazite ore in rare earth ore not only has complex mineral composition, but also has a monazite content of only 1-5 %. The highest content may reach more than 10 %, but the lowest content may only account for about 0.5 %. It is associated with heavy minerals such as yttrium phosphate, zirconium fluorite, rutile, ilmenite, etc., and gangue minerals are mostly quartz, feldspar, chlorite, electrochlorite, garnet, etc., for this kind of monazite ore, it is necessary to combine gravity separation, magnetic separation, electric separation and other processes for separation.
#2 High Technical Requirements
After the rare earth ore concentrate is decomposed to obtain mixed rare earth compounds, in order to obtain a single pure rare earth element, a purification process is required for each element. This process requires very complicated and difficult, so the requirements for process and technology are very high. There are two main reasons:
# The physical and chemical properties of rare earth elements are very similar.
The physical and chemical properties of rare earth elements are very similar. Most of the rare earth ion radii are between the adjacent two elements. They are stable trivalent states in aqueous solution and protected by water substances. The affinity between rare earth ions and water is very large, so the separation and purification process technology requirements are very high.
# There are many impurities associated with rare earth ore.
After the decomposition of rare earth concentrate, there are many impurities in the mixed rare earth compounds, such as uranium, thorium, niobium, tantalum, titanium, zirconium, iron, calcium, silicon, fluorine, phosphorus, etc., so the separation technology is very complicated.
Therefore, in the process technology of sorting rare earth elements, it is necessary to consider not only the separation between more than a dozen rare earth elements with extremely similar physical and chemical properties, but also the separation between rare earth elements and associated impurities.
#3 Rare Earth Mine Pollution
The development and utilization technology of rare earth will not only pollute the surrounding water environment and ecological environment, but also affect the downstream rare earth ore elements.
Some rare earth mines will adopt the mining process of ' in-situ leaching ', that is, the liquid injection hole is directly excavated on the surface, and the electrolyte solution is injected into the ore body through the liquid injection hole. The rare earth ions adsorbed on the surface of the clay ore body are exchanged with the cations in the electrolyte solution to form the rare earth mother liquor, and the rare earth is extracted from the mother liquor after recovery.
The mother liquor formed in this process will leak. Moreover, with the migration of surface water containing water and infiltration of atmospheric rainfall in the weathering zone, the residual rare earth in the ore-bearing weathering zone will be brought into the downstream surface water or the lower upper aquifer below. Eventually lead to surface water and groundwater in the content of rare earth and metal ions increased, so that the pH value changes. Therefore, it will not only pollute the water quality, but also increase the difficulty of downstream rare earth mining.
04 What are the Rare Earth Ore Processing Methods?Back
Rare earth mineral composition is complex, contains a lot of minerals and gangue minerals, so it is difficult to select rare earth ore, according to its mineral and associated gangue and other mineral physical and chemical properties of different, select the appropriate beneficiation process.
#1 Gravity Separation Method
The gravity separation of rare earth ore is based on the different density of rare earth minerals and gangue minerals. It is mainly aimed at the separation of rare earth minerals from gangue minerals such as quartz and calcite with low density, which can effectively achieve pre-enrichment or obtain rare earth concentrate. For example, gravity separation is often used for coastal placer ore, or gravity separation is often used for the beneficiation of rare earth vein ore as pre-enrichment.
#2 Flotation Method
Flotation of rare earth ore is one of the main methods of rare earth ore separation. 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 concentrate. For example, in Baotou Baiyun Obo ore, because the density and magnetic properties of fluorocarbon ore and monazite are basically the same, flotation process is adopted, or after gravity separation in coastal placer, flotation method is often used to obtain rare earth concentrate from heavy sand.
#3 Magnetic Separation Method
Magnetic separation of rare earth ore is aimed at some rare earth minerals with weak magnetism or rare earth minerals with magnetite minerals. Using the different specific magnetization coefficients of rare earth ore and associated gangue and other minerals, magnetic separators with different magnetic field strengths are used for separation. For example, low-intensity magnetic separation is used to separate ilmenite from monazite in coastal placer, or high-intensity magnetic separation is used to separate monazite from zircon, quartz and other minerals. In the flotation of rare earth ore, sometimes in order to simplify the flotation process and save flotation reagents, the high-intensity magnetic separation process is also used to enrich the rare earth ore in advance.
#4 Radiation Beneficiation Method
The radiation beneficiation of rare earth ore is to use the different thorium content of rare earth ore and gangue species in the ore to separate the rare earth ore and gangue minerals by y radiation separator. The general radiation beneficiation method is mostly used for pre-selection of rare earth ore. At present, the application is less.
#5 Electrostatic Separation Method
Rare earth ore can be separated by electric separation method, mainly because rare earth ore belongs to non-good conductor. Therefore, it can be separated from minerals with good conductivity by using its different conductivity and associated minerals. General electric separation is mostly used for heavy sand cleaning after gravity separation of coastal placer.
#6 Chemical Beneficiation Method
The chemical beneficiation method of rare earth ore is mostly used for rare earth deposits attached to kaolin or clay in the form of ions. Based on the characteristics that rare earth ions are easily soluble in sodium chloride or ammonium sulfate solution, the chemical beneficiation method of leaching first and then precipitation adopted. And for easily soluble acid or fluorine carbonate rare earth ore which is prone to phase transition at high temperature, the flotation method can be carried out first, enrichment, and then purified by chemical beneficiation.
In the above article, we mainly tell the reason why rare earth ore is difficult to process and the 6 processing methods of rare earth ore. Because the rare earth ore is difficult to select, the demand is large and non-renewable, so the mineral processing technology is very high. As for which process is selected, it is necessary to analyze the ore properties, and then customize the corresponding mineral processing technology according to the actual situation of the mineral plant. Welcome to click the Chat button to learn more about rare earth mineral processing.