Nickel is a ductile silver-white metal with a characteristic shine. Refers to heavy non-ferrous metals. Nickel is a valuable alloying additive. 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, are mined using special technologies.
When combined with other metals, nickel is capable of forming hard and durable nickel alloys:
- nickel-copper alloy (Monel)– a copper-based alloy with nickel as an alloying additive. The composition usually contains 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 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 ferromagnet, Curie point – 358°C, melting point – 1455°C, boiling point – 2730-2915°C. Density - 8.9 g/cm 3, coefficient of thermal expansion -13.5∙10 −6 K −1. In air, compact nickel is stable, while highly dispersed nickel is pyrophoric.
Nickel has the following properties:
- plasticity and malleability;
- strength at high temperatures;
- resistance to oxidation in water and air;
- hardness and sufficient viscosity;
- high corrosion resistance;
- ferromagnetic;
- good catalyst;
- polishes well.
The surface of nickel 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 acidic solutions. In addition, nickel is able to maintain 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). Another disadvantage of nickel is the fact that pure nickel does not occur in nature. It is obtained through expensive technologies, which affects its cost.
Application area
The main area of application of nickel is metallurgy. In it, he is involved in the production of high-alloy stainless steels. By adding nickel to molten iron, metallurgists obtain strong and ductile alloys that have increased corrosion resistance and resistance to high temperatures. It is worth noting that nickel alloys retain their qualities under repeated prolonged heating.
Due to these properties, stainless and heat-resistant nickel steel is used:
- in the food and chemical industry;
- 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 production of interior elements of buildings;
- in the furniture industry;
- in the manufacture of household appliances and household utensils;
Due to its ductility and ease of forging, nickel can be used to produce very thin products, such as strips, strips and sheets of nickel. Nickel is also actively used in the production of wire and rods.
Nickel
NICKEL-I; m.[German Nickel] Chemical element (Ni), a silvery-white, refractory metal with a strong luster (used in industry).
◁ Nickel, oh, oh. N. mine. Nth ore. N-th alloys. Nth coating.
nickel(lat. Niccolum), chemical element of group VIII of the periodic table. The name is from the German Nickel - the name of an evil spirit that allegedly interfered with the miners. Silver-white metal; density 8.90 g/cm 3, t pl 1455°C; ferromagnetic (Curie point 358°C). Very resistant to air and water. The main minerals are nickelite, millerite, pentlandite. About 80% of nickel is used for nickel alloys. It is also used for the production of batteries, chemical equipment, for anti-corrosion coatings (nickel plating), as a catalyst for many chemical processes.
NICKELNICKEL (lat. Niсsolum), Ni, chemical element with atomic number 28, atomic weight 58.69. The chemical symbol for the element Ni is pronounced the same as the name of the element itself. Natural nickel consists of five stable nuclides (cm. NUCLIDE): 58 Ni (67.88% by weight), 60 Ni (26.23%), 61 Ni (1.19%), 62 Ni (3.66%) and 64 Ni (1.04%). In the periodic system of D.I. Mendeleev, nickel is included in group VIIIB and together with iron (cm. IRON) and cobalt (cm. COBALT) In the 4th period in this group it forms a triad of transition metals with similar properties. Configuration of the two outer electronic layers of the nickel atom 3 s 2
p 6
d 8
4s 2
. It forms compounds most often in the oxidation state +2 (valence 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).
The radius of the neutral nickel atom is 0.124 nm, the radius of the Ni 2+ ion is from 0.069 nm (coordination number 4) to 0.083 nm (coordination number 6). The sequential ionization energies of the nickel atom are 7.635, 18.15, 35.17, 56.0 and 79 eV. According to the Pauling scale, the electronegativity of nickel is 1.91. Standard electrode potential Ni 0 /Ni 2+ –0.23 V.
The simple substance nickel in compact form is a shiny silvery-white metal.
History of discovery
Already from the 17th century. The miners of Saxony (Germany) knew of ore, which in appearance resembled copper ore, but did not yield copper when smelted. It was called kupfernickel (German: Kupfer - copper, and Nickel - the name of the gnome who slipped waste rock to the miners instead of copper ore). As it turned out later, kupfernickel is a compound of nickel and arsenic, NiAs. The history of the discovery of nickel stretched over almost half a century. The first conclusion about the presence of a new “semi-metal” in kupfernickel (that is, according to the terminology of that time, a simple substance intermediate in properties between metals and non-metals) was made by the Swedish metallurgist A. F. Kronstedt (cm. KRONSTEDT Axel Fredrik) in 1751. However, for more than twenty years this discovery was disputed and the prevailing point of view was that Kronstedt received not a new simple substance, but some kind of compound with sulfur of either iron, bismuth, cobalt, or some other metal.
Only in 1775, 10 years after Kronstedt’s death, the Swede T. Bergman carried out research that allowed him to conclude that nickel is a simple substance. But nickel was finally established as an element only at the beginning of the 19th century, in 1804, after scrupulous research by the German chemist I. Richter (cm. RICHTER Jeremiah Benjamin), who, for purification, carried out 32 recrystallizations of nickel sulfate (nickel sulfate) and, as a result of recovery, obtained pure metal.
Being in nature
In the earth's crust, the nickel content is about 8·10 -3% by mass. It is possible that enormous amounts of nickel - about 17 10 19 tons - are contained in the Earth's core, which, according to one common hypothesis, consists of an iron-nickel alloy. If this is so, then the Earth consists of approximately 3% nickel, and among the elements that make up the planet, nickel ranks fifth - after iron, oxygen, silicon and magnesium. Nickel is found in some meteorites that are an alloy of nickel and iron (called iron-nickel meteorites). Of course, such meteorites are of no importance as a practical source of nickel. The most important nickel minerals: nickel (cm. NICKELIN)(modern name for kupfernickel) NiAs, pentlandite (cm. PENTLANDITE)[nickel and iron sulfide composition (Fe,Ni) 9 S 8 ], millerite (cm. MILLERIT) NiS, garnierite (cm. GARNIERIT)(Ni, Mg) 6 Si 4 O 10 (OH) 2 and other nickel-containing silicates. In sea water, the nickel content is approximately 1·10 -8 –5·10 -8%
Receipt
A significant portion of nickel is obtained from sulfide copper-nickel ores. From enriched raw materials, matte is first prepared - a sulfide material containing, in addition to nickel, also impurities of iron, cobalt, copper and a number of other metals. By flotation method (cm. FLOTATION) nickel concentrate is obtained. Next, the matte is usually processed to remove iron and copper impurities, and then fired and the resulting oxide is reduced to metal. There are also hydrometallurgical methods for producing nickel, in which an ammonia solution is used to extract it from ore. (cm. AMMONIA) or sulfuric acid (cm. SULFURIC ACID). For additional purification, rough nickel is subjected to electrochemical refining.
