Kalium

Kalium Chemische Eigenschaften,Einsatz,Produktion Methoden

ERSCHEINUNGSBILD

WEISSE BIS GRAUE STüCKE

CHEMISCHE GEFAHREN

Reagiert sehr heftig mit Wasser, Feuer- und Explosionsgefahr. Schnelle Zersetzung unter Einfluss von Luft und Feuchtigkeit unter Bildung brennbarer/explosionsfähiger Gase (z.B. Wasserstoff, ICSC-Nr. 0001).

ARBEITSPLATZGRENZWERTE

TLV nicht festgelegt (ACGIH 2005).
MAK nicht festgelegt (DFG 2006).

AUFNAHMEWEGE

Schwerwiegende lokale Wirkungen auf allen Aufnahmewegen.

WIRKUNGEN BEI KURZZEITEXPOSITION

WIRKUNGEN BEI KURZZEITEXPOSITION:
Siehe ICSC 0357 (Kalium hydroxid).

LECKAGE

Gefahrenbereich verlassen! Fachmann zu Rate ziehen! Chemikalienschutzanzug mit umgebungsluftunabhängigem Atemschutzgerät. Verschüttetes Material mit trockenem Pulver abdecken.

R-Sätze Betriebsanweisung:

R14/15:Reagiert heftig mit Wasser unter Bildung hochentzündlicher Gase.
R34:Verursacht Verätzungen.

S-Sätze Betriebsanweisung:

S8:Behälter trocken halten.
S43:Zum Löschen . . . (vom Hersteller anzugeben) verwenden (wenn Wasser die Gefahr erhöht, anfügen: "Kein Wasser verwenden").
S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn möglich, dieses Etikett vorzeigen).

Aussehen Eigenschaften

K; wachsweiches, an frischen Schnittstellen silberweißes Metall, meist mit einer grauen Kruste überzogen.

Gefahren für Mensch und Umwelt

Kalium oxidiert an feuchter Luft. Mit Wasser reagiert es stürmisch unter Bildung von Wasserstoff und Kalilauge, wobei es schmilzt und den Wasserstoff entzündet. Es reagiert äußerst heftig bis explosionsartig mit Halogenen, Halogeniden des Zinns, Silbers, Schwefels, Phosphors und Siliciums, ferner mit Halogenwasserstoffen, Schwermetalloxiden, Säuren, Säurechloriden, Aktivkohle und Graphit, Ammoniumnitrat, Nitroverbindungen, Schwefelkohlenstoff und allen Peroxiden, Chloraten und Perchloraten. Die Die Oxide und Hydroxide sowie Salze der meisten Schwermetalle werden beim Erhitzen mit Kalium, teilweise explosionsartig, zu den Metallen reduziert.
Vorsicht vor Kalium mit gelben, okerfarbigen oder braunen Überzügen: Diese Überzüge bestehen wahrscheinlich aus Kaliumperoxiden oder -hyperoxiden und können bereits beim Ansetzen eines Schneidemessers explosionsartig reagieren.
Hautkontakt mit Kaliummetall führt zu Verbrennungen bzw. extrem schweren tiefgreifenden Verätzungen durch Kalilauge. Letztere sind in die Tiefe fortschreitende Quellungen und Auflösung betroffener Gewebe (daher gefährlicher als Säureverätzungen). Am Auge entstehen durch Laugenspritzer oder Kaliumpartikel schwere Reizerscheinungen oder Verätzungen oder Verätzngen an der Bindehaut sowie Trübung und Geschwürbildung an der Hornhaut.

Schutzmaßnahmen und Verhaltensregeln

Aufbewahrung unter Parrafinöl, Behälter dicht geschlossen halten. Kontakt mit Luft, insbesondere mit Wasser vermeiden.
Trockene Schutzhandschuhe nur als kurzfristigen Schutz benutzen.

Verhalten im Gefahrfall

Vor Wasser schützen. Trocken aufnehmen und in Gebiden mit Paraffinölfüllung als Sondermüll entsorgen.
Sand, trockenes Salz oder Soda verwenden.
Auf keinen Fall Wasser, CO₂ oder Halone als Löschmittel verwenden.

Erste Hilfe

Nach Hautkontakt: Nach trockenem Entfernen von Metallteilchen betroffene Haut mit sehr viel Wasser spülen.
Nach Augenkontakt: Bei Augenkontakt mit viel Wasser bei gut geöffnetem Lid mindestens 15 Min. spülen. Sofort einen Augenarzt hinzuziehen.
Nach Verschlucken: Viel Wasser trinken lassen. Erbrechen vermeiden. Sofort Arzt hinzuziehen.
Ersthelfer: siehe gesonderten Anschlag

Sachgerechte Entsorgung

Synthesereste unter Paraffinöl sammeln. In trockenes n-Butanol oder tert. Butanol eintragen und durch leichtes Erwärmen vorsichtig lösen. Nach anschließender Ehanol- und Wasserzugabe wird das Gemisch neutralisiert und im Ausguß entsorgt.
Größere Mengen unter Paraffinöl als Sondermüll entsorgen.

