Lanthanum
Lanthanum
is a soft, malleable, ductile, silver-white metal. It is chemically active,
it is one of the most reactive of the rare-earth metals: it oxidizes rapidly
in air and it reacts with water to form the hydroxide. Lanthanum is easily
ignited, its salts are often very insoluble.
Applications
Lanthanum
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. La2O2 is used to make special
optical glasses (infrared adsorbing glass, camera and telescope lenses). If
added in small amounts it improves the malleability and resistence
of steel. Lanthanum is used as the core material in carbon arc electrodes.
Lanthanum salts are included in the zeolite catalysts
used in petroleum refining because thay stabilize
the zeolite at high temperatures.
Lanthanium in the environment
Lanthanum
can rarely be found in nature, as it occurs in very small amounts. It is
anyway one of the more abundant rare-earch elements.
Lanthanum is usually found only in two different kinds of ores. World
production of lanthanum oxide in around 12.000 tonnes
per year, and currently nown reseves
of lanthanum are around 6 million tonnes.
The use of
lanthanum is still growing, due to the fact that it is suited to produce catalysers and to polish glass.
Health effects of lanthanum
Lanthanum 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. Lanthanum can also cause cancer with humans, as it enlarges the
chances of lung cancer when it is inhaled. Finally, it can be a threat to
the liver when it accumulates in the human body.
Environmental effects of lanthanum
Lanthanum 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. Lanthanum
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 Lanthanum causes damage to cell membranes, which has
several negative influences on reproduction and on the functions of the
nervous system. It strongly accumulates in mussels.