Raw ore

Solitary stone

Monazite, also known as phosphate cerium lanthanum ore.

Chemical composition and properties: (Ce, La, Y, Th) [PO4]. The composition changes greatly. The content of rare earth oxides in mineral composition can reach 50-68%. The isomorphic mixtures include Y, Th, Ca, [SiO4], and [SO4]. Solitary stone is soluble in H4, HClO4, and H2SO4.

Crystal structure and morphology: monoclinic crystal system, orthorhombic columnar crystal type. The crystal is plate-shaped, with stripes on the crystal surface, sometimes in the form of columns, cones, or grains.

Physical properties: Yellowish brown, brown, red, occasionally green. Translucent to transparent. Stripes are white or light reddish yellow in color. Has a strong glass luster. Hardness ranging from 5.0 to 5.5. Sexual fragility. The specific gravity ranges from 4.9 to 5.5. Weakness in electromagnetic properties. Emits green light under X-rays. Not emitting light under cathode rays.

Formation state: Produced in granite and granite pegmatite; Rare metal carbonate rocks; In Yunyingyan and quartzite; In Yunxia syenite, syenite, and alkaline syenite pegmatite; Alpine type veins; In mixed rocks; And in weathered crust and sand ore.

Purpose: Mainly used for extracting rare earth elements.

Origin: The main resources of monazite with economic mining value are alluvial or coastal sand deposits. More important coastal sand deposits are located along the coasts of Australia, Brazil, and India. In addition, Sri Lanka, Madagascar, South Africa, Malaysia, China, Thailand, South Korea, North Korea and other places all contain heavy sand deposits of monazite.

The production of monazite has shown a downward trend in recent years, mainly due to the radioactive thorium element in the ore, which is harmful to the environment.

Fluorocarbon cerium ore

Chemical composition properties: (Ce, La) [CO. Mechanical mixtures include SiO2 and Al2O5. Fluorocarbon cerium ore is easily soluble in dilute HCl, HNO2SO4, and H4.

Crystal structure and morphology:

Hexagonal crystal system. Compound cubic double cone crystal. The crystal is in the shape of hexagonal columns or plates. Fine grained aggregates.

Physical properties: yellow, reddish brown, light green or brown. Glass luster, grease luster, with white and yellow stripes, transparent to semi transparent. Hardness of 4-4.5, brittle, specific gravity of 4.72-5.12, sometimes radioactive and weakly magnetic. Transparent in thin films, colorless or pale yellow under transmitted light, and does not emit light under cathode rays.

Formation state: Produced in rare metal carbonate rocks; Granite and granite pegmatite; Quartz veins related to granite syenite; Quartz iron manganese carbonate veins; In sand mines.

Usage: It is an important mineral raw material for extracting cerium group rare earth elements. Cerium group elements can be used to make alloys, improve the elasticity, toughness, and strength of metals, and are important components for making jet aircraft, missiles, engines, and heat-resistant machinery. It can also be used as a protective shell against radiation. In addition, cerium group elements are also used to make various colored glasses.

Yttrium phosphate ore

Chemical composition and properties: Y [PO4]. Y20.4% and P2O56% in the ingredients. Yttrium group rare earth elements are mixed in, mainly including ytterbium, erbium, dysprosium, and gadolinium. Zirconium, uranium, thorium and other elements have replaced yttrium, accompanied by silicon replacing phosphorus. Generally speaking, the uranium content in yttrium phosphate ore is higher than that of thorium. Yttrium phosphate has stable chemical properties. Crystal structure and morphology: tetragonal crystal system, complex tetragonal bipyramid, granular and blocky.

Physical properties: yellow, reddish brown, sometimes yellow green, also brown or light brown. The streaks are light brown in color. Glass luster, grease luster. Hardness of 4-5, specific gravity of 4.4-5.1, with weak multi-color and radioactivity.