Physical and chemical properties
Nickel is a malleable and ductile metal. It has a cubic face-centered crystal lattice (parameter a = 0.35238 nm). Melting point 1455°C, boiling point about 2900°C, density 8.90 kg/dm3. Nickel is ferromagnetic (cm. FERROMAGNETIC), Curie point (cm. CURIE POINT) about 358°C
Compact nickel is stable in air, while highly dispersed nickel is pyrophoric (cm. PYROPHORIC METALS). The surface of nickel is covered with a thin film of NiO oxide, which firmly protects the metal from further oxidation. Nickel also does not react with water and water vapor contained in the air. Nickel practically does not interact with such acids as sulfuric, phosphoric, hydrofluoric and some others.
Nickel metal reacts with nitric acid, resulting in the formation of nickel(II) nitrate Ni(NO 3) 2 and the corresponding nitrogen oxide is released, for example:
3Ni + 8HNO 3 = 3Ni(NO 3) 2 + 2NO + 4H 2 O
Only when heated in air to temperatures above 800°C does nickel metal begin to react with oxygen to form the oxide NiO.
Nickel oxide has basic properties. It exists in two polymorphic modifications: low-temperature (hexagonal lattice) and high-temperature (cubic lattice, stable at temperatures above 252°C). There are reports of the synthesis of nickel oxide phases with the composition NiO 1.33-2.0.
When heated, nickel reacts with all halogens (cm. HALOGEN) with the formation of dihalides NiHal 2. Heating nickel and sulfur powders leads to the formation of nickel sulfide NiS. Both water-soluble nickel dihalides and water-insoluble nickel sulfide can be obtained not only “dry”, but also “wet”, from aqueous solutions.
With graphite, nickel forms carbide Ni 3 C, with phosphorus - phosphides of the compositions Ni 5 P 2, Ni 2 P, Ni 3 P. Nickel also reacts with other non-metals, including (under special conditions) with nitrogen. Interestingly, nickel is capable of absorbing large volumes of hydrogen, resulting in the formation of solid solutions of hydrogen in nickel.
Such water-soluble nickel salts as NiSO 4 sulfate, Ni(NO 3) 2 nitrate and many others are known. Most of these salts, upon crystallization from aqueous solutions, form crystalline hydrates, for example, NiSO 4 .7H 2 O, Ni(NO 3) 2 .6H 2 O. Insoluble nickel compounds include Ni 3 (PO 4) 2 phosphate and Ni 2 SiO silicate 4 .
When alkali is added to a solution of nickel(II) salt, a green precipitate of nickel hydroxide precipitates:
Ni(NO 3) 2 + 2NaOH = Ni(OH) 2 + 2NaNO 3
Ni(OH) 2 has weakly basic properties. If a suspension of Ni(OH) 2 in an alkaline medium is exposed to a strong oxidizing agent, for example bromine, then nickel(III) hydroxide appears:
2Ni(OH) 2 + 2NaOH + Br 2 = 2Ni(OH) 3 + 2NaBr
Nickel is characterized by the formation of complexes. Thus, the Ni 2+ cation forms a hexaammine complex 2+ and a diaquatetraammine complex 2+ with ammonia. These complexes with anions form blue or violet compounds.
When fluorine F2 acts on a mixture of NiCl2 and KCl, complex compounds appear that contain nickel in high oxidation states: +3 - (K3) and +4 - (K2).
Nickel powder reacts with carbon monoxide (II) CO, and easily volatile tetracarbonyl Ni(CO) 4 is formed, which finds great practical application in the application of nickel coatings, the preparation of high-purity dispersed nickel, etc.
A characteristic reaction of Ni 2+ ions with dimethylglyoxime leads to the formation of pink-red nickel dimethylglyoximate. This reaction is used in the quantitative determination of nickel, and the reaction product is used as a pigment in cosmetic materials and for other purposes.
Application
The main share of smelted nickel is spent on the preparation of various alloys. Thus, adding nickel to steel increases the chemical resistance of the alloy, and all stainless steels necessarily contain nickel. In addition, nickel alloys are characterized by high toughness and are used in the manufacture of durable armor. An alloy of iron and nickel, containing 36-38% nickel, has a surprisingly low coefficient of thermal expansion (this is the so-called Invar alloy), and it is used in the manufacture of critical parts of various devices.
In the manufacture of electromagnet cores, alloys under the general name permalloy are widely used. (cm. PERMALLOY). These alloys, in addition to iron, contain from 40 to 80% nickel. Nichrome spirals used in various heaters, which consist of chromium (10-30%) and nickel, are well known. Coins are minted from nickel alloys. The total number of different nickel alloys in practical use reaches several thousand.
The high corrosion resistance of nickel coatings allows the use of thin nickel layers to protect various metals from corrosion by nickel plating. At the same time, nickel plating gives the products a beautiful appearance. In this case, an aqueous solution of double ammonium and nickel sulfate (NH 4) 2 Ni(SO 4) 2 is used for electrolysis.
Nickel is widely used in the manufacture of various chemical equipment, in shipbuilding, in electrical engineering, in the manufacture of alkaline batteries, and for many other purposes.
Specially prepared dispersed nickel (the so-called Raney nickel) is widely used as a catalyst for a wide variety of chemical reactions. Nickel oxides are used in the production of ferritic materials and as pigments for glass, glazes and ceramics; oxides and some salts serve as catalysts for various processes.
Biological role
Nickel is one of the microelements (cm. MICROELEMENTS) necessary for the normal development of living organisms. However, little is known about its role in living organisms. It is known that nickel takes part in enzymatic reactions in animals and plants. In animals, it accumulates in keratinized tissues, especially feathers. Increased nickel content in soils leads to endemic diseases - ugly forms appear in plants, and eye diseases in animals associated with the accumulation of nickel in the cornea. Toxic dose (for rats) - 50 mg. Volatile nickel compounds are especially harmful, in particular its tetracarbonyl Ni(CO) 4 . The maximum permissible concentration for nickel compounds in air ranges from 0.0002 to 0.001 mg/m 3 (for various compounds).
encyclopedic Dictionary. 2009 .
Synonyms:See what “nickel” is in other dictionaries:
NICKEL- (symbol Ni), a metal with an atomic weight of 58.69, serial number 28, belongs, together with cobalt and iron, to group VIII and row 4 of the periodic system of Mendeleev. Ud. V. 8.8, melting point 1,452°. In their usual connections N.... ... Great Medical Encyclopedia
- (symbol Ni), a silvery-white metal, TRANSITION ELEMENT, discovered in 1751. Its main ores are nickel sulfide iron ores (pentlandite) and nickel arsenide (nickel). Nickel has a complex purification process, including differentiated decomposition... ... Scientific and technical encyclopedic dictionary
- (German Nickel). The metal is silver-white in color and is not found in its pure form. Recently it has been used for making tableware and kitchenware. Dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. NICKEL German. Nickel... Dictionary of foreign words of the Russian language
Nickel- is a relatively hard grayish-white metal with a melting point of 1453 degrees. C. It is ferromagnetic, characterized by malleability, ductility, strength, and resistance to corrosion and oxidation. Nickel is mainly... Official terminology
Nickel belongs to the transition metals of the first long period and in the periodic table of D.I. Mendeleev is located in the VIIIA subgroup along with iron and cobalt.
