Beryllium Chemische Eigenschaften,Einsatz,Produktion Methoden
ERSCHEINUNGSBILD
GRAUES BIS WEISSES PULVER.
PHYSIKALISCHE GEFAHREN
Staubexplosion der pulverisierten oder granulierten Substanz in Gemischen mit Luft m?glich.
CHEMISCHE GEFAHREN
Reagiert mit starken S?uren und starken Basen unter Bildung brennbarer/explosionsf?higer Gase (z.B. Wasserstoff, ICSC-Nr. 0001). Bildet schlagempfindliche Gemische mit einigen chlorierten L?semitteln wie Kohlenstofftetrachlorid und Trichlorethylen.
ARBEITSPLATZGRENZWERTE
TLV: 0.002 mg/m?(als TWA), 0.01 mg/m?(als STEL); Krebskategorie A1(best?tigte krebserzeugende Wirkung beim Menschen); Beabsichtigte ?nderung 0.00002 mg/m?Haut, Inhal. Sensibilisierung (ACGIH 2005).
MAK: Sensibilisierung der Atemwege und der Haut; Krebserzeugend Kategorie 1; (DFG 2005).
AUFNAHMEWEGE
Aufnahme in den K?rper durch Inhalation des Aerosols und durch Verschlucken.
INHALATIONSGEFAHREN
Verdampfung bei 20°C vernachl?ssigbar; eine gesundheitssch?dliche Partikelkonzentration in der Luft kann jedoch beim Dispergieren schnell erreicht werden.
WIRKUNGEN BEI KURZZEITEXPOSITION
WIRKUNGEN BEI KURZZEITEXPOSITION: Das Aerosol dieser Substanz reizt die Atemwege. Inhalation des Staubes oder Rauches kann zu chemischer Pneumonie führen. Exposition kann zum Tod führen. Die Auswirkungen treten u.U. verz?gert ein. ?rztliche Beobachtung notwendig.
WIRKUNGEN NACH WIEDERHOLTER ODER LANGZEITEXPOSITION
Wiederholter oder andauernder Kontakt kann zu Hautsensibilisierung führen. Risiko der Lungensch?digung bei wiederholter oder l?ngerer Exposition gegenüber Staubpartikeln mit nachfolgender chronischer Berylliumkrankheit (Husten, Gewichtsverlust, Schw?che). Krebserzeugend für den Menschen.
LECKAGE
Gefahrenbereich verlassen! Fachmann zu Rate ziehen! Verschüttete Substanz sorgf?ltig in Beh?ltern sammeln; falls erforderlich vorher Anfeuchten. An sicheren Ort bringen. Chemikalienschutzanzug mit umgebungsluftunabh?ngigem Atemschutzger?t. NICHT in die Umwelt gelangen lassen.
R-S?tze Betriebsanweisung:
R49:Kann Krebs erzeugen beim Einatmen.
R25:Giftig beim Verschlucken.
R26:Sehr giftig beim Einatmen.
R36/37/38:Reizt die Augen, die Atmungsorgane und die Haut.
R43:Sensibilisierung durch Hautkontakt m?glich.
R48/23:Giftig: Gefahr ernster Gesundheitssch?den bei l?ngerer Exposition durch Einatmen.
R20:Gesundheitssch?dlich beim Einatmen.
S-S?tze Betriebsanweisung:
S53:Exposition vermeiden - vor Gebrauch besondere Anweisungen einholen.
S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn m?glich, dieses Etikett vorzeigen).
Beschreibung
Beryllium is widely distributed in the earth's crust at trace concentration, 2.8 mg/kg. The element was first discovered by Vauquelin in 1797. Wohler and Bussy in 1828 independently isolated beryllium in the metallic form from its oxide. In nature, beryllium occurs in several minerals, mostly combined with silica and alumina. The most common minerals are beryl, 3BeO•Al2O3•6SiO2; chrysoberyl, BeO•Al2O3; phenacite, 2BeO•SiO2; and bertrandite, 4BeO•2SiO2•H2O. Also, it is found in trace amounts in the ore feldspar, and in volcanic ash. It's abundance in the sea water is estimated in the range 5.6 ppt.
