Monazite

Formula: (Ce, La, Nd, Th)PO₄ (the most common member)

Mohs scale hardness: 5-5,5

Specific gravity: 4.6–5.7 (4.98–5.43) g/cm³

^{Rare earth elements:}^La^,^Ce, ^Dy^,^Eu^,^Tb^,^Nd,^Sm^,^Pr

^{Rare earth content, %:}^(Ce,La,...)2^O3^{50–68 (REOmax=}^69,7%)

Other constituents, %: U₃O₈

Mineralklasse: Phosphate

Application: Raw material for production of REE

During the processing of monazite, plants use the following types of separation:

Promising methods for the extraction of monazite:

Chemical separation
Special methods of separation
Mountain Pass rare earth mine (USA) They use flotation.
Bayan Obo REE−Fe−Nb Ore Deposit (China) They use flotation.
Nolans Bore Deposit (Australia)
Van Rhynsdorp and Naboomspruit (South Africa)

Other major monazite sources are heavy mineral sands from so-called placerdeposits which are usually mined by dredging or scraping, followed by screening and concentration in spiral concentrators. Mineral concentrates are then washed, dried and fed into magnetic separators to remove e.g. ilmenite and other magnetic minerals. In a subsequent step electrically conducting and nonconducting heavy minerals are typically separated in electrostatic plate separators followed by induced roll separators that help to distinguish induced magnetic from non-magnetic minerals (i.e. xenotime and monazite from zircon). The former two minerals can then be separated by wet table or air table taking advantage of their slightly different specific gravities.

An example of such a placer rutile-zircon-ilmenite deposits is at Eneabba on Australia’s west coast north of Perth, which produced about 2,500 t of monazite annually, with monazite making up 0.5% to 7.0% of the heavy minerals. Present-day production is from India, Malaysia, Sri Lanka, Thailand, and Brazil. In India, monazite production from titania-zircon placers is government controlled, and a domestic plant processes monazite concentrate into REE products.

References

https://en.wikipedia.org
http://www.rareearthtechalliance.com
http://www.dakotamatrix.com/products/4293/monazite-ce
http://www.mindat.org/min-2750.html
https://sites.google.com/site/concentrationofminerals/how-to-choose-a-method-for-the-separation-of-minerals/selection-of-methods-for-separating-of-titanium-minerals/euxenite