WO2020040665A1

WO2020040665A1 - Method for lining metallurgical units, and apparatus for carrying out same

Info

Publication number: WO2020040665A1
Application number: PCT/RU2019/000580
Authority: WO
Inventors: Роман Александрович ЧЕГЛОВ
Original assignee: Общество с ограниченной ответственностью "Севен Рефракториз"
Priority date: 2018-08-20
Filing date: 2019-08-16
Publication date: 2020-02-27
Also published as: EP3858491A1; EP3858491A4; RU2692390C1

Abstract

The group of inventions relates to the field of metallurgy and can be used in a technique for lining metallurgical units and other thermal units using a gunning method. In the present method for lining metallurgical units, a composition is prepared by moistening a dry refractory mixture with water in a turbulent stream of compressed air. The composition stream is then rarefied and impregnated with a hardener in an additional stream of compressed air. Before the prepared composition is applied to the internal surfaces of the units, the composition is condensed. In the present apparatus for lining metallurgical units, a nozzle housing comprises a rarefaction chamber fitted with a branch pipe for a mixture of a hardener and compressed air. The outlet end of the nozzle is tapered. The inventions are directed at improving the quality of the preparation of a lining mixture, and at simplifying structural design.

Description

METHOD OF LAYING OF METALLURGICAL UNITS AND DEVICE FOR ITS IMPLEMENTATION

The group of inventions relates to the field of metallurgy, and in particular to the technologies for lining metallurgical and other thermal units using the shotcrete method and its hardware design.

In the general case, the method of lining by shotcreting the surfaces of various aggregates and the design of the device for its implementation are given in the reference literature [Brief Polytechnic Word. - M.: State Publishing House of technical and theoretical literature. (Editorial Council: Yu. A. Stepanov, F.S. Demyanyuk, A.A. Znamensky, etc.) 1956, p. 954, the term "shotcrete"]. The method includes applying a special cement mortar (for metallurgical units — a refractory mixture) under the action of compressed air carried out by means of a cement gun (lining device). The dry mixture is loaded into a cement gun, from which it enters a hose under air pressure, ending with a nozzle tip. Before entering the nozzle, the mixture is automatically wetted. The resulting shotcrete (pneumatic concrete) has great strength, density, water and air tightness.

The most complete level of technology in the field of flameless spraying of refractory materials and its analysis are described in detail in the RF patent for the invention “Device for shotcrete of refractory material and nozzle for shotcrete” [Description of the invention to the RF patent Na 2363543 of 01.22.2004, IPC B05B 7/14, B05B 13/00, publ. 08/10/2009 Bull. NW 22]: Two widely used methods of shotcrete are known for the creation and repair of refractory lining: nozzle shotcrete and compacted concrete shotcrete (density higher than 2.4 kg / cm ³ ) with a pump. Unlike other injection methods, these shotcrete methods do not require the creation of formwork for casting refractory linings and, when applied, provides- easy lining even on irregular shapes or in cases where formwork is difficult to construct. Accordingly, gunning methods have become widely used in the creation and repair of refractory linings, especially in furnaces, for example, blast furnaces, blast furnaces, electric furnaces, casting ladles, casting troughs, oxygen converters, reheating furnaces, etc. .

In the nozzle shotcrete method (“dry” shotcrete method), dry powder material to be “shotcrete” is pneumatically fed through a conveying hose to the nozzle assembly where water is added to form a wet, very viscous shotcrete with good adhesive properties. The shotcrete mass is thrown out of the nozzle so that it adheres and hardens on a portion of the furnace wall, thereby creating or restoring the refractory lining of the furnace.

The method of gunning with a nozzle does not require preliminary mixing of the material with water, and thus, when it is used, it is possible to carry out work quickly and within a short period of time after notification, with minimal cleaning of the equipment. Also, its use does not require the mandatory use of a mold for casting a lining, which ensures a reduction in the cost of work and an increase in labor efficiency, as well as the possibility of manufacturing, for example, repairing both hot and cold lining of furnaces.