Beryllium oxide is a component of precious stones, emerald, aquamarine and topaz. Beryllium is utilized in nuclear reactors to moderate the velocity of slow neutrons. It is hot-pressed to appropriate shapes and sizes that yield high strength and ductility for its applications.
Chemische Eigenschaften
Beryllium is a gray shiny metal or powder, or
fine granules which resemble powdered aluminum.
Beryllium is slightly soluble in water. All beryllium compounds
are soluble in water, to some degree. Berylore is the
primary source of beryllium, although there are numerous
other sources.
Physikalische Eigenschaften
As the first element in group 2 (IIA), beryllium has the smallest, lightest, and most stableatoms of the alkali earth metals. Its melting point is 1278° C, its boiling point is 2970°C, andits density is 1.8477 g/cm
3. Its color is whitish-gray.
Origin of Name
Beryllium was originally known as “glucina” (glucose) from the Greek
word glukos, meaning “sugar,” because of the sweet taste of a few of its salt compounds. Later, beryllium was given the Greek name beryllos after the greenish-blue gemstone beryl (emeralds) that was later found to contain the element beryllium.
Occurrence
Since its discovery, beryllium has been classed as the 36th most abundant of the elementsfound in the Earth’s crust. Beryllium’s principle source is a mineral composed of a complex ofberyllium, silicon, and oxygen. It is usually found in deposits as hexagonal crystalline formsin Brazil, Argentina, South Africa, and India as well as in Colorado, Maine, New Hampshire,and South Dakota in the United States. Some deposits have been found in Canada. Manycrystals of the mineral may be very large One chunk that measured 27 feet long length andweighed a 25 tons was found in Albany, Maine in 1969.One method of obtaining beryllium metal is by chemical reduction, whereby berylliumoxide is treated with ammonium fluoride and some other heavy metals to remove impuritieswhile yielding beryllium fluoride. This beryllium fluoride is then reduced at high temperaturesusing magnesium as a catalyst, which results in deposits of “pebbles” of metallic beryllium.Another method for obtaining beryllium metal is by electrolysis of a solution of berylliumchloride (BeCl
2) along with NaCl as an electrolyte in solution that is kept molten but belowthe melting point of beryllium. (
4Be has a relatively high melting point of 2,332.4°F.) Theberyllium metal does not collect at the negative cathode as do metals in other electrolyticcells, but rather beryllium metal pieces are found at the bottom of the cell at the end of theprocess.
Charakteristisch
Beryllium is one-third as dense as aluminum. Fresh-cut surfaces of the metal oxidize,thus resisting further oxidation, as does aluminum. It is a lightweight, hard, brittle metal. Itcan be machined (rolled, stretched, and pounded) into many shapes and is used to producelightweight alloys.
Verwenden
Source of neutrons when bombarded with alpha particles according to the equation 94Be + 42He 612C + 10n. This yields about 30 neutrons per million alpha particles. Also as neutron reflector and neutron moderator in nuclear reactors. In beryllium copper and beryllium aluminum alloys (by direct reduction of beryllium oxide with carbon in the presence of Cu or Al). In aerospace, aircraft and satellite structures; x-ray transmission windows; missile parts; nuclear weapons; fuel containers; precision instruments; rocket propellants; navigational systems; heat shields; and mirrors. For fiber optics and cellular network communications systems.
Vorbereitung Methode
Metallic beryllium is produced by reduction of beryllium halide with sodium, potassium or magnesium. Commercially, it is obtained primarily from its ore, beryl. Beryllium oxide is separated from silica and alumina in ore by melting the ore, quenching the solid solution, and solubilizing in sulfuric acid at high temperatures and pressure. Silica and alumina are removed by pH adjustment. Beryllium is converted to its hydroxide. Alternatively, beryl is roasted with complex fluoride. The products are dissolved in water and then pH is adjusted to produce beryllium hydroxide.