Beschreibung

Potassium has atomic number 19 and the chemical symbol K, which is derived from its Latin name kalium . Potassium was first isolated from potash, which is potassium carbonate (K₂CO₃). Potassium occurs in nature only in the form of its ion (K⁺) either dissolved in the ocean or coordinated in minerals because elemental potassium reacts violently with water . Potassium ions are essential for the human body and are also present in plants. The major use of K⁺ can be found in fertilisers, which contains a variety of potassium salts such as potassium chloride (KCl), potassium sulfate (K₂SO₄) and potassium nitrate (KNO₃).

Chemische Eigenschaften

Potassium is a soft silvery metal, tarnishing upon exposure to air.

Physikalische Eigenschaften

Elemental potassium is a soft, butter-like silvery metal whose cut surface oxidizes in dryair to form a dark gray potassium superoxide (KO₂) coating. KO₂ is an unusual compound,in that it reacts with both water and carbon dioxide to produce oxygen gas. It appears morelike a hard wax than a metal. Its density (specific gravity) is 0.862 g/cm³, its melting point is63.25°C, and its boiling point is 760°C. It has an oxidation state of +1 and reacts explosivelywith room temperature air or water to form potassium hydroxide as follows: 2K + 2 H₂O→? 2KOH + H₂. This is an endothermic reaction, which means the heat generated is greatenough to ignite the liberated hydrogen gas. Potassium metal must be stored in a non-oxygen,non-aqueous environment such as kerosene or naphtha.

Isotopes

A total of 18 isotopes of potassium have been discovered so far. Just two ofthem are stable: K-39 makes up 93.2581% of potassium found in the Earth’s crust, andK-41 makes up 6.7301% of the remainder of potassium found on Earth. All the other16 potassium isotopes are unstable and radioactive with relatively short half-lives, and asthey decay, they produce beta particles. The exception is K-40, which has a half-life of1.25×10⁹ years.

Origin of Name

Its symbol “K” is derived from the Latin word for alkali, kalium, but it is commonly called “potash” in English.

Occurrence

Potassium is the eighth most abundant element in the Earth’s crust, which contains about2.6% potassium, but not in natural elemental form. Potassium is slightly less abundant thansodium. It is found in almost all solids on Earth, in soil, and in seawater, which contains 380ppm of potassium in solution. Some of the potassium ores are sylvite, carnallite, and polyhalite. Ore deposits are found in New Mexico, California, Salt Lake in Utah, Germany, Russia,and Israel. Potassium metal is produced commercially by two processes. One is thermochemical distillation, which uses hot vapors of gaseous NaCl (sodium chloride) and KCl (potassiumchloride); the potassium is cooled and drained off as molten potassium, and the sodium chloride is discharged as a slag. The other procedure is an electrolytic process similar to that used toproduce lithium and sodium, with the exception that molten potassium chloride (which meltsat about 770°C) is used to produce potassium metal at the cathode.

Charakteristisch

Because its outer valence electrons are at a greater distance from its nuclei, potassium ismore reactive than sodium or lithium. Even so, potassium and sodium are very similar in theirchemical reactions. Due to potassium’s high reactivity, it combines with many elements, particularly nonmetals. Like the other alkali metals in group 1, potassium is highly alkaline (caustic) with a relatively high pH value. When given the flame test, it produces a violet color.

Verwenden

In synthesis of inorganic potassium Compounds; in organic syntheses involving condensation, dehalogenation, reduction, and polymerization reactions. As heat transfer medium together with sodium: Chem. Eng. News 33, 648 (1955). Radioactive decay of 40K to 40Ar used as tool for geological dating.

synthetische

Potassium metal is not produced commercially by a fused salt electrolysis of the chloride —as is sodium—for several reasons: the metal is too soluble in the molten chloride to separate and float on top of the bath; potassium metal vapors may also issue from the molten bath, thus creating hazardous conditions; and potassium superoxide may form in the cell and react explosively with potassium metal. Consequently, the established method of preparing potassium metal commercially? involves the reduction of molten potassium chloride by metallic sodium at elevated temperatures (850°C). Molten potassium chloride is fed into the midpoint of a steel vessel provided with a fractionating tower packed with stainless steel rings. Sodium is vaporized at the bottom and rises countercurrent to the molten potassium chloride with which it reacts according to the equilibrium expression.
Although the left-hand side of the equation is favored thermodynamically, the escape of the potassium vapors causes the reaction to proceed very efficiently to the right. The potassium vapors are condensed and the product normally contains sodium metal as the only major impurity up to about 1 % by weight. This product is sometimes purified by fractionating it in a 38 ft high 316 stainless steel tower equipped with a reflux return reservoir. The condensate is potassium metal of 99.99 % purity.

