RU2674048C2 - Method for production of steel and portland cement in single process and technological chamber for implementing method - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to ferrous metallurgy and can be used to produce in a single process of steel and portland cement of a given composition. According to the invention, the liquid-phase reduction of cast iron is carried out, along with the adjustment of the chemical composition of the slag melt, the saturation of the melt with lime, accelerated cooling of clinker and cleaning it from metallic inclusions with obtaining portland cement. After the liquid-phase reduction of cast iron, oxidative refining of steel from impurities is carried out, along with separation of steel from refining slag, deoxidation and alloying of steel, and the adjustment of the chemical composition of the slag melt is carried out in the process of its saturation. In the process chamber melting-saturation spend liquid-phase reduction of cast iron, oxidative refining of steel from impurities and the saturation of the slag melt with lime. Saturation of the slag melt with lime is carried out by creating in a thickening melt the conditions for the formation of alite first, and then of low-melting clinker minerals. Deoxidation and alloying of steel is carried out in a casting ladle or furnace-ladle unit.

EFFECT: invention can be used to produce in a single process of steel and portland cement of a given composition.

2 cl, 3 dwg, 3 ex, 12 tbl

Description

The invention relates to ferrous metallurgy and the production of building materials. The method can be used to obtain steel and Portland cement given compositions. As raw materials for the implementation of the method, iron ore, lime, coal, mill scale, slag melts, substandard iron-carbon melts, waste slag, scrap, dust from an air treatment system, coal energy wastes, etc. are used.

A known method of producing steel [1], including blast furnace production of cast iron, refining cast iron in an oxygen converter and deoxidation-alloying of steel in a ladle-furnace assembly (ACP). This method has the following disadvantages: firstly, the method requires large capital costs for the preparation of iron ore and coke; secondly, expensive coking coals are used for the production of coke; thirdly, significant capital costs in the implementation of the method do not allow its use in mini-factories.

A known method of producing steel of a given composition from materials containing iron oxides [2], including liquid-phase reduction of cast iron in a bubbler, crankcase melting chamber with continuous cast iron discharge into the ladle - “Romelt Process”, oxidative refining of impurities in the process of filling the ladle and deoxidation in AKP. This method has the following disadvantages: firstly, the skull melting chamber has large heat losses; secondly, in the bubble chamber the low efficiency of heat transfer from the afterburning zone to the melt.

The closest in technical essence and the achieved effect to the claimed method, in terms of steel production, is a method in which reducing smelting is carried out in a lined converter rotating around its longitudinal axis - “Dored process” [3], and refining and deoxidation-alloying spend in another Converter, also rotating around its longitudinal axis "Kaldo-process" [4]. Intensive mixing of the melting components in a rotating melting chamber allows creating better conditions for carrying out metallurgical processes, since most of them are limited in the diffusion region, in addition, the rotating surface intensively works to transfer heat from the afterburning zone to the melt. However, this method has several disadvantages. Firstly, the melting chamber has a complex drive, since in addition to rotation around the longitudinal axis, it must provide an inclination for the release of melting products. This makes the equipment bulky and complicates the conditions of its operation. Secondly, the effectiveness of the method is reduced due to long downtime associated with the repair of the lining. Thirdly, the production of steel in several units leads to an increase in capital and production costs.

All of the considered methods for producing steel do not involve the processing of the resulting fire-liquid slag melts into Portland cement. Moreover, a significant part of the slag is simply sent to the dump, harming the environment.

A known method of producing cement clinker from a fire-liquid blast furnace slag in a converter [5]. When implementing this method, the melt is heated to (1900-2000) º C. Heating the melt to such temperatures significantly complicates the implementation of the method due to the low durability of the lining and increased fuel consumption. In addition, this method allows you to process only the slag formed in the process of reducing smelting, where the content of iron oxides is negligible.

The closest in technical essence and the achieved effect is a method for producing cast iron and components for slag Portland cement [6]. The invention consists in the following. Flame-liquid slag, obtained as a result of various metallurgical industries, leads to a given composition of Portland cement clinker or an active mineral additive by reducing the metal oxides contained in it and introducing the missing components into it. Moreover, the main volume of lime is introduced at the final stage of smelting. Thus, the method of producing Portland cement clinker includes liquid-phase reduction of cast iron, adjustment of the chemical composition of slag melt, saturation of the melt with lime, accelerated cooling of the clinker and its purification from metal inclusions. At the same time, at all stages of melting, heating is combined with mixing of the melt. In addition, at the reduction and oxidation stages of melting, the melt temperature and the composition of the input materials are controlled depending on the viscosity. And saturation is carried out with a thickening melt in the temperature range of formation of tricalcium silicate - alite. The resulting product is cleaned of metal inclusions by selective grinding of the non-metallic component and extracting it from the mixture by air flow. This method has the following disadvantages: firstly, the method does not include measures aimed at obtaining steel; secondly, the process of saturation of the melt in the temperature range of the formation of tricalcium silicate does not allow to regulate the formation of fusible clinker minerals, which reduces the quality of the resulting cement.

The objective of the invention is to develop a method for the joint production of steel and Portland cement, as well as the development of a process chamber for implementing the method. The solution of these problems will eliminate the disadvantages inherent in the known methods, namely: to obtain steel of a given composition during the implementation of the method, to improve the quality of cement obtained from slag by creating conditions for the formation of low-melting clinker minerals, and also to increase the economic efficiency of steel and Portland cement production by obtaining from one heating of two marketable products.

The problem is solved by the claimed method for the joint production of steel and Portland cement, including liquid-phase reduction of cast iron, adjustment of the chemical composition of the slag melt, saturation of the melt with lime, accelerated cooling of the clinker and its cleaning from metal inclusions. Moreover, the method is characterized in that after the liquid phase reduction of cast iron, impurities are refined, steel is separated from refined slag, carbon refined and deoxidized-alloyed steel. Correction of the chemical composition of the slag melt is carried out in the process of its saturation with lime. At the same time, at least the liquid-phase reduction of cast iron, the refinement of impurities and the refinement of carbon are carried out in one technological chamber, successively creating conditions for the implementation of each process in it. Saturation of the slag melt with lime is carried out, creating conditions in the thickening melt for the formation of first alite and then fusible clinker minerals. The charge of charge materials in the process of liquid-phase reduction is controlled so that the fictitious velocity of the gases leaving the bath is in the range (0.3-1.7) m / s, and the excess slag formed as a result of the recovery is discharged. melting stages are regulated by means of afterburning of exhaust gases in it. In the event of an excess of combustible gases, the excess part is burned out outside the chamber, and in case of their shortage additional fuel is introduced into the chamber.

In special cases, the method is implemented in one technological chamber — the melting chamber — liquid-phase reduction of cast iron is carried out, impurities are refined, carbon refined, and steel is deoxidized and alloyed, and slag melt is saturated with lime in another technological chamber — a saturation chamber. The separation of steel from the refining slag is carried out by the release of slag. All slags involved in saturation are mixed.

In special cases, the method is implemented in one technological chamber — the melting-saturation chamber — liquid-phase reduction of cast iron is carried out, impurities are refined, carbon refined and lime slag is saturated with lime. The separation of steel from the refining slag is carried out after the refining of carbon by the release of steel. Deoxidation-alloying of steel is carried out outside the process chamber.

In particular cases of the implementation of the method, the slag generated during the steel production process is partially or completely directed to accelerated cooling and cleaning of metal inclusions to obtain an active mineral additive for cement as the target product.

In special cases of the method implementation, when the gases leaving the melting chamber are afterburned, additional fuel is introduced into the dust and gas mixture, the content of which in the afterburned mixture varies in the range of 0-100%.

In particular cases of the implementation of the method for the afterburning of the gases leaving the melting chamber, a recovery boiler with liquid slag removal is used, moreover, slag is accumulated before the melt is removed and conditions are created for the reduction of iron contained in the melt. To do this, a reducing agent, flux and iron-containing materials are introduced into the melt, and melt mixing and separate release of cast iron and slag are also organized.

In special cases, the implementation of the method as a liquid phase in the liquid-phase reduction of cast iron, both recycled slag and slag formed in other industries are used.

The problem is also solved by the claimed process chamber for the joint production of steel and Portland cement by the proposed method, made in the form of a lined cylindrical-conical surface with a larger diameter in the central zone along the length. The process chamber is mounted to rotate around a horizontal axis. The technological chamber contains non-rotating inserts introduced into it from both sides to form a supply channel for supplying materials to the chamber, to form a discharge channel for removing dust and gas mixture from the chamber, and to place melting control devices. A gap is formed between the inner surface of the chamber and the outer surface of each insert to supply the gaseous components of the melt to the afterburning zone. A loading hatch, a slide gate for the release of liquid smelting products and a sampling mechanism are installed on the camera body.

In special cases, the implementation of non-rotating inserts made with the possibility of removing them from the chamber for quick replacement when the lining is worn.

In particular cases of implementation, irregularities - lifters are made on the surface of the lining of the chamber.

In particular cases of implementation, the process chamber is made in the form of a chamber selected from the group including a melting chamber, a saturation chamber, and a melting-saturation chamber.

In special cases of implementation, the process chamber is made in the form of a melting chamber, and a shutter system is installed in the outlet channel connecting the chamber to the recovery boiler or steam-jet vacuum pump.

In special cases of implementation, the process chamber is designed as a saturation chamber or a melting-saturation chamber, while a dust collecting unit is installed in front of the recovery boiler.

