Nickel material. Nickel and nickel alloys: chemical composition, properties, applications. Nickel ion detection reaction

Nickel is a ductile silver-white metal with a characteristic luster. Refers to heavy non-ferrous metals. Nickel is a valuable alloying addition. Nickel is not found in nature in its pure form; it is usually found in ores. Pure nickel (Nickel/Nickel), Nickel 200 and Nickel 201, is mined by special technologies.

In combination with other metals, nickel is able to form hard and durable nickel alloys:

• nickel-copper alloy (Monel/Monel)- copper-based alloy with nickel as an alloying additive. The composition is usually up to 67% nickel and up to 38% copper. This group of alloys includes: Monel 400, Monel 401, Monel 404, Monel R-405, Monel K-500, etc.
• nickel-chromium alloy (Inconel)– austenitic heat-resistant alloy. This group includes: Inconel 600, Inconel 601, Inconel 617, Inconel 625, Inconel 690, Inconel 718, Inconel 725, Inconel X-750, etc.
• nickel-iron-chromium alloy (Inconloy/Incoloy)- it is possible to add molybdenum, copper, titanium to the alloy. This group includes: Incoloy 20, Incoloy 800, Incoloy 800H, Incoloy 800HT, Incoloy 825, Incoloy 925, etc.
• nickel-molybdenum alloy (Hastelloy/Hastelloy)- possible presence in the composition of chromium, iron and carbon. This group includes: Hastelloy C-4, Hastelloy C-22, Hastelloy C-276, Hastelloy B-2, etc.

Nickel properties

Nickel is a ferromagnetic, Curie point - 358°C, melting point - 1455°C, boiling point - 2730-2915°C. Density - 8.9 g / cm 3, thermal expansion coefficient -13.5 ∙ 10 -6 K -1. Compact nickel is stable in air, while highly dispersed nickel is pyrophoric.

Nickel has the following properties:

• plasticity and malleability;
• strength at high temperatures;
• resistance to oxidation in water and in air;
• hardness and sufficient viscosity;
• high corrosion resistance;
• ferromagnetic;
• good catalyst;
• well polished.

The nickel surface is coated with a thin layer of NiO oxide, which protects the metal from oxidation.

Advantages and disadvantages

The main advantages of nickel and alloys are heat resistance, heat resistance and increased mechanical strength (pressure up to 440 MPa). The advantages also include operation in hot concentrated alkaline and acid solutions. In addition, nickel is able to retain its magnetic properties at low temperatures.

The main disadvantage of nickel is a significant decrease in thermoEMF values ​​during rapid cooling after annealing (up to 600°C). Also, the disadvantages of nickel include the fact that pure nickel does not occur in nature. It is obtained by expensive technologies, which affects its cost.

Application area

The main application of nickel is metallurgy. In it, he is involved in the production of high-alloy stainless steels. By adding nickel to the iron melt, metallurgists obtain strong and ductile alloys that have increased corrosion resistance and resistance to high temperatures. It should be noted that nickel alloys retain their qualities during repeated prolonged heating.

Due to these properties, stainless and heat-resistant nickel steel is used:

• in the food and chemical industries;
• in the petrochemical industry and construction;
• in medicine and pharmaceuticals;
• in aviation and mechanical engineering;
• in the manufacture of submarine cables;
• in the manufacture of heating elements for industrial equipment;
• in the production of permanent magnets;
• in the production of machine tools and special equipment;
• in the manufacture of interior elements of buildings;
• in the furniture industry;
• in the manufacture of household appliances and household utensils;

Due to its malleability and ease of forging, nickel is used to produce very thin products such as nickel strips, strips and sheets. Nickel is also actively used in the production of wire and rods.

Position in the periodic system:

Nickel is an element of the tenth group, the fourth period of the periodic system of chemical elements D.I. Mendeleev, with atomic number 28. It is designated by the symbol Ni (lat. Niccolum).

The structure of the atom:

The configuration of the outer electron shells of the atom is 3s23p63d84s2; ionization energies Ni0 3048-4.jpg Ni+ 3048-5. Pauling electronegativity 1.80; atomic radius 0.124 nm, ionic radius (coordination numbers are indicated in brackets) Ni2+ 0.069 nm (4), 0.077 nm (5), 0.083 nm (6)

Oxidation states: Forms compounds most often in the oxidation state +2 (valency II), less often in the oxidation state +3 (valence III) and very rarely in the oxidation states +1 and +4 (valency I and IV, respectively).

Nickel is a simple substance

Distribution in nature:

Nickel is quite common in nature - its content in the earth's crust is approx. 0.01% (mass). It occurs in the earth's crust only in bound form; iron meteorites contain native nickel (up to 8%). Its content in ultrabasic rocks is approximately 200 times higher than in acidic ones (1.2 kg/t and 8 g/t). In ultramafic rocks, the predominant amount of nickel is associated with olivines containing 0.13 - 0.41% Ni. It replaces iron and magnesium isomorphically. A small part of nickel is present in the form of sulfides. Nickel exhibits siderophilic and chalcophilic properties. With an increased content of sulfur in the magma, nickel sulfides appear along with copper, cobalt, iron, and platinoids. In a hydrothermal process, together with cobalt, arsenic and sulfur, and sometimes with bismuth, uranium and silver, nickel forms elevated concentrations in the form of nickel arsenides and sulfides. Nickel is commonly found in sulfide and arsenic-bearing copper-nickel ores.

• - nickeline (red nickel pyrite, kupfernickel) NiAs,
• - chloantite (white nickel pyrites) (Ni, Co, Fe) As2,
• - garnierite (Mg, Ni)6(Si4O11)(OH)6*H2O and other silicates,
• - magnetic pyrites (Fe, Ni, Cu) S,
• - arsenic-nickel shine (gersdorfite) NiAsS,
• - pentlandite (Fe, Ni) 9S8.