Nickel crystallizes in a cubic face-centered lattice with a period at room temperature equal to 0.352387 nm. The atomic diameter of nickel is 0.248 nm. The density of nickel (8.897 g/cm3) is almost the same as that of copper and is twice the density of titanium, so nickel is classified as a heavy non-ferrous metal.
The physical properties of nickel are given in table. 7. The latent heat of fusion of nickel is approximately the same as that of magnesium, and slightly greater than that of aluminum. Its specific heat capacity is relatively low and is only slightly higher than the heat capacity of copper. The specific electrical and thermal conductivity of nickel is less than that of copper and aluminum, but significantly exceeds the electrical and thermal conductivity of titanium and many other transition metals. The elastic modulus of nickel is approximately the same as that of iron.
Nickel is a ferromagnetic metal, but its ferromagnetism is much less pronounced than that of iron and cobalt. The Curie point for nickel is 358 °C; above this temperature, nickel goes into a paramagnetic state.
Pure nickel is a silver-colored metal. During high-temperature oxidation of nickel, two oxide layers are formed: the inner one is light green and the outer one is dark green. These two layers are composed of oxide, but differ in the amount of oxygen.
Nickel is characterized by higher corrosion resistance in atmospheric conditions compared to other technical metals, which is due to the formation of a thin and durable protective film on its surface. Nickel is sufficiently stable not only in fresh water, but also in sea water. Mineral acids, especially nitric acid, have a strong effect on nickel. Alkaline and neutral salt solutions have little effect on nickel even when heated; in acidic salt solutions it corrodes quite strongly. In concentrated alkali solutions, nickel is stable even at high temperatures.
Nickel at room temperature does not interact with dry gases, but the presence of moisture noticeably increases the rate of its corrosion in these environments. Nickel contaminated with oxygen is prone to hydrogen disease.
Raw materials for nickel production
Currently, nickel plants process mainly two types of ores, which differ sharply in chemical composition and properties: oxidized nickel and sulfide copper-nickel. The significance of these ores for the domestic nickel industry and abroad is different. In Russia, the share of nickel obtained from sulfide ores is increasing from year to year, and in foreign countries, on the contrary, oxidized ores are becoming increasingly important.
Oxidized nickel ores are rocks of secondary origin, consisting mainly of hydrated magnesium silicates, aluminosilicates and iron oxide. Nickel minerals in them constitute an insignificant part of the ore mass. Nickel is most often found in the form of bunseite (NiO), garnierite [(Ni, Mg)O · SiO 3 · nH 2 O] or revdenskite. In addition to nickel, a useful component of these ores is cobalt, the content of which is usually 15...25 times less than the content of nickel. Sometimes copper is present in oxidized ores in small quantities (0.01...0.02%).
Waste rock, which makes up the bulk of the ore, is represented by clay Al 2 O 3 2SiO 2 2H 2 O, talc 3MgO 4SiO 2 2H 2 O, other silicates, brown ironstone Fe 2 O 3 nH 2 O, quartz and limestone.
Oxidized nickel ores are characterized by exceptional compositional variability in the content of both valuable components and waste rock. These compositional fluctuations are observed even in the massif of one deposit. Possible limits of concentrations of ore components are characterized by the following figures, %: Ni – 0.7...4; Co – 0.04…0.16; SiO 2 – 15...75; Fe 2 O 3 – 5…65; Al 2 O 3 – 2…25; Cr 2 O 3 – 1…4; MgO – 2…25; CaO – 0.5…2; constitutional moisture – up to 10…15.
Oxidized nickel ores are similar in appearance to clay. They are characterized by a porous, loose structure, low strength of the pieces, and high hygroscopicity. Rational methods for enriching such ores have not yet been found, and after appropriate preparation they directly go into metallurgical processing.
In sulfide ores, nickel is present mainly in the form of pentlandide, which is an isomorphic mixture of nickel and iron sulfides of variable ratio, and partly in the form of a solid solution in pyrrhotite.
The main companion of nickel in sulfide ores is copper, contained mainly in chalcopyrite. Due to their high copper content, these ores are called copper-nickel ores. In addition to nickel and copper, they necessarily contain cobalt, platinum group metals, gold, silver, selenium and tellurium, as well as sulfur and iron. Thus, sulfide copper-nickel ores are polymetallic raw materials of a very complex chemical composition. During their metallurgical processing, 14 valuable components are currently extracted.
The chemical composition of sulfide copper-nickel ores is as follows, %: Ni – 0.3...5.5; Cu – 0.2…1.9; Co – 0.02…0.2; Fe – 30…40; S – 17…28; SiO 2 – 10…30; MgO – 1…10; Al 2 O 3 – 5…8. The structure of copper-nickel ores can be continuous, veined or disseminated. The last two types of ores are more common. Depending on the depth of occurrence, ore is mined both open-pit and underground.
Unlike oxidized nickel ores, copper-nickel ores are characterized by high mechanical strength, are non-hygroscopic and can be enriched.
The main method of beneficiation of sulfide copper-nickel ores is flotation. Sometimes flotation enrichment is preceded by magnetic separation, aimed at separating pyrrhotite into an independent concentrate. The possibility of carrying out magnetic separation is due to the relatively high magnetic susceptibility of pyrrhotite.
The separation of pyrrhotite concentrate during ore enrichment improves the quality of the primary nickel concentrate due to the removal of a significant part of iron and sulfur from it and simplifies its subsequent metallurgical processing. However, when obtaining pyrrhotite concentrate, there is a need for its mandatory processing in order to extract nickel, sulfur and platinum group metals.
Flotation enrichment of copper-nickel ores can be collective or selective. In collective flotation, copper-nickel concentrate is obtained by separating waste rock. However, selective flotation does not provide complete separation of copper and nickel. The selection products in this case will be copper concentrate with a relatively low nickel content and nickel-copper concentrate, which differs from the ore in a higher Ni: Cu ratio.
Thus, depending on the adopted enrichment scheme for sulfide copper-nickel ores, it is possible to obtain collective copper-nickel, copper, nickel and pyrrhotite concentrates, the composition of which is given in Table. 8.
Methods for obtaining nickel
Sulfide ores and oxidized ores are processed in various ways - pyro- and hydrometallurgical.
Smelting of sulphide ores and concentrates for matte
Ores with a total content of more than 2–5% copper and nickel are considered rich and are smelted without preliminary enrichment.
Ores and concentrates contain the same minerals, so the same processing methods can be applied to them after the necessary preparation.
When the ore is heated to 400–600 °C, even before melting begins, chalcopyrite and nickel-containing sulfides decompose:
6(NiS, FeS) → 2Ni 3 S 2 + 6FeS + S 2,
4CuFeS 2 → 2Cu 2 S + 4FeS + S 2,
2Fe 7 S 8 → 14FeS + S 2.
As a result of these reactions, a complex set of minerals is transformed into a mixture of simple sulfides: Ni 3 S 2, FeS and Cu 2 S.
At the temperatures required to melt the slag, consisting of gangue oxides and fluxes, the sulfides of copper, nickel and iron are infinitely soluble in each other; they form a copper-nickel matte, separated from the slag in the form of a heavier liquid layer.
