Combined carbothermic production of calcium from carbonate. RU patent 2501871.
 Calcium carbide / 2501733Method includes thermal processing of crushed limestone and coal with discharge of gaseous products, which are applied for production of carbonic acid. Thermal processing is carried out in one reactor. At the first stage in the process of introduction of raw material into reactor it is subjected to heating to 1000°-1200°C by transmission of heat from constructive elements of loading canal and by exposure of raw material to plasma beam in zone of free movement of raw material particles. Thermal processing of raw material is realised in atmosphere of carbon dioxide. Further synthesis of calcium carbide is realised at temperature, at least, 1700-1800°C by induction heating of reaction mass. Obtained calcium carbide liquid is discharged. Gaseous products, from which carbon oxide and carbon dioxide are separated, are discharged from upper part of reactor, and at least, part of discharged carbon dioxide is applied for filling loading canal. For production of carbonic acid volume of carbon dioxide, remaining after filling loading canal and entire volume of carbon oxide are applied. |
 Plasma-carbon production method of rare-earth metals, and device for its implementation / 2499848Method involves carbon thermal reduction of oxide compound of rare-earth metal in vacuum so that powder of rare-earth metal carbide, which is free from residues of oxygen impurity, is obtained. Then, it is cooled down and mixed with high-melting metal powder in the ratio that is sufficient for performance of exchange reactions between rare-earth metal carbide and high-melting metal, and mixture is heated with hot volumetric plasma discharge to the temperature of ≥1800°C. With that, evaporating rare-earth metal is collected on condensers and hard-alloy carbide of high-melting metal is obtained. The device includes a vacuum system, cathode and anode assemblies arranged concentrically in the chamber, and a steam line and a condenser-cooler, which are coaxial to them. With that, an internal electrode represents an anode of high-current vacuum plasma discharge burning in an annular discharge cavity formed with coaxial cylindrical electrodes. The anode is made from high-melting electrically conducting material in the form of a crucible having a capacity, and a thin-wall cathode enveloping it, outside which there located is a starting resistance heater, is also made from high-melting electrically conducting material, for example tungsten, tantalum or graphite. |
| Method of processing kyanite concentrate / 2489503 Method involves mixing a concentrate, a carbonaceous reducing agent and a pore-forming additive in form of ammonium sulphate, pelletising the obtained mixture, firing and holding at maximum temperature with reduction of silicon dioxide to a gaseous monoxide, crushing the obtained sinter, treatment thereof with ammonium bifluoride and calcining the reaction mass to obtain an aluminium-containing product, wherein ammonium sulphate is taken in an amount of 10-20% of the mass of the concentrate; before pelletising, the mixture is milled to obtain particles with size of 50-75 mcm in amount of at least 80%; the mixture is fired at temperature of 1690-1750°C; ammonium bifluoride is taken in amount of 0.4-14% of the mass of the sinter; and the reaction mass is calcined at 700-900°C. Before treatment with ammonium bifluoride, the sinter can be treated with 10-20% hydrochloric acid. The degree of extraction of aluminium oxide from the concentrate is increased by 1.3-9.9%. Content of aluminium oxide in the end product reaches 97.7% with content of silicon oxide impurities of 0.13-1.0%. |
 Method of processing solid or melted substances / 2484152Solid or melted substances are loaded on graphite body heated, at least, partially, inductively. Reducing agents are introduced therein, other than graphite carbon to collect flowing reduced and/or gasified melt. Note here that reducing agents are introduced along with solid or melted loaded particles. Said reducing agents represent natural gas, coal dust, brown coal dust, hydrocarbons, hydrogen, carbon oxide and/or ammonia to be introduced together with steam, oxygen, carbon dioxide and/or halogens or halogen hydrides. |
 Reducing method of metals from oxides / 2476035Reducing method of metals from oxides refers to reducing technologies of metals from non-organic oxides, at which preparation of homogeneous mixture is performed from ultradisperse powders of metal oxide and carbon, supply of prepared mixture under pressure to high-temperature zone in the well, which is formed with plasmatron jet, decomposition of metal oxide with formation of carbon dioxide that is removed through upper tuyeres of the well, and finished product is removed in the form of ultradisperse metal powder through tap holes in lower part of the well. |