Much is known about nickel in organisms. It has been established, for example, that its content in human blood changes with age, that in animals the amount of nickel in the body is increased, and finally, that there are some plants and microorganisms - "concentrators" of nickel, containing thousands and even hundreds of thousands of times more nickel, than the environment.

Opening history:

Nickel (English, French and German Nickel) was discovered in 1751. However, long before that, Saxon miners were well aware of the ore, which outwardly resembled copper and was used in glass making to color glass green. All attempts to obtain copper from this ore were unsuccessful, and therefore at the end of the 17th century. The ore was named Kupfernickel, which roughly means "Copper Devil". This ore (red nickel pyrite NiAs) was studied in 1751 by the Swedish mineralogist Kronstedt. He managed to obtain a green oxide and, by reducing the latter, a new metal called nickel. When Bergman received the metal in a purer form, he found that the properties of the metal were similar to those of iron; Nickel has been studied in more detail by many chemists, beginning with Proust. Nikkel is a curse word in the language of miners. It was formed from the distorted Nicolaus - a generic word that had several meanings. But chiefly the word Nicolaus served to characterize two-faced people; in addition, it meant "a mischievous little spirit", "a deceitful idler", etc. Russian literature of the early 19th century. the names nikolan (Scherer, 1808), nikolan (Zakharov, 1810), nicol and nickel (Dvigubsky, 1824) were used

Physical properties:

Nickel is a malleable and ductile metal. It has a cubic face-centered crystal lattice (parameter = 0.35238 nm). Melting point 1455°C, boiling point about 2900°C, density 8.90 kg/dm3. Nickel is a ferromagnet with a Curie point of about 358°C.

Electrical resistivity 0.0684 µOhm m.

Coefficient of linear thermal expansion b=13.5?10?6 K?1 at 0 °C.

Coefficient of volumetric thermal expansion in = 38--39?10?6 K?1.

Modulus of elasticity 196--210 GPa.

Chemical properties:

Nickel atoms have an external electronic configuration of 3d84s2. The most stable oxidation state for nickel is Ni(II). Nickel forms compounds with oxidation states +1, +2, +3 and +4. At the same time, nickel compounds with an oxidation state of +4 are rare and unstable. Nickel oxide Ni2O3 is a strong oxidizing agent. Nickel is characterized by high corrosion resistance - it is stable in air, in water, in alkalis, in a number of acids. Chemical resistance is due to its tendency to passivation - the formation of a dense oxide film on its surface, which has a protective effect. Nickel actively dissolves in dilute nitric acid: (3 Ni + 8 HNO_3 (30%) 3 Ni(NO_3)_2 + 2 NO + 4 H_2O) and in hot concentrated sulfuric acid: (Ni + 2 H_2SO_4 NiSO_4 + SO_2 + 2 H_2O)

With hydrochloric and dilute sulfuric acids, the reaction proceeds slowly. Concentrated nitric acid passivates nickel, however, when heated, the reaction still proceeds (the main product of nitrogen reduction is NO2). With carbon monoxide CO, nickel easily forms a volatile and very toxic carbonyl Ni (CO) 4. Finely dispersed nickel powder is pyrophoric (self-ignites in air) .Nickel burns only in powder form. Forms two oxides NiO and Ni2O3 and, respectively, two hydroxides Ni(OH)2 and Ni(OH)3. The most important soluble nickel salts are acetate, chloride, nitrate, and sulfate. Aqueous solutions of salts are usually colored green, and anhydrous salts are yellow or brown-yellow. Insoluble salts include oxalate and phosphate (green), three sulfides: NiS (black), Ni3S2 (yellowish-bronze) and Ni3S4 (silver-white). Nickel also forms numerous coordination and complex compounds. For example, nickel dimethylglyoximate Ni(C4H6N2O2)2, which gives a distinct red color in acidic media, is widely used in qualitative analysis for the detection of nickel. An aqueous solution of nickel sulfate has a green color. Aqueous solutions of nickel(II) salts contain the hexaaquanickel(II) 2+ ion.

Receipt:

The total reserves of nickel in ores at the beginning of 1998 are estimated at 135 million tons, including reliable reserves of 49 million tons. The main nickel ores - nickel (kupfernickel) NiAs, millerite NiS, pentlandite (FeNi) 9S8 - also contain arsenic, iron and sulfur; Inclusions of pentlandite also occur in igneous pyrrhotite. Other ores from which Ni is also mined contain Co, Cu, Fe, and Mg impurities. Sometimes nickel is the main product of the refining process, but more often it is obtained as a by-product in other metal technologies. Of the reliable reserves, according to various sources, from 40 to 66% of nickel is in "oxidized nickel ores" (ONR), 33% - in sulfide, 0.7% - in others. As of 1997, the share of nickel produced by the processing of OHP was about 40% of the world's production. In industrial conditions, OHP is divided into two types: magnesian and ferruginous. Refractory magnesian ores, as a rule, are subjected to electric smelting for ferronickel (5--50% Ni + Co, depending on the composition of the raw material and technological features). . Depending on the composition of the raw materials and the applied technological schemes, the final products of these technologies are: nickel oxide (76-90% Ni), sinter (89% Ni), sulfide concentrates of various compositions, as well as electrolytic metal nickel, nickel powders and cobalt. Less ferruginous - nontronite ores are melted into matte. At enterprises operating on a full cycle, the further processing scheme includes converting, matte roasting, electrosmelting of nickel oxide to obtain metallic nickel. Along the way, the extracted cobalt is produced in the form of metal and/or salts. Another source of nickel: in the ashes of the coals of South Wales in England - up to 78 kg of nickel per ton. The increased content of nickel in some coals, oil, shales indicates the possibility of nickel concentration by fossil organic matter. The reasons for this phenomenon have not yet been elucidated.