The essence of the invention is to combine in space and, as far as possible, in time the known physicochemical processes used to produce cast iron, steel and cement clinker.

To obtain steel and cement of a given composition, it is necessary to carry out a certain set of private physicochemical and physical processes. It is impossible to combine all these processes in time. For example, mutually exclusive processes such as oxidative refining and deoxidation cannot be carried out simultaneously. In this regard, the list of necessary private processes is divided into groups in which these processes can occur simultaneously. Thus, groups of private processes known from the prior art that are associated with liquid-phase reduction of cast iron, with the refinement of steel impurities, with the refinement of carbon steel, with the deoxidation and alloying of steel, with the adjustment and saturation of the slag melt, have appeared. In the proposed method, all private technological processes, including those belonging to different groups, are combined in space, that is, sequentially carried out in one technological chamber or in parallel in the same type of technological chambers. This allows you to bring the time of carrying out incompatible operations from different groups as close as possible, and in some cases allows you to group compatible operations in a new way, replacing expensive processes with cheaper ones. For example, if cast iron and steel are successively obtained in the same volume, then alloying elements such as Mo, Ni, Co, etc. can be introduced in the recovery process upon receipt of cast iron, without using expensive ferroalloys at the stage of deoxidation-alloying of steel. Thus, within the metallurgical part of the method, not only steel is obtained, but also cast iron of a given composition.

It is known from the prior art that for liquid-phase reduction, a skull melting chamber is used in which continuous melting companies can be carried out without repairing the lining. However, creating good conditions for melting in such a chamber is difficult. These chambers are characterized by poor heat transfer from the afterburning zone to the melt, high heat loss, insufficient mixing of metal with slag, etc. In addition, a method is known in which melting is carried out sequentially in lined melting chambers rotating around a longitudinal axis. This allows you to create good conditions for smelting, but significantly reduces the duration of the smelting company due to forced stops on the repair of the lining.

In the proposed method, melting is carried out in a rotating lined chamber, and the problem of wear lining is solved by quickly replacing the old chamber with a new one. This becomes possible due to the fact that the release of melting products is carried out not by tilting the camera, as in the known method, but through a slide gate or loading door located on its body. Now the rotation takes place around a fixed horizontal axis. In this regard, the camera drive has been greatly simplified, which means that there is nothing stopping the camera with the worn lining from being removed from the support rollers and installing a new one ready for operation in its place. In addition, the implementation of the melting chamber in a single housing allows you to create a vacuum in it, which greatly expands the range of physicochemical processes used in the method.

It is known from the prior art that a rotating lined surface works well for transferring heat from the afterburning zone to the bath. In this regard, the heating of the chamber is carried out by means of afterburning over the melt of the necessary part of the combustible gases generated in the bath, and in case of their deficiency, additionally introduced fuel. To do this, an oxygen-containing blast is fed into the afterburning zone, the flow rate of which is regulated depending on the amount of heat left in the chamber. In addition, during rotation, the melt is mixed in the bath. Melting in rotary kilns is known in the art, both in metallurgy and in cement production. Thus, heating and mixing of melts of any viscosity, including thickening, are combined in a rotating process chamber. This makes it possible to carry out in one technological chamber all operations related to both the production of steel and the production of clinker. However, from an economic point of view, it is not always advisable to carry out all operations in one chamber. If the method is used in the slag processing mode and the volume of steel obtained is small, then all technological processes, except for deoxidation-alloying of steel, are carried out in one technological chamber - the melting-saturation chamber. In this case, deoxidation-doping is carried out in a casting ladle or automatic gearbox. If the method is implemented within the framework of metallurgical production, in order to obtain a given composition of steel, then two technological chambers are used, namely: a melting chamber and a saturation chamber. In the melting chamber, all processes associated with the production of steel are carried out, and in the saturation chamber, the slag formed during the steelmaking process is processed. This approach allows to increase the volume and range of smelted steel.

Possible designs of the process chamber used to implement the proposed method will be discussed below on the example of some possible preferred, but not limiting forms of implementation with reference to the positions of the figures of the drawings, which are schematically represented:

Figure 1 is a longitudinal vertical section of the process chamber in the working position;

Figure 2 is a section along the line AA of the technological chamber of Figure 1;

Figure 3 - process chamber of figure 1 in the position of the replacement chamber

All cameras used in the method have the same design and differ only in details. The camera body 1 is made of several symmetrically located sections formed by conical and cylindrical surfaces. The central cylindrical section 2 has the largest diameter. It has a loading hatch 3, slide gates 4 and a sampling mechanism 5. Conical sections 6 are located on both sides of the central one, which again turn into lateral cylindrical sections 7 of smaller diameter. On the central cylindrical section 2 are the bandages of the rolling bearings (not shown in the drawings), and on the side 7 - drive crowns of gears (not shown in the drawings). The inner surface of the chamber 1 has a lining 8, which minimizes heat loss through the housing. In particular forms of the method, artificial irregularities are applied to the surface of the lining 8 - lifters (not shown in the drawings) that intensify the mixing of the bath during the rotation of the chamber. On both sides, non-rotating inserts 9 and 10 are introduced into the necks of chamber 1. One insert 9 is a feed, materials are introduced through it, and the other insert 10 is a discharge, a dust-gas phase is removed through it. In private forms, the implementation of the insertion method 9, 10 is performed with the ability to quickly remove them from the camera 1 when replacing the old camera 1 with a new one. So, in accordance with the embodiment of FIG. 3, for the possibility of quick removal of the insert 9, 10 are mounted on the wheeled carts 11. In the feed insert 9 are placed channels and mechanisms for supplying melt, solid materials and blast to the bath (not indicated by positions in the drawings). In addition, insert 9 contains burners for afterburning additional fuel over the melt (not shown in the drawings or not indicated by positions). In the outlet insert 10, a channel is placed through which the dust and gas phase is discharged to a waste heat boiler (not indicated in the drawings). A gap 12 is left between the rotating surface of the chamber 1 and the fixed surface of the inserts 9, 10, through which gaseous components of the melting are fed into the afterburning zone. Position 13 denotes the horizontal axis of rotation of the chamber 1. In addition, position 14 denotes the metal in the chamber 1, and position 15 denotes slag.

The release of liquid smelting products is carried out through a slide gate 4 located on the central cylindrical section 2 of chamber 1. At the same time, by turning the chamber 1, the outlet opening is brought to metal 14 or slag 15, depending on which product is to be let out. To service the slide gate 4, the camera 1 is rotated so that the shutter 4 is in the upper position. In special cases, the implementation of the method, for ease of operation, two slide shutters are installed on the camera body 1, placing them diametrically opposite (not shown in the drawings). In this case, the tinning of one shutter 4 is combined with the release of metal 14 through another.

In private forms of implementing the method, when it is necessary to remove all refining slag containing harmful impurities, a vacuum installation is used. After the maximum possible slag discharge, a nozzle connected to the vacuum chamber is introduced into the melting chamber. As a result of the movement of this pipe in the slag layer, the less dense slag is finely removed from the metal surface.

The process of sampling from the chamber is mechanized. The sampling mechanism 5 is installed on the cylindrical section 2 of the housing of the process chamber 1. The operator brings the sampling mechanism 5 to the place where the melt must be taken. At the command of the remote control, the melt is sucked into the intake, similar to how a syringe draws medicine. The melt drawn into the receiver passes through the window of the refrigerator, which, shifting, cuts the sample from the retracted melt cylinder. The sample is pushed out of the refrigerator window into the container with a gas stream, and the refrigerator frame returns to its original position, passing the rod of the intake, which, moving in the opposite direction, pushes the unused melt back into the chamber.

The supply of solid materials to the chamber, depending on its fractional composition, is carried out by pipelined pneumatic transport or chute. At the same time, oxygen-containing blast, neutral gas or other gas mixtures are used as a transporting medium, depending on the conditions created in the chamber.

If it becomes necessary to replace the chamber 1 due to significant damage to the lining 8, non-rotating inserts 9.10 are removed from the necks of the chamber 1 located on the lateral cylindrical sections 7 by moving the wheeled carts 11, the chamber 1 is replaced and the non-rotating inserts 9, 10 are introduced again by the wheeled carts 11, 10 into the newly installed camera 1.

The melting chamber, in contrast to the saturation chamber and the melting-saturation chamber, has wider possibilities for creating the required working pressure and atmosphere composition in it. In the outlet channel for controlling the dust and gas flow, a shutter system is installed that allows you to connect the chamber to both the recovery boiler and the steam-jet vacuum pump, depending on the conditions created in it. In private forms of implementation, the gates do not just close and open the channel, but allow throttling the exhaust gas stream. Depending on the conditions created in it, oxygen-containing blast, a neutral gas, or a mixture of neutral gas and technical oxygen are fed through the side (end) slots 12 into the melting chamber, depending on the conditions created therein.

When creating a vacuum in the melting chamber, the end slots 12 are closed by cuffs that block the access of air to the chamber 1, but do not exclude its rotation. In special cases, an inert gas overpressure is created at the outer surface of the cuffs. This allows, on the one hand, to press the cuff more tightly against the chamber body, and on the other hand, in case of suction, it will fill the chamber with inert gas, but not air. In addition, when evacuating, the supply and exhaust channels in the inserts 9, 10 are closed, and the slide gates 4, the sampling mechanism 5, and the loading hatch 3 are not compacted, since they become impermeable to gas during rotation and interaction with the melt.