The impure hydroxide obtained above is purified by converting to a double salt, ammonium beryllium fluoride, which subsequently, on thermal decomposition, gives beryllium fluoride. The latter is heated with magnesium metal BERYLLIUM 97 to form pure beryllium metal:
BeF +Mg→Be + MgF2
It finally is purified by either vacuum melting or chelation with an organophosphate reagent followed by liquid-liquid extraction. Beryllium halide alternatively may be reduced to the metal or converted to alloy by electrolysis.
Definition
beryllium: Symbol Be. A grey metallicelement of group 2 (formerly IIA)of the periodic table; a.n. 4; r.a.m.9.012; r.d. 1.85; m.p. 1278°C; b.p.2970°C. Beryllium occurs as beryl(3BeO.Al
2O
3.6SiO
2) and chrysoberyl(BeO.Al
2O
3). The metal is extractedfrom a fused mixture of BeF
2/NaF byelectrolysis or by magnesium reductionof BeF
2. It is used to manufactureBe–Cu alloys, which are used innuclear reactors as reflectors andmoderators because of their low absorptioncross section. Berylliumoxide is used in ceramics and in nuclearreactors. Beryllium and its compoundsare toxic and can causeserious lung diseases and dermatitis.The metal is resistant to oxidation byair because of the formation of anoxide layer, but will react with dilutehydrochloric and sulphuric acids.Beryllium compounds show high covalentcharacter. The element wasisolated independently by F. W?hlerand A. A. Bussy in 1828.
Reaktionen
Most chemical reactions of beryllium are similar to those of aluminum and, to a lesser extent, magnesium. In general, all the common mineral acids attack beryllium forming their corresponding salts with evolution of hydrogen:
Be + 2HCl → BeCl2 + H2
Cold, concentrated nitric acid, however, has no effect when mixed with the metal.
Reactions with alkalies first produce insoluble beryllium hydroxide with evolution of hydrogen. Excess alkali converts the hydroxide to water-soluble beryllate:
Be(OH)2 + 2NaOH → Na2BeO2 + H2O
Beryllium does not react with oxygen at ordinary temperatures and normal atmosphere. When heated above 700°C, the metal combines with nitrogen, (in an oxygen-free atmosphere) forming beryllium nitride, Be3N2.
Beryllium combines with carbon when heated above 900°C in the absence of air to form beryllium carbide.
2Be + 2C→（>900℃）→Be2C
Beryllium reacts incandescently with fluorine or chlorine, producing beryllium fluoride or chloride.
Allgemeine Beschreibung
A grayish-white hard light metal. Denser than water, but the powder may float. May be toxic by inhalation. Will burn if involved in a fire.
Air & Water Reaktionen
Highly flammable. Insoluble in water.
Reaktivit?t anzeigen
Boron trifluoride reacts with incandescence when heated with alkali metals or alkaline earth metals except magnesium [Merck 11th ed. 1989]. Finely divided or amalgamated metal reacts with HCl, dil HNO3, or dil H2SO4; attacked by strong base with evolution of hydrogen gas [Merck 11th ed. 1989]. BERYLLIUM has been determined experimentally that a mixture of BERYLLIUM with carbon tetrachloride or with trichloroethylene will flash or spark on heavy impact [ASESB Pot. Incid. 39 1968]. The reaction between beryllium and the vapors of phosphorus proceeds with incandescence [Mellor 8:842 1946-47].
Hazard
The elemental metallic form of beryllium is highly toxic, as are most of its compounds.When inhaled, the fumes, dust, or particles of beryllium are highly carcinogenic. Some berylliumcompounds are toxic when they penetrate cuts in the skin (e.g., when an old fluorescenttube breaks). Beryllium oxide when inhaled can result in a fatal disease known as berylliosis(similar to, but more toxic than, silicosis).
As with many other chemicals, beryllium has its positives and negatives. Although it is animportant industrial chemical, the handling of beryllium is best left to experienced workersand laboratory personnel in proper facilities.
Industrielle Verwendung
Among structural metals, beryllium (symbolBe) has a unique combination of properties. Ithas low density (two thirds that of aluminum),high modulus per weight (five times that ofultrastrength steels), high specific heat, highstrength per density, excellent dimensionalstability, and transparency to x-rays. Berylliumis expensive, however, and its impactstrength is low compared to values for mostother metals.
Beryllium is a steel-gray lightweight metal,used mainly for its excellent physical propertiesrather than its mechanical properties. Except formagnesium (Mg), it is the lightest in weight ofcommon metals, with a density of 1855 kg/m3.It also has the highest specific heat (1833J/kg K) and a melting point of 1290°C. It isnonmagnetic, has about 40% the electrical conductivityof copper, a thermal conductivity of190 W/m K, high permeability to x-rays, andthe lowest neutron cross section of any metalhaving a melting point above 500°C.
m?gliche Exposition
Beryllium is used extensively in
manufacturing electrical components, chemicals, ceramics,
nuclear reactors; in the aerospace industry; and X-ray tubes.
Beryllium and Compounds 423
A number of alloys are produced in which beryllium is
added to yield greater tensile strength, electrical conductivity,
and resistance to corrosion and fatigue. The metal is
used as a neutron reflector in high-flux test reactors. Human
exposure occurs mainly through inhalation of beryllium dust
or fumes by beryllium ore miners, beryllium alloy makers
and fabricators; phosphor manufacturers; ceramic workers;
missile technicians; nuclear reactor workers; electric and
electronic equipment workers; and jewelers. The major
source of beryllium exposure of the general population is
thought to be the burning of coal. Approximately 250,000
pounds of beryllium is released from coal and oil-fired burners.
EPA estimates the total release of beryllium to the
atmosphere from point sources is approximately 5500
pounds per year. The principal emissions are from beryllium
copper alloy production. Approximately 721,000 persons
living within 12.5 mi (20 km) of point sources are
exposed to small amounts of beryllium (median concentration
0.005 μ/m3). Levels of beryllium have been reported in
drinking water supplies and in small amounts in food.
Carcinogenicity
Beryllium and beryllium compounds are known to be human carcinogens based on sufficient evidence of carcinogenicity from studies in humans. Beryllium and beryllium compounds were first listed in the Second Annual Report on Carcinogens as reasonably anticipated to be human carcinogens based on sufficient evidence of carcinogenicity from studies in experimental animals. The listing was revised to known to be human carcinogens in the Tenth Report on Carcinogens in 2002.
Environmental Fate
Beryllium compromises the immune system. Enzymes catalyzed by magnesium or calcium can be inhibited by beryllium; succinic dehydrogenase is activated. Beryllium exposure leads to a deficiency in lung carbon monoxide diffusing capacity. Hypercalcemia (excess of calcium in the blood) can occur.
Because of the toxicity of beryllium vapor and dust, all operations should be carried out in properly ventilated rooms, and with vented equipment. Source exhaust has been found to be most effective. In the presence of poorly controlled high workplace concentrations, finedust masks with filters of the specific safety level must be worn.
Versand/Shipping
UN1567: Beryllium powder, Hazard class: 6.1;
Labels: 6.1—Poisonous material, 4.1—Flammable solid.
Structure and conformation
The space lattice of Beryllium belongs to the hexagonal system, and its close-packed hexagonal lattice has constants of a = 0.228 nm, c = 0.3977 nm (188 ℃).
Inkompatibilit?ten
Beryllium metal reacts with strong acids;
alkalis (forming combustible hydrogen gas), oxidizable
materials. Forms shock sensitive mixtures with some
chlorinated solvents, such as carbon tetrachloride and
trichloroethylene. Incompatible with caustics, chlorinated
hydrocarbons, oxidizers, molten lithium.
Waste disposal
For beryllium (powder),
waste should be converted into chemically inert oxides
using incineration and particulate collection techniques.
These oxides should be returned to suppliers if possible.
Recovery and recycling is an alternative to disposal for beryllium
scrap and pickle liquors containing beryllium.
Beryllium Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