Application:

Nickel is the basis of most superalloys, high-temperature materials used in the aerospace industry for parts of power plants. Monel metal (65 - 67% Ni + 30 - 32% Cu + 1% Mn), heat resistant up to 500 °C, very corrosion resistant; white gold (for example, 585 samples contains 58.5% gold and an alloy (ligature) of silver and nickel (or palladium)); nichrome, an alloy of nickel and chromium (60% Ni + 40% Cr); permalloy (76% Ni + 17% Fe + 5% Cu + 2% Cr), has a high magnetic susceptibility with very low hysteresis losses; invar (65% Fe + 35% Ni), almost does not elongate when heated; In addition, nickel alloys include nickel and chromium-nickel steels, nickel silver, and various resistance alloys such as constantan, nickeline, and manganin. Nickel is present as a component of a number of stainless steels.

Chemical Technology.

Raney nickel is used as a catalyst in many chemical engineering processes.

Radiation technologies.

The nuclide 63Ni, which emits β-particles, has a half-life of 100.1 years and is used in krytrons and electron capture detectors (ECDs) in gas chromatography.

The medicine.

It is used in the manufacture of bracket systems (titanium nickelide).

Prosthetics.

Coin business.

Nickel is widely used in the production of coins in many countries. In the United States, the 5 cent coin is colloquially known as the nickel.

The use of nickel in alloys

Nickel is the basis of most heat-resistant materials used in the aerospace industry for parts of power plants.

• monel metal (65 - 67% Ni + 30 - 32% Cu + 1% Mn), heat resistant up to 500 °C, very corrosion resistant;
• nichrome, resistance alloy (60% Ni + 40% Cr);
• permalloy (76% Ni + 17% Fe + 5% Cu + 2% Cr), has a high magnetic susceptibility with very low hysteresis losses;
• invar (65% Fe + 35% Ni), almost does not elongate when heated.
• In addition, nickel alloys include nickel and chromium-nickel steels, nickel silver, and various resistance alloys such as constantan, nickeline, and manganin.

All stainless steels necessarily contain nickel, because nickel increases the chemical resistance of the alloy. Nickel alloys are also characterized by high toughness and are used in the manufacture of durable armor. In the manufacture of the most important parts of various devices, an alloy of nickel with iron (36-38% nickel) is used, which has a low coefficient of thermal expansion.

In the manufacture of electromagnet cores, alloys under the general name permalloy are widely used. These alloys, in addition to iron, contain from 40 to 80% nickel. Coins are minted from nickel alloys. The total number of various nickel alloys that find practical application reaches several thousand.

Nickel in its pure form finds its main application as protective coatings against corrosion in various chemical environments. Protective coatings on iron and other metals are obtained by two well-known methods: plating and electroforming. In the first method, the clad layer is created by joint hot rolling of a thin nickel plate with a thick iron sheet. The ratio of the thicknesses of nickel and the metal to be coated in this case is approximately 1:10. In the process of joint rolling, due to mutual diffusion, these sheets are welded, and a monolithic two-layer or even three-layer metal is obtained, the nickel surface of which protects this material from corrosion.

This kind of hot method of creating protective nickel coatings is widely used to protect iron and unalloyed steels from corrosion. This significantly reduces the cost of many products and devices made not from pure nickel, but from relatively cheap iron or steel, but covered with a thin protective layer of nickel. Nickel-plated iron sheets are used to make large containers for transportation and storage of, for example, caustic alkalis, which are also used in various chemical industries.

The galvanic method of creating protective coatings with nickel is one of the oldest methods of electrochemical processes. This operation, commonly known in the art as nickel plating, is in principle a relatively simple process. It involves some preparatory work of very thorough cleaning of the surface of the metal being plated and the preparation of an electrolytic bath consisting of an acidified solution of a nickel salt, usually nickel sulfate. In electroplating, the material to be coated serves as the cathode and a nickel plate as the anode. In a galvanic circuit, nickel is deposited on the cathode with an equivalent transition from the anode to the solution. The nickel plating method is widely used in engineering, and a large amount of nickel is consumed for this purpose.

Recently, the method of electroplating with nickel has been used to create protective coatings on aluminum, magnesium, zinc and cast iron. The paper describes the application of the method of nickel plating of aluminum and magnesium alloys, in particular for the protection of duralumin blades of propeller aircraft. Another paper describes the use of nickel-plated cast iron drying drums in the paper industry; a significant increase in the corrosion resistance of the drums and an increase in the quality of paper on nickel-plated drums compared to conventional cast-iron drums without nickel plating were established.

Nickel plating is carried out by electroplating using electrolytes containing nickel(II) sulfate, sodium chloride, boron hydroxide, surfactants and brighteners, and soluble nickel anodes. The thickness of the resulting nickel layer is 12 - 36 microns. Surface gloss stability can be ensured by subsequent chromium plating (chromium layer thickness 0.3 µm).

Currentless nickel plating is carried out in a solution of a mixture of nickel(II) chloride and sodium hypophosphite in the presence of sodium citrate:

NiCl 2 + NaH 2 PO 2 + H 2 O \u003d Ni + NaH 2 PO 3 + 2HCl

The process is carried out at pH 4 - 6 and 95 °C.

Manufacture of iron-nickel, nickel-cadmium, nickel-zinc, nickel-hydrogen batteries.

The most common "cons" in chemical current sources are zinc, cadmium, iron, and the most common "pluses" are oxides of silver, lead, manganese, nickel. Nickel compounds are used in the manufacture of alkaline batteries. By the way, the nickel-iron battery was invented in 1900 by Thomas Alva Edison.