Vorbereitung Methode

Potassium superoxide (KO2) can create oxygen from water vapor (H2O) and carbon dioxide (CO2) and is used in respiratory equipment and is produced by burning potassium metal in dry air.

Definition

potassium: Symbol K. A soft silverymetallic element belonging to group1 (formerly IA) of the periodic table(see alkali metals); a.n. 19; r.a.m.39.098; r.d. 0.86; m.p. 63.7°C; b.p.774°C. The element occurs in seawaterand in a number of minerals,such as sylvite (KCl), carnallite(KCl·MgCl2·6H2O), and kainite(MgSO4·KCl·3H2O). It is obtained byelectrolysis. The metal has few usesbut potassium salts are used for awide range of applications. Potassiumis an essential element for livingorganisms. The potassium ion,K+, is the most abundant cation inplant tissues, being absorbed throughthe roots and being used in suchprocesses as protein synthesis. In animalsthe passage of potassium andsodium ions across the nerve-cellmembrane is responsible for thechanges of electrical potential thataccompany the transmission of impulses.Chemically, it is highly reactive,resembling sodium in itsbehaviour and compounds. It alsoforms an orange-coloured superoxide,KO₂, which contains the O2^- ion.Potassium was discovered by SirHumphry Davy in 1807.

Allgemeine Beschreibung

Potassium is potassium mixed with some other metal, usually sodium. Potassium is a liquid under normal conditions. Potassium reacts vigorously with water to form potassium hydroxide, a corrosive material and hydrogen, a flammable gas. The heat from this reaction may be sufficient to ignite the hydrogen. Potassium alloy may ignite spontaneously in contact with air. Once ignited, potassium burns quite violently. Potassium is used as a heat exchange fluid.

Air & Water Reaktionen

Reacts vigorously with oxygen. Reacts vigorously with water even at less than 100°C [Merck, 11th ed., 1989]. Water (caustic solution, H2) The oxidation of potassium in air is so rapid that the heat generated by the reaction melts and ignites the metal. This is particularly the case when pressure is applied at ordinary temperatures [Sidgwick 1. 1950]. Potassium burns in moist air at room temperature [Mellor 2:468. 1946-47]. The higher oxides of potassium, formed in air, react explosively with pure potassium, sodium, sodium-potassium alloys, and organic matter [Mellor 2, Supp. 3:1559. 1963].

Health Hazard

Potassium reacts with the moisture on skin and other tissues to form highly corrosive potassium hydroxide. Contact of metallic potassium with the skin, eyes, or mucous membranes causes severe burns; thermal burns may also occur due to ignition of the metal and liberated hydrogen.

Flammability and Explosibility

Potassium metal may ignite spontaneously on contact with air at room temperature. Potassium reacts explosively with water to form potassium hydroxide; the heat liberated generally ignites the hydrogen formed and can initiate the combustion of potassium metal itself. Potassium fires must be extinguished with a class D dry chemical extinguisher or by the use of sand, ground limestone, dry clay or graphite, or "Met-L-X?" type solids. Water or CO2, extinguishers must never be used on potassium fires.

mögliche Exposition

Used as a reagent and in sodiumpotassium alloys which are used as high-temperature heat transfer media.

Environmental Fate

Potassium metal in the environment will react with air, oxidizing the exposed surfaces, and reacts violently with water, yielding potassium hydroxide and hydrogen gas, which reacts with oxygen in air, producing flame.

Lager

Safety glasses, impermeable gloves, and a fire-retardant laboratory coat should be worn at all times when working with potassium, and the metal should be handled under the surface of an inert liquid such as mineral oil, xylene, or toluene. Potassium should be used only in areas free of ignition sources and should be stored under mineral oil in tightly sealed metal containers under an inert gas such as argon. Potassium metal that has formed a yellow oxide coating should be disposed of immediately; do not attempt to cut such samples with a knife since the oxide coating may be explosive.

Versand/Shipping

UN2257Potassium, Hazard Class: 4.3; Labels: 4.3-Dangerous when wet material. UN1420 Potassium, metal alloys and metal alloys, liquid, Hazard Class: 4.3; Labels: 4.3-Dangerous when wet material. UN3089 Metal powder, flammable, n.o.s. Hazard Class: 4.2; Labels: 4.2-Spontaneously combustible material.

