Nickel

68.077 %

{ syn. }

26.233 %

1.14%

3.634 %

{ syn. }

0.926 %

Risk

Powder

Nickel is a chemical element with the chemical symbol Ni and atomic number 28 It is one of the transition metals in the periodic table it is according to the older method of counting in the 8th transition group or iron-platinum group after the recent in the group 10 or nickel group.

• 4.1 Physical Properties
• 4.2 Chemical Properties

• 7.1 Use as a metal
• 7.2 use as an alloying

• 9.1 Inorganic nickel compounds
• 9.2 Organic nickel compounds
• 9.3 nickel complexes

History

Nickel was the first time for 1751 prepared in pure form by Axel Frederic CRONSTEDT. He named the metal nickel in 1754, derived from copper nickel (Swedish kopparnickel ), a native of the Erzgebirge word for Rotnickelkies. So called miners ore that looked like copper ore, but could be obtained from the copper, as it was of mountain spirits ( " nickels " ) bewitched. A similarly puckish etymology is found in cobalt.

The first coin of pure nickel was minted in 1881.

Occurrence

Solidity, that is occurring in elemental form nickel could so far only be detected at 24 localities (as of 2010) and is one of the rare, but by the International Mineralogical Association (IMA ) recognized minerals ( System-Nr. by Strunz 1.AA .05 or outdated 1/A.08-10 ). Its mass fraction of the earth's crust is about 0.01 %.

Most of the nickel production is obtained from nickel-containing ores, mainly from garnierite, a mixture of Népouit ( approximately 46% nickel) and Willemseite (about 29% nickel), and the mineral pentlandite ( 34% nickel). In addition, lateritic nickel ore, nickel pyrrhotite ( pyrrhotite and pentlandite from Verwachsungsaggregat ) and some other nickel minerals such as millerite (about 64-65 % nickel) and Nickeline (about 44% nickel) are broken down as raw materials for nickel production. Overall, so far (as of 2010) 200 nickel minerals known, and some have far higher nickel contents than those already mentioned, however, are in contrast to those before much rarer.

In order to reduce the nickel economically, the nickel content of the ore must be at least 0.5%. The major deposits are found in Canada ( Sudbury basin ), New Caledonia, Russia ( Norilsk and Kola Peninsula ), Australia and Cuba. A frequent companion of nickel is cobalt.

Production and representation

Representation of the copper -nickel Feinstein's

The majority of nickel is obtained from nickel-and copper-containing ores such as nickel pyrrhotite. In order to make the extraction economically, the nickel must first be concentrated by flotation to about five percent nickel content. Thereafter, the ore is roasted, similarly to the production of copper. In this case, the ore is preroasted in order to convert a part of the iron sulphide to iron oxide. Then silicates and coke are added to slagging the iron oxide as an iron silicate. Same time, the copper -nickel matte nickel, copper and iron sulfide forms. Since this is specifically heavier than the iron silicate slag, the two phases can be tapped separately.

Then, the rough stone is poured into a converter and added silica. It is blown oxygen. Thus, the residual iron sulfide is roasted to iron oxide and slagged it. There is the copper -nickel Feinstein, of which about 80 % of copper and nickel and about 20% of sulfur.

Extraction of crude nickel

To obtain the Rohnickels the nickel must be separated from the copper. These fuses are the Feinstein with sodium sulfide Na2S. This forms only between copper and sodium sulfide, a low melting double sulfide. It is easy to be separated to form two phases of copper - sodium double sulfide ( liquid) and nickel sulfide. After the separation of the nickel sulphide is roasted to nickel oxide and then reduced with coke to nickel.

Recovery of pure and Reinstnickel

To gain pure nickel, the crude nickel is electrolytically refined. For this, the crude nickel as the anode, a nickel sheet metal as a cathode in an electrolytic cell. The electrolyte is a nickel salt solution. During electrolysis, go to the anode nickel and noble all ingredients in solution. All the nobler elements remain fixed and will fall as anode mud under the electrode. This serves as an important source for the production of noble metals such as gold or platinum. At the cathode, nickel ions are reduced from the solution to nickel, all the baser elements remain in solution. The purity of electrolytic nickel is around 99.9 %.

For the extraction of Reinstnickel with a purity of 99.99 % is available as a special process the Mond process, named after Ludwig Mond, who discovered in 1890 nickel tetracarbonyl. This method relies on the formation and decomposition of the Nickeltetracarbonyls. These finely divided Rohnickelpulver is placed at 80 ° C in a stream of carbon monoxide. Here, gaseous nickel tetracarbonyl forms. This is free of airborne dust and hot headed decomposition chamber in a 180 ° C. Inside are small nickel spheres. This is linked to the nickel carbonyl decomposes back to nickel and carbon monoxide. It arises because very pure nickel.

Properties

Physical Properties

Nickel is a silvery- white metal that is one with a density of 8.9 g/cm3 for the heavy metals. It is medium hard ( Mohs hardness 3.8 ), malleable, ductile, and can be excellent polish. Nickel is ferromagnetic such as iron and cobalt, wherein the Curie temperature is 354 ° C. The metal crystallizes in a face-centered cubic crystal structure ( copper type) in the space group with the lattice parameters a = 352.4 pm and four formula units per unit cell. Another metastable modification with body-centered cubic packing of spheres could be obtained in thin layers on iron or gallium arsenide. It has 183 ° C, a significantly lower Curie temperature.