Formation state: mainly produced in granite and granite pegmatite. It also occurs in alkaline granite and related mineral deposits. It is also produced in sand mines. Usage: Used as a mineral raw material for extracting rare earth elements during large-scale enrichment.

Lanthanum vanadium brown curtain stone

A joint research team from Yamaguchi University, Ehime University, and the University of Tokyo in Japan has released a statement stating that they have discovered a new type of mineral containing rare earths in Mie Prefecture. Rare earth elements play a role in transforming traditional industries and developing high-tech fields, turning stones into gold. The new mineral was discovered in April 2011 in the mountains of Ise City, Mie Prefecture. It is a special type of brown curtain stone containing rare earth lanthanum and rare metal vanadium. On January 1st, this mineral was recognized as a new mineral by the Mineralogical Society and named "Lanthanum Vanadium Brown Curtain Stone".

finished product

Rare earth carbonate chloride

These are the two main primary products in the rare earth industry. Generally speaking, there are currently two main processes for producing these two products.

One process is concentrated sulfuric acid roasting, which involves mixing rare earth concentrate with sulfuric acid in a rotary kiln for roasting. After leaching with roasted mining water, soluble rare earth sulfates enter the aqueous solution, which is called the leaching solution. Then add ammonium bicarbonate to the leachate, and the rare earth will precipitate as carbonate. After filtration, the rare earth carbonate will be obtained.

Another process is called caustic soda process, abbreviated as alkaline process. Generally, 60% rare earth concentrate is stirred with concentrated alkali solution and melted at high temperature to decompose the rare earth concentrate into rare earth hydroxide. The alkali cake is washed with water to remove sodium salt and excess alkali, and then the washed rare earth hydroxide is dissolved in hydrochloric acid to form rare earth chloride solution. The acidity is adjusted to remove impurities, and the filtered rare earth chloride solution is concentrated and crystallized to obtain solid rare earth chloride.

Rare earth phosphate ore

In addition to being present in various rare earth minerals, a significant portion of rare earth elements in nature also coexist with apatite and phosphate rock minerals. Due to the ionic radius of rare earths (0 848～0.  106 nm) and Ca2+(0 106 nm is very close, and rare earths are present in phosphate rocks in a homomorphic manner. The total reserves of phosphate ore in the world are about 100 billion tons, with an average rare earth content of 0 5 ‰, it is estimated that the total amount of rare earths associated with phosphate ore in the world is 50 million tons.

In response to the low rare earth content and special occurrence state in minerals, various recovery processes have been studied both domestically and internationally, which can be divided into wet and hot methods

In the wet process, it can be divided into nitric acid method, hydrochloric acid method, and sulfuric acid method according to the different decomposition acids. There are various ways to recover rare earths from phosphorus chemical processes, all of which are closely related to the processing methods of phosphate ore.

During the thermal production process, rare earths mainly enter the silicate slag. A large amount of hydrochloric acid or nitric acid can be used for decomposition and leaching, followed by filtration to remove silica. Then, TBP and other extraction methods can be used to recover rare earths, with a rare earth recovery rate of up to 60%.

With the continuous utilization of phosphate ore resources, there is a shift towards the development of low-quality phosphate ore. The sulfuric acid wet process phosphoric acid process has become the mainstream method in the phosphate chemical industry, and the recovery of rare earths from sulfuric acid wet process phosphoric acid has become a research hotspot. In the production process of sulfuric acid wet process phosphoric acid, the process of controlling the enrichment of rare earths in phosphoric acid and using organic solvent extraction to extract rare earths is more advantageous than the methods developed earlier.

Mixed rare earth elements

A metal extracted from rare earth minerals containing lanthanum, cerium, praseodymium, neodymium, and a small amount of mixed oxides or chlorides of samarium, europium, and gadolinium through molten salt electrolysis. Light rare earths with a total rare earth content greater than 98% and cerium content greater than 48%. It is prone to oxidation to black in the air and can react with water at room temperature, accelerating with increasing temperature. Can be used as flint, alloy additive, hydrogen storage material, etc.