If some of the sulfur is oxidized during smelting or removed by pre-roasting, the distribution of copper, nickel and iron between the matte and slag will depend on the affinity of these metals for oxygen and sulfur. Under smelting conditions, the affinity for sulfur, which determines the possibility of the metal transforming into matte, is greater for copper than for nickel, and for nickel greater than for iron. The affinity of the same metals for oxygen decreases in the reverse order. If there is insufficient sulfur for sulfidation of all metals, copper will first go into matte, then nickel and, finally, part of the iron. The more iron goes into the matte, the greater the completeness of sulfidation of copper and nickel, but matte diluted with iron sulfide will be poor. To completely convert nickel into matte when smelting ore or concentrate, do not strive for complete slagging of the iron, leaving part of it in the matte.
Cobalt's affinity for sulfur and oxygen occupies an intermediate position between iron and nickel.
The molten matte is blown through a converter, adding quartz; Iron, when oxidized, becomes slagged with silica.
The main product of the converter process - copper-nickel matte - is an alloy of copper and nickel sulfides containing 1-3% iron.
During blowing, cobalt is partially slaged along with iron.
Converter slag is sometimes sent to a separate process for cobalt extraction. Noble metals are concentrated almost entirely in the matte.
The cooled matte is crushed, crushed and subjected to flotation. In this case, two concentrates are obtained: nickel, consisting of almost pure Ni 3 S 2, and copper, containing Cu 2 S; the latter is processed into copper using ordinary copper concentrate by smelting into matte and blowing in a converter.
The nickel concentrate is fired, oxidizing it according to the reaction
The gray nickel oxide powder thus obtained, containing cobalt oxides and platinum metals, is reduced with coal in electric furnaces to metal, which is poured into anodes.
Nickel anodes are subjected to electrolytic refining, simultaneously extracting cobalt and copper residue from the electrolyte, and platinum group metals from the sludge.
Rich lump copper-nickel ores are smelted into matte in shaft furnaces, if the waste rock of these ores is not too refractory. In some cases, for ores containing a lot of magnesium oxide or other refractory components, it is necessary to resort to electric smelting.
Flotation concentrates and fine fractions of rich ores are smelted in reverberatory or electric furnaces; If the sulfur content in these materials is high, pre-firing is used.
The choice of smelting method largely depends on the composition of the raw materials and local economic conditions, in particular on the availability of a particular fuel and the price of electricity.
Hydrometallurgical method for processing sulfide ores
According to this method, crushed ore or concentrate is treated with a solution of ammonia and (NH 4) 2 SO 4 in autoclaves under an excess air pressure of about 506.7 kN/m 2 (7 at). Copper, nickel and cobalt go into solution in the form of complex ammonium salts, for example, by the reaction
NiS + 2O 2 + 6NH 3 = Ni(NH 3) 6 SO 4.
Vigorous oxidation of sulfides is accompanied by the release of heat, the excess of which is removed by refrigerators, maintaining a temperature of 70–80 ºС in the autoclave; the sulfur included in the concentrate is oxidized to S 2 O3 2−, S 3 O 6 2− and SO 4 2−, and iron precipitates in the form of hydroxide and basic sulfates.
The filtered solution is boiled to precipitate copper according to the reaction
Cu 2+ + 2S 2 O 3 2− = CuS + SO 4 2− + S + SO 2.
After this, the partially remaining copper in the solution is precipitated with hydrogen sulfide, and the solution purified from it, containing nickel and cobalt, is treated in an autoclave with hydrogen at a pressure of about 2.5 Mn/m2 (25 at) and a temperature of about 200 ºC.
First, the bulk of the nickel is deposited
Ni(NH3) 6 2+ + H 2 = Ni + 2NH 4 + + 4NH 3
in the form of particles with a particle size from 2 to 80 microns. After filtering the precipitate, the remaining nickel and cobalt are separated from the solution with hydrogen sulfide.
With further treatment of the sulfide precipitate with oxygen and ammonia in the autoclave, the cobalt dissolves. The insoluble precipitate, containing predominantly nickel sulfide, is returned to the main leaching, and cobalt is separated from the solution by the action of hydrogen under pressure.
The circuit is complex and requires expensive equipment; however, it allows you to extract up to 95% Ni, about 90% Cu and 50–75% Co from complex concentrates.
Smelting of oxidized ores for matte
The currently most common method of processing oxidized nickel ores by smelting into matte is based on the difference in the affinity of iron and nickel for oxygen and sulfur.
Nickel is converted into matte by sulfidation - an alloy of Ni 3 S 2 and FeS; the bulk of the iron is removed with the slag:
6FeS + 6NiO = 6FeO + 2Ni 3 S 2 + S 2,
2FeO + SiO 2 = FeSiO 4.
Oxidized ores do not contain sulfur, so it must be introduced by adding pyrite or gypsum during smelting. Gypsum, being reduced to calcium sulfide, sulfides iron and nickel. The action of gypsum during melting is more complex than the action of pyrite, but in many cases they still use gypsum rather than pyrite, since gypsum is cheaper than pyrite and does not give
ferrous slags.
When processing oxidized nickel ores, it is most advantageous to use local cobalt-containing pyrite, which contains very little copper and no noble metals.
Nickel matte, obtained by smelting ore with pyrite or gypsum, contains up to 60% Fe, which is then separated from nickel by blowing liquid matte in a converter. During conversion, selective oxidation of iron occurs and it is slagged with quartz added to the converter - a nickel matte almost free of iron is obtained. Converter slag is rich in nickel, so it is a recyclable product - it is returned to ore smelting or sent for separate processing to extract cobalt.
Feinstein is poured into molds, then crushed and fired tightly:
2Ni3S2 + 7O2 = 6NiO + 4SO2.
Nickel oxide is mixed with a low-sulfur reducing agent, such as petroleum coke, and melted in an electric furnace at 1500 ºC to produce liquid nickel.
Nickel is cast into anodes for electrolytic refining or granulated by pouring it into water in a thin stream.
Smelting of oxidized ores into nickel cast iron (ferronickel)
High-grade oxidized ores are sometimes smelted in electric furnaces with coal, reducing all of the iron, nickel and cobalt into naturally alloyed cast iron.
Similar smelting of relatively poor ores is also carried out in blast furnaces, but it has limited use.
Despite the predominant use of nickel in special steels, smelting it in the form of an alloy with iron is not always acceptable: the alloy contains cobalt, manganese, chromium and other impurities, the random combinations of which do not always allow the use of the valuable properties of these metals.
Critical method of processing oxidized ores
According to this method, ore mixed with coal is heated in tubular rotary kilns at a temperature of about 1050 ºC, which allows only part of the iron to be reduced along with nickel and cobalt. Reduced metals are obtained in the form of grains mixed with semi-molten slag. The cooled slag is crushed and the critical alloy is extracted from it using an electromagnet. The method is not widely used for the same reasons as the previous one - due to the impossibility of using cobalt separately.