| Procedure for depletion of solid copper-zinc slag / 2398031 Invention refers to procedure for depletion of solid copper-zinc slag. The procedure consists in supply of charge containing solid copper-zinc slag and carbonic reducer at weight ratio of slag to solid carbonic reducer 1: (0.06-0.1) into heated furnace. Also charge in the heated furnace is blasted with oxygen containing oxidant by means of upper not-immersed blast; consumption of oxygen-containing oxidant is determined by contents of oxygen in it from condition of 60-110 kg per ton of slag. Further there is produced a rich with copper phase and zinc is transferred into a gas phase. |
 Method of processing of iron-titanium concentrate / 2385962Method includes formation of charge consisting of concentrate and sodium carbonate by means of intergrinding of components and reduction of charge components at presence of taken with excess carbonaceous reducing material at temperature 850-1300°C. Additionally batch material reduction is implemented up to providing of content of metallic iron in the range of particles dimensions 10-300 mcm not less than 80%. Received partly reduced conservative mass, consisting of metalise phase containing main part of iron and vanadium and oxide phase, containing main part of titanium and vanadium, it is grinned up to size not more than 300 mcm. Then it is implemented leaching of vanadium from reaction mass and leaching residue is separated from vanadate solution. After separation residue of leaching is subject to gravitational separation in water flow with separation of metalised and oxide phases. Metalised and oxide phases are separately subject to wet magnetic separation for receiving of metallic iron and titanium oxide concentrate. Additionally wet magnetic separation is implemented in the range of field intensity 20-300 E. |
 Reduction method of metal and oxygen compositions / 2360982At reduction of metal and oxygen composition effect as reducer, herewith at first stage gaseous CO is passed into reaction chamber, containing specified composition of metal and oxygen. In conditions, providing conversion of CO into solid carbon and carbon dioxide, formed solid carbon is introduced into metal and oxygen composition. At the second stage solid carbon, which is introduced into metal and oxygen composition at the first stage, reduces metal and oxygen composition. Additionally at the second stage it is, at least, the first material- promoter, conducive reduction of specified metal and oxygen composition. Additionally the first material- promoter contains the first metal- promoter and/or composition of the first metal- promoter. |
| Method of tin manufacturing from cassiterite concentrate / 2333268 Invention concerns tin metallurgy field and can be used for tin manufacturing while treatment of cassiterite concentrates. Method of tin manufacturing from cassiterite concentrate with content of 35-50% SnO2 includes batch preparation by blending of tin concentrate with coal and flux additive. In the capacity of flux additive it is used sodium carbonate and sodium nitrate. Melting is implemented at temperature 850-1000°C during 2 hours. For mentioned concentrate it is kept up following mass ratio: concentrate : coal : sodium carbonate : sodium nitrate, equal to 1 : (0.2-0.25) : (0.12-0.15) : (0.06-0.08). It allows without concentrate pretreatment to provide tin manufacturing of 98% purity at less in comparison with tradition approach, temperature. |
 Method of reduction of metal oxides / 2317342Charge in form of mixture of oxides and reductant is fed to heated furnace and is mixed in way of temperature rise at passage of gas mixture through charge in way of temperature rise. Size of particles of oxides does not exceed 2-4 mm. Used as reductant are hydrocarbons and/or oxygen derivatives of hydrocarbons and/or their polymers. Reduction process is completed within range of temperatures of forming final product at preset phase state. |
| Combined carbothermic production of calcium from carbonate / 2501871 Proposed method comprises making the charge from calcium carbonate, primarily, from chemically deposited chalk or high-quality sifting in production of limestone and carbon, primarily from reused graphite, obtained at final stage of carbothermic process. Note here that starting charge is pelletised, placed in furnace and heated in vacuum in one unit at three steps. At first step, calcium carbonate is dissociated in the presence of carbon at 600-700°C for 2-4 hours and residual pressure of 40-50 Pa to remove carbon monoxide. At second step, calcium carbide (CaC2) is synthesized at 1400-1500°C and 100-150 Pa to remove carbon monoxide. At third step, calcium carbine is dissociated to produce elementary calcium and graphite at 1300-1400°C and < 10 Pa. |
