Tantal Chemische Eigenschaften,Einsatz,Produktion Methoden
ERSCHEINUNGSBILD
SCHWARZER FESTSTOFF IN VERSCHIEDENEN FORMEN.
PHYSIKALISCHE GEFAHREN
Staubexplosion der pulverisierten oder granulierten Substanz in Gemischen mit Luft möglich.
CHEMISCHE GEFAHREN
Reagiert mit Halogenen und Oxidationsmitteln unter Feuer- und Explosionsgefahr.
ARBEITSPLATZGRENZWERTE
TLV: 5 mg/m?(als TWA); (ACGIH 2005).
MAK: (Einatembare Fraktion) 4 mg/m? (Alveolengängige Fraktion) 1.5 mg/m? (DFG 2005).
INHALATIONSGEFAHREN
Eine belästigende Partikelkonzentration in der Luft kann beim Dispergieren schnell erreicht werden.
WIRKUNGEN BEI KURZZEITEXPOSITION
WIRKUNGEN BEI KURZZEITEXPOSITION: Reizt möglicherweise mechanisch.
LECKAGE
Zündquellen entfernen. Persönliche Schutzausrüstung: Atemschutzgerät, P1-Filter für inerte Partikel. Verschüttetes Material mit inertem Absorptionsmittel abdecken. Verschüttetes Material aufsaugen. An sicheren Ort bringen.
R-Sätze Betriebsanweisung:
R11:Leichtentzündlich.
R36/37/38:Reizt die Augen, die Atmungsorgane und die Haut.
R20/21/22:Gesundheitsschädlich beim Einatmen,Verschlucken und Berührung mit der Haut.
S-Sätze Betriebsanweisung:
S16:Von Zündquellen fernhalten - Nicht rauchen.
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
S33:Maßnahmen gegen elektrostatische Aufladungen treffen.
S36/37/39:Bei der Arbeit geeignete Schutzkleidung,Schutzhandschuhe und Schutzbrille/Gesichtsschutz tragen.
S36:DE: Bei der Arbeit geeignete Schutzkleidung tragen.
Chemische Eigenschaften
Tantalum is a refractory metal in Group V-B of the periodic table. The pure metal is ductile, steel-blue to gray solid or black, odorless powder.
Physikalische Eigenschaften
Tantalum has properties similar to niobium and vanadium above it in group 5. It is a veryhard and heavy metal with a bluish color when in its rough state, but if polished, it has a silveryshine. It is ductile, meaning it can be drawn into fine wires, and also malleable, meaningit can be hammered and worked into shapes. Thin strips and wires of tantalum will ignite inair if exposed to a flame.
Tantalum’s melting point is 2,996°C, which is almost as high as tungsten and rhenium. Itboiling point is 5,425°C, and its density is 19.3 g/cm
3.
Isotopes
There are 49 isotopes of tantalum. Only the isotope Ta-181 is stable andaccounts for 99.988% of the total mass of the element on Earth. Just 0.012% of the element’s mass is contributed by Ta-180, which has a half-life of 1.2×10
+15 years and isthus considered naturally stable. The remaining 47 isotopes are all artificially producedin nuclear reactions or particle accelerators and have half-lives ranging from a few microsecondsto few days to about two years.
Origin of Name
Tantalum was named after Tantalus, who was the father of Niobe, the
queen of Thebes, a city in Greek mythology. (Note: The element tantalum was originally
confused with the element nobelium.)
Occurrence
Tantalum is the 51st most abundant element found on Earth. Although it is found in afree state, it is usually mixed with other minerals and is obtained by heating tantalum potassiumfluoride or by the electrolysis of melted salts of tantalum. Tantalum is mainly obtainedfrom the following ores and minerals: columbite [(Fe, Mn, Mg)(Nb, Ta)
2O
6]; tantalite [(Fe,Mn)(Ta, Nb)
2O
6]; and euxenite [(Y, Ca, Er, La, Ce, U, Th)(Nb, Ta, Ti)
2O
6]. Tantalum’s oresare mined in South America, Thailand, Malaysia, Africa, Spain, and Canada. The UnitedStates has a few small native deposits but imports most of the tantalum it uses.
Since tantalum and niobium are so similar chemically, a solvent process must be employedto separate them from the common ores. They are dissolved in a solvent, resulting in 98% pure niobium oxide being extracted during this part of the process. This is followed by 99.5%pure tantalum oxide being extracted in a second solvent process.
