Geochemistry and Main Uses of Minerals - Thanatia: The Destiny of the Earth's Mineral Resources - page 529

and in a solid state, as a cooler. Carbon monoxide is used as a reduction agent
in many metallurgic processes. Other carbon compounds are used as solvents, in
cooling systems, for welding and the cutting of materials.
The recently isolated graphene undertaken by A. Geim and K. Novoselov at the
University of Manchester in 2003, is a one-atom thick sheet of graphite. It is one of
the strongest materials known to Man but is flexible, transparent, chemically inert
and biocompatible. It is an outstanding conductor of heat and electricity and is
made of carbon - a very abundant element in the Earth's crust. Its applications are
expected to soar in many ICT systems like new elastic, light and reinforced screens
for mobile phones, touch screens and TVs. It is also expected to substitute copper
wires for light and e cient graphene electricity conductors, or in denser and faster
integrated circuits, to name a few applications. Its capacity for substituting many
mass used scarce metals in today's ICT appliances gives new hope to the issue of
metal criticality. Graphene is thus a clear case of technological achievement 18 .
B.2.12 Cerium
Cerium is a silvery metallic element, belonging to the lanthanide group. Although
cerium forms part of the REE, it is not rare at all, since it is easily separated from
REO mixtures. In fact it is the most common rare earth and is more abundant
than lead. It is commonly found in orthite, monazite, bastnaesite, rhabdophane or
in zircon.
It is an e cient polishing agent in glass, metals, jewellery and electronics.
Cerium (IV) oxide is used in auto catalytic converters to oxidise CO emissions,
or as a catalyst for self-cleaning ovens. Cerium compounds are also used as cata-
lysts in petroleum refining. In compact fluorescent lamps, cerium is responsible for
the green light. Cerium (IV) oxide bestows high transparency to glass and low re-
flectance to UV light. Associated with other REE, it is used in the motion picture
industry to provide carbon arc lighting. Cerium is also used as an alloying element
with iron, aluminium and magnesium. By 2015 cerium is expected to constitute a
40% share of the global REE supply.
B.2.13 Cesium
Cesium is the most electropositive and least abundant of the five naturally occur-
ring alkali metals. The most important use for cesium has been in research and
development, primarily in chemical and electrical applications.
Cesium occurs as the hydrated aluminosilicate pollucite but the world's only
commercial source is at Bernic Lake, Manitoba. Cesium is mainly obtained as a
byproduct of the Li industry.
18 See http : ==www:graphene:manchester:ac:uk=. Accessed Jan. 2013.