The saturation chamber and the melting-saturation chamber have a different set of mechanisms placed on the feed insert 9 and the housing of the chamber 1. The cameras are equipped based on the operations that they perform. So, for example, on the saturation chamber housing, a gate for the release of liquid products is not installed melting, and on the feed insert there is no channel for supplying ferrometals. However, unlike the melting chamber, a dust collecting unit is installed in front of the recovery boiler and the melting-saturation chamber. Its installation greatly facilitates the working conditions of the recovery boiler. In addition, when removing hot gases from dust, such components as Na ₂ O, K ₂ O, ZnO, PbO, etc. sublimate and easily pass the dust collecting unit, while the remaining components are separated. Thus, the more conventional particles are recovered in the dust collector, the higher will be the concentration of sublimated components in the mixture, which is delayed after cooling in the aspiration system. Mixtures with a high concentration of sublimated components are sold on the market as raw materials for further processing, and a mixture with a lean sublimation content is sent to accelerated cooling to obtain an active mineral additive.

The dust and gas phase remaining after the afterburning in the melting chamber is taken to a recovery boiler for complete afterburning and heat recovery. At the same time, in special cases of implementation, the recovery boiler provides steam to the generator’s turbine and steam jet vacuum pump. In order to ensure constant regular operation of the turbine and periodic operation of the vacuum pump, additional fuel is introduced into the dust and gas mixture before afterburning. Steam coal is used as additional fuel, fuel oil, natural gas, etc. The introduction of additional fuel stabilizes the thermal operation of the boiler, making it independent of the amount of physical and chemical heat coming from the melting chamber. So, with intensive purging of the bath with oxygen, the exhaust gases can receive such an amount of physical and chemical heat that the introduction of additional fuel is not required, and its content in the re-burned mixture will be 0%. And when creating a vacuum in the melting chamber, the boiler is separated from the chamber by a shutter, and it works autonomously, consuming 100% of additional fuel. Thus, the content of additional fuel in the afterburned mixture during the smelting process varies in the range (0-100)%. This allows us to ensure at all stages of the smelting continuous regular operation of the turbine of the electric generator and the periodic operation of the steam-jet vacuum pump. Obtaining in the smelting process of secondary energy resources makes it possible to fully compensate for the cost of electricity for the production of oxygen and argon used in the method.

In the proposed method, liquid phase reduction is used. In this regard, to start melting in the melting chamber, you must have a melt. When using the method for the first time, the initial melt is obtained by melting the charge mixture by burning additional fuel in the chamber. With the further use of the method, reverse slag or slag obtained from other industries is used as the initial melt. In this description, slag is called negotiable, which is formed as a result of the implementation of the method. This may be the slag formed in the melting chamber, the waste heat boiler, etc.

Coal, coke, semi-coke, thermocoke, shale, peat, fly ash of thermal power plants (TPPs) operating on coal, wood, etc. are used as a metal and fuel reducing agent. When fuel is introduced into the melting chamber under the influence of temperature, it is divided into coke residue and volatiles. The coke residue is kneaded into the melt, where it participates in the reduction and carburization of cast iron, and the volatile and CO formed in the melt enter the afterburning zone above the bath. To replenish the incoming part of the heat balance, a partial or complete afterburning of the gas mixture above the bath is made. In this case, the open surface of the chamber is heated, which, as a result of rotation, goes under the melt, giving it heat. When using fuel with a low volatile content, combustible gas is additionally introduced into the afterburning zone. If the fuel has a high volatile content, then it is preliminarily degassed, obtaining fuel with a given volatile content and associated gas.

The iron ore, mill scale, scrap, melts of ferrous slags, melts of substandard cast irons and steels, dump slags, dust from an air-cleaning system, etc. are used as iron-containing raw materials in the method. These materials are used individually or as part of a mixture of iron-containing materials.

The charge mixture includes iron-containing materials, a reducing agent and flux. The charge mixture is fed into the melting chamber by pneumatic transport or another channel through the feed insert. When loading the mixture by pneumatic transport, various gases or gas mixtures are used. The choice of gas mixture depends on the conditions created in the chamber. At the recovery stage of smelting, oxygen-containing blast is used as transport, which allows partially transferring the sulfur contained in the charge to the gas phase, and when feeding materials at the deoxidation-doping stage, inert gas is used as transport in order not to increase the partial pressure of oxygen in the chamber. In those cases when the materials cannot be introduced through the feed insert, they are introduced through the loading hatch.

During metallurgical smelting, foam is formed due to the exit of the gas phase to the surface of the melt. The foam mode promotes the activation of heat and mass transfer processes, and also reduces the dust removal of charge materials from the chamber, working as a filter. The charge supply to the chamber is controlled so that the foam on the surface of the melt is not bubbling, that is, separate bubbles, and does not pass into the spray when the gas phase begins to destroy the foam. The foam mode is estimated by the fictitious velocity of the gases leaving the melt. It is defined as the second volumetric flow rate of gas, referred to the area of the melt mirror. In the process of filling the cylindrical melting chamber with the melt, the area of the mirror of the melt increases, which leads to a decrease in the fictitious speed. In this regard, to increase the productivity of the unit, the charge of charge materials as the chamber is full is increased so that the fictitious velocity of the gases leaving the bath is always in the range (0.3-1.7) m / s. In this case, the dust and gas channel phase to the waste heat boiler, must ensure the passage of a given volume of gas without increasing the pressure in the chamber above 150 kPa. Exceeding the specified pressure in the chamber leads to increased wear of the equipment.

Since the method generally uses iron-containing raw materials that have not undergone deep enrichment, more than metal is formed in the process of slag reduction. In this regard, the excess slag formed during the liquid-phase reduction process is periodically discharged. When carrying out liquid-phase reduction of cast iron in the melting chamber, the supply of charge materials is performed until the melt volume in the chamber reaches the maximum permissible value. After the release of excess slag, reduction smelting is continued until a predetermined volume of cast iron is recovered. When a predetermined volume of cast iron is recruited, excess slag is discharged and proceed to refinement of impurities. In this regard, it should be noted that in the process of liquid-phase reduction of cast iron in the chamber, favorable conditions are created for the conversion of sulfur from cast iron to slag.

During refining, excess impurities and carbon are removed from the iron-carbon melt for a given steel composition. This is usually done by oxidizing them. In this regard, the process is often called oxidative refining. In the prior art, the broader name “Refining” is used, since in addition to oxidative refining, for example, copper sulfide refining is used, etc. An important factor determining the intensity of refining is the condition for the interaction of metal and slag. In the proposed method, refining is carried out under conditions of joint mixing of metal and slag in a rotating chamber. Thus, favorable conditions for refining are created, and it passes intensively, almost in a washing regime.

Grouping simultaneously performed private physicochemical processes, refining is divided into two stages: refining of impurities and refining of carbon. After refining the impurities, the metal is separated from the refining slag. This is done so that the phosphorus contained in the slag does not transfer back to the metal. If steel is left in the chamber for deoxidation-alloying, the slag is discharged after refining impurities in order to use the heat generated during the refining of carbon to form new slag. If the deoxidation-alloying of steel is carried out outside the chamber, then it is released after the specified carbon content is obtained, that is, after carbon refining.

For oxidative refining of impurities, oxygen is supplied to the bath. To increase the basicity of the slag and reduce the evaporation of the metal in the zone of contact with oxygen, lime is introduced into the oxygen stream. The presence of highly basic oxidized slag in the melting chamber is an indispensable condition for the removal of phosphorus from the metal and its retention in the slag. The temperature regime at this stage is regulated by the flow of oxygen into the metal. If the intensity of the supply of blast into the bath is high, then the afterburning in the chamber of the resulting CO is not performed.

Carbon refining is also carried out by oxidizing it. The oxidation is carried out by blast oxygen or a solid oxidizing agent, that is, due to the reduction of iron oxides. In the first case, the bath gains heat, and in the second, it loses. Another way to oxidize carbon is to supply oxygen not to the melt, but to the afterburning zone with intensive mixing of the bath during rotation. In this case, irregularities in the lining trap oxygen and carry it into the bath. Such oxidation is referred to as blast oxidation, where the oxygen supply can be minimal and dosed by the speed of the chamber. Depending on how much excess carbon needs to be removed from the metal, a plan for its oxidation is determined, which uses all of the above methods of oxygen delivery. At the same time, they begin to oxidize carbon with blast into the melt, and end with the reduction of iron oxides in the slag.

In parallel with the oxidation of carbon, slag is prepared for deoxidation-doping. At the same time, they try to maximize the use of heat generated during the oxidation of carbon. A feature of the new slag is that it should work at low partial oxygen pressures in the chamber. Under these conditions, the iron contained in the slag is reduced, the melting point of the slag increases, and it thickens. To prevent this, Al ₂ O ₃ is introduced into the slag as a diluent. Alumina is introduced in the form of bauxite, fireclay, aluminum slag, etc. In addition, if thermal conditions allow, materials are introduced into the new slag for direct alloying of the metal with elements such as Mn, Cr, etc. In this regard, an important condition for carrying out this stage of smelting is compliance with the temperature regime. When carbon is oxidized, the melting point of the metal increases. That is, in order for the metal to remain liquid, it is necessary to increase the temperature of the bath as carbon is removed from it. In addition to heating the bath, thermal energy is spent on the oxidation of carbon by a solid oxidizing agent, on heating the input materials, etc. In this case, the main heat in the bath comes from the oxidation of carbon by blast. Moreover, not all carbon is oxidized. The part of carbon determined by the task should remain in steel, and the other part is reserved for direct alloying and vacuum-carbon deoxidation. Thus, in the case of a lack of carbon in the metal, the incoming part of the heat balance is replenished with the heat generated during the combustion of additional fuel. For this, burners are used, which are located on the feed insert. In this case, heat transfer from the afterburning zone to the bath occurs not through slag, but through the lining as a result of rotation of the melting chamber. This is important in conditions where the slag due to its high content of chromium oxide or other oxides introduced for direct alloying is temporarily inactive and prone to foaming.