Positive electrodes based on nickel oxides have a sufficiently large positive charge, they are stable in the electrolyte, are well processed, relatively inexpensive, have a long service life and do not require special care. This set of properties made nickel electrodes the most common. Some batteries, in particular zinc-silver batteries, have better specific characteristics than nickel-iron or nickel-cadmium batteries. But nickel is much cheaper than silver, and expensive batteries last much less.

Nickel oxide electrodes for alkaline batteries are made from a paste containing nickel oxide hydrate and graphite powder. Sometimes the functions of a conductive additive instead of graphite are performed by thin nickel petals uniformly distributed in nickel hydroxide. This active mass is stuffed into conductive plates of various designs.

In recent years, another method for the production of nickel electrodes has become widespread. The plates are pressed from a very fine powder of nickel oxides with the necessary additives. The second stage of production is the sintering of the mass in a hydrogen atmosphere. This method produces porous electrodes with a very developed surface, and the larger the surface, the greater the current. Batteries with electrodes made by this method are more powerful, more reliable, lighter, but also more expensive. Therefore, they are used in the most critical objects - electronic circuits, current sources in spacecraft, etc.

Nickel electrodes, made from the finest powders, are also used in fuel cells. Here, the catalytic properties of nickel and its compounds are of particular importance. Nickel is an excellent catalyst for complex processes occurring in these current sources. By the way, in fuel cells, nickel and its compounds can be used for the manufacture of both “plus” and “minus”. The only difference is in the additives.

The nuclide 63 Ni emitting β + particles has a half-life of 100.1 years and is used in krytrons. Recently, nickel plates have been used instead of cadmium plates in mechanical interrupters of a neutron beam in order to obtain neutron pulses with a high energy value.

• It is used in the manufacture of bracket systems.
• Prosthetics

The formation of a scarlet precipitate upon the addition of dimethylglyoxime to an ammonia solution of the analyzed mixture is the best reaction for the qualitative and quantitative determination of nickel. But nickel dimethylglyoximate isn't just for analysts. The beautiful deep color of this complex compound attracted the attention of perfumers: nickel dimethylglyoximate is added to lipstick. Some of the compounds similar to nickel dimethylglyoximate are the basis for very light fast paints.

There are interesting indications of the use of nickel plates in ultrasonic devices, both electrical and mechanical, as well as in modern designs of telephone sets.

There are some areas of technology where pure nickel is used either directly in powder form or in the form of various products obtained from pure nickel powders.

One of the areas of application of powdered nickel is catalytic processes in the hydrogenation reactions of unsaturated hydrocarbons, cyclic aldehydes, alcohols, aromatic hydrocarbons.

The catalytic properties of nickel are similar to those of platinum and palladium. Thus, the chemical analogy of the elements of the same group of the periodic system is reflected here as well. Nickel, being a cheaper metal than palladium and platinum, is widely used as a catalyst in hydrogenation processes.

For these purposes, it is advisable to use nickel in the form of the finest powder. It is obtained by a special mode of hydrogen reduction of nickel oxide in the temperature range of 300-350°.

The impure metal was first obtained in 1751 by the Swedish chemist A. Kronstedt, who also proposed the name of the element. A much purer metal was obtained in 1804 by the German chemist I. Richter. The name "Nickel" comes from the mineral kupfernickel (NiAs), already known in the 17th century and often misleading miners by its external resemblance to copper ores (German: Kupfer - copper, Nickel - mountain spirit, allegedly slipping miners instead of ore waste rock). Since the middle of the 18th century, nickel has been used only as an integral part of alloys similar in appearance to silver. The widespread development of the nickel industry at the end of the 19th century was associated with the discovery of large deposits of nickel ores in New Caledonia and Canada and the discovery of its “ennobling” effect on the properties of steels.

Distribution of Nickel in nature. Nickel is an element of the earth's depths (in the ultrabasic rocks of the mantle it is 0.2% by weight). There is a hypothesis that the earth's core consists of nickel iron; in accordance with this, the average nickel content in the earth as a whole is estimated to be about 3%. In the earth's crust, where Nickel is 5.8·10 -3%, it also tends to a deeper, so-called basalt shell. Ni in the earth's crust is a satellite of Fe and Mg, which is explained by the similarity of their valence (II) and ionic radii; in the minerals of divalent iron and magnesium, nickel is present as an isomorphic impurity. Nickel's own minerals are known to be 53; most of them were formed at high temperatures and pressures, during solidification of magma, or from hot aqueous solutions. Nickel deposits are associated with processes in magma and weathering crust. Commercial nickel deposits (sulfide ores) are usually composed of nickel and copper minerals. On the earth's surface, in the biosphere, Nickel is a relatively weak migrant. It is relatively small in surface waters, in living matter. In areas dominated by ultramafic rocks, the soil and plants are enriched in nickel.

