Blei Chemische Eigenschaften,Einsatz,Produktion Methoden
ERSCHEINUNGSBILD
BLäULICH-WEISSER ODER SILBERGRAUER FESTSTOFF IN VERSCHIEDENEN FORMEN. LäUFT AN BEI KONTAKT MIT LUFT.
PHYSIKALISCHE GEFAHREN
Staubexplosion der pulverisierten oder granulierten Substanz in Gemischen mit Luft möglich.
CHEMISCHE GEFAHREN
Beim Erhitzen bilden sich giftige Rauche. Reagiert mit Oxidationsmitteln. Reagiert mit heißer konzentrierter Salpetersäure, siedender konzentrierter Salzsäure und Schwefelsäure. Wird in Gegenwart von Sauerstoff angegriffen von Wasser und schwachen organischen Säuren.
ARBEITSPLATZGRENZWERTE
TLV: () 0.05 mg/m?(als TWA); Krebskategorie A3 (bestätigte krebserzeugende Wirkung beim Tier mit unbekannter Bedeutung für den Menschen); BEI vorhanden (ACGIH 2005).
MAK: Krebserzeugend Kategorie 2; Keimzellmutagen Kategorie 3A; (DFG 2006).
EG Arbeitsplatzgrenzwerte: (als TWA) 0.15 mg/m? (EG 2006).
AUFNAHMEWEGE
Aufnahme in den Körper durch Inhalation und durch Verschlucken.
INHALATIONSGEFAHREN
Eine gesundheitsschädliche Partikelkonzentration in der Luft kann beim Dispergieren schnell erreicht werden, besonders als Pulver.
WIRKUNGEN NACH WIEDERHOLTER ODER LANGZEITEXPOSITION
Möglich sind Auswirkungen auf Blut, Knochenmark, Zentralnervensystem, peripheres Nervensystemund Nieren. Führt zu Blutarmut, Enzephalopathie (z.B. Krämpfe), peripherer Nervenkrankheit, Bauchkrämpfen und Nierenschäden. Fruchtbarkeitsschädigend oder entwicklungsschädigend. Wahrscheinlich krebserzeugend für den Menschen.
LECKAGE
Verschüttetes Material in Behältern sammeln; falls erforderlich durch Anfeuchten Staubentwicklung verhindern. Reste sorgfältig sammeln. An sicheren Ort bringen. NICHT in die Umwelt gelangen lassen. Persönliche Schutzausrüstung: Atemschutzgerät, P3-Filter für giftige Partikel.
R-Sätze Betriebsanweisung:
R61:Kann das Kind im Mutterleib schädigen.
R33:Gefahr kumulativer Wirkungen.
R40:Verdacht auf krebserzeugende Wirkung.
R48/20:Gesundheitsschädlich: Gefahr ernster Gesundheitsschäden bei längerer Exposition durch Einatmen.
R62:Kann möglicherweise die Fortpflanzungsfähigkeit beeinträchtigen.
R36/38:Reizt die Augen und die Haut.
R20/22:Gesundheitsschädlich beim Einatmen und Verschlucken.
S-Sätze Betriebsanweisung:
S53:Exposition vermeiden - vor Gebrauch besondere Anweisungen einholen.
S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn möglich, dieses Etikett vorzeigen).
S61:Freisetzung in die Umwelt vermeiden. Besondere Anweisungen einholen/Sicherheitsdatenblatt zu Rate ziehen.
S36/37:Bei der Arbeit geeignete Schutzhandschuhe und Schutzkleidung tragen.
S36:DE: Bei der Arbeit geeignete Schutzkleidung tragen.
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
Beschreibung
Lead was one of the earliest metals used by humans, with
possible use extending as far back as the seventh millennium
BC, and reaching its preindustrial peak usage during the
reign of the Roman Empire, around the beginning of the
Common Era.
Chemische Eigenschaften
Lead is a lustrous silvery metal that tarnishes in the presence
of air and becomes a dull bluish gray. The chemical symbol,
Pb, is derived from plumbum, the Latin word for waterworks,
because of lead’s extensive use in ancient water pipes. Lead
has four electrons in its valence shell, but only two ionize
readily. The usual oxidation state of lead in inorganic compounds
is therefore +2 rather than +4. Lead generally forms
stable compounds; the most important ones are lead oxide
(PbO) and lead carbonate (PbCO
3)
2. Four stable lead isotopes
exist in nature (
208Pb ,
206Pb ,
207Pb, and
204Pb , in order of
abundance). Lead mined from deposits of different geologic
eras has entered the environment, so that today there are wide
variations and extensive mixture of isotopic ratios of lead in
commerce and in the environment. These differences in
isotopic ratios may sometimes be used as nonradioactive
tracers in environmental and metabolism studies.