 Method of production of cleaned coal for metallurgical processes and method of production of reduced metal and slag containing oxidized non-ferrous metal with the use of this coal / 2302450Proposed method is based on use of cleaned coal for production of high-quality reduced metal. Coal is first kept in organic solvent simultaneously with heating, thus obtaining cleaned coal suitable for metallurgy which possesses higher thermoplasticity as compared with starting coal. Then, mixture of cleaned coal and starting material is subjected to agglomeration in agglomerator and agglomerate thus obtained is reduced at heating in furnace provided with movable hearth; then, it is molten by further heating, thus obtaining reduced melt which is cooled and hardened in furnace provided with movable hearth, thus obtaining solid material, after which reduced solid material is withdrawn from furnace. Then, slag is removed with the use of screen and reduced metal is extracted. |
| Method of reduction of metal oxides / 2317342 Charge in form of mixture of oxides and reductant is fed to heated furnace and is mixed in way of temperature rise at passage of gas mixture through charge in way of temperature rise. Size of particles of oxides does not exceed 2-4 mm. Used as reductant are hydrocarbons and/or oxygen derivatives of hydrocarbons and/or their polymers. Reduction process is completed within range of temperatures of forming final product at preset phase state. |
| Method of tin manufacturing from cassiterite concentrate / 2333268 Invention concerns tin metallurgy field and can be used for tin manufacturing while treatment of cassiterite concentrates. Method of tin manufacturing from cassiterite concentrate with content of 35-50% SnO2 includes batch preparation by blending of tin concentrate with coal and flux additive. In the capacity of flux additive it is used sodium carbonate and sodium nitrate. Melting is implemented at temperature 850-1000°C during 2 hours. For mentioned concentrate it is kept up following mass ratio: concentrate : coal : sodium carbonate : sodium nitrate, equal to 1 : (0.2-0.25) : (0.12-0.15) : (0.06-0.08). It allows without concentrate pretreatment to provide tin manufacturing of 98% purity at less in comparison with tradition approach, temperature. |
| Reduction method of metal and oxygen compositions / 2360982 At reduction of metal and oxygen composition effect as reducer, herewith at first stage gaseous CO is passed into reaction chamber, containing specified composition of metal and oxygen. In conditions, providing conversion of CO into solid carbon and carbon dioxide, formed solid carbon is introduced into metal and oxygen composition. At the second stage solid carbon, which is introduced into metal and oxygen composition at the first stage, reduces metal and oxygen composition. Additionally at the second stage it is, at least, the first material- promoter, conducive reduction of specified metal and oxygen composition. Additionally the first material- promoter contains the first metal- promoter and/or composition of the first metal- promoter. |
| Method of processing of iron-titanium concentrate / 2385962 Method includes formation of charge consisting of concentrate and sodium carbonate by means of intergrinding of components and reduction of charge components at presence of taken with excess carbonaceous reducing material at temperature 850-1300°C. Additionally batch material reduction is implemented up to providing of content of metallic iron in the range of particles dimensions 10-300 mcm not less than 80%. Received partly reduced conservative mass, consisting of metalise phase containing main part of iron and vanadium and oxide phase, containing main part of titanium and vanadium, it is grinned up to size not more than 300 mcm. Then it is implemented leaching of vanadium from reaction mass and leaching residue is separated from vanadate solution. After separation residue of leaching is subject to gravitational separation in water flow with separation of metalised and oxide phases. Metalised and oxide phases are separately subject to wet magnetic separation for receiving of metallic iron and titanium oxide concentrate. Additionally wet magnetic separation is implemented in the range of field intensity 20-300 E. |
| Procedure for depletion of solid copper-zinc slag / 2398031 Invention refers to procedure for depletion of solid copper-zinc slag. The procedure consists in supply of charge containing solid copper-zinc slag and carbonic reducer at weight ratio of slag to solid carbonic reducer 1: (0.06-0.1) into heated furnace. Also charge in the heated furnace is blasted with oxygen containing oxidant by means of upper not-immersed blast; consumption of oxygen-containing oxidant is determined by contents of oxygen in it from condition of 60-110 kg per ton of slag. Further there is produced a rich with copper phase and zinc is transferred into a gas phase. |