Physical properties of Nickel. Under normal conditions Nickel exists in the form of a β-modification having a face-centered cubic lattice (a = 3.5236Å). However, nickel subjected to cathodic sputtering in an H 2 atmosphere forms an α-modification having a hexagonal close-packed lattice (a = 2.65Å, c = 4.32Å), which, when heated above 200°C, transforms into a cubic modification. Compact cubic Nickel has a density of 8.9 g/cm 3 (20 °C), atomic radius 1.24Å, ionic radii: Ni 2+ 0.79Å, Ni 3+ 0.72Å; t pl 1453 °C; bp about 3000 °C; specific heat capacity at 20°C 0.440 kJ/(kg K); temperature coefficient of linear expansion 13.3 10 -6 (0-100 °C); thermal conductivity at 25°C 90.1 W/(m K) ; also at 500 °C 60.01 W/(m K) . Electrical resistivity at 20°C 68.4 nom m, i.e. 6.84 microhm cm; temperature coefficient of electrical resistance 6.8 10 -3 (0-100 °C). Nickel is a malleable and malleable metal that can be used to make the thinnest sheets and tubes. Tensile strength 400-500 MN / m 2 (i.e. 40-50 kgf / mm 2); elastic limit 80 MN/m 2 , yield strength 120 MN/m 2 ; elongation 40%; modulus of normal elasticity 205 Gn/m 2 ; Brinell hardness 600-800 MN/m 2 . In the temperature range from 0 to 631 K (the upper limit corresponds to the Curie point) Nickel is ferromagnetic. Nickel's ferromagnetism is due to structural features of the outer electron shells (3d 8 4s 2) of its atoms. Nickel, together with Fe (3d 6 4s 2) and Co (3d 7 4s 2), also ferromagnets, belongs to elements with an unfinished 3d electron shell (to 3d transition metals). The electrons of the unfinished shell create an uncompensated spin magnetic moment, the effective value of which for Nickel atoms is 6 μ B, where μ B is the Bohr magneton. The positive value of the exchange interaction in Nickel crystals leads to a parallel orientation of the atomic magnetic moments, that is, to ferromagnetism. For the same reason, alloys and a number of nickel compounds (oxides, halides, and others) are magnetically ordered (have a ferro-, less often ferrimagnetic structure). Nickel is a component of the most important magnetic materials and alloys with a minimum thermal expansion coefficient (permalloy, monel metal, invar, and others).

Chemical properties of Nickel. Chemically, Ni is similar to Fe and Co, but also to Cu and noble metals. In compounds, it exhibits variable valency (most often 2-valent). Nickel is a medium activity metal. Absorbs (especially in a finely divided state) large quantities of gases (H 2 , CO and others); Nickel saturation with gases worsens its mechanical properties. Interaction with oxygen begins at 500 °C; in a finely dispersed state Nickel is pyrophoric - spontaneously ignites in air. Of the oxides, NiO is the most important - greenish crystals, practically insoluble in water (the mineral bunsenite). The hydroxide precipitates from solutions of nickel salts with the addition of alkalis in the form of a voluminous apple-green precipitate. When heated, Nickel combines with halogens, forming NiX 2 . Burning in sulfur vapor, gives a sulfide similar in composition to Ni 3 S 2 . Monosulfide NiS can be obtained by heating NiO with sulfur.

Nickel does not react with nitrogen even at high temperatures (up to 1400 °C). The solubility of nitrogen in solid nickel is approximately 0.07% by weight (at 445°C). Ni 3 N nitride can be obtained by passing NH 3 over NiF 2 , NiBr 2 or metal powder at 445°C. Under the action of phosphorus vapor at high temperature, Ni 3 P 2 phosphide is formed in the form of a gray mass. In the Ni - As system, the existence of three arsenides has been established: Ni 5 As 2 , Ni 3 As (the mineral maucherite) and NiAs. Many metallides have a structure of the nickel-arsenide type (in which As atoms form the densest hexagonal packing, all octahedral voids of which are occupied by Ni atoms). Unstable Ni 3 C carbide can be obtained by slow (hundreds of hours) carburization (cementation) of Nickel powder in a CO atmosphere at 300°C. In the liquid state, nickel dissolves an appreciable amount of C, which precipitates in the form of graphite upon cooling. When graphite is isolated, Nickel loses malleability and the ability to be processed by pressure.

In the series of voltages, Ni is to the right of Fe (their normal potentials are -0.44 V and -0.24 V, respectively) and therefore dissolves more slowly than Fe in dilute acids. Nickel is resistant to water. Organic acids act on Nickel only after prolonged contact with it. Sulfuric and hydrochloric acids slowly dissolve Nickel; dilute nitric acid - very easy; concentrated HNO 3 passivates Nickel, but to a lesser extent than iron.

When interacting with acids, salts of 2-valent Ni are formed. Almost all salts of Ni (II) and strong acids are highly soluble in water, their solutions are acidic due to hydrolysis. Sparingly soluble salts of such relatively weak acids as carbonic and phosphoric. Most Nickel salts decompose upon calcination (600-800°C). One of the most commonly used salts, NiSO 4 sulfate, crystallizes from solutions in the form of emerald green crystals of NiSO 4 ·7H 2 O - nickel vitriol. Strong alkalis do not affect Nickel, but it dissolves in ammonia solutions in the presence of (NH 4) 2 CO 3 with the formation of soluble ammonias, colored in intense blue; most of them are characterized by the presence of complexes 2+ and . Hydrometallurgical methods for extracting Nickel from ores are based on the selective formation of ammoniates. NaOCl and NaOBr are precipitated from solutions of Ni (II) salts, hydroxide Ni (OH) 3 black. In complex compounds, Ni, in contrast to Co, is usually 2-valent. The complex compound of Ni with dimethylglyoxime (C 4 H 7 O 2 N) 2 Ni is used for the analytical determination of Ni.

At elevated temperatures Nickel interacts with nitrogen oxides, SO 2 and NH 3 . Under the action of CO on its finely divided powder, carbonyl Ni(CO) 4 is formed upon heating. Thermal dissociation of carbonyl produces the purest Nickel.