The tensile strength of annealed nickel is located at 400-450 MPa with an elongation at break of between 30-45 %. The hardness values ​​are around 80 HB. Cold -hardened nickel is its elongation at break less than 2%, achieved strengths up to 750 MPa at 180 HB hardness values ​​. Nickel Semi-finished products with 99% Ni content can be highly work-hardened.

The isotope 62Ni has the highest binding energy per nucleon of all isotopes of all elements.

Chemical Properties

Nickel is very stable at room temperature against air, water, hydrochloric acid and alkalis. Dilute acids attack nickel only very slowly. To concentrated oxidizing acids ( nitric acid) occurs analogous to the stainless steel passivation one. Soluble nickel is in dilute nitric acid (about 10 - to 15 - percent ). Also, a semi-concentrated nitric acid (about 30 percent ) still causes significant passivation. The most common oxidation state II, are rare -I, 0, I III IV and observed. In nickel tetracarbonyl nickel has an oxidation number 0 nickel (II ) salts dissolve in water to form aqua complexes with greenish color.

Finely divided nickel reacts with carbon monoxide at 50 to 80 ° C to nickel carbonyl, Ni (CO ) 4, a colorless, highly toxic liquid. This is used as an intermediate for the production of pure nickel on the Moon procedure. At 180 to 200 ° C is again divided into nickel tetracarbonyl nickel, and carbon monoxide.

Physiology

The controversial essentiality of nickel is offset by the existence of several enzymes that normally contain nickel, but that are not dependent, as its role as a cation can be adopted by other divalent cations. In humans, it involves three proteins, which are known to bind nickel:

• Alpha -fetoprotein binds nickel, but is not dependent, as no enzyme
• Aciredukton dioxygenase, an enzyme of the methionine salvage pathway, binds usually nickel or another divalent cation
• Polyribonucleotide 5'- hydroxylkinase Clp1, required as a cofactor magnesium, manganese or nickel

For plants and various microorganisms, the essentiality of nickel by isolation of several enzymes (eg, urease, co- F430 ) containing nickel in the active site, as well as by detection of deficiencies in nickel -depleted environment, which is characterized by the addition of Ni ( II fix ) salts, secured.

In electrophysiology nickel ions are used to block voltage-activated calcium channels.

Health problems

Nickel with nickel dermatitis is the most common trigger for contact allergy: in Germany are estimated to be 1.9 to 4.5 million people sensitized to nickel. Why are metals and alloys that come in contact with the skin, increasingly rare nickel plated. About 10 % of all children are sensitized to nickel. Renewed contact with the allergen they can respond with a contact allergy.

Inhalation of inorganic nickel compounds is associated with an increased cancer risk for squamous cell carcinoma of the lung and upper respiratory tract. Such malignant neoplasms are recognized in Germany for occupational exposure as an occupational disease (BK 4109). In addition, a higher nickel content in the breathing air and drinking water a risk factor for sensitization to nickel in children.

Economic Importance

Nickel is a metal required in small amounts, most of the production goes into the production of stainless steels and nickel alloys. The reserves of mineable from today's perspective nickel deposits are 70-170 million tons. At present, the world each year more than one million tonnes (2006: 1,340 million tons) promoted.

Use as metal

Pure nickel metal is used in finely divided form as a catalyst in the hydrogenation of unsaturated fatty acids. Due to its chemical resistance, nickel is used for equipment in chemical laboratories and the chemical industry (eg nickel crucible for clues ). For nickel metal alloys with a precisely known relationship be established ( eg for coins).

Nickel is used as the coating metal for corrosion protection ( " nickel " ) of metal objects: Because of its protective properties against oxidation metals ( especially iron ) are coated by electroplating technology for specific purposes with a nickel layer.

The metal was also used previously for the production of nickel versions of eyewear.

As a beta emitter, the nickel isotope 63Ni is used in electron capture in gas chromatographs.

Use as an alloying

Nickel is an important alloying metal, which is used mainly for steel refining. The largest part of the nickel goes there. It makes steel resistant to corrosion and increases its hardness, toughness and ductility. Nickel alloy steels are used in particularly corrosive environments. The stainless steel V2A (name based on the ' test batch 2 austenitic " in the Krupp steelworks, corresponds X12CrNi18 -8) containing 8% nickel in addition to 18% chromium, V4A (brand names Cromargan or stainless steel ) 11% in addition to 18% chromium and 2% molybdenum.