As the supply of blast decreases and stops in the melting chamber, reduction processes begin, which lead to a decrease in the partial pressure of oxygen, and, as a result, to slag deoxidation. The stage of deoxidation-alloying begins. Joint mixing of metal with deoxidized slag reduces the oxygen content in the metal. However, in the vast majority of cases, a significantly lower gas content in the iron-carbon melts is required. In this regard, the proposed method uses vacuum-carbon and precipitating deoxidation.

Upon receipt of unalloyed steels of usual quality, deoxidation is carried out in a casting ladle during metal production or in automatic gearboxes. If precipitating deoxidation is carried out in the melting chamber, then the deoxidizing agent is usually introduced into the pre-deoxidizing bath without interrupting the rotation of the melting chamber. In this case, the deoxidizer may be in the role of an alloying element. Therefore, in the prior art, this stage is called "deoxidation-doping." For deoxidation, Mn, Si, Al, V, Ti, etc. are used. In private forms of implementing the method, the introduction of deoxidants into the melt is carried out by a special mechanism, which is placed in the feed insert.

The manufacture of the melting chamber in a single housing allows you to organize a vacuum in it in the range (0.001-100) kPa. A higher vacuum is not used, since its achievement significantly complicates the design of the unit. The decrease in pressure in the chamber allows you to expand the list of physicochemical processes used in the method due to vacuum-carbon deoxidation, increased decarburization of the metal, direct alloying, etc.

Vacuum-carbon deoxidation consists in the fact that by lowering the partial pressure of CO in the melting chamber, the reaction [C] + [O] = {CO} is shifted to the right, that is, conditions are created for the removal of oxygen from the metal. Partial pressure is reduced both by creating a vacuum in the chamber and by replacing the atmosphere in it with an inert gas. In addition, the proposed method uses a combined method of conducting vacuum-carbon deoxidation, including creating a vacuum in the chamber, followed by filling it with an inert gas. This allows, on the one hand, to reduce the evaporation of iron during the evacuation process, and on the other hand, it makes it possible to more precisely control the composition of the new atmosphere in the melting chamber.

Increased decarburization of the metal is carried out in several stages. First, the partial pressure of CO is reduced in the melting chamber to shift the reaction [C] + [O] = {CO} to the right, and then a gas mixture of oxygen and inert gas is introduced into the chamber to carry out the carbon oxidation reaction at a lower partial pressure of CO.

Direct doping consists in shifting the reaction (MeО) + [C] = {CO} + [Me] to the right by lowering the partial pressure of CO in the melting chamber, i.e. restore the alloying element, which under normal conditions is not restored. In this case, direct alloying is carried out in a chamber filled with an inert gas so that the CO released during the metal reduction does not worsen the vacuum.

The mass of alloying components introduced into the iron-carbon melt by direct alloying is limited by the carbon content in the metal. Therefore, in the production of high alloy steels, the traditional method of introducing alloying components with ferroalloys is used. For this, a ferroalloy feed mechanism is located on the feed insert. In private forms of implementation, a pneumatic chute is used for this purpose, and an inert gas is used as a transporting medium. In addition, the pneumatic chute is also used to introduce some charge materials that cannot be introduced into the melting chamber by pipeline pneumatic transport. When introducing a large number of alloying components, the bath is thermally balanced by burning additional gas fuel.

In private forms of implementing the method, in order to maximally separate the metal from the slag upon release, the slag is thickened. To do this, lime is additionally introduced into the slag. After the slag has thickened, the melting chamber is turned with the slide gate down and the metal is released without fear that the slag will fall into the ladle. The slag remaining in the melting chamber is circulating and proceeds to the next metallurgical cycle.

In private forms of implementing the method, deoxidation-alloying is carried out in a casting ladle. For this, the bucket is closed with a lid with a receiving pipe. Inert gas is pumped under the cover. As the bucket is filled, a deoxidizer is introduced into the metal. In this case, the inert gas is displaced from the bucket and rises along the pipe towards the metal, protecting the metal stream from oxidation. After the bucket has taken all the metal, the inlet is closed and an inert gas is supplied under the lid to create a slight overpressure. This allows you to protect the metal from oxidation and evaporation during its movement to the place of subsequent processing.

In private forms of implementing the method, when the chamber is heated in a neutral gas environment, the combustion products are sent not to the recovery boiler, which at this moment is working autonomously, but to the dust collector of the steam-jet vacuum pump. At the same time, the exhaust gases do not enter the steam-jet vacuum pump, but go through another channel to the aspiration system, where they are burned and cleaned. To do this, a shutter system is installed in front of the vacuum pump, which allows directing the exhaust gas stream to the steam jet vacuum pump or to the suction system, depending on the conditions created in the chamber.

In private forms of implementing the method, after the release of metal from the smelting chamber, inspection and restoration of the lining are performed. If foci of destruction of the lining are found, then a shotcrete mixture is applied to them. Through the feed insert, a nozzle is introduced into the chamber for feeding material, and the chamber is turned defect to the nozzle. After the focal violations of the lining are eliminated, a dust cloud is created in the melting chamber from the materials included in the repair mixture. As a result of the rotation of the melting chamber, refractory materials settle on the lining. This can significantly extend the life of the camera until it is replaced.

In special cases, the implementation of the method using a recovery boiler with liquid slag removal. In this case, the slag is not immediately removed, but left in the drive, where they create conditions for partial or complete reduction of the iron contained in it. The main amount of iron enters the waste heat boiler in the form of dust extractor from the melting chamber during liquid-phase reduction, when an iron-containing mixture is introduced. To reduce iron, a reducing agent, flux, and iron-containing materials are fed into the storage ring and the melt is mixed. The volume of the drive is calculated so that the production of pig iron and slag is performed once per metallurgical cycle. The reduction of iron in the recovery boiler allows you to additionally obtain cast iron, which is introduced into the melting chamber at the recovery stage of smelting and slag of a given composition, which is used in the production of cement and an active mineral additive for it.

In private forms of implementing the method, the melt is fed into the chamber through a channel located on the feed insert. At the same time, a bucket or feeder is used to raise the melt into the channel, in which excessive pressure is created. The input of the melt through the feed insert is produced without interrupting the rotation of the melting chamber, that is, during the melting process.

In private forms of implementing the method for the involvement in the production of materials that cannot be loaded into the chamber through the feed insert, use the loading hatch located in the Central part of the chamber. Large volumes of melt, large scrap, etc. are introduced through the hatch. This allows you to expand the list used in the method of materials and reduce the time of loading.

In the proposed method, the saturation process is carried out both in the saturation chamber and in the melting-saturation chamber. The saturation process includes the following particular processes: the introduction of corrective additives into the initial melt, the formation of alite and the formation of low-melting minerals. The composition is adjusted by introducing additives that regulate the content of Fe ₂ O ₃ and Al ₂ O ₃ into the melt. Carrying out the adjustment of the composition during the saturation process allows, on the one hand, to reduce the melting time, and on the other hand, makes it possible to use the introduced materials to optimize the temperature regime.

In particular cases of the implementation of the method, the initial slag is obtained by mixing the slag formed in the process of steel production. The averaged melt is divided into two parts in accordance with the production necessity. One part of the slag is sent for accelerated cooling in order to obtain an active mineral additive, and the other part is sent for saturation.

Before saturation, the melt has a temperature that is maintained based on the carbon content in the steel. In this case, the initial slag melt already contains lime, which is used as a flux in steel production. Introducing new lime and mixing the melt leads to the formation of dicalcium silicate - belite, which, interacting with free lime, forms tricalcium silicate - alite. To activate the process of alitization, the melt temperature is kept in the range (1350-1500) ºС depending on the composition of the raw material mixture. At temperatures below the specified range, the formation of alite is delayed, and exceeding the specified range unreasonably increases the energy consumption for the implementation of the method. The formation of minerals is accompanied by heat. To the melt temperature does not go beyond the specified temperature range, corrective additives are introduced. Thus, the introduction of corrective additives allows not only to replenish the raw mix with the missing components, but also to optimize the temperature regime of the alite formation process. If the melt temperature is below the specified range, the melt is heated by introducing fuel into the melting chamber. When using solid fuel, its mineral part remains in the raw mix, adjusting the content of the main components. The duration of the alite formation process is determined by the composition of the mixture and is in the range (10-30) minutes. The completion of the synthesis of alite is judged by the decrease in the heat generated in the chamber.