Hydrometallurgy of oxidized ores
According to one of these methods, known in the literature as the Cuban method, crushed ore is subjected to reduction roasting in mechanical multi-hearth furnaces in a generator gas environment. At 600–700 ºС, nickel and cobalt are reduced to metals, and iron is reduced only to oxide. Next, the ore is leached with an ammonia solution in the presence of carbon dioxide and atmospheric oxygen. Nickel forms water-soluble ammonia by the reaction
2Ni + 12NH 3 + 2CO 2 + O 2 = 2Ni(NH 3) 6 CO 3.
After the waste rock is separated by thickening and washing, the solution is treated with live steam. As a result of the removal of excess ammonia, hydrolysis occurs with the release of basic nickel carbonates into the sediment:
2Ni(NH 3) 6 CO 3 + H 2 O = NiCO 3 Ni(OH) 2 + CO 2 + 12NH 3.
Ammonia from the gases is absorbed by water and again sent for leaching. Nickel oxide is sintered on sintering machines and supplied as sinter to steel mills.
This silver-gray metal belongs to the transition metal - it has both alkaline and acidic properties. The main advantages of the metal are malleability, ductility, and high anti-corrosion properties. Where and how nickel is used - read below.
Due to the presence of an oxide film on the surface, the metal is endowed with the ability to perfectly resist corrosion. In addition, the coating of this metal reliably protects parts and objects made from other materials from oxidation. This is why nickel is widely used in modern industry.
In addition, the element has not only anti-corrosion properties. It perfectly resists the effects of various alkalis. Due to this, it is used to protect all kinds of aluminum, iron and cast iron parts intended for use in aggressive environments. Including for the manufacture of aircraft blades, tanks for transporting hazardous substances and other equipment for the chemical industry.
If we talk about other areas of our life where the use of nickel is on a large scale today, it is worth mentioning production:
- prostheses and braces for medical needs;
- batteries;
- chemical reagents;
- "white gold" in the jewelry industry;
- windings for strings of musical instruments.
Alloys
Due to its anti-corrosion properties, the element is widely used for the production of various alloys from iron, copper, titanium, tin, molybdenum, etc. More than 80 percent of the total volume of Ni mined worldwide is consumed for this, deposits of which are located in Russia (Ural, Murmansk and Voronezh regions, Norilsk region) South Africa, Canada, Greece, Albania and other countries. Ni is used to make stainless steel. Alloys with iron are used in almost all branches of modern industry, as well as in the construction of any civil or industrial facilities.
As a result of different percentage combinations with copper, the alloys Monel, Constantine and others are obtained. They are used for the manufacture of coins, storage tanks for sulfuric, perchloric or phosphoric acid, spare parts and machine parts (valves, heat exchangers, bushings, springs, impeller blades) intended for use under high loads.
Alloys with the addition of chromium - nichrome - are heat-resistant and therefore are used for the manufacture of structural elements of gas turbines, parts of jet engines, and equipment for nuclear reactors.
By adding molybdenum, alloys are obtained that are resistant to acids and other aggressive compounds (dry chlorine).
Alloys containing aluminum, iron, copper and cobalt - alnic and magneto - have the properties of permanent magnets and are used in the manufacture of various radio measuring instruments and electrical equipment.
Products made from invar - an alloy with the addition of iron (Ni - 35 percent, Fe - 65%) have the property of practically not stretching when heated.
Other Applications
One of the most common uses of nickel in industry today is nickel plating, which is the application of a thin layer of nickel (thickness ranging from 12 to 36 micrometers) to the surface of other metals using an electroplating method. Anti-corrosion treatment is carried out in this way:
- metal pipes;
- dishes;
- tableware;
- faucets and taps for the kitchen or bathroom;
- furniture fittings and other decorative products.
Objects treated in this way will be reliably protected from moisture for a long time, and also, thanks to the silver coating that will not fade over time, will retain a presentable appearance.
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NICKEL, Ni, a chemical element of group VIII of the periodic system, belonging to the triad of the so-called. iron metals (Fe, Co, Ni). Atomic weight 58.69 (2 isotopes are known with atomic weights 58 and 60); serial number 28; The usual valency of Ni is 2, less commonly 4, 6 and 8. In the earth's crust, nickel is more abundant than cobalt, accounting for about 0.02% by weight. In the free state, nickel is found only in meteoric iron (sometimes up to 30%); in geological formations it is contained exclusively in the form of compounds - oxygen, sulfur, arsenic, silicates, etc. (see Nickel ores).
Properties of nickel. Pure nickel is a silvery-white metal with a strong shine that does not fade when exposed to air. It is hard, refractory and easy to polish; in the absence of impurities, (especially sulfur), it is very flexible, malleable and malleable, capable of being rolled into very thin sheets and drawn into wire with a diameter of less than 0.5 mm. The crystalline form of nickel is cube. Specific gravity 8.9; cast products have a specific gravity of ~8.5; rolling he might. increased to 9.2. Mohs hardness ~5, Brinell 70. Ultimate tensile strength 45-50 kg/mm 2, with elongation 25-45%; Young's modulus E 20 = (2.0-2.2)x10 6 kg)cm 2; shear modulus 0.78 10 6 kg/cm 2 ; Poisson's ratio μ =0.3; compressibility 0.52·10 -6 cm 2 /kg; the melting point of nickel, according to the latest most accurate definitions, is 1455°C; boiling point is in the range of 2900-3075°C.
Linear coefficient of thermal expansion 0.0000128 (at 20°C). Heat capacity: specific 0.106 cal/g, atomic 6.24 cal (at 18°C); heat of fusion 58.1 cal/g; thermal conductivity 0.14 cal cm/cm 2 sec. °C (at 18°C). Sound transmission speed 4973.4 m/sec. The electrical resistivity of nickel at 20°C is 6.9-10 -6 Ω-cm with a temperature coefficient of (6.2-6.7)·10 -3. Nickel belongs to the group of ferromagnetic substances, but its magnetic properties are inferior to those of iron and cobalt; for nickel at 18°C the magnetization limit is J m = 479 (for iron J m = 1706); Curie point 357.6°C; the magnetic permeability of both nickel itself and its ferroalloys is significant (see below). At ordinary temperatures, nickel is quite resistant to atmospheric influences; water and alkalis, even when heated, have no effect on it. Nickel dissolves easily in dilute nitric acid with the release of hydrogen and is much more difficult to dissolve in HCl, H 2 SO 4 and concentrated HNO 3. When heated in air, nickel oxidizes from the surface, but only to a small depth; when heated, it easily combines with halides, sulfur, phosphorus and arsenic. Market grades of metallic nickel are the following: a) ordinary metallurgical nickel, obtained by reduction from its oxides using coal, usually contains from 1.0 to 1.5% impurities; b) malleable nickel, obtained from the previous one by remelting with the addition of about 0.5% magnesium or manganese, contains an admixture of Mg or Mn and contains almost no sulfur; c) nickel prepared according to the Mond method (via nickel carbonyl) is the purest product (99.8-99.9% Ni). Common impurities in metallurgical nickel are: cobalt (up to 0.5%), iron, copper, carbon, silicon, nickel oxides, sulfur and occluded gases. All these substances, with the exception of sulfur, have little effect on the technical properties of nickel, reducing only its electrical conductivity and slightly increasing its hardness. Sulfur (present in the form of nickel sulfide) sharply reduces the malleability and mechanical strength of nickel, especially at elevated temperatures, which is noticeable even when containing<0,005% S. Вредное влияние серы объясняется тем, что сульфид никеля, растворяясь в металле, дает хрупкий и низкоплавкий (температура плавления около 640°С) твердый раствор, образующий прослойки между кристаллитами чистого никеля.
