In
India, monazite is the principal source of rare earths and thorium.
It
occurs in association with other heavy minerals such as ilmenite,
rutile, zircon, etc. in concentrations of 0.4 – 4.3% of total
heavies in the beach and inland placer deposits of the country. The
resource estimates of monazite in the beach and inland placer
deposits have been enhanced from 10.70 million tonnes in 2009 to
11.935 million tonnes in 2016.
IREL
(India) Limited, (Formerly known as Indian Rare Earths Limited)
a Government of India undertaking,
and KMML, a Kerala State Government undertaking,
are actively engaged in mining and processing of beach sand minerals
from placer deposits. IREL produced 956 tonnes rare earths in
2017
The
installed capacity of monazite (96% pure) separation plant of IREL at
Manavalakurichi is 6,000 tpy while that of KMML at Chavara is 240 tpy
IREL
has a plant at Udyogamandal, Aluva, located in Ernakulam district,
Kerala, wherein the monazite obtained from Manavalakurichi is
chemically treated to separate rare earths in its composite chloride
form and thorium as hydroxide upgrade.
Ground
monazite is digested with caustic soda lye to produce trisodium
phosphate (TSP) and mixed hydroxide slurry. This slurry is used for
production of diverse rare earth compounds. Elaborate solvent
extraction and ion exchange facilities were built to produce
individual RE oxides, like oxides of Y, Ce, Nd, Pr and La of specific
purities. India is the second largest supplier of yttrium in the
world and the maximum production is reported from this plant in
Kerala.
Uranium
values present in monazite which are recovered in the form of nuclear
grade ammonium diuranate (ADU) are vital supplement to the indigenous
supply of uranium. Thorium is separated in its pure oxalate form. A
part of it is taken to OSCOM for further processing by solvent
extraction to produce thorium nitrate. A small part of the purified
thorium nitrate is converted to nuclear grade thorium oxide powder
for supply to Bhabha Atomic Research Centre (BARC) and Nuclear Fuel
Complex (NFC) for developing thorium based fuel for nuclear reactors.
IREL has built a large stockpile of impure
thorium hydroxide upgrade associated with rare earths and unreacted
materials.
Indian
Rare Earths Ltd signed a sale purchase agreement with Toyota
Corporation, Japan and their subsidiary Toyotsu Rare Earth India Pvt
Ltd, Vizag (TREI) on 9th December, 2015 for supply of Rare Earth
Chloride (RECL) being produced at Monazite Processing Plant (MoPP) at
IREL's OSCOM Unit in Odisha to TREI for value addition purpose.
During the year 2016, IREL has supplied over 1,200 tonnes of RECL on
dry metric basis to TREI. IREL expects to supply substantially higher
tonnage to TREI during the 2nd contract year