However, in the method of gunning with a nozzle, it is difficult to completely wet and thoroughly mix the material and the stream of water when transporting them in a pipe or nozzle. This is especially true when using short, less than 1.5 m long shotcrete tubes. In these cases, the disadvantage related to thorough mixing results in less than optimal and desired homogeneity of the applied mass, lower density and increased open porosity, as well as an increase in material waste due to rebound of aggregated particles and poor adhesion of the masses, and to an excessive drop of material from the pipe. The problem associated with the great dryness or poor wettability of the shotcrete material that is applied to the desired location is that part of the material does not adhere to the substrate, and this leads to the loss of deflected particles (known as “rebound”), which leads to a decrease in the proportion of applied material adhered to the wall of the aggregate, thereby deteriorating the quality and durability of its refractory lining. The density of such a lining in practice does not exceed 1, 8-2, 3 kg / cm ³ .

The listed drawbacks are deprived of pump spraying methods (“wet” spraying methods), which create refractory linings that have greater uniformity of properties and better physical properties than those obtained by spraying with a nozzle; they are usually used to create high-density monolithic structures. When using the method of spraying with a pump, the shotcrete mass is obtained by mixing the dry material with water in a separate mixer before being fed to the shotcrete device. The dry powder material is pre-mixed with water in a mixer and then pumped through a feed hose to a shotcrete device (pump), which is used to throw the shotcrete mass onto the formation surface. Typically, a reagent is added to the shotcrete to improve adhesion at the nozzle before the shotcrete material is applied to the surface of the furnace wall. This method is used for applying dense refractory mixtures with high strength. This type of mixture cannot be applied using dry shotcrete equipment.

The disadvantages of this method are that it is necessary to mix the dry material with water in a separate container until an appropriate consistency is achieved. Thus, the material for the shotcrete method is mixed before it is fed by the injection pump into the shotcrete device, which requires additional equipment, such as a mixer, and expensive means for feeding and considerable labor expenses, compared with the method of shotcrete nozzle. In addition, it is important to precisely control the amount of water supplied to the shotcrete material when using the shotcrete method with a pump to maintain the correct consistency. For this, a qualified operator is required to apply the lining by pump spraying to maintain the correct amount of water to obtain the desired composition. If too little water is used, setting or premature hardening of the shotcrete material may occur in the pump or feed hose. Conversely, if an excess amount of water is used, then a separation of accumulations of solid particles and fine powder contained in the shotcrete material to be sprayed may occur, with the formation of layers of refractory material that are uneven and of poor quality.

An additional disadvantage of the method of shotcrete pumping is the complexity of the interaction of the mixer and the pump. A certain amount of shotcrete material remains in the supply hose and nozzle, which leads to the appearance of material waste and an increase in the cost of labor for the operation and cleaning of the equipment. Also, the equipment for such a shotcrete method is cumbersome and requires more staff.

In addition, unlike the nozzle shotcrete method, which can be used when repairing furnace walls at temperatures above 1000 ° C, attempts to use the shotcrete method with a pump to repair refractory linings at high temperatures have not been successful.

To eliminate the above drawbacks, the corresponding devices were created — see Ne 2363543 for a description of the invention.

One embodiment of a device for gunning a refractory material comprises a nozzle with an internal channel having an inlet end into which wetted material is introduced, and an outlet end from which the material is sprayed. The inner tubular element contains one a through hole and a plurality of through grooves arranged in a circle. The outer channel is located around the inner channel and communicated with it, and has an inlet end for introducing gas into it, which is passed through the outer channel and pushes the wetted material passing through the inner channel.

The device according to the second embodiment contains a hose for supplying material, where water is supplied through a special inlet to wet the material. An inlet pipe connects the hollow flange to the inlet end of the outer tubular member. The wetted material is led out through the nozzle, the mixing chamber being located in the intermediate position and in communication with the material supply hose and containing an inlet for introducing the mixing gas.

Among the shortcomings of the above device variants, it should be noted that work exclusively with the “wet” composition finally prepared for spraying — only a working stream is formed for applying high-quality lining layers to the surfaces of various units. As a result, the nozzle design is complicated and its dimensions increase, which makes it difficult to work in limited volumes and cramped conditions. In addition, when working with injection pump equipment, all, although to a lesser extent, characteristic drawbacks of this shotcrete method are retained - a certain amount of shotcrete material remains in the feed hose and nozzle, which leads to the appearance of waste material and an increase in cost labor costs for the operation and cleaning of equipment.

In addition, in a number of other shotcrete technologies, a method of vortex (flare) shotcrete of cylindrical liners and a device for its implementation are known [Description of the invention to RF patent N 2108397 of 08/28. 1995, IPC C21C 5/44, F27D 1/16, publ. 10.04. 1998]. The method includes feeding the shotcrete components flowing out of the nozzle of the shotcrete tