Brazil
has
large deposits
of REEs
concentrated in several geological environments and conditions. Some
of these deposits occur
in
the Nb-rich and phosphate-rich Araxá Carbonatite Complex, which
has been exploited
for four decades.
The
other deposits are represented by the monazite-rich placers with
zircon (as
the main product),
ilmenite, rutile and secondarily siliceous sands and garnet.
Investments in Brazil are poorly developed because of the lack of
technology and wrong governmental policies. Coastal placer deposits
are monazite-rich forming one of the important Brazilian sources.
The
circular structure of Monte Alegre at Pará state contains values in
U3O8
(300- 1800 ppm) [~250-1500 ppm U], ThO2
(850-1800 ppm) and La2O3
(0.1-0.7 ppm CeO2=0.3-1.0
ppm and 0.1-0.0.7 ppm) and is deeply weathered.
The
quartzites of Serra de Itiuba (Bahia) have
concentrations of cheralite, monazite and Fe-autunite with
significant grades of REE. Cryolite deposits of Pitinga (Amazon),
exploited for Sn and Nb since the beginning of 1970, contain
0.03%Y2O3
and 0.036% HREE, mostly in the mine tailings.
Euxenite
and samarskite from pegmatites of Serra do Pangarito (Minas Gerais)
are rich in REEs
(13% Y2O3
from the total REE of37%).
In pegmatites from Sabinópolis, Divino do Ubá and Generosa values
of
Y2O3
(12.1-28.6%),
Ce2O3
(0.81-8.62%) are
attained
in samarskite, and
significant values are obtained in the pegmatites from Rio Pomba
(Minas Gerais) in the range 7-29% REE-oxides.
In
the pegmatites from the Serra da Mesa (Goias) the REE xalues
varies
from 0.03-4.76% Y2O3
and 0.04-4.35%Y2O3
in ixiolite and Ti-ixiolite. Another impostant area with pegmatites
and alluvial deposits is the Rio Tajaui (Amapá) in uranothorianite
(0.2- 0.5% La2O3
and 0.4-0.6% Nd2O3)
in an unexplored region.
The
albitites of Espinharas (Paraiba state) contains high grades of La
(2.7-195 ppm), Ce (3.2-220 ppm), Pr (0.33-29.9 ppm), Nd (1.1-88.5
ppm), Sm (0.5-37.9 ppm), Eu (0.05-7.11 ppm), Gd (0.63-51.7 ppm), Tb
(0.09-12.9 ppm), Dy (0.55- 12.5 ppm), Ho (0.09-34.1 ppm) Er
(0.25-12.9 ppm), Tm (0.05-15.8 ppm) and Yb (0.3-88.7 ppm) indicating
high potential for REEs.
Some
outstanding deposits of pyrochlore of Araxá (Zero Area) are famous
for the REE contents (3.2% Ce2O3,
2%La2O3,
1%Y2O3,
0.2% Sm2O3,
0.7% Nd2O3,
and 0.4% Pr6O11
occurring as fine-grained phosphate minerals in the weathered
carbonatite.
The
spectacular intrusive alkaline dome of Seis Lagos (Amazon), found
through airborne gammaspectrometric survey, is Nb-rich where the
values of total REE reached 20% in the lateritic cover.
In
conclusion, the potential for exploration of REE in Brazil are vast
and promising.
Rare
earths are extracted from the tailings of the niobium produced by the
Companhia Brasileira de Metalurgia e Mineração – CBMM, the
largest niobium
producer in the world.
In
2011 Vale
identified promsing
REE
mieralization
at its Salobo copper mine in Caraja, and undertook
a feasibility study
In
2012 Brazilian
miner World
Mineral Resource
‘s
owner
João
Carlos Cavalcanti was
investigaing a REE deposit in western Bahia that he clained has a
grade similar to the
Chinese deposits.
The
Brazilian company Resind
has declared supplying the internal market to be its goal and
already claims to have already developed a technology to produce an
alloy of rare earths.
Mineração
Taboca,
a subsidiary of the Peruvian company Minsur, is currently in the
final stages of analyzing the REE potential of the Pitinga site in
Amazonas.