In order to activate the formation of fusible minerals - tricalcium aluminate and tetracalcium aluminoferrite, the raw material mixture is cooled to a temperature at which these minerals are formed. Typically, the temperature of the melt is kept in the range (1150-1350) º C. If the specified range is exceeded, the process of smoothing formation is delayed, and with a decrease, the decomposition of alite begins. To cool the mixture, limestone is introduced into the saturation chamber. As a result of the endothermic decarbonization reaction, the temperature of the mixture decreases, and the resulting lime is involved in the synthesis of fusible minerals. It should be noted that when cooling the raw material mixture, the temperature of the lining decreases slightly, since the clinker has low thermal conductivity, and the main cooling occurs in the foci on the surface of the limestone. As the formation of fusible minerals, the volume of the liquid phase in the melting chamber decreases. Thus, in order to obtain the specified mineralogical composition of clinker, the smelter determines the moment of unloading clinker into the refrigerator by the volume of the liquid phase remaining in the mixture. If you release the clinker earlier, then the product will have more glass and less fusible minerals, and if you delay the release, the alite decomposition process may begin and free lime will appear in the clinker.

The rotation of the chamber around the horizontal axis leads to the formation of clinker balls in it, similar to those obtained in traditional cement kilns. To unload clinker into the refrigerator, the loading hatch located in the central part of the chamber is opened, the chamber is turned with the hatch down and, swinging it, all the material is released into the refrigerator.

A clinker final cooling refrigerator is located in close proximity to the melting chamber in order to accelerate the start of controlled cooling of the product. Cooling is done by air flow. To obtain a given mineralogical composition of clinker, (0-30)% steam is added to the cooled air. The introduction of steam of more than 30% leads to corrosion and equipment failure in the dust cleaning section.

After accelerated cooling, the clinker and the active mineral additive are cleaned of metal inclusions. To do this, in accordance with the specified parameters of the cement, a mixture is formed, which includes clinker, an active mineral additive and gypsum. Cleaning is carried out in the process of selective grinding of the cement mixture. As a result, the entire non-metallic component of the mixture is transferred to the dust fraction (0-0.08) mm and is extracted by controlled air flow into a volume with pure material, and the denser and not crushed metal remains in the crushing and grinding equipment until the ceramics are completely separated. Cement purified from metal is sent to the consumer, and the metal is returned to the melting chamber for liquid-phase reduction.

Further, the above and other advantages and advantages of the proposed method will be illustrated by some possible, but not limiting examples of its implementation using the inventive process chamber.

Example 1. The preparation of steel 08 [7].

The melting chamber 1 has a cylindrical-conical shape (central cylindrical 2, conical 6 and side cylindrical 7 sections (parts)), lined with magnesite lining 8. The inner diameter of the central cylindrical part 2 of chamber 1 is 3.3 m. The length of the central cylindrical part 2 of the chamber 1 along the lining - 5.2 m. The diameter of the necks (lateral cylindrical sections 7) through which inserts 9, 10 are introduced is 1.25 m. The outer diameter of the inserts 9, 10 is 1.15 m. The mass of the melting chamber without melt is 115 tons Permissible melt volume that may be present chamber - 12.9 m ³ .Plavilnaya camera 1 is rotated about a horizontal axis 13 onto the support rollers. The frequency of rotation of the melting chamber 1 during the melting process is changed in the range (0-30) rpm. Four symmetrically located actuators set the rotation, which are synchronized during the operation of hydraulic couplings. Torque is transmitted through two gears symmetrically located relative to the center of the chamber (the drive is not shown in the drawings).

After the previous smelting, 4.9 tons of recycled slag remains, which temperature is 1450 ° C. In addition, 1.82 tons of pig iron obtained in the storage of the waste heat boiler during the previous metallurgical cycle are introduced into the melting chamber through the channel located in feed insert 9. . The temperature of the injected iron is 1450 ° C. The melt thus obtained is used to start liquid-phase reduction. Smelting reduction is conducted at a melt temperature of ^about 1450 C. As the iron-containing material is a mixture consisting of 70% iron ore - Fe _tot = 58%, 20% mill scale - Fe _tot = 71% and 10% metallic fraction of beads (0-10 ) mm, which are the product of air-gravity cleaning of waste slag. The crushed ore and scale are fed into the melting chamber by pneumatic transport together with a reducing agent and flux, and metal fines are fed simultaneously with the charge during the entire reduction melting through the channel located in the feed insert 9 and intended for introducing ferroalloys. In total, 107.82 tons of iron-containing mixture are fed into the melting chamber during the reduction smelting process. In addition, as the charge materials in the melting chamber 1 is introduced coal grade "T" - 34.77 tons and lime -13.24 tons. Fractional composition of non-metallic charge materials (0-5) mm. The flow rate of the input materials is controlled so that the fictitious velocity of the gases leaving the bath is in the range (0.3-1.7) m / s. In this case, the foam on the surface of the bath does not go into spray mode, but uniformly covers the entire melt mirror. When the melt volume in the chamber reaches the maximum permissible value, the melting is interrupted. The outlet of the slide gate 4 is set above the metal level and the slag located in the melting chamber is discharged. After the slag is discharged, smelting is continued. In total, 36.27 tons of slag are obtained during the liquid phase reduction process. At the same time, 4.1 tons of slag are left in the chamber for oxidative smelting, and 32.17 tons of slag are discharged. At the end of reduction smelting, 69.8 tons of cast iron are accumulated in the melting chamber, the composition of which is given in Table 1. To gain this volume, smelting is interrupted three times. The total time of reduction smelting, taking into account stops for slag discharge, is 3.97 hours. To maintain the heat balance, part of the gases generated in the melting chamber is burned. To do this, technical oxygen is introduced into the afterburning zone through the slots 12 between the rotating surface of the chamber 1 and the side inserts 9, 10 15147 nm ³ . At the same time, 75.13 tons of gas and 2.98 tons of dust are discharged from the melting chamber to the recovery boiler. The degree of afterburning of the exhaust gas by carbon components is 44.09%. The temperature of the outgoing dust-gas mixture - 1615 ^of S.Pered afterburning in a waste heat boiler in the mixture is further added 11% coal. The result is 8,8MPa steam pressure, temperature 535 ^C and a flow rate of 82 t / h. This steam is enough for the regular operation of an electric generator turbine with a capacity of 21.3 MW. In order to reduce the loss of metal and obtain slag of a given composition in the boiler storage, conditions are created for the reduction of iron. For this purpose, a lime-carbon mixture is introduced into the storage ring and induction mixing of the melt is organized. The reduction products — slag and cast iron — accumulate during the entire metallurgical cycle, and are released at the oxidative stage of smelting, when the melt has the smallest input. In this example, 1.82 tons of pig iron and 9.63 tons of slag are obtained for the entire metallurgical cycle in the boiler drive.

When oxidative refining of impurities in the bath serves oxygen - 1159 nm ³ . The purge time is 550 s. In order to reduce the formation of brown smoke, lime is introduced into the oxygen stream - 1.93 tons. As a result of purging and intensive mixing of the bath, slag is formed into which the removed impurities pass from the metal. At the same time, 6.73 tons of slag and 68.09 tons of steel remain in the melting chamber, the composition of which is indicated in table1. To maintain thermal balance, 106 nm ^{3 of} oxygen is supplied to the afterburning zone. In the process of oxidative refining of impurities, 0.26 tons of dust and 2.56 tons of the gas phase, with a degree of afterburning over carbon components of 12%, are discharged from the melting chamber. The temperature of the dust and gas mixture leaving the waste heat boiler is 1590 ° C. Before the afterburning, 14% of the coal is introduced into the mixture. This allows you to ensure regular operation of the turbine of the generator. The refinement of impurities is completed by the release of slag. It is difficult to release all the slag, so about 10% of the slag is forced to remain in the melting chamber. Vacuum slag pumping is not used in this example.

In the next stage, the smelting process refining carbon and preparing slag for deoxidation-doping. At the beginning, carbon is oxidized by blasting. For this, 1863 nm ³ oxygen is supplied to the bath. In order to use the heat generated in the bath, slag-forming components are introduced in parallel, namely: 3.97 tons of lime and 1.78 tons of bauxite. Bauxites contain Al ₂ O ₃ - a fluidizing component in deoxidized slag. In addition, materials are added to the slag, which will be restored at the stage of deoxidation-alloying. In this example, for direct alloying contribute 0.58 tons of manganese ore. After a predetermined amount of blast has been supplied to the bath, its supply is stopped, and oxidation continues due to the reduction of iron oxides contained at that moment in the slag. To maintain thermal balance, 581 nm ^{3 of} oxygen is supplied to the afterburning zone. At the same time, 0.12 tons of dust and 5.62 tons of the gas phase, with a degree of afterburning over the carbon components of 30%, leave the melting chamber. The temperature of the dust and gas mixture is 1710 ° C. Before burning in the recovery boiler, 12% of coal is introduced into the mixture. This allows you to ensure regular operation of the turbine of the generator. After this step, 66.49 tons of steel remain in the melting chamber, the composition of which is shown in Table 1 and 6.33 tons of deoxidized slag.

