 |
|
|||
|
|
|
|||
 |
|
Review
paper Rare earths:
the unseen metals High
profile and primary commodities such as copper, zinc and others share the global limelight
with respect to mining, industrial processes, and numerous end products for household and
commercial markets. Apart from base metals, noble metals enjoy stock market notoriety and
media attention. In contrast, rare earths furtively experience a plethora of residential,
institutional, and industrial applications. The relatively abundant metallic elements
commonly known as the “rare earths” present a low key image worldwide. The group is
normally comprised of 15 lanthanides of which cerium is the most abundant plus scandium,
thorium, and yttrium. The main host minerals consist of bastnäsite, monazite, and
xenotime. Other sources include allanite and spent heavy mineral sands from uranium
processing operations such as in Australia. Countries such as China and the United States
are the largest producers of rare earth materials while over 30 other countries both
contribute smaller quantities for worldwide consumption and generate commercial products.
Global reserves of rare earth elements are dominated by China (43 %), the CIS (19 %), and
the United States (13 %). The People’s Republic of China accounted for the majority of
the world’s annual production of raw rare earths in the year 2002. The perceived “rare
metals” have a strategic importance while being well suited to electronic and other
diverse end uses. The supply and demand of rare earth products during the past decades
have been relatively steady and subject to fluctuations in delivered price. As a
condensation of the state-of-the-art in this fascinating industry, the paper serves to
highlight the properties, sources, and recovery of these forgotten metals which find use
in numerous unseen applications. It is intended to apprise the reader of the salient facts
of these useful metallic elements that globally go unnoticed since they are overshadowed
by the popularity and grandeur of precious metals such as gold and platinum. |
|