Inkompatibilitäten

Air contact causes spontaneous ignition. Violent reaction with water, forming heat, spattering, corrosive potassium hydroxide and explosive hydrogen. The heat from the reaction can ignite the hydrogen that is generated. A powerful reducing agent. Violent reaction with oxidizers, organic materials; carbon dioxide; heavy metal compounds; carbon tetrachloride; halogenated hydrocarbons; easily oxidized materials; and many other substances. Store under nitrogen, mineral oil, or kerosene. Oxidizes and forms unstable peroxides under storage conditions. Potassium metal containing an oxide coating is an extremely dangerous explosion hazard and should be removed by an expert and destroyed.

Waste disposal

Excess potassium and waste material containing this substance should be placed in an appropriate container under an inert atmosphere, clearly labeled, and handled according to your institution's waste disposal guidelines. Experienced personnel can destroy small scraps of potassium by carefully adding t-butanol or nbutanol to a beaker containing the metal scraps covered in an inert solvent such as xylene or toluene.

Kalium Upstream-Materialien And Downstream Produkte

Upstream-Materialien

Downstream Produkte

7440-09-7(Kalium)Verwandte Suche:

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• potassium,metalalloys
• CHLORO POTASSIUM
• CONDUCTANCE STANDARD 300 000 UMHO
• CONDUCTANCE STANDARD SOLUTION B
• CONDUCTANCE STANDARD SOLUTION C
• CONDUCTIVITY CALIBRATION STANDARD 10
• CONDUCTIVITY CALIBRATION STANDARD 100
• CONDUCTIVITY CALIBRATION STANDARD 1,000
• CONDUCTIVITY CALIBRATION STANDARD 10,000
• CONDUCTIVITY CALIBRATION STANDARD 100,000
• CONDUCTIVITY CALIBRATION STANDARD 147
• CONDUCTIVITY CALIBRATION STANDARD 718
• CONDUCTIVITY STANDARD, 100,000 MICROSIEMENS/CM
• CONDUCTIVITY STANDARD, 1000 MICROSIEMENS/CM
• CONDUCTIVITY STANDARD, 100 MICROSIEMENS/CM
• CONDUCTIVITY STANDARD, 10 MICROSIEMENS/CM
• CONDUCTIVITY STANDARD, 12,900 UMHOS
• CONDUCTIVITY STANDARD 1413
• CONDUCTIVITY STANDARD, 1413 MICROSIEMENS/CM
• CONDUCTIVITY STANDARD, 1.413 UMHOS
• CONDUCTIVITY STANDARD, 1500 MICROSIEMENS/CM
• CONDUCTIVITY STANDARD, 2000 MICROSIEMENS/CM
• CONDUCTIVITY STANDARD, 24.8 MICROSIEMENS/CM
• CONDUCTIVITY STANDARD, 2765 MICROSIEMENS/CM
• CONDUCTIVITY STANDARD, 46.7 MICROSIEMENS/CM
• CONDUCTIVITY STANDARD, 58,640 UMHOS
• CONDUCTIVITY STANDARD, 6,668 UMHOS
• CONDUCTIVITY STANDARD, 718 UMHOS
• Potassium, solid, 99.95% (metals basis)
• Potassium, AAS standard solution, Specpure(R), K 1000μg/ml
• Potassium, Oil based standard solution, Specpure(R), K 5000μg/g
• Potassium, plasma standard solution, Specpure(R), K 10,000μg/ml
• Potassium sticks, 98% (metals basis)
• Potassium cubes, 98% (metals basis)
• Potassium, Oil based standard solution, Specpure(R), K 1000μg/g
• Potassium, plasma standard solution, Specpure(R), K 1000μg/ml
• Potassium, ampoulled under Argon
• potassium metallic
• Potassium, 98%, chunks, in mineral oil
• Potassium AA Standard,1000 ppm in HNO3
• Potassium sticks (99%) (packed in mineral oil)
• PotassiuM radioactive environMent standard substance
• POTASSIUM (CUBES) UNDER PROTECTIVE LIQUI
• POTASSIUM ICP STANDARD TRACEABLE TO SRM
• POTASSIUM STANDARD SOLUTION TRACEABLE TO
• PotassiuM cubes, 99.5% (Metals basis)
• POTASSIUM CHLORIDE FERTILIZER
• POTASSIUM CHLORIDE STANDARD
• POTASSIUM CHLORIDE STANDARD SOLUTION B
• POTASSIUM CHLORIDE STANDARD SOLUTION C
• POTASSIUM CHLORIDE CONDUCTIVITY
• POTASSIUM, ANALYTICAL STANDARD
• POTASSIUM ATOMIC ABSORPTION SINGLE ELEMENT STANDARD
• POTASSIUM ATOMIC ABSORPTION STANDARD
• POTASSIUM ATOMIC ABSORPTION STANDARD SOLUTION
• POTASSIUM ATOMIC SPECTROSCOPY STANDARD
• POTASSIUM AA/ICP CALIBRATION/CHECK STANDARD
• POTASSIUM AA SINGLE ELEMENT STANDARD