Charakteristisch
Tantalum is almost as chemically inert at room temperatures (it has the ability to resistchemical attacks, including hydrofluoric acid) as are platinum and gold. It is often substitutedfor the more expensive metal platinum, and its inertness makes it suitable for constructingdental and surgical instruments and artificial joints in the human body.
Verwenden
In pen points; analytical weights; apparatus and instruments for chemical, surgical, and dental use instead of platinum, in tantalum capacitors (a type of electrolytic condenser, trademarked "Tantalytic").
Vorbereitung Methode
It was identi?ed that tantalum minerals exists in over 70 differentchemicalcompositions.Thoseofgreatesteconomic importance are tantalite, microlite, and wodginite; however, it is common practice to name any tantalum-containing mineral concentrate as “tantalite”. Tantalum resources are widespread, with the most important known resources being found in Brazil and Australia. In mid-2008, the main mining operations were in Australia, Brazil,Canada,Mozambique,andEthiopiaandinmid-2009, in Brazil, Ethiopia, and China, with additional quantities originating in central Africa, Russia, and Southeast Asia. There is continued interest in exploration of this element in other countries, primarily in Egypt, Canada, Mozambique, and Saudi Arabia.
The major world mine producers of tantalum in 2010 were Brazil (180 tons), Mozambique (110 tons), Rwanda (100 tons), and Australia (80 tons). Other countries produced around 170 tons, so the total world production of tantalum was approximately 670 tons. The major producers of tantalum mineral concentrates are Australia, Brazil, and Canada.
Definition
A silvery transition
element. It is strong, highly resistant to corrosion,
and is easily worked. Tantalum is
used in turbine blades and cutting tools
and in surgical and dental work.
Symbol: Ta; m.p. 2996°C; b.p. 5425 ±
100°C; r.d. 16.654 (20°C); p.n. 73; r.a.m.
180.9479.
Allgemeine Beschreibung
Tantalum dust is a black odorless powder. Mp: 2996°C; bp: approx. 5250°C. Density: 16.65 g cm-3. Insoluble in water. Tantalum oxide dust is a white, microcrystalline powder Mp: 1800°C. Density: 7.6 g cm-3. Insoluble in water. The mixture is listed as a toxic inhalation hazard by OHSA.
Hazard
The dust and powder of tantalum are explosive. Several tantalum compounds are toxic ifinhaled or ingested, but the metal itself is nonpoisonous.
Health Hazard
Tantalum has a low order of toxicity
but has produced transient inflammatory
lesions in the lungs of animals.
Surgical implantation of tantalum metal
products such as plates and screws has not
shown any adverse tissue reaction, thus demonstrating
its physiological inertness.
Sicherheitsprofil
An inhalation hazard. Some industrial skin injuries from tantalum have been reported. Systemic industrial poisoning, however, is apparently unknown. Questionable carcinogen with experimental tumorigenic data. The dry powder iptes spontaneously in air. Incompatible with bromine trifluoride, fluorine, lead chromate. See also specific tantalum compounds.
Carcinogenicity
Although Oppenheimer et al., using embedded metal foil technique, have elicited two malignant ?brosarcomas in 50 embeddings of tantalum metal in 25Wistar rats aftera latent period of714days, these results remain a controversial issue. Miller et al. have studied tumorigenic transforming potential of tungsten, iron, nickel, and cobalt with tantalum as a comparison on an immortalized nontumorigenic human osteoblast-like cell line. No tumorigenic activity of Ta was reported, but data are not shown.
In the recent study, intramuscularly pellets (1mm 2mm cylinders) of weapons-grade WA were implantedtosimulateshrapnelwounds.Ratswereimplanted with 4 (low dose) or 20 pellets (high dose) of WA. Tantalum (20 pellets) and nickel (20 pellets) served as negative and positive controls, respectively. Rats implanted with tantalum (n=46) did not develop tumors.
Versand/Shipping
UN3089 Metal powders, flammable, n.o.s., Hazard Class: 4.1; Labels: 4.1-Flammable solid.
Inkompatibilitäten
A flammable solid; the dry powder can ignite spontaneously in air. Incompatible with lead chromate. A strong reducing agent; incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, bromine trifluoride, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides. Tantalum metal is attacked by hydrogen fluoride, fused alkalis, fuming sulfuric acid.
Waste disposal
Sanitary landfill if necessary; recover if possible because of economic value. Technology exists for tantalum recovery from spent catalysts, for example.
Tantal Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