To carry out deoxidation-alloying with a shutter system located in the outlet channel, the melting chamber is separated from the recovery boiler and connected to a steam-jet vacuum pump. The recovery boiler at this time works offline. In order for the boiler to ensure the regular operation of the turbine of the electric generator and the steam-jet vacuum pump, 3.4 tons of coal are fed into the furnace. The vacuum pump reaches a residual pressure in the chamber of 50 Pa after 1152 s. During evacuation, all hydrogen and, partially, nitrogen and oxygen are removed from the steel. After reaching a predetermined residual pressure, the shutter connecting the melting chamber to the steam jet vacuum pump is closed. When discharged in the melting chamber, conditions are created for the reduction of manganese ore from slag - direct alloying and vacuum-carbon deoxidation. To reduce the evaporation of the metal, the smelting chamber is filled with argon and again connected to a recovery boiler. However, the shutter is not fully opened. In order to preserve the atmosphere of argon in the melting chamber, it is fed through the side slots 12 at a low flow rate. For the final precipitation deoxidation and alloying 0.25 tons of ferrosilicon and 0.01 tons of aluminum are introduced into the bath. To replenish the incoming part of the heat balance and preheat the metal to a predetermined temperature before discharge, 162 m ^{3 of} natural gas is fed into the afterburning zone, which is mixed with oxygen in a gas burner. After carrying out all the processes associated with deoxidation-alloying, 67 tons of steel remain in the melting chamber, the composition of which is given in Table 1 and 5.9 tons of slag. In order to prevent slag from entering the ladle, it is thickened. Before thickening, 1.83 tons of excess slag are produced. 0.63 tons of lime is fed into the remaining slag. Lime is served by pneumatic conveying. Argon is used as a transport. When mixing, the slag thickens, and the metal is released into the ladle, without fear that the slag will fall into the metal. When released from the melting chamber, the metal is protected from oxidation by an inert gas.

Before the next melting begins, the lining is inspected using cameras located on the side inserts 9.10 for this. If foci of destruction of the lining are found, then a shotcrete mixture is applied to them. After the focal violations of the lining are eliminated, a dust cloud is created in the melting chamber from the materials included in the repair mixture. To do this, 0.53 tons of dry repair mixture are introduced into the chamber through the nozzle. During the rotation of the melting chamber, the dust partially settles and is fixed on the lining, and partially replenishes the thickened slag located in the melting chamber. After carrying out preventive measures, 4.9 tons of slag remains in the melting chamber, which transfers to the next metallurgical cycle. In the process of all smelting, when necessary, take samples of metal and slag. Sampling from the chamber is performed using the mechanism 5 for sampling.

During the entire metallurgical cycle, 49.69 tons of slag are released from the smelting chamber and the recovery boiler. All the resulting slag is processed into Portland cement clinker. For this, the slag obtained during the metallurgical cycle is divided into three portions of 16.56 tons each. The composition of the averaged slag is shown in table 2.

The saturation chamber is lined with chamotte and has a cylindrical-conical shape (central cylindrical 2, conical 6 and lateral cylindrical 7 sections (parts)). The inner diameter of the central cylindrical part 2 of the chamber 1 is 3.3 m. The length of the central cylindrical part 2 of the chamber 1 along the lining is 8.0 m. The diameter of the necks (lateral cylindrical parts 7) through which inserts 9, 10 are inserted is 1.25 m The outer diameter of the inserts 9, 10 is 1.15 m. The mass of the melting chamber is 152 tons. The permissible melt volume that can be in the chamber is 23.0 m ³ . The camera 1 rotates around an axis 13 on the support rollers. The frequency of rotation of the chamber 1 is regulated in the range (0-30) rpm. Four symmetrically located drives set the rotation, which are synchronized during the operation of hydraulic couplings. Torque is transmitted through two gears symmetrically located relative to the center of the chamber. In the central part 2 of the chamber 1 there is a hatch 3 for loading the melt and unloading the clinker into the refrigerator. The refrigerator is placed directly under the saturation chamber. Cooling is carried out by a stream of air in a fluidized bed. The outlet channel of the saturation chamber and the outlet channel of the refrigerator are connected into one channel in the waste heat boiler. Next, the dust-gas mixture enters the aspiration system. In this regard, the camera and the refrigerator work alternately. While loading new material into the saturation chamber, the refrigerator cools the previous batch of clinker. The temperature of the lining of the chamber before loading the material is 1300 ° C. To start the process, 12.2 tons of lime and 1.3 tons of iron ore are introduced into the rotating melting chamber 1 through the feed insert 9. As a result of rotation of the melting chamber 1, the material is heated to the temperature of the lining. At this point, clinker cooling in the refrigerator is completed. The discharge channel is switched to the saturation chamber. A portion of the slag melt is introduced into the chamber. To heat the chamber 1, 1.58 tons of coal are fed into it, and 2226 nm ^{3 of} oxygen and 917 nm ^{3 of} air are introduced through the side slots 12. Including air conveying. As a result of fuel combustion and the formation of clinker minerals, the mixture is heated to 1420 ° C. The synthesis of alite and belite lasts 25 minutes. After this time, the temperature in the chamber begins to decrease. To start the synthesis of fusible minerals, the mixture is forced to cool. To do this, 5.91 tons of limestone are introduced into the chamber. As a result of the endothermic decarbonization reaction, the temperature of the mixture decreases to 1300 ° C. As a result of saturation of a portion of the melt with lime, 33.53 tons of clinker are obtained. Clinker is released into the refrigerator when about 3% of the liquid phase remains in the chamber. The composition of the clinker is shown in table 3. To unload it, open the hatch 3 located in the central part 2 of the chamber, turn the chamber with the hatch down and, swinging the chamber, release the material into the refrigerator. The total time taken to saturate one portion of slag is 1.57 hours. The clinker cooling time in the refrigerator is 0.27 hours. This time is not taken into account when calculating the processing time, since during the cooling of clinker in the refrigerator to the melting-saturation chamber already pour the next batch of melt. The time spent on saturation of all slag obtained during the metallurgical cycle is 4.72 hours, and the time of the metallurgical cycle is 5.45 hours.

Thus, in the considered example, 67 tons of steel 08 [7] and 100.6 tons of Portland cement clinker were obtained saturation coefficient KH = 0.91, silicate modulus n = 1.63, alumina modulus p = 1.65 [9]. In addition, during the entire metallurgical cycle, a dust collection system located behind the waste heat boiler of the melting chamber detained 3.36 tons of fly ash. Fly ash contains 7.8% K ₂ O and is marketed as fertilizer. In addition, during the entire metallurgical cycle, the regular operation of the turbine with an electric capacity of 21.3 MW was ensured. As a result of this, 116085 kWh of electricity was produced. The resulting energy was directed to the production of oxygen used in the method. In the smelting process, technical oxygen is used in a volume of 21474 nm ³ with a maximum consumption for reduction smelting of 4000 nm ³ / h. Its production requires 10,000 kWh. electricity. Thus, the method provides the reproduction of oxygen and argon used in the method, and the nitrogen formed during the production of oxygen is sold on the market.

Table 1 The dynamics of changes in the composition of the iron-carbon melt during the smelting process

Si Mn Al S P C After liquid phase recovery 0.05 0.05 0 0.02 0.06 4.49 After refining impurities 0 0 0 0.01 0.008 3,092

After carbon refining 0 0 0 0.008 0.005 0.213 After deoxidation - alloying 0.28 0.48 0.001 0.003 0.006 0,085

Table 2 The composition of the mixture of slag obtained in the melting process

FeO SiO ₂ Al ₂ O ₃ Cao MgO MnO Na ₂ O K ₂ O TiO ₂ S P ₂ O ₅ 1.46 33.61 13.67 48.59 1.60 0.13 0.07 0.14 0.52 0.19 0.03

Table 3 The composition of clinker obtained in the process of saturation of slag.

FeO SiO ₂ Al ₂ O ₃ Cao MgO MnO Na ₂ O K ₂ O TiO ₂ S P ₂ O ₅ 4.66 20.15 7.68 65.64 0.84 0,07 0.05 0.11 0.28 0.49 0.04

Example 2. Obtaining steel 08 [7] and Portland cement in the process of processing slag coming from electric arc steel furnaces (DSP).

During the oxidative refining of steel in the particleboard, slag is formed, which contains a large amount of iron (see table 4). Sending this slag to the dump leads to the loss of a significant amount of metal and an increase in the cost of maintaining the dump. In addition, in the process of working sites for the preparation of scrap, a large amount of metal fines is formed (0-10) mm. Sending this stuff to the steelmaking furnace leads to significant metal losses associated with its oxidation. In order to preserve the indicated metal to the maximum, its melting must be carried out in a reducing atmosphere. In this example, we consider the processing of slag melts obtained in the electric steelmaking process involving metallic fines in the production.

After oxidative refining in the chipboard, the slag goes to the unit described in Example 1. For the smelting start, 4.9 tons of slag after the previous smelting and 1.45 tons of pig iron from the recovery boiler are in the melting chamber. Received the slag ladle of 26 tons is poured through the loading hatch 3 into the melting chamber. As an iron-containing raw material, a mixture consisting of 30% iron ore –Fe _total = 58%, 20% mill scale — Fe _total = 71% and 50% metal beads of the fraction (0-10) mm is used. Ore and crushed scale are fed into the melting chamber by pneumatic conveying together with the charge, and metal fines are fed in parallel with the charge during reduction smelting along the channel located in the feed insert and intended for introducing ferroalloys into the chamber. The content of the reducing agent in the charge is calculated in such a way as to restore not only the iron contained in the slag, but also the iron introduced with the charge. In total, during the reduction smelting process, 67.1 tons of iron-containing mixture, 23.3 tons of coal and 2.39 tons of lime are fed into the melting chamber. Moreover, the charge flow rate is regulated in accordance with the foam mode in the chamber. After 40 minutes the chamber is completely filled with the melt, and excess slag is released. The next ladle portion is poured - 26 tons of slag. After 25 minutes, the chamber is again filled and the slag is released. Since there is no longer enough space in the melting chamber to accept the whole ladle portion of slag, further melting is carried out as in example 1, restoring the iron-containing mixture. Due to the fact that the charge mixture is enriched in the metal of kings, filling the melting chamber with cast iron occurs 43 minutes faster than in example 1. Over 3.26 hours, 69.8 tons of cast iron are recovered in the melting chamber, the composition of which is shown in Table 1. During this time, 42.2 tons of slag are released from the smelting chamber and 4.1 tons are left to the next melting stage. The oxidizing step of the smelting is carried out as in example 1. After a full metallurgical cycle, 67 tons of steel are obtained, the composition of which is shown in table 1. The total melting time, including the entire metallurgical cycle and the restoration of the lining after metal production, is 4.74 hours.

