Mining Methods Vary Widely - Mining and the Environment: From Ore to Metal - page 222

discussed below, is a potential future source of nuclear fuel, but it i nds some application out-
side the nuclear energy i eld, such as alloyed with magnesium. The radioactive metal radium
is used in medical technology as are many radioactive isotopes produced in nuclear reactors.

Rare Earths
Rare Earth metals, shown at the bottom of the Periodic Table (see Chapter Eleven) as a
block of two rows of elements but occupying only two positions in the periodic table of ele-
ments, are neither rare nor Earths. The thirty rare Earth elements comprise the lanthanide
and actinide series, the latter comprising only radioactive elements, including uranium and
thorium ( Case 5.2 ). Apart from uranium, thorium, actinium, and protactinium, the other
elements in the actinide series and one element in the lanthanide series, promethium, are
synthetic elements (also called trans-uranic elements). The name rare Earth originates from
difi culties experienced prior to 1945 in purifying the metals from their oxides, due to their
complex chemistry. Ion-exchange and solvent extraction processes are used today to quickly
produce high purity, low-cost rare Earths, but the old name remains. All of the rare Earth
metals are found in group 3 of the periodic table, and the 6th and 7th periods. The lantha-
nides series comprises the 15 elements in the periodic table with atomic numbers 57 to 71.
Often included with the lanthanides are scandium (atomic number 21) and yttrium (atomic
number 39). Because of their similar physical and chemical characteristics, the lanthanide
elements and yttrium often occur together in nature. While scandium may occur with the
rare Earth elements, it is also found in a range of other minerals (Spooner 2005).
The rare Earth metal thorium is an alternative to uranium as fuel for nuclear reactors.
The most common ore of thorium, the phosphate mineral monazite, which contains up to
12% of thorium oxide, also contains other economically extractable rare Earth metals such
as cerium, lanthanum, and neodymium, together with yttrium and iridium.
Industry uses rare Earth metals in a wide range of specialized applications, but in small
amounts compared to most other mined metals. A few examples follow, which illustrate
the diverse uses of these metals: (1) chemical catalysis, especially in petroleum rei ning
(cerium used in the petroleum industry and emissions control catalysts for gasoline and
diesel fueled vehicles); (2) battery manufacturing (lanthanum used in the production of

Industry uses rare Earth metals
in a wide range of specialized
applications, but in small amounts
compared to most other mined
metals.

CASE 5.2
The Case of Bukit Merah in Malaysia

In the early 1980s, the Asian Rare Earth (ARE) Company
commenced extraction of the rare Earth yttrium oxide from
monazite in the town of Bukit Merah in Malaysia. Yttrium
fi nds application as chemical catalysts or pigments which
can be used for colour TV screens. The extraction process
leaves a sludge containing concentrated amounts of
NORM - meaning 'naturally occurring radioactive materials'.
ARE commenced operation without having a permanent
and safe waste disposal option for produced NORM. A
few years later ARE made front page news when it was
alledged that the radioactive waste had contributed to the
deterioration in children's health. In 1983, eight residents

fi led a legal complaint against ARE. While neither estab-
lished facts nor scientifi c proof was produced to support
the claim that the alleged health problems were related
to the operation of ARE, the company was forced to cease
operations in 1994 due to mounting public pressure in
Malaysia and Japan, combined with a shortage of locally
mined monazite and increasing competition from newly
emerging rare Earth producers in China.
It took almost ten years and tens of millions of US$
to develop a closure plan for the operation. Eventually a
secure land fi ll was built for the fi nal disposal of NORM
and other radioactive materials at the ARE site.