Nickel Applications. The bulk of metallurgical nickel is used for the production of ferronickel and nickel steel. A major consumer of nickel is also the production of various special alloys (see below) for the electrical industry, mechanical engineering and chemical equipment manufacturing; This area of nickel application has shown an increasing growth trend in recent years. Laboratory apparatus and utensils (crucibles, cups), kitchen and tableware are prepared from malleable nickel. Large quantities of nickel are used for nickel plating of iron, steel and copper products and in the production of electric batteries. Lamp electrodes for radio equipment are made from chemically pure nickel. Finally, reduced pure nickel in powder form is the most commonly used catalyst for all kinds of hydrogenation (and dehydrogenation) reactions, for example, in the hydrogenation of fats, aromatic hydrocarbons, carbonyl compounds, etc.
Nickel alloys . The qualitative and quantitative composition of the nickel alloys used is very diverse. Alloys of nickel with copper, iron and chromium (most recently also with aluminum) are of technical importance - often with the addition of a third metal (zinc, molybdenum, tungsten, manganese, etc.) and with a certain content of carbon or silicon. The nickel content in these alloys varies from 1.5 to 85%.
Alloys Ni-Cu form a solid solution at any ratio of components. They are resistant to alkalis, diluted H 2 SO 4 and heating up to 800 ° C; their anti-corrosion properties increase with increasing Ni content. Bullet shells are made from an alloy of 85% Cu + 15% Ni, and small change coins are made from an alloy of 75% Cu + 25% Ni. Alloys with 20-40% Ni are used for the manufacture of pipes in condensing units; the same alloys are used for lining tables in kitchens and buffets and for making stamped ornamental decorations. Alloys with 30-45% Ni are used for the production of rheostatic wire and standard electrical resistances; This includes, for example, nickel and constantan. Ni-Cu alloys with a high Ni content (up to 70%) are characterized by high chemical resistance and are widely used in apparatus and mechanical engineering. Monel metal is the most widely used.
Alloys Ni-Cu-Zn quite resistant to organic acids (acetic, tartaric, lactic); with a content of about 50% copper, they are collectively called nickel silver. The copper-rich hardware alloy ambarak contains 20% Ni, 75% Cu and 5% Zn; In terms of stability, it is inferior to Monel metal. Alloys such as bronze or brass containing nickel are sometimes also called nickel bronze.
Alloys Ni-Cu-Mn, containing 2-12% Ni, called manganina, are used for electrical resistances; in electrical measuring instruments an alloy of 45-55% Ni, 15-40% Mn and 5-40% Cu is used.
Alloys Ni-Cu-Cr resistant to alkalis and acids, with the exception of HCl.
Alloys Ni-Cu-W have recently gained great importance as valuable acid-resistant materials for chemical equipment; with a content of 2-10% W and not more than 45% Cu, they are well rolled and very resistant to hot H 2 SO 4. The alloy of the composition has the best qualities: 52% Ni, 43% Cu, 5% W; A small amount of Fe is acceptable.
Alloys Ni-Cr. Chromium dissolves in nickel up to 60%, nickel in chromium up to 7%; in alloys of intermediate composition there are crystal lattices of both types. These alloys are resistant to moist air, alkalis, dilute acids and H 2 SO 4; with a content of 25% Cr or more, they are also resistant to HNO 3; the addition of ~2% Ag makes them easy to roll. At 30% nickel, the Ni-Cr alloy is completely devoid of magnetic properties. An alloy containing 80-85% Ni and 15-20% Cr, along with high electrical resistance, is very resistant to oxidation at high temperatures (withstands heating up to 1200°C); it is used in electric resistance ovens and household heating devices (electric irons, braziers, stoves). In the USA, Ni-Cr is used to make cast pipes for high pressures used in plant equipment.
Alloys Ni-Mo They have high acid resistance (at >15% Mo), but have not become widespread due to their high cost.
Alloys Ni-Mn(with 1.5-5.0% Mn) resistant to alkalis and moisture; their technical application is limited.
Alloys Ni-Fe form a continuous series of solid solutions; they form a large and technically important group; depending on the carbon content they are either steel or cast iron. Conventional grades of nickel steel (pearlite structure) contain 1.5-8% Ni and 0.05-0.50% C. The nickel additive makes the steel very tough and significantly increases its elastic limit and bending impact resistance without affecting ductility and weldability . Critical machine parts are prepared from nickel steel, such as transmission shafts, axles, spindles, axles, gear clutches, etc., as well as many parts of artillery structures; steel with 4-8% Ni and<0,15% С хорошо поддается цементации. Введение никеля в чугуны(>1.7% C) promotes the release of carbon (graphite) and the destruction of cementite; Nickel increases the hardness of cast iron, its tensile and bending resistance, promotes uniform distribution of hardness in castings, facilitates machining, imparts fine grain and reduces the formation of voids in castings. Nickel cast iron used as an alkali-resistant material for chemical equipment; The most suitable for this purpose are cast irons containing 10-12% Ni and ~1% Si. Steel-like alloys with a higher nickel content (25-46% Ni at 0.1-0.8% C) have an austenitic structure; they are very resistant to oxidation, to the action of hot gases, alkalis and acetic acid, have high electrical resistance and a very low expansion coefficient. These alloys are almost non-magnetic; when the Ni content is within 25-30%, they completely lose their magnetic properties; their magnetic permeability (in low-strength fields) increases with increasing nickel content and m.b. further enhanced by special heat treatment. Alloys in this category include: a) ferronickel (25% Ni at 0.3-0.5% C), used for the manufacture of motor valves and other machine parts operating at elevated temperatures, as well as non-magnetic parts of electrical machines and rheostatic wire; b) invar; c) platinite (46% Ni at 0.15% C) is used in electric lamps instead of platinum for soldering wires into glass. Permalloy alloy (78% Ni at 0.04% C) has a magnetic permeability μ = 90000 (in a field of 0.06 gauss); magnetization limit I m = 710. Some alloys of this type are used in the manufacture of underwater electrical cables.