During the entire metallurgical cycle, 59.48 tons of slag are released from the smelting chamber and the recovery boiler. The composition of the averaged slag is given in table 5. All the formed slag is divided into four portions of 14.87 tons each. In this case, three portions are sent for saturation, and the fourth, to fit into the metallurgical cycle, is sent for granulation to obtain an active mineral additive. The saturation chamber as in example 1. The temperature of the lining of the chamber before loading the material –1300ºС. To start the process, 12.24 tons of lime and 1.3 tons of iron ore are introduced into the rotating melting chamber through the feed insert. As a result of rotation of the melting chamber, the material is heated to the lining temperature. At this point, clinker cooling in the refrigerator is completed. The discharge channel is switched to the saturation chamber. A portion of the slag melt is introduced into the chamber. To heat the chamber, 1.65 tons of coal are fed into it, and 2328 nm ³ oxygen and 923 nm ³ air are introduced through the side slots. Including air conveying. As a result of fuel combustion and the formation of clinker minerals, the mixture is heated to 1420 ° C. The synthesis of alite and belite lasts 25 minutes. After this time, the temperature in the chamber begins to decrease. To start the synthesis of fusible minerals, the mixture is forced to cool. To do this, 5.97 tons of limestone are introduced into the chamber. As a result of the endothermic decarbonization reaction, the temperature of the mixture decreases to 1300 ° C. Clinker is released into the refrigerator when about 3% of the liquid phase remains in the chamber. As a result of saturation of one portion of slag, 33.26 tons of clinker are obtained. The composition of the clinker will be given in table 6. For unloading, open the hatch located in the central part of the chamber, turn the chamber with the hatch down, and swinging the chamber, release the material into the refrigerator. The total time taken to saturate one portion of slag is 1.56 hours. The clinker cooling time in the refrigerator is 0.27 hours. The time spent to saturate all slag sent for saturation is 4.68 hours, and the metallurgical cycle time is 4, 74 hours.

Thus, in the considered example, 67 tons of steel 08 [7] and 99.78 tons of Portland cement clinker KH = 0.91, n = 1.68, p = 1.64 [9] and 14.87 tons of active mineral additive were obtained for cement, the quality factor K = 1.83 [10]. In addition, throughout the metallurgical cycle, a dust collection system located behind the recovery boiler, the melting chamber detained 1.95 tons of fly ash. Fly ash contains 7.5% K ₂ O and is marketed as fertilizer. In addition, during the entire metallurgical cycle, the regular operation of the turbine with an electric capacity of 21.3 MW was ensured. As a result of this, 100,962 kWh of electricity was produced. The resulting energy was directed to the production of oxygen used in the method. In the smelting process, technical oxygen is used in a volume of 15924 nm ³ with a maximum consumption for reduction smelting of 3000 nm ³ / h. Its production requires 7245 kWh. electricity. Thus, the method provides the reproduction of oxygen and argon used in the method, and the nitrogen formed during the production of oxygen can be implemented.

Table 4 The composition of the slag obtained for processing from a chipboard

FeO SiO ₂ Al ₂ O ₃ Cao MgO MnO Na ₂ O K ₂ O TiO ₂ S P ₂ O ₅ 41.96 17.44 4.92 23.33 7.10 5.14 0.00 0.00 0.00 0.01 0.11

Table 5 The composition of the mixture of slag obtained during the melting

FeO SiO ₂ Al ₂ O ₃ Cao MgO MnO Na ₂ O K ₂ O TiO ₂ S P ₂ O ₅ 1.23 34.17 13.44 48.44 1,62 0.13 0,07 0.15 0.53 0.20 0.03

Table 6 The composition of the clinker obtained in the process of saturation of the slag.

FeO SiO ₂ Al ₂ O ₃ Cao MgO MnO Na ₂ O K ₂ O TiO ₂ S P ₂ O ₅ 4,59 20.29 7.51 65.70 0.85 0,07 0.05 0.11 0.28 0.51 0.04

Example 3. Recycling of TPP wastes to produce steel 35GS [8], Portland cement clinker [9] and active mineral additives (AMD) [10].

A thermal power plant with a total capacity of 400 MW includes 4 power units of 100 MW each. To generate energy, brown coal is obtained from the Berezovsky deposit in the Krasnoyarsk Territory. At TPPs, boilers with liquid slag removal are used, on which storage tanks are provided, which allow organizing periodic slag production. Every 120 minutes, 29.14 tons of slag melt with a temperature of 1450 ° C are discharged from the boilers and fed to the processing site with a ladle. In addition to the fire-liquid slag in the dust removal system of thermal power plants for a specified period of time, 8.22 tons of fly ash are formed. The temperature of the ash fed to processing is 26 ° C. The composition of the slag melt and fly ash of TPPs is given in table 7.

The overall dimensions of the melting-saturation chamber are similar to the saturation chamber of Example 1. The difference between the melting-saturation chamber and the saturation chamber consists in the presence of a gate 4 for discharging liquid melting products on the chamber body 1, as well as in the location of the refrigerator, which is located 12 m away from the chamber. The refrigerator has its own aspiration system. Clinker is transferred from the chamber to the refrigerator by a scraper conveyor. During the melting process, the scraper conveyor is removed, making room for the installation of ladles into which liquid melting products are released. The dust-gas mixture leaving the melting-saturation chamber passes through a battery cyclone lined with refractory materials, a waste heat boiler and an aspiration system.

To load materials, the melting chamber is turned upward through the hatch. The hatch is opened and poured 29.14 tons of slag melt received from boilers of thermal power plants. The hatch is closed and the camera is turned on. Through the feed insert during the rotation of the melting chamber for 33.08 minutes serves fly ash and charge mixture. As a result, 8.22 tons of fly ash from TPP, 1.4 tons of coal, 15.75 tons of iron ore, 1.33 tons of lime are introduced into the chamber. For afterburning combustible gases generated in the melting chamber through the slots 12 between the rotating surface of the chamber and the side inserts enter technical oxygen in a volume of 5178.57 nm ³ . Ash and charge materials are supplied by pneumatic transport. As the transporting medium, technical oxygen is used. Its consumption is taken into account in oxygen for afterburning. During the liquid phase reduction process, 11.13 tons of pig iron and 33.64 tons of slag are formed in the melting chamber. In this case, 17.61 tons of gas, 0.68 tons of dust and 0.18 tons of gas impurities go from the melting chamber to the recovery boiler. The temperature of the dust and gas mixture at the outlet of the melting chamber is 1540 ° C. The composition of the resulting slag is shown in table 8, and the composition of cast iron in table 9. Recovery smelting ends with the release of 13.46 tons of excess slag, which is sent for accelerated cooling in order to obtain an active mineral additive. The recovery phase of the smelting, taking into account the loading of the material and the release of excess slag, is 48.08 minutes.

To carry out oxidative refining through the channel located in the feed insert 9, 508.4 nm ^{3 tons of} technical oxygen are introduced into the melt. To increase the basicity of the remaining slag (20.18 tons), 11.49 tons of lime are introduced into the melting chamber. At the same time, 30% of the lime is added together with the blast through the lance, and 70% - by pneumatic transport through the feed insert. As transport use technical oxygen. To obtain a steel melt with a given carbon content of 0.34%, according to the Fe-C phase equilibrium diagram, it is necessary to heat the bath to 1535 ° C. To obtain such a temperature of the melt in the melting chamber, the generated in the chamber CO and additionally introduced natural gas 328.57 nm ³ . As a result of oxidative refining, 10.5 tons of steel and 31.23 tons of slag are obtained. The composition of the resulting slag is shown in table 8, and the composition of cast iron in table 9. At the same time, 2.95 tons of gas and 0.66 tons of dust go from the melting chamber to the waste heat boiler. After oxidative refining, steel is released. During the production process, it is deoxidized-alloyed in the casting ladle. To do this, 0.01 tons of aluminum, 0.104 tons of ferrosilicon and 0.126 kg of ferromanganese are introduced into the bucket. The result is 10.73 tons of reinforcing steel 35GS. The composition of the steel after deoxidation-alloying is given in table 9. The time of oxidative refining taking into account the release of metal is 12.5 minutes.

In the process of oxidative refining, a slag melt with a high lime content and a high temperature is obtained. In this regard, the mixture does not produce additional heating. On the contrary, the introduced 1.45 tons of iron ore and 0.94 tons of lime compensate for the heat released during alitogenesis and allow the raw material mixture to be kept in a given range. The temperature of the mixture at the end of alitogenesis is –1482 ° C. The completion of the alitogenesis process is determined by the reduction of heat generated in the melting chamber. The time of the hot saturation period, including the introduction of corrective additives and the formation of alite - 27.3 minutes.

