Yttrium phosphateRare earth element deposit(Rare earth ore) is one of the main ore minerals.containYttrium trioxide61.40%, often containing erbium, cerium, lanthanum, thorium and other elements.
It is mainly produced in graniteGranite pegmatite、Alkaline granite, alkaline granite pegmatite and related depositschemical propertyIt is stable and can also be produced in placers.Phosphyttrite is an important raw material for extracting yttrium and yttrium group rare earth.[1]
Chinese name
Xenotime
Foreign name
xenotime
Composition
Yttrium and erbium oxides, phosphorus pentoxide
Type
One of the main ore minerals of rare earth element deposits
Y[POfour]Theoretical composition: 61.4% oxide containing yttrium and erbium.Phosphorus pentoxide38.6%, sometimes containing thorium dioxide, uranium dioxide (5%), zirconium oxide (3%).[2]
Phosphyttrite belongs to the selective distribution type of yttrium rich rare earth (Note 1), and its distribution value (mass fraction ω/%) is La 0.87,Ce 3.97，Pr 0.25，Nd 1.86，Sm 1.49，Eu 0.79，Gd 5.34，Tb 0.75，Dy 10.56，Ho3.23，Er 7.57，Tu 0.98，Yb 11.80，Lu 1.12，Y 49.42。Note 1:Rare earth element distribution(REE assembly) refers to the proportional relationship between the contents of rare earth elements in rocks or minerals.That is, take the total content of rare earth elements in rocks or minerals as 100, and the proportion of each rare earth element in it.Generallyrare earth elementOr its oxide percentage.In minerals, according to the distribution, they can be divided into two types: complete distribution type and selective distribution type.The former refers to the cerium group and yttrium group with similar content of rare earth elements, or either the cerium group or the yttrium group can be selected, that is, the type with uncertain distribution.
physical property
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The crystal structure of yttrium phosphate is tetragonal system.Space group D194h-Ifour/and。a0=0.689nm，c0=0.604nm。z=4。Spectral lines of main powders: 1.749 (100), 1.703 (80), 3.343 (80).The crystals are in the shape of square bipyramids, square columns and square bipyramids, in the shape of yellow, reddish brown, brown or yellowish green.It has glass grease luster.Cleavage (100) is complete.The hardness is 4-5.Density 4400~4800kg/mthree。Often radioactive.Soluble in hot concentrated sulfuric acid and phosphoric acid.
Occurrence and application
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The domestic production areas include Yangjiang County in Guangdong, Qionghai County in Hainan, Baotou City in Inner Mongolia, Gupo Mountain in Guangxi, Xihua Mountain in Dayu, Jiangxi, Xinfeng Snow Mountain in Guangdong, Baima in Luchuan, Guangxi, Yingshan in Hubei, Guangshui, etc.
It is mainly produced in granite andGranite pegmatiteMedium, sometimes also produced inNepheline syeniteAnd gneissParagenetic mineralZircon, monazite, etc.After weathering, oval particles with rounded edges and corners exist in the sand.
Zircon is the mineral most easily confused with xenotime. The difference between the two minerals lies in: ① Zircon is mostly long columnar, while xenotime tends to be short columnar; ②Phosphyttrite has relatively complete cylindrical cleavage, but the cylindrical cleavage of zircon is incomplete; ③The refractive index of xenotime is not as high as that of zircon; ④The birefringence of xenotime is much higher than that of zircon; ⑤Sometimes double crystals appear in xenotime, while double crystals are never seen in zircon; ⑥Some xenotime ores are electromagnetic, similar to ilmenite, but zircon has no such property.If necessary, it can be distinguished by the presence of phosphorus and electron probe analysis.[3]