| Reducing method of metals from oxides / 2476035 Reducing method of metals from oxides refers to reducing technologies of metals from non-organic oxides, at which preparation of homogeneous mixture is performed from ultradisperse powders of metal oxide and carbon, supply of prepared mixture under pressure to high-temperature zone in the well, which is formed with plasmatron jet, decomposition of metal oxide with formation of carbon dioxide that is removed through upper tuyeres of the well, and finished product is removed in the form of ultradisperse metal powder through tap holes in lower part of the well. |
| Method of processing solid or melted substances / 2484152 Solid or melted substances are loaded on graphite body heated, at least, partially, inductively. Reducing agents are introduced therein, other than graphite carbon to collect flowing reduced and/or gasified melt. Note here that reducing agents are introduced along with solid or melted loaded particles. Said reducing agents represent natural gas, coal dust, brown coal dust, hydrocarbons, hydrogen, carbon oxide and/or ammonia to be introduced together with steam, oxygen, carbon dioxide and/or halogens or halogen hydrides. |
| Method of processing kyanite concentrate / 2489503 Method involves mixing a concentrate, a carbonaceous reducing agent and a pore-forming additive in form of ammonium sulphate, pelletising the obtained mixture, firing and holding at maximum temperature with reduction of silicon dioxide to a gaseous monoxide, crushing the obtained sinter, treatment thereof with ammonium bifluoride and calcining the reaction mass to obtain an aluminium-containing product, wherein ammonium sulphate is taken in an amount of 10-20% of the mass of the concentrate; before pelletising, the mixture is milled to obtain particles with size of 50-75 mcm in amount of at least 80%; the mixture is fired at temperature of 1690-1750°C; ammonium bifluoride is taken in amount of 0.4-14% of the mass of the sinter; and the reaction mass is calcined at 700-900°C. Before treatment with ammonium bifluoride, the sinter can be treated with 10-20% hydrochloric acid. The degree of extraction of aluminium oxide from the concentrate is increased by 1.3-9.9%. Content of aluminium oxide in the end product reaches 97.7% with content of silicon oxide impurities of 0.13-1.0%. |
| Plasma-carbon production method of rare-earth metals, and device for its implementation / 2499848 Method involves carbon thermal reduction of oxide compound of rare-earth metal in vacuum so that powder of rare-earth metal carbide, which is free from residues of oxygen impurity, is obtained. Then, it is cooled down and mixed with high-melting metal powder in the ratio that is sufficient for performance of exchange reactions between rare-earth metal carbide and high-melting metal, and mixture is heated with hot volumetric plasma discharge to the temperature of ≥1800°C. With that, evaporating rare-earth metal is collected on condensers and hard-alloy carbide of high-melting metal is obtained. The device includes a vacuum system, cathode and anode assemblies arranged concentrically in the chamber, and a steam line and a condenser-cooler, which are coaxial to them. With that, an internal electrode represents an anode of high-current vacuum plasma discharge burning in an annular discharge cavity formed with coaxial cylindrical electrodes. The anode is made from high-melting electrically conducting material in the form of a crucible having a capacity, and a thin-wall cathode enveloping it, outside which there located is a starting resistance heater, is also made from high-melting electrically conducting material, for example tungsten, tantalum or graphite. |
FIELD: metallurgy.
SUBSTANCE: proposed method comprises making the charge from calcium carbonate, primarily, from chemically deposited chalk or high-quality sifting in production of limestone and carbon, primarily from reused graphite, obtained at final stage of carbothermic process. Note here that starting charge is pelletised, placed in furnace and heated in vacuum in one unit at three steps. At first step, calcium carbonate is dissociated in the presence of carbon at 600-700°C for 2-4 hours and residual pressure of 40-50 Pa to remove carbon monoxide. At second step, calcium carbide (CaC2) is synthesized at 1400-1500°C and 100-150 Pa to remove carbon monoxide. At third step, calcium carbine is dissociated to produce elementary calcium and graphite at 1300-1400°C and < 10 Pa.
EFFECT: higher efficiency, simplified process, application of cheap reducing agent.
1 tbl
The invention relates to metallurgy and concerns a method for obtaining calcium. The invention may be used for obtaining of alkaline and alkaline-earth metals, but mostly it is designed for production of calcium when using co the way of restoration. The method consists of three stages: the dissociation of calcium carbonate in the presence of carbon getting charges calcium oxide - carbon; at the second stage, the synthesis of calcium carbide with its subsequent decay in the third stage of the metal calcium and carbon, and all three stages are held in one cycle in a single device.