Getting Nickel. About 80% of nickel from its total production is obtained from copper-nickel sulfide ores. After selective enrichment by flotation, copper, nickel and pyrrhotite concentrates are isolated from the ore. Nickel ore concentrate mixed with fluxes is smelted in electric mines or reverberatory furnaces in order to separate waste rock and extract Nickel into a sulfide melt (matte) containing 10-15% Ni. Typically, electrosmelting is preceded by partial oxidative roasting and agglomeration of the concentrate. Along with Ni, a part of Fe, Co and almost completely Cu and noble metals pass into the matte. After separation of Fe by oxidation (by blowing liquid matte in converters), an alloy of Cu and Ni sulfides is obtained - matte, which is slowly cooled, finely ground and sent to flotation to separate Cu and Ni. Nickel concentrate is calcined in a fluidized bed to NiO. The metal is obtained by reduction of NiO in electric arc furnaces. Anodes are cast from rough nickel and refined electrolytically. The content of impurities in electrolytic Nickel (grade 110) 0.01%.

To separate Cu and Ni, the so-called carbonyl process is also used, based on the reversibility of the reaction: Ni + 4CO = Ni(CO) 4 . The preparation of carbonyl is carried out at 100–200 atm and at 200–250 °C, and its decomposition is carried out without air at atm. pressure and about 200 °C. The decomposition of Ni(CO) 4 is also used to obtain nickel coatings and the manufacture of various products (decomposition on a heated matrix).

In modern "autogenous" processes, smelting is carried out due to the heat released during the oxidation of sulfides with oxygen-enriched air. This makes it possible to refuse carbonaceous fuels, to obtain gases rich in SO 2 suitable for the production of sulfuric acid or elemental sulfur, and also to dramatically increase the efficiency of the process. The most perfect and promising is the oxidation of liquid sulfides. Processes based on the treatment of nickel concentrates with solutions of acids or ammonia in the presence of oxygen at elevated temperatures and pressures (autoclave processes) are becoming more and more widespread. Nickel is usually brought into solution, from which it is isolated as a rich sulfide concentrate or metal powder (by reduction with hydrogen under pressure).

Of the silicate (oxidized) ores, Nickel can also be concentrated in the matte when fluxes - gypsum or pyrite - are introduced into the smelting charge. Reduction-sulfiding smelting is usually carried out in shaft furnaces; the resulting matte contains 16-20% Ni, 16-18% S, the rest is Fe. The technology for extracting Nickel from matte is similar to that described above, except that the Cu separation operation often fails. With a low content of Co in oxidized ores, it is advisable to subject them to reduction smelting to obtain ferronickel, which is directed to steel production. To extract Nickel from oxidized ores, hydrometallurgical methods are also used - ammonia leaching of pre-reduced ore, sulfuric acid autoclave leaching, and others.

Nickel application. The vast majority of Ni is used to obtain alloys with other metals (Fe, Cr, Cu, and others), which are distinguished by high mechanical, anticorrosive, magnetic, or electrical and thermoelectric properties. In connection with the development of jet technology and the creation of gas turbine plants, heat-resistant and heat-resistant chromium-nickel alloys are especially important. Nickel alloys are used in the construction of nuclear reactors.

This means that the amount of Nickel is consumed for the production of alkaline batteries and anti-corrosion coatings. Malleable nickel in its pure form is used for the manufacture of sheets, pipes, etc. It is also used in the chemical industry for the manufacture of special chemical equipment and as a catalyst for many chemical processes. Nickel is a very scarce metal and, if possible, should be replaced by other, cheaper and more common materials.

The processing of Nickel ores is accompanied by the release of toxic gases containing SO 2 and often As 2 O 3 . Very toxic is the CO used in the refining of Nickel by the carbonyl method; highly toxic and easily volatile Ni(CO) 4 . Its mixture with air explodes at 60 °C. Control measures: tightness of equipment, enhanced ventilation.

Nickel is an essential trace element in the body. Its average content in plants is 5.0 10 -5% per crude substance, in the body of terrestrial animals 1.0 10 -6%, in marine animals - 1.6 10 -4%. In the animal organism Nickel is found in the liver, skin and endocrine glands; accumulates in keratinized tissues (especially in feathers). It has been established that Nickel activates the enzyme arginase and influences oxidative processes; in plants, it takes part in a number of enzymatic reactions (carboxylation, hydrolysis of peptide bonds, and others). On soils enriched with Nickel, its content in plants can increase by 30 times or more, which leads to endemic diseases (in plants - ugly forms, in animals - eye diseases associated with increased accumulation of Nickel in the cornea: keratitis, keratoconjunctivitis).

Nickel (chemical element) Nickel(lat. Niccolum), Ni, a chemical element of the first triad of group VIII of the Mendeleev periodic system, atomic number 28, atomic mass 58.70; silvery-white metal, malleable and ductile. Natural N. consists of a mixture of five stable isotopes: 58 Ni (67.76%), 60 Ni (26.16%), 61 Ni (1.25%), 63 Ni (3.66%), 64 Ni (1 ,16%).

History reference. The impure metal was first obtained in 1751 by the Swedish chemist A. Cronstedt, suggested and element name. A significantly purer metal was obtained in 1804 by the German chemist I. Richter. Name "N." comes from the mineral kupfernickel (NiAs), already known in the 17th century. and often misleading the miners with an external resemblance to copper ores (German: Kupfer - copper, Nickel - a mountain spirit, allegedly slipping empty rock instead of ore to the miners). From the middle of the 18th century N. was used only as an integral part of alloys, similar in appearance to silver. The widespread development of the nickel industry at the end of the 19th century. associated with the discovery of large deposits of nickel ores in New Caledonia and Canada and the discovery of its “ennobling” effect on the properties of steels.

distribution in nature. N. is an element of the earth's depths (in the ultrabasic rocks of the mantle it is 0.2% by weight). There is a hypothesis that the earth's core consists of nickel iron; in accordance with this, the average content of N. in the earth as a whole is estimated to be about 3%. In the earth's crust, where N. 5.8 × 10-3%, it also tends to a deeper, so-called basalt shell. Ni in the Earth's crust is a companion of Fe and Mg, which is explained by the similarity of their valence (II) and ionic radii; N. enters the minerals of divalent iron and magnesium in the form of an isomorphic impurity. N.'s own minerals are known to be 53; most of them were formed at high temperatures and pressures, during solidification of magma, or from hot aqueous solutions. N. deposits are associated with processes in the magma and weathering crust. Industrial deposits of N. (sulfide ores) are usually composed of N. minerals and copper (see. Nickel ores). On the earth's surface, in the biosphere, N. is a relatively weak migrant. It is relatively small in surface waters, in living matter. In areas dominated by ultramafic rocks, the soil and plants are enriched in nickel.