To activate the formation of low-melting minerals, the temperature of the mixture is reduced to 1268 ° C. For this, 8.33 tons of limestone are introduced into the melting chamber. The introduction of materials at the saturation stage is carried out by pneumatic transport. As transport use air. As a result, 388.62 nm ^{3 of} air enters the melting chamber at the saturation stage.

The rotation of the saturation chamber around the horizontal axis leads to the formation of clinker balls in it, similar to those obtained in traditional cement kilns. Clinker is released into the refrigerator when about 3% of the liquid phase remains in the chamber. For unloading, the loading hatch is opened, the scraper conveyor is brought in, the chamber is turned with the hatch down and, swinging the chamber, 38.35 tons of clinker are released into the refrigerator. The composition of the clinker is characterized by the following parameters: saturation coefficient KH = 0.91, silicate module n = 1.94, alumina module p = 1.61. The chemical composition of the clinker is shown in table 10. In the process of saturation, 4.61 tons of gas and 0.11 tons of dust leave the melting chamber. The time taken to saturate the melt with lime and release clinker into the refrigerator is 52.3 minutes. Clinker cooling time in the refrigerator is 16.3 minutes. This time is not taken into account when calculating the processing time, since the next batch of melt is already poured into the melting-saturation chamber during cooling of clinker in the refrigerator.

During the melting process, 1.63 tons of dust and gas impurities pass through a discharge channel through a battery cyclone. As a result of the slip of the sublimated components through a hot dust collector, they enrich the dust that is delayed after cooling in the aspiration system. Thus, 0.54 tons of sublimated mixture enriched in the mixture are recovered from the gas stream in an aspiration system. The concentrate containing 29.29% Na ₂ O and 29.81% K ₂ O is sent for further processing. In addition, 1.09 tons of melt are accumulated in the hot cyclone tank. The dynamics of the dust composition during the dust cleaning process is given in Table 11. The melt extracted from the hot cyclone is mixed with slag discharged after the recovery smelting stage. The resulting mixture is directed to accelerated cooling (granulation) in order to obtain an active mineral additive for Portland cement. The result is 14.56 tons of active mineral additives with a quality factor of K = 1.86 [10]. The composition of the active mineral additives are shown in table 12.

The dust-gas mixture leaving the aspiration system of boilers of TPP contains SO ₂ . Before the gas is released into the atmosphere, the gas is purified by the calcareous method. The result is CaSO ₄ , which is also a component of Portland cement. Gypsum is introduced into the cement mixture during grinding at the rate of (1-4)% in terms of SO ₃ [9]. In this case, 0.429 tons of SO ₃ are obtained.

Before joint grinding, a mixture is formed from the obtained cement components, including clinker, an active mineral additive and gypsum. During grinding, the mixture is cleaned of metal inclusions by selective grinding of the non-metallic component and its extraction from the mixture by air flow. Cement purified from metal is sent to the consumer, and the extracted metal is introduced into the melting chamber at the recovery stage of the smelting.

Thus, in the considered example, for 112.9 minutes, 14.56 tons of active mineral additives are obtained, quality factor K = 1.86 [10], 10.73 tons of 35GS reinforcing steel [8], 38.35 tons of Portland cement clinker [ 9], 0.429 tons of sulfuric anhydride and 0.54 tons of dry mix with a content of 29.29% Na ₂ O and 29.81% K ₂ O.

Table 7 The composition of the slag melt and fly ash TPP.

∑FeO SiO ₂ Al ₂ O ₃ Cao MgO MnO Na ₂ O K ₂ O TiO ₂ S FROM Slag TPP 9.16 30.53 11.19 42.89 6.11 0.00 0.01 0.01 0.00 0.1 0.00 Fly ash 3.61 12.12 4.41 16.89 2.40 0.00 3.87 3.97 0.00 0.00 52.75

Table 8 The dynamics of the composition of the slag.

∑FeO SiO ₂ Al ₂ O ₃ Cao MgO MnO Na ₂ O K ₂ O TiO ₂ S P2O5 After recovery 0.10 35.08 11.89 45.78 6.01 0.02 0.49 0.50 0.05 0,07 0.01 After refining 0.94 24.02 7.84 62.45 3.91 0.02 0.32 0.33 0.04 0.11 0.03

Table 9 Dynamics of changes in the composition of the iron-carbon melt during the smelting process.

Si Mn Al S P C Cast iron after the smelting recovery phase 0,087 0.02 0 0.008 0.06 4.49 Steel after oxidative refining 0 0 0 0.006 0.005 0.34 Steel after deoxidation - alloying 0.750 1.002 0.024 0.006 0.006 0.344

Table 10 The composition of Portland cement clinker.

Fe ₂ O ₃ SiO ₂ Al ₂ O ₃ Cao MgO MnO Na ₂ O K ₂ O TiO ₂ SO ₃ P ₂ O ₅ 4.07 20.59 6.54 64.68 3.20 0.02 0.26 0.27 0.04 0.30 0.02

Table 11 Dynamics of changes in the composition of dust in the process of dust cleaning.

∑FeO SiO ₂ Al ₂ O ₃ Cao MgO Na ₂ O K ₂ O TiO ₂ Zno S FROM The amount of dust from a PC 17.25 13.25 3.99 34.63 1.86 10.57 10.76 0.04 0.96 1.15 5.54 Delay mountains cyclone. 21.89 16.81 5.06 43.95 2.35 1.34 1.37 0.05 0.00 0.15 7.04 Delay in syst asp. 7.84 6.12 1.81 15.73 0.91 29.29 29.81 0.02 2.78 3.17 2.52

Table 12 The composition of the active mineral supplements

∑FeO SiO ₂ Al ₂ O ₃ Cao MgO MnO Na ₂ O K ₂ O TiO ₂ S FROM 1.74 33.7 11.38 45.64 5.74 0.02 0.55 0.56 0.06 0.08 0.53

Literature:

1.Bigeev A.M., Bigeev V.A. "Metallurgy of steel." - Magnitogorsk MSTU 2000 p.

2.Romenets V.A. The Romelt Process. - M.: MISIS, Ed. “Ore and Metals” 2005 p. 294

3. I.Yu. Kozhevnikov "Cox-free metallurgy of iron." - M.: Metallurgy 1970 p. 166

4.Kudrin V.A. "Metallurgy of steel." - M.: Metallurgy 1989, p. 261;

5.X.S. Vorobyov, D.Ya. Mazurov “Thermotechnical calculations of cement kilns and apparatuses. M.: High School 1962 p. 107.

6.RU2534682

7. GOST1050-2013 “Metal products from unalloyed structural high-quality and special steels. General specifications "

8. GOST5781-82 "Hot-rolled steel for reinforcing reinforced concrete structures. Technical conditions"

9. GOST10178-85 “Portland cement and slag Portland cement. Technical conditions

10. GOST3476-74 "Blast-furnace and electrothermophosphoric granulated slags for the production of cements."

Claims (2)

1. A method of producing steel and Portland cement, including melting the iron-containing charge, liquid phase reduction of cast iron and steel production, adjusting the chemical composition of the slag melt, saturating the slag melt with lime, accelerated cooling of the clinker and cleaning it of metal inclusions to produce Portland cement, characterized in that after the liquid phase iron recovery is carried out by oxidative refining of steel from impurities, separation of steel from refining slag, deoxidation and alloying of steel, and adjustment of the chemical composition of the slag melt is carried out during its saturation, while melting the iron-containing charge, liquid phase reduction of cast iron, oxidative refining of steel from impurities and saturation of the slag melt with lime is carried out in a melting-saturation technological chamber, and steel is deoxidized and alloyed in a casting ladle or unit ladle furnace, while the saturation of the slag melt with lime is carried out by creating conditions in the thickening melt for the formation of alite first, and then - fusible clinker minerals, moreover, the charge of the charge materials during the liquid phase reduction of cast iron is controlled so that the fictitious velocity of the exhaust gases from the bath is in the range (0.3-1.7) m / s, and the excess slag resulting from the recovery is released at the same time, the thermal regime in the technological chamber of melting-saturation at all stages of melting is regulated by means of afterburning of exhaust gases in it, and in the case of excess gases, they are removed and burned in a waste heat boiler, and in case of insufficient Atka gas - additional fuel is introduced into the chamber. 2. Technological melting-saturation chamber used in the production of steel and Portland cement by the method according to claim 1, comprising a housing made of a lined and with a symmetrical cylindrical-conical surface with a larger diameter in the central zone along its length, mounted for rotation around a horizontal axis and containing non-rotating inserts inserted into it from both sides, made with the possibility of forming supply channels that supply iron-containing raw materials, reducing agent, flux to the chamber, fuel, an oxidizing agent, a deoxidizing agent and ferroalloys, a discharge channel designed to drain the dust and gas mixture from the chamber to the waste heat boiler through the dust collecting unit, and to place cameras and devices allowing to control the melting course, with each insert being installed with the formation between the inner surface of the chamber and the outer the surface of the insertion of a slit for supplying gaseous melting components to the chamber selected from the group including oxygen-containing blast, inert gas, or a mixture thereof, non-rotating avki adapted to their removal from the chamber, wherein the chamber body is mounted on the loading door, gate for discharging liquid fusion products and a mechanism for sampling.

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