The closest adopted for the prototype, is a Method for producing calcium and device for its obtaining (Russian Federation Patent №2205241 from 15.03. 2002, Bulletin of inventions # 19 dated 16 March 2003).
The disadvantage of this method is to use as a reducing agent aluminium powder, the cost of which is currently rather high consumption accounts for 45-50 kg per kg of produced calcium, and the share of the reducing agent in the cost exceeds 40%.
The disadvantage is the inability to obtain high extracts calcium from the source of raw materials. The recovery process goes through education, all the poorer for calcium calcium aluminates. The calcium from poorer aluminates cannot be recovered due to thermodynamic limitations. Theoretical removing calcium at a cold process does not exceed 65%at high temperature is not above 75%. In practice, recovery does not reach 62-72%.
Disadvantage of this method is also increased consumption of aluminum due to its partial (5-6%) oxidation of carbon dioxide in the dissociation of calcium carbonate in the first stage of the recovery process.
Disadvantage of this method is also a large amount of toxins after recovery, amounting to 1.5 t on t received calcium reduces the specific output devices recovery and the need for disposal and recycling of slag
A method of obtaining of calcium from the technical calcium carbide (Doronin N.A. Calcium. - M: gosatomizdat, 1962. - 190).
The disadvantage of this method is the use of technical calcium carbide produced from the ore-thermal furnaces of burnt lime metallurgical class, where the content of oxides CaO+MgO not exceed 85-88%. Technical calcium carbide from this material contains up to 25% of impurities (mainly oxides of calcium and magnesium), that reduces the specific output devices recovery and violates the technological process.
The disadvantage is the inability to obtain high purity calcium due to the passage of adverse reactions from the impurities, contained in the technical carbide of calcium.
Disadvantage of this method is also the need for pre-selection of products adverse reactions that reduce removing calcium from calcium carbide due to its losses and waste, also complicates the design of the capacitor.
In the basis of the invention is to provide a method of receipt of calcium, which allows the use of cheaper restorer, improve specific productivity, reduce the number of technological operations, reduce energy costs.
The problem is solved in such a way that batch preparation lead from calcium carbonate, mainly from chemically precipitated chalk or high-quality screenings upon receipt of limestone, and carbon as reducing agents, mainly from working graphite, received at the final stage, the original briquetted and heating in vacuum spend stepped in one device in three stages, with the first stage of dissociation of calcium carbonate in the presence of carbon at temperatures within the range of temperatures of 600-700°C for 2-4 hours and residual pressure of gases 40-50 PA with the removal of carbon monoxide, on the second stage of synthesis of calcium carbide (CaC2) at a temperature of 1400-1500°C and a pressure of 100-150 PA with the removal of carbon monoxide, on the third - dissociation of calcium carbide from the receipt of elemental calcium and carbon in the form of graphite 1300-1400°C and a pressure of less than 10 PA.
Calcium is ready production, and carbon is used for the preparation of the charge for the first stage of the process, which is a 50% reduction of the need in carbon.
Produced on the last stage of carbon has the properties of graphite and, if necessary, and if necessary, can be used according to its purpose, as the finished products. Thus, the combined the process of obtaining calcium has only gas emissions, consisting of mainly of carbon dioxide, and has no solid waste.
The table shows the specific examples of the method.
No.Composition of charge
StageTemperature, C
Pressure, PA
Time, hour
Removing Ca, %
1CaCO3 +4C
1 600-700 40-50 2 21400-1500
100-150 4 31300-1350
Less than 10
8 97Method of obtaining of calcium in the blend mode carbothermic reduction of calcium carbonate in a vacuum, which includes batch preparation of calcium carbonate and carbon, briquetting her and heating in vacuum stepped in one device in three stages, the first of whom spend dissociation of calcium carbonate in the presence of carbon at temperatures within the range of temperatures of 600-700°C for 2-4 hours and residual pressure 40-50 PA with the removal of carbon monoxide, on the second - synthesis of calcium carbide (CaC2 ) when 1400-1500°C and a pressure of 100 to 150 PA with the removal of carbon monoxide and the third - dissociation of calcium carbide from the receipt of elemental calcium and graphite 1300-1400°C and a pressure of less than 10 PA, and batch preparation lead from calcium carbonate, mainly of chemically precipitated chalk or high-quality screenings upon receipt of limestone, and carbon, mainly from working graphite produced at the third stage of the combined process.