Physikalische Eigenschaften
Lead is a bluish-white, heavy metallic element with properties that are more metal-like thanthe properties of metalloids or nonmetals. Lead can be found in its native state, meaning thatelemental metallic lead can be found in deposits in the Earth’s crust. However, most lead isfirst mined as galena ore (lead sulfide, PbS). The galena is mixed with lead sulfate, lead sulfide,and lead oxide and is then roasted at a high temperature. The air supply is reduced, followedby an increase in heat and the vaporization of the sulfates and oxides of lead, which are drawnoff as gases. The molten lead is then recovered.
Lead is only slightly soluble in water. However, it is also toxic. This is the reason lead isno longer used to pipe fresh water into homes. It does not react well with acids, with theexception of nitric acid. Lead’s melting point is 327.46°C, its boiling point is 1,740°C, andits density is 11.342 g/cm
3.
Isotopes
There are 47 isotopes of lead, four of which are stable. One of these four is Pb-204, which makes up 1.4% of the natural abundance of lead found on Earth. In reality thisisotope is not stable but has a half-life that is so long (1.4×10
+17 years), with some of theancient deposits still existing, that it is considered stable. The other three stable isotopes oflead and their proportion to the total natural abundance are as follows: Pb-206 = 24.1%,Pb-207 = 22.1%, and Pb-208 = 52.4%. All the other isotopes are radioactive.
Origin of Name
From the Latin word alumen, or aluminis, meaning “alum,” which is a
bitter tasting form of aluminum sulfate or aluminum potassium sulfate.
Occurrence
Lead is the 35th most abundant element on Earth. Although it has been found in its freeelemental metal state, it is usually obtained from a combination of the following ores: galena(PbS), anglesite (PbSO
4), cerussite (PbCO
3), and minum (Pb
3O
4). Lead ores are locatedin Europe (Germany, Rumania, and France), Africa, Australia, Mexico, Peru, Bolivia, andCanada. The largest deposits of lead in the United States are in the states of Missouri, Kansas,Oklahoma, Colorado, and Montana.
One of the most famous mining towns is the high-altitude western city of Leadville,Colorado. The boom started with the gold rush of the 1860s, followed by silver mining in the1870s and 1880s. Today, this city is the site of mining operations not only for lead, but alsofor zinc and molybdenum. At the height of its fame, Leadville had a population of almost50,000 people. Today the population is about 2,500.
Lead is commonly obtained by roasting galena (PbS) with carbon in an oxygen-rich environmentto convert sulfide ores to oxides and by then reducing the oxide to metallic lead.Sulfur dioxide gas is produced as a waste product. Large amounts of lead are also recoveredby recycling lead products, such as automobile lead-acid electric storage batteries. About onethirdof all lead used in the United States has been recycled.
Charakteristisch
Although lead can be found as a metal in the Earth’s crust, it is usually mined and refinedfrom minerals and ores. Lead is one of the most common and familiar metallic elementsknown. Although it is somewhat scarce, found at proportions of 13 ppm, it is still more prevalentthan many other metals. Lead is noncombustible. and it resists corrosion.
When lead, which is very soft, is freshly cut, it has shiny blue-white sheen, which soonoxidizes into its familiar gray color. Lead is extremely malleable and ductile and can be workedinto a variety of shapes. It can be formed into sheets, pipes, buckshot, wires, and powder.Although lead is a poor conductor of electricity, its high density makes it an excellent shieldfor protection from radiation, including X-rays and gamma rays.
Verwenden
Construction material for tank linings, piping, and other equipment handling corrosive gases and liqs used in the manufacture of sulfuric acid, petroleum refining, halogenation, sulfonation, extraction, condensation; for x-ray and atomic radiation protection; manufacture of tetraethyllead, pigments for paints, and other organic and inorganic lead Compounds; bearing metal and alloys; storage batteries; in ceramics, plastics, and electronic devices; in building construction; in solder and other lead alloys; in the metallurgy of steel and other metals.
Definition
lead: Symbol Pb. A heavy dull greysoft ductile metallic element belongingto group 14 (formerly IVB) ofthe periodic table; a.n. 82; r.a.m.207.19; r.d. 11.35; m.p. 327.5°C; b.p.1740°C. The main ore is the sulphidegalena (PbS); other minor sources includeanglesite (PbSO
4), cerussite (PbCO
3), and litharge (PbO). Themetal is extracted by roasting the oreto give the oxide, followed by reductionwith carbon. Silver is also recoveredfrom the ores. Lead has a varietyof uses including building construction,lead-plate accumulators, bullets,and shot, and is a constituent of suchalloys as solder, pewter, bearing metals,type metals, and fusible alloys.Chemically, it forms compoundswith the +2 and +4 oxidation states,the lead(II) state being the more stable.
