Applications
The metal is used as a core for the Carbon electrodes of arc lamps, for
incandescent mantles for gas lighting. Cerium is used in Aluminium and Iron
alloys, in stainless steel as a precipitation hardening agent, to make permanent
magnets. Cerium oxide is part of the catalyst of catalytic converters used to
clean up exhaust vehicles, it also catalyzes the reduction of Nitrogen oxides
(NOx) to Nitrogen gas. All new cars are now equipped with catalytic conveter
which consist in a ceramic or metal substrate, a coating of Aluminium and Cerium
oxides and a layer of finely dispersed metal such as Platinum or Rhodium, which
is the active surface.
Cerium sulphide (Ce2S3) is likely to replace Cadmium in red pigments for
containers, toys, household wares and crates, since Cadmium is now considered
Environmentally undesiderable.
Other uses of Cerium are in flat-screen televisions, low-energy light bulbs and
magnetic-optic compact discs, in Chromium plating. The use of Cerium is still
growing, due to the fact that it is suited to produce catalysers and to polish
glass.
Cerium in the environment
Cerium is the most abundant of the rare earth elements. It makes up about 0.0046
% of the Earth's crust by weight. Cerium comes mainly from the major lanthanide
ores but some is obtained from perovskite, a Titanium mineral and allanite, both
of which can have enough Cerium to make them viable sources. Production amounts
to 23.000 tonnes a year, but this amount is likely to increase since more and
more Cerium is used nowadays.
Health effects of Cerium
Cerium is one of the rare chemicals, that can be found in houses in equipment
such as colour televisions, fluorescent lamps, energy-saving lamps and glasses.
All rare chemicals have comparable properties.
Cerium is mostly dangerous in the working envIronment, due to the fact that
damps and gasses can be inhaled with air. This can cause lung embolisms,
especially during long-term exposure. Cerium can be a threat to the liver when
it accumulates in the human body.
Cerium has no know biological role, but it has been noted that Cerium salts
stimulate metabolism.
Environmental effects of Cerium
Cerium is dumped in the environment in many different places, mainly by
petrol-producing industries. It can also enter the environment when household
equipment is thrown away. Cerium will gradually accumulate in soils and water
soils and this will eventually lead to increasing concentrations in humans,
animals and soil particles.
With water animals Cerium causes damage to cell membranes, which has several
negative influences on reproduction and on the functions of the nervous system.
Thanks to its use in catalytic converters Cerium is slowly improving the
atmosphere of cities, or wherever diesel engines operates. Diesel engines emits
particulates, Carbon particles only a few micrometers in diameter. One way to
reduce particulates emissions is trap them in a ceramic filter and then burn
them off. If a little Cerium oxide is added to the fuel itself, it will catalyse
the burning of the particulates and eliminate them.