Physical and chemical properties. Under normal conditions, N. exists in the form of a b-modification, which has a face-centered cubic lattice (a = 3.5236). But N., subjected to cathodic sputtering in an atmosphere of H2, forms an a-modification, which has a hexagonal lattice of the closest packing (a = 2.65, c = 4.32), which, when heated above 200 ° C, turns into a cubic one. Compact cubic N. has a density of 8.9 g/cm 3 (20 °С), atomic radius 1.24 , ionic radii: Ni2+ 0.79 , Ni3+ 0.72 ; t pl 1453 °С; t kip about 3000 °C; specific heat capacity at 20 °C 0.440 kJ / (kg K) ; temperature coefficient of linear expansion 13.310-6 (0 – 100 °C); thermal conductivity at 25 ° C 90.1 wml (m K); the same at 500 ° C 60.01 vm / (m K) . Electrical resistivity at 20 °C 68.4 nom m, i.e. 6.84 μΩ cm; temperature coefficient of electrical resistance 6.8×10-3 (0 – 100 °C).

N. is a malleable and ductile metal; it is possible to produce the thinnest sheets and tubes from it. Ultimate tensile strength 400 – 500 MN/m 2 (i.e. 40‒50 kgf/mm 2 ), elastic limit 80 MN/m 2 , yield strength 120 MN/m 2 ; elongation 40%; modulus of normal elasticity 205 Gn/m 2 ; Brinell hardness 600‒800 MN/m 2 . In the temperature range from 0 to 631 K (the upper limit corresponds to curie point) N. ferromagnetic. Ferromagnetism N. is due to structural features of the outer electron shells (3d8 4s2) of its atoms. N., together with Fe (3d6 4s2) and Co (3d7 4s2), also ferromagnets, belongs to elements with an unfinished 3d electron shell (to 3d transition metals). The electrons of the unfinished shell create an uncompensated spin magnetic moment, the effective value of which for H atoms is 6 mB, where mB is Bora magneton. Positive value exchange interaction in N. crystals leads to a parallel orientation of the atomic magnetic moments, i.e., to ferromagnetism. For the same reason, alloys and a number of compounds of nitrogen (oxides, halides, etc.) are magnetically ordered (they have a ferro-, more rarely a ferrimagnetic structure, see Fig. Magnetic structure). N. is one of the most important magnetic materials and alloys with a minimum value of the coefficient of thermal expansion ( permalloy, monel metal, invar and etc.).

Chemically, Ni is similar to Fe and Co, but also to Cu and noble metals. In compounds, it exhibits variable valency (most often 2-valent). N. - a metal of medium activity, Absorbs (especially in a finely divided state) large amounts of gases (H2, CO, etc.); N.'s saturation with gases worsens its mechanical properties. Interaction with oxygen begins at 500 °C; in a finely dispersed state, N. is pyrophoric - it ignites spontaneously in air. Of the oxides, the most important oxide is NiO - greenish crystals, practically insoluble in water (the mineral bunsenite). Hydroxide precipitates from solutions of nickel salts when alkalis are added in the form of a voluminous apple-green precipitate. When heated, H. combines with halogens, forming NiX2. Burning in sulfur vapor, it gives a sulfide similar in composition to Ni3 S2. Monosulfide NiS can be obtained by heating NiO with sulfur.

N. does not react with nitrogen even at high temperatures (up to 1400 °C). The solubility of nitrogen in solid nitrogen is approximately 0.07% by weight (at 445°C). Ni3N nitride can be obtained by passing NH3 over NiF2 , NiBr2 or metal powder at 445°C. Under the action of phosphorus vapor at high temperature, phosphide Ni3 P2 is formed in the form of a gray mass. In the Ni – As system, the existence of three arsenides has been established: Ni5 As2 , Ni3 As (the mineral maucherite), and NiAs. Many metallides. Unstable Ni3C carbide can be obtained by slow (hundreds of hours) carburization (cementation) of H. powder in a CO atmosphere at 300°C. In the liquid state, N. dissolves an appreciable amount of C, which precipitates on cooling in the form of graphite. When graphite is isolated, N. loses malleability and the ability to be processed by pressure.

In the series of voltages, Ni is to the right of Fe (their normal potentials are ‒0.44 V and ‒0.24 V, respectively) and therefore dissolves more slowly than Fe in dilute acids. In relation to water N. is steady. Organic acids act on N. only after prolonged contact with it. Sulfuric and hydrochloric acids slowly dissolve N.; dilute nitric acid - very easy; concentrated HNO3 passivates H., however, to a lesser extent than iron.

When interacting with acids, salts of 2-valent Ni are formed. Almost all salts of Ni (II) and strong acids are highly soluble in water, their solutions are acidic due to hydrolysis. Sparingly soluble salts of such relatively weak acids as carbonic and phosphoric. Most N. salts decompose upon calcination (600 – 800°C). One of the most commonly used salts, NiSO4 sulfate, crystallizes from solutions in the form of emerald green crystals of NiSO4 × 7H2 O - nickel vitriol. Strong alkalis do not affect N., but it dissolves in ammonia solutions in the presence of (NH4) 2 CO3 with the formation of soluble ammonia, painted in intense blue; most of them are characterized by the presence of complexes 2 + and . Hydrometallurgical methods for extracting nitrogen from ores are based on the selective formation of ammonia. NaOCI and NaOBr are precipitated from solutions of Ni (II) salts, Ni (OH) 3 hydroxide is black. IN complex compounds Ni, unlike Co, is usually 2-valent. Complex compound of Ni with dimethylglyoxime(C4 H7 O2 N)2 Ni serves for the analytical determination of Ni.