Alloys Ni-Fe-Cr- also a very important technical group. Chrome-nickel steel, used in mechanical and engine building, usually contains 1.2-4.2% Ni, 0.3-2.0% Cr and 0.12-0.33% C. In addition to high viscosity, it also has significant hardness and resistance wear and tear; temporary tensile strength, depending on the nature of the heat treatment, ranges between 50 and 200 kg/mm 2; is used for the manufacture of crankshafts and other parts of internal combustion engines, parts of machine tools and machines, as well as artillery armor. In order to increase hardness, a large amount of chromium (from 10 to 14%) is introduced into the steel for steam turbine blades. Chromium-nickel steels containing >25% Ni resist the action of hot gases well and have minimal fluidity: they can be subjected to significant forces at high temperatures (300-400°C) without showing residual deformations; used for the manufacture of valves for motors, parts of gas turbines and conveyors for high-temperature installations (for example, glass annealing furnaces). Ni-Fe-Cr alloys containing >60% Ni are used for the manufacture of cast machine parts and low-temperature parts of electrical heating devices. As hardware materials, Ni-Fe-Cr alloys have high anti-corrosion properties and are quite resistant to HNO 3. In chemical apparatus manufacturing, chromium-nickel steel is used, containing 2.5-9.5% Ni and 14-23% Cr at 0.1-0.4% C; it is almost non-magnetic, resistant to HNO 3, hot ammonia and oxidation at high temperatures; Mo or Cu additive increases resistance to hot acid gases (SO 2 , HCl); Increasing the Ni content increases the machinability of steel and its resistance to H2SO4, but reduces its resistance to HNO3. This includes Krupp stainless steels (V1M,V5M) and acid-resistant steels(V2A, V2H, etc.); Their heat treatment consists of heating to ~ 1170°C and quenching in water. Used as alkali-resistant material nickel-chromium cast iron(5-6% Ni and 5-6% Cr with a content of >1.7% C). Nichrome alloy, containing 54-80% Ni, 10-22% Cr and 5-27% Fe, sometimes with the addition of Cu and Mn, is resistant to oxidation within temperatures up to 800 ° C and is used in heating devices (sometimes by the same name denote the Ni-Cr alloys described above that do not contain Fe).
Alloys Ni-Fe-Mo were offered as hardware material. An alloy of 55-60% Ni, 20% Fe and 20% Mo has the highest acid resistance and anti-corrosion properties, when containing< 0,2% С; присадка небольшого количества V еще более повышает кислотоупорность; Мn м. б. вводим в количестве до 3%. Сплав вполне устойчив по отношению к холодным кислотам (НСl, H 2 SO 4), за исключением HNO 3 , и к щелочам, но разрушается хлором и окислителями в присутствии кислот; он имеет твердость по Бринеллю >200, well rolled, forged, cast and processed on machines.
Alloys Ni-Fe-Cu used in chemical equipment (steel with 6-11% Ni and 16-20% Cu).
Alloys Ni-Fe-Si. To build acid-resistant equipment, silicon-nickel steels of the Durimet brand are used, containing 20-25% Ni (or Ni and Cr in a 3:1 ratio) and ~ 5% Si, sometimes with the addition of Cu. They are resistant to cold and hot acids (H 2 SO 4, HNO 3, CH 3 COOH) and salt solutions, less resistant to HCl; Amenable to hot and cold machining.
In alloys Ni-AI the formation of a chemical compound AINi takes place, dissolving in an excess of one of the alloy components.
Alloys based on the system are beginning to acquire technical importance. Ni-AI-Si. They turned out to be very resistant to HNO 3 and cold and hot H 2 SO 4, but they are almost impossible to machine. Such, for example, is a new acid-resistant alloy for cast products, containing about 85% Ni, 10% Si and 5% Al (or Al + Cu); its Brinell hardness is about 360 (it is reduced to 300 by annealing at 1050°C).
Nickel metallurgy . The main area of application of nickel is the production of special grades of steel. During the war of 1914-18. at least 75% of all nickel was spent for this purpose; under normal conditions ~65%. Nickel is also widely used in its alloys with non-ferrous (non-ferrous) metals, ch. arr. with copper (~15%). The remaining amount of nickel is used: for the production of nickel anodes - 5%, malleable nickel - 5% and various products - 10%.
Nickel production centers have repeatedly moved from one area of the globe to another, which was explained by the presence of reliable ore deposits and the general economic situation. Industrial smelting of nickel from ores began in 1825-26 in Falun (Sweden), where nickel containing sulfur pyrite was found. In the 90s of the last century, Swedish deposits were apparently almost exhausted. Only during the war of 1914-18, due to an increase in demand for nickel metal, Sweden supplied several tens of tons of this metal (maximum 49 tons in 1917). In Norway, production began in 1847-50.
The main ore here was pyrrhotite with an average content of 0.9-1.5% Ni. Production in Norway on a small scale (maximum - about 700 tons per year during the 1914-18 war) continues to this day. In the middle of the last century, the center of the nickel industry was concentrated in Germany and Austria-Hungary. At first it was based here exclusively on the arsenic ores of the Black Forest and Gladbach, and from 1901, and especially during the war of 1914-18, on the oxidized ores of Silesia (Frankenstein). The development of nickel ore deposits in New Caledonia began in 1877. Thanks to the use of these ores, world production of nickel in 1882 reached almost 1000 tons. The ore mined here was processed locally only in limited quantities, but the bulk of it was sent to Europe. Only in recent years, due to increased transport tariffs, hl. arr. rich mattes containing 75-78% Ni, in the amount of nickel about 5000 tons per year. Currently, it is proposed to obtain metallic nickel in New Caledonia, for which purpose the Nickel Society is constructing a refining plant that will use the electrical energy of a hydroelectric station on the Yate River. The nickel industry in Canada (North America) began in the late 1980s. last century. Until recently, there were two companies here; one English - Mond Nickel Co. and another American - International Nickel Co. At the end of 1928, both companies merged into a powerful global trust called the International Nickel Company of Canada, supplying the market with about 90% of the world's nickel production and exploiting deposits located near the city of Sedbury. Mond Nickel Co. melts its ores at a plant in Coniston into matte, which is sent to England for further processing at a plant in Claydach. International Nickel Co. The matte smelted at the Conpercliffe plant is sent to the Port Colborne plant for metal production. World nickel production has reached 40,000 tons in recent years.
