Beryllium - SpeedyLook encyclopedia

Notable characteristics

Beryllium has the point melting highest of all light metals. It is lighter and six times more resistant than aluminum.

Its Ductilité is roughly 1/3 larger than that of the Acier. It has excellent a thermal Conductivité, is nonmagnetic and resists the nitric Acid concentrated.

It is strongly permeable with the x-rays, and releases from the Neutron S when it is struck by particles alpha, like those emitted by the Radium or the Polonium.

The Normal conditions of temperature and pressure, beryllium resists oxidation when it is exposed to the air. It is formed a fine oxide coating which gives him its capacity to stripe glass.

In nature, one finds it mainly in the form of oxides or of complex aluminosilicates called beryls , whose invaluable representatives most known are the emerald and the Aigue navy.

Uses

It is mainly employed like agent hardening in some Alliage S, in particular the Moldamax, a copper-beryllium alloy used for the manufacture of moulds for plastics.

Its alloys are at the same time light, rigid, resistant to heat and have a low dilation coefficient. It is built-in certain special alloys, for example of the Matériaux usable for friction.

One finds them in the clubs of golf, the hair springs (antimagnetic), the gyroscopes, of the space and aeronautical applications. It was used in Formule 1 for its exceptional performances in term of relationship between its modulus of elasticity and its density, then for the realization of clamps of brake and pistons in the alloy Aluminum-Beryllium shape. It was thereafter interdict in the engines of competition because of its high toxicity. It was used before that in aeronautics for the springs of valves of the piston engine (bronzes with beryllium). Beryllium is also used in some nuclear reactors, like component of Céramique S industrialists, technological and micro-electronic.

The beryllium oxide is used in electronic, particularly into high Fréquence and in the field of the High voltage. This body has the property indeed to be a good Isolant (weak dielectric losses), while having good a thermal Conductibilité. However its use as insulator in the Semiconductor S, (between the silicon chips and the cases), largely yielded the place to other matters much less toxic such as for example the Alumine. Its employment like insulator and material of external contact in electronics, like its incorporation in greases silicones being also abandoned, because of the very important health risks.

It also makes it possible to manufacture tools not deflagrating for the industry of the explosives.

In the civilian, one uses it to very form domes of Haut-parleur S the acute ones of high-quality, able to reproduce frequencies up to 60.000 Hertz.

Some uses of its crystalline properties:

filter neutrons, to obtain beams of “clean” neutrons removed from other particles;
window with X-rays, for example window of a Tube to x-rays or of a Detecting of x-rays: the window isolates the interior of the apparatus from the environment;
in the form of oxide, moderating material in the nuclear reactors.

In Geomorphology and Paléosismologie, the isotope 10 Be, created by the cosmic rays, is used for the Datation by cosmogenic isotopes of surfaces or the determination of rate of erosion.

Beryllium was employed in Dentisterie where it enters the composition of alloys intended for the realization of dental prostheses (crowns, reinforcements of bridge). Its capacity to facilitate the adhesion of ceramics made it incorporate in a great number of alloys, invaluable or not invaluable, intended for the realization of covers for crowns or bridges céramo-metal. Since 2002, the ISO standard limits beryllium to 0,02% of the total mass. However, a great number of people still have in mouth of alloys containing of the higher contents beryllium.

History

The name beryllium comes from the Greek word βήρυλλος ( beryllos ), Béryl which comes itself from bêrullos , crystal. At one time it was named glucinium , of the Greek γλύκύς ( glykys ), soft, a qualifier due to the sweetened taste of its salts.

This element was discovered by Nicolas Louis Vauquelin, in 1798, in the form of oxide (BeO) in the Béryl and the emeralds. Friedrich Wöhler and A.A. Bussy independently insulated it in 1828 while making react Potassium on Chlorure of beryllium.

Sources of contamination

The low natural abundance of beryllium (3×10 -4 %) does not pose a particular environmental problem. But its industrial use, in the coal mines, the aircraft industry and the industry of the nuclear weapons, make that this element is spread in the Atmosphère and settles in the environment while contaminating water, the ground, the air and the human body. It there of the polemics on its use in dentistry in the dental prostheses.

Contamination of the human body

The contamination of the human body by beryllium is done by several ways:

by inhalation of the air which contains beryllium particles;
by drinking water and contaminated food ingestion;

Contamination by drinking water

In general, the concentration of beryllium in natural water and the waste water vary between 0,1 μg/l and 500 μg/l, but when this concentration exceeds 0,2 μg/l, one starts has to speak about an environmental problem.

Contamination by the air

Beryllium can be very harmful when it is inhaled. In fact, there is a great correlation between the beryllium rate in the human Urine and that in the air, which proves that the contamination in the human body is not due only to atmosphere but water pollutions also.

Toxicity

Beryllium is a very toxic, not-radioactive metal. It is placed among the most toxic metals like the Arsenic, the Cadmium, the Chrome, the Plomb and the mercury. One can find it in natural water and the industrial effluents with the state of traces. Beryllium acts like a poison Cancérigène, affecting the cellular membranes and binding to some regulating Protéines in the cells. Beryllium can remain detectable in the urine up to 10 years after the exposure.

The detection of beryllium in the Human body with very high amounts was always accompanied by harmful effects with variable gravity. Beryllium has inhibiting effects on alkaline phosphatase, hepatic adenosine triphosphatase and the synthesis of DNA, which will be reflected on the human health by various effects which are divided into several categories:

Noncarcinogenic effects

The inhalation of the great beryllium concentrations (higher than 1mg per m 3 of air) as well as a prolonged inhalation higher than ten year, even with small amount a named disease chronic disease of beryllium or Bérylliose can generate (or CBD for Chronic Beryllium Disease). This kind of disease affects the lungs and present the many ones in commun runs with the Pneumonie.

Whereas the ingestion of beryllium by the human body did not show direct and harmful effects on the Estomac and the Intestin, the ingestion of beryllium by animals generates the presence of lesions on the level of these bodies.

Certain people can become hypersensitive S with beryllium and develop a reaction allergic to this element. At few people, the exposure direct of beryllium because of the lesions of the Skin and the ignitions in the respiratory tracts.

Carcinogenic effects

Several studies were made on the increase in the number of deaths due to a Lung cancer at the people employed in factories using beryllium.

Analyzes damage of beryllium in the work world

The test of proliferation of the lymphocytes is the most effective test and most precise to detect if the workmen working on nuclear reactors present symptoms of the CBD or Chronic Berylium disease . A positive test indicates that the immune system of the individual is able to react to the presence of beryllium in the organization and that the patient presents a very high risk to develop this disease during the exposure.

Protection

The workmen of the factories whose beryllium is an omnipresent metal in the production, are particularly exposed. Nevertheless, of the adapted work conditions (in particular, the wearing of gloves and thick protective clothing) can largely decrease these risks.

Sources

World Health Organization, Geneva 2001: “Beryllium and international Beryllium compounds” Concise off chemical assesment document 32
Soil Investigation and Human Health Risk Assessment for the Rodney Street Community, Colborne Port: March 2002, Appendix 2 Page 32 off 106
U.S Department off Health and Human Services, public health services Agency for toxic Substances and Disease Registry “Toxicological off Profiles Beryllium” september 2002
T.D. Luckey and B. Venugopal. In: Toxicity metal in Mammals, Share 1. Physiologic and Chemical Basis For Toxicity Metal, Plenum Near, New York (1977), p. 43.
W.R. Griffith and D.N. Skilleter. In: Metals and Their Compounds in the Environment, VCH, Weinheim (1991), p. 775.

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