At elevated temperatures, N. interacts with nitrogen oxides, SO2 and NH3. Under the action of CO on its finely divided powder, upon heating, carbonyl Ni (CO) 4 is formed (see Fig. Metal carbonyls). Thermal dissociation of the carbonyl yields the purest H.

Receipt. About 80% of its total production (excluding the USSR) is obtained from copper-nickel sulfide ores. After selective enrichment by flotation, copper, nickel and pyrrhotite concentrates are isolated from the ore. Nickel ore concentrate mixed with fluxes is smelted in electric shafts or reverberatory furnaces in order to separate waste rock and extract nickel into a sulfide melt (matte) containing 10 – 15% Ni. Usually, electric smelting (the main smelting method in the USSR) is preceded by partial oxidative roasting and concentrate agglomeration. Along with Ni, a part of Fe, Co and almost completely Cu and precious metals pass into the matte. After separation of Fe by oxidation (by blowing liquid matte in converters), an alloy of Cu and Ni sulfides is obtained - matte, which is slowly cooled, finely ground and sent to flotation to separate Cu and Ni. Nickel concentrate is calcined in a fluidized bed to NiO. The metal is obtained by reduction of NiO in electric arc furnaces. Anodes are cast from draft N. and refined electrolytically. The content of impurities in electrolyte N. (grade 110) is 0.01%.

To separate Cu and Ni, the so-called. carbonyl process based on the reversibility of the reaction:

The preparation of carbonyl is carried out at 100 – 200 atm and at 200 – 250°C, and its decomposition is carried out without access to air at atmospheric pressure and about 200°C. The decomposition of Ni (CO) 4 is also used to obtain nickel coatings and manufacture various products (decomposition on a heated matrix).

In modern "autogenous" processes, melting is carried out due to the heat released during the oxidation of sulfides with oxygen-enriched air. This makes it possible to abandon carbonaceous fuels, obtain gases rich in SO2 suitable for the production of sulfuric acid or elemental sulfur, and also dramatically increase the efficiency of the process. The most perfect and promising is the oxidation of liquid sulfides. Processes based on the treatment of nickel concentrates with solutions of acids or ammonia in the presence of oxygen at elevated temperatures and pressures (autoclave processes) are becoming more and more widespread. Usually N. is transferred to a solution, from which it is isolated in the form of a rich sulfide concentrate or metal powder (by reduction with hydrogen under pressure).

Of the silicate (oxidized) ores, N. can also be concentrated in matte when fluxes, such as gypsum or pyrite, are introduced into the smelting charge. Reduction-sulfiding smelting is usually carried out in shaft furnaces; the resulting matte contains 16 – 20% Ni, 16 – 18% S, and the rest is Fe. The technology for extracting N. from the matte is similar to that described above, except that the Cu separation operation often falls out. With a low content of Co in oxidized ores, it is advisable to subject them to reduction smelting to obtain ferronickel, which is directed to steel production. Hydrometallurgical methods are also used to extract nitrogen from oxidized ores—ammonia leaching of preliminarily reduced ore, sulfuric acid autoclave leaching, and others.

Application. The vast majority of Ni is used to obtain alloys with other metals (Fe, Cr, Cu, etc.), which are distinguished by high mechanical, anticorrosion, magnetic, or electrical and thermoelectric properties. In connection with the development of jet technology and the creation of gas turbine plants, heat-resistant and heat-resistant chromium-nickel alloys are especially important (see. Nickel alloys). N. alloys are used in the construction of nuclear reactors.

A significant amount of hydrogen is used for the production of alkaline batteries and anticorrosive coatings. Malleable N. in its pure form is used for the manufacture of sheets, pipes, etc. It is also used in the chemical industry for the manufacture of special chemical equipment and as a catalyst for many chemical processes. N. is a very scarce metal and, if possible, should be replaced by other, cheaper and more common materials.

The processing of N.'s ores is accompanied by the release of poisonous gases containing SO2 and often As2O3. Very toxic is the CO used in the refining of N. by the carbonyl method; highly toxic and highly volatile Ni(CO)4. Its mixture with air explodes at 60 °C. Control measures: tightness of equipment, enhanced ventilation.

A. V. Vanyukov.

Nickel in the body is essential trace element. Its average content in plants is 5.0 × 10-5% per crude substance, in the body of terrestrial animals 1.0 × 10-5%, in marine animals - 1.6 × 10-5%. In an animal organism N. is found in a liver, skin and endocrine glands; accumulates in keratinized tissues (especially in feathers). The physiological role of N. is studied insufficiently. It has been established that N. activates the enzyme arginase and affects oxidative processes; in plants, it takes part in a number of enzymatic reactions (carboxylation, hydrolysis of peptide bonds, etc.). On soils enriched with N., its content in plants can increase 30 times or more, which leads to endemic diseases (in plants - ugly forms, in animals - eye diseases associated with increased accumulation of N. in the cornea: keratitis, keratoconjunctivitis).

I. F. Gribovskaya.

Ripan R., Chetyanu I., Inorganic Chemistry, vol. 2 - Metals, trans. from rum., M., 1972, p. 581‒614; Metallurgist's Handbook for Non-Ferrous Metals, v. 2 -