Processing of nickel ores is carried out exclusively by dry methods. Hydrometallurgical methods, which have been repeatedly recommended for ore processing, have not yet found application in practice. These methods are currently sometimes applied only to the processing of intermediate products (mattes) obtained as a result of dry processing of ores. The use of the dry route for the processing of nickel ores (both sulfur and oxidized) is characterized by the implementation of the same principle of gradual concentration of valuable components of the ore in the form of certain products, which are then processed into metals to be extracted. The first stage of such concentration of foam components of nickel ores is carried out by ore smelting into matte. In the case of sulfur ores, the latter are smelted in the raw or pre-burnt state in shaft or flame furnaces. Oxidized ores are melted in shaft furnaces with the addition of sulfur-containing materials to their charge. Ore smelting matte, rostein, turns out to be unsuitable for its direct processing into the valuable metals it contains, due to their relatively low concentration in this product. In view of this, the ore smelting matte is subjected to further concentration either by firing it followed by smelting in a shaft furnace, or by oxidative smelting on the bottom of a flame furnace, or in a converter. These contractile, or concentration, matte melts, produced in practice one or more times, have the ultimate goal of obtaining the pure most concentrated matte (fin matte), consisting only of sulfides of valuable metals with a certain amount of the latter in a free state. Finite mattes obtained in practice are of two types depending on their composition. When processing oxidized New Caledonian ores that do not contain valuable metals other than nickel, the matte is an alloy of nickel sulfide (Ni 3 S 2) with a certain amount of metallic nickel. As a result of processing sulfurous Canadian ores containing both nickel and copper, the resulting matte is an alloy of copper and nickel sulfides with a certain amount of these metals in a free state. Depending on the composition of the matte, their processing into pure metals also changes. The simplest is the processing of matte containing only nickel; processing of copper-nickel matte is more difficult and may carried out in various ways. The processing of oxidized ores into matte with sulfur-containing additives (gypsum) was proposed by Garnieri in 1874. The processing of these ores in Frankenstein (Germany) was carried out as follows. To the ore mixture containing 4.75% Ni, 10% gypsum or 7% anhydrite and 20% limestone were added; a certain amount of fluorspar was also added here. This entire mixture was thoroughly mixed, crushed and then pressed into bricks, which, after drying, were smelted in a shaft furnace with a coke consumption of 28-30% of the weight of the ore. The daily productivity of the shaft furnace reached 25 tons of ore. The cross-section of the furnace at the tuyere level is 1.75 m2; its height is 5 m. The lower part of the shaft to a height of 2 m had water jackets. The slags are highly acidic; 15% Ni was lost in them. Rostein composition: 30-31% Ni; 48-50% Fe and 14-15% S. The matte was granulated, crushed, fired and melted in a cupola furnace in a mixture with 20% quartz and at a coke consumption of 12-14% of the weight of the roasted matte for a concentrated matte of the following average composition: 65% Ni, 15% Fe and 20% S. The latter was converted into matte: 77.75% Ni, 21% S, 0.25-0.30% Fe and 0.15-0.20% Cu. Carefully crushed matte is fired in fiery furnaces (with manual or mechanical raking) until the sulfur is completely removed. At the end of firing, a certain amount of NaNO 3 and Na 2 CO 3 is added to the fired mass, not only to facilitate the burning of sulfur, but also to convert the As and Sb sometimes present in the matte into antimony and arsenic acid salts, which are then leached water from the calcined product. The NiO obtained as a result of firing is subjected to reduction, for which nickel oxide is mixed with flour and water and cubes are formed from the resulting dough, which are then heated in crucibles or retorts. At the end of reduction, the temperature rises to 1250°C, which promotes the welding of individual reduced Ni particles into a solid mass.
International Nickel Co. processes its sulfur ores trace. arr. Ore smelting, depending on their size, is carried out either in shaft or in flame furnaces. Lump ores are pre-roasted in heaps; firing duration is from 8 to 10 months. Roasted ore is smelted mixed with some unroasted ore in shaft furnaces. No fluxes are added, since the ore is self-fluxing. Coke consumption is 10.5% of the weight of the ore mixture. About 500 tons of ore are smelted in the furnace per day. The ore smelting matte is converted into high-grade matte. The converter slag is partly returned to the converter, and partly goes into the ore smelting charge. The composition of ores and products is given in the table:
Fine ore is roasted in Wedja furnaces to a sulfur content of 10-11% and then smelted in a flame furnace. Converter slag containing 79.5% (Cu + Ni), 20% S and 0.30% Fe is processed by the Orford process, which consists of melting matte in the presence of Na 2 S. The latter causes delamination of the smelting products into two layers: the upper one, representing alloy Cu 2 S + Na 2 S, and the lower one, containing almost pure nickel sulfide. Each of these layers is processed into a corresponding metal. The upper, copper-containing layer, after Na 2 S is separated from it, is subjected to conversion, and the lower, nickel, layer is subjected to chlorinating roasting, leaching (and it is freed from some amount of copper contained in it), and the resulting so. Nickel oxide is reduced. A certain amount of copper-nickel matte is subjected to oxidation roasting and subsequent reduction smelting into a copper-nickel alloy known as Monel metal.
Mond Nickel Co. enriches its ores; the resulting concentrates are subjected to sintering on Dwight-Lloyd machines, the agglomerate from which goes into the shaft furnace. The ore smelting matte is converted, the resulting matte is processed using the Mond method, for which the matte is crushed, fired and leached with H 2 SO 4 to remove most of the copper in the form of CuSO 4 . The residue, containing NiO with some copper, is dried and fed into the apparatus, where it is reduced at 300°C with hydrogen (water gas). The reduced, finely crushed nickel enters the next apparatus, where it is brought into contact with CO; in this case, volatile nickel carbonate is formed - Ni(CO) 4, which is transferred to the third apparatus, where the temperature is maintained at 150°C. At this temperature, Ni(CO) 4 decomposes into metallic Ni and CO. The resulting nickel metal contains 99.80% Ni.
In addition to the above two methods for producing nickel from copper-nickel matte, there is also the Hybinette method, which makes it possible to obtain nickel by electrolytic means. Electrolytic nickel contains: 98.25% Ni; 0.75% Co; 0.03% Cu; 0.50% Fe; 0.10% C and 0.20% Pb.
The issue of nickel production in the USSR has a hundred-year history. Already in the 20s of the last century, nickel ores were known in the Urals; At one time, the Ural nickel ore deposits, containing about 2% Ni, were considered as one of the main sources of raw materials for the world nickel industry. After the discovery of nickel ores in the Urals, M. Danilov, P. A. Demidov and G. M. Permikin carried out a number of experiments in their processing. In Revdinsk for 1873-77. 57.3 tons of metallic nickel were obtained. But further resolution of the task was stopped after the discovery of richer and more powerful deposits of nickel ores in New Caledonia. The issue of domestic nickel was again brought up for resolution under the influence of circumstances caused by the war of 1914-18. In the summer of 1915, at the Ufaleysky plant, P. M. Butyrin and V. E. Vasiliev conducted experiments in smelting matte in a flame furnace. At the same time, experiments were carried out on the extraction of nickel from Ufaley ores at the St. Petersburg Polytechnic Institute G. A. Kashchenko under the guidance of prof. A. A. Baikov, and in the fall of 1915, test melts were carried out in a fiery furnace at the plant. In the summer of 1916, at the Revdinsky plant, experiments were carried out in the smelting of copper-nickel matte from low-grade nickel ores (0.86% Ni) and low-copper pyrites (1.5% Cu). The smelting was carried out in a shaft furnace. At the same time, Revda nickel-containing brown iron ores were smelted in a blast furnace into nickel cast iron (all the nickel ore is concentrated in cast iron), which was supplied under a contract with the maritime department to its Leningrad factories. All of the above studies, due to a number of circumstances, were not completed at that time in the form of corresponding factory processes. In recent years, the problem of obtaining nickel from the Ural ores has again come up for solution, and its practical implementation, in accordance with the nickel content in the ores, should proceed in two directions. The nickel content in the Ural ores is low, and according to it the ores are divided into two grades: 1st and 2nd. Grade 1 ores, suitable for pyrometallurgical processing, contain on average about 3% Ni; 2nd grade ore - about 1.5% and below. The last ores cannot be processed by smelting without prior enrichment. Another possibility for processing low-grade nickel ores is the hydrometallurgical route; he d.b. still studied. Currently, a plant is being built in the Urals to process 1st grade ores.