About 20 % of the nickel can be used ( in Germany) for the production of other nickel alloys:

• Constantan, an alloy of 55 % copper and 45% nickel, which has an approximately constant resistivity over a wide temperature range. It is mainly used for precise resistors.
• Nickel -base superalloys are alloys specially designed for use at high temperatures and in corrosive media. See, for example, in aircraft engines and gas turbines of power plants application.
• Raney nickel, a nickel -aluminum alloy, which is an important catalyst for the hydrogenation of organic compounds.
• German silver, a copper-nickel -zinc alloy with 10-26 % nickel content, which is particularly resistant to corrosion and is mainly used for cutlery and electrical devices.
• Monel, also a copper -nickel alloy with about 65 % nickel, 33 % copper and 2% iron, which is characterized by special chemical resistance, including by fluorine. It is therefore used for fluorine - pressure gas cylinders.
• Austenitic cast iron with nodular graphite, a special nodular cast iron with up to 20% nickel, for use in corrosive environments and at high temperatures.

Proof

The detection reaction for the most soluble in water with green color nickel (II ) salts is determined gravimetrically in the quantitative analysis and qualitative performed in cation separation transition with dimethylglyoxime solution ( Tschugajews reagent). Nickel salts are, if appropriate, previously precipitated as gray, black nickel (II ) sulphide by ammonium sulfide and dissolved in nitric acid. The specific detection is possible by reaction with dimethylglyoxime in ammoniacal solution. It falls raspberry-red bis ( dimethylglyoximato ) nickel ( II) complex of:

.

Since nickel from ammoniacal solution quantitatively precipitated with dimethylglyoxime, this evidence can also be used for the quantitative gravimetric analysis of nickel. From ammoniacal solution can also be done by means of Electrogravimetry at a platinum gauze electrode, a quantitative determination. Similar to other heavy metals, nickel is usually determined today by atomic spectroscopy or mass spectrometry and ultra-trace quantitatively. Extremely sensitive is the inverse voltammetry with adsorptive accumulation of the Ni- Dimethyglyoxim Complex at hanging mercury drop or mercury film electrodes.

Compounds

Nickel compounds takes mainly in the oxidation state II. The levels 0, I, III and IV are rare and usually unstable. Nickel forms a plurality mostly colored complexes.

Inorganic nickel compounds

• Nickel ( II) chloride, NiCl2 is a yellow, highly hygroscopic solid, which is used as a dye for ceramic and for the preparation of nickel catalysts. In addition to the anhydrous form, there are aqueous nickel (II) chloride, for example, the green nickel (II ) chloride hexahydrate, which crystallized from aqueous nickel chloride solutions.
• Nickel ( II) hydroxide Ni (OH ) 2, and nickel (III) oxyhydroxide NiO (OH) are used to store electrical energy in nickel-cadmium batteries and other nickel.
• Nickel ( II) oxide NiO, and nickel ( III) oxide are Ni2O3 green or black solids and are used for producing ceramic and glass electrodes. In addition, they are used as catalysts for the hydrogenation of organic compounds.
• Nickel (II ) nitrate Ni (NO3) 2
• Nickel (II) -sulfate NiSO4 and ammonium nickel ( II) sulfate ( (NH4) 2Ni (SO4) 2.6 H2O) are used in the plating ( nickel ).
• Nickel ( II ) carbonate is used as pigment for nico3 ceramic products and for the production of nickel.
• Nickel ( II ) sulphide NiS precipitates from ammonia, but not acidic, nickel-containing solution with ammonium sulfide. This allows nickel to be separated with the ammonium sulfide group in the cation separation process.
• Nickel ( II) cyanide, Ni ( CN) 2 is used in metallurgy and electroforming.
• Nickel ( II ) borate Ni ( BO2 ) 2 is used as a catalyst.
• Nickelantimonid NiSb is, for example, used in field plates.

Organic nickel compounds

Nickel tetracarbonyl Ni ( CO) 4 is a colorless, highly toxic liquid. It is an important intermediate in the Mond process. Nickel tetracarbonyl was the first discovered metal carbonyl compound.

Nickel complexes

Nickel and thereby v. a nickel ( II) ion forms many, mostly colored complexes. The coordination numbers 6, 5 or 4 are most common. For weak, monodentate ligands, such as water, they are usually present as octahedral and paramagnetic high-spin complexes with coordination number 6. Strong ligands such as cyanide form square-planar, diamagnetic low-spin complexes. Also a square-planar complex forms dimethylglyoxime, since the complex is additionally stabilized by hydrogen bonds. The latter bis ( dimethylglyoximato ) nickel ( II ) complex is responsible for the wet-chemical nickel detection of importance. Anionic nickel complexes ending in " - niccolat ".

Examples of amine complexes are the blue Tetraamminnickel (II ) - and purple Hexaamminnickel (II ) complex. Both compounds are obtained by addition of ammonia to nickel (II ) salt solutions:

By the addition of potassium to nickel (II ) salt solutions is first produced the nickel (II ) - cyanide is dissolved in an excess of potassium cyanide to a yellow Kaliumtetracyanoniccolat (II):

A similar compound is formed with potassium thiocyanate. A very sensitive compound is the Kaliumhexafluoroniccolat ( IV) ( K2 [ NiF6 ] ). With a strong reducing agent can be from Kaliumtetracyanoniccolat ( II) of the dinuclear complex K4 [ Ni2 (CN ) 6] produced with monovalent nickel. In addition, there is a variety of complexes with organic ligands such as ethylenediamine or anions of carboxylic acids.