Vorbereitung Methode
The geometric mean soil lead level is 38 mg/kg. Lead
rarely occurs in the elemental state, but exists widely
throughout the world in a number of ores, the most common
of which is the sulfide, galena. The other minerals of commercial
importance are the oxides, carbonate (cerussite), and
the sulfate (anglesite), which are much less common.
Lead also occurs in various uranium and thorium minerals,
arising directly from radioactive decay. Because certain
isotopes are concentrated in lead derivatives from such
sources, both the atomic weight and the density of the
samples vary significantly from normal lead. Lead ores
generally occur in nature in association with silver and
zinc. Other metals commonly occurring with lead ores are
copper, arsenic, antimony, and bismuth. Most of the world production of arsenic, antimony, and bismuth is a result of
their separation from lead ores. Commercial lead ores may
contain as little as 3% lead, but a lead content of 10% is
most common. The ores are concentrated to ≥ 40% lead
content before smelting. A variety of mechanical separation
processes may be employed for the concentration of lead
ores, but the sulfide ores are generally concentrated by
flotation processes.
Allgemeine Beschreibung
Soft silver-bluish white to gray metal.
Air & Water Reaktionen
Insoluble in water.
Reaktivität anzeigen
In the presence of carbon, the combination of chlorine trifluoride with aluminum, copper, Lead, magnesium, silver, tin, or zinc results in a violent reaction [Mellor 2, Supp. 1: 1956]. A solution of sodium azide in copper pipe with Lead joints formed copper and Lead azide, both are detonating compounds [Klotz 1973]. Sodium acetylide becomes pyrophoric when mixed with metals like Lead. Mixtures of trioxane with 60% hydrogen peroxide in contact with metallic Lead when heated detonated. Lead containing rubber ignited in a nitric acid atmosphere. Lead is incompatible with strong oxidants such as: ammonium nitrate, chlorine trifluoride, hydrogen peroxide, etc.
Health Hazard
The acute toxicity of lead and inorganic lead compounds is moderate to low.
Symptoms of exposure include decreased appetite, insomnia, headache, muscle and
joint pain, colic, and constipation. Inorganic lead compounds are not significantly
absorbed through the skin.
Chronic exposure to inorganic lead via inhalation or ingestion can result in damage
to the peripheral and central nervous system, anemia, and chronic kidney disease.
Lead can accumulate in the soft tissues and bones, with the highest accumulation in
the liver and kidneys, and elimination is slow. Lead has shown developmental and
reproductive toxicity in both male and female animals and humans. Lead is listed by
IARC in Group 2B ("possible human carcinogen") and by NTP as "reasonably
anticipated to be a carcinogen," but is not considered to be a "select carcinogen"
under the criteria of the OSHA Laboratory Standard.
Brandgefahr
Flash point data for Lead are not available, however, Lead is probably non-combustible.
Flammability and Explosibility
Lead powder is combustible when exposed to heat or flame.
Industrielle Verwendung
Not only is lead the most impervious of all common metals to x-rays and gamma radiation, it also resists attack by many corrosive chemicals, most types of soil, and marine and industrial environments. Although lead is one of the heaviest metals, only a few applications are based primarily on its high density. The main reasons for using lead often include low melting temperature, ease of casting and forming, good sound and vibration absorption, and ease of salvaging from scrap.
With its high internal damping characteristics, lead is one of the most efficient sound attenuators for industrial, commercial, and residential applications. Sheet lead, lead-loaded vinyls, lead composites, and lead-containing laminates are used to reduce machinery noise. Lead sheet with asbestos or rubber sandwich pads are commonly used in vibration control.
Carcinogenicity
Lead and lead compounds are reasonably anticipated to be human carcinogens based on limited evidence of carcinogenicity from studies in humans and sufficient evidence of carcinogenicity from studiesin experimental animals.
Lager
work with lead dust, molten lead, and lead salts capable of forming
dusts should be conducted in a fume hood to prevent exposure by inhalation.
Inkompatibilitäten
Violent reactions of lead with sodium azide, zirconium, sodium acetylide, and
chlorine trifluoride have been reported. Reactivity of lead compounds varies
depending on structure.
Waste disposal
Excess lead and waste material containing this substance should be placed in an appropriate
container, clearly labeled, and handled according to your institution's waste disposal
guidelines. For more information on disposal procedures, see Chapter 7 of this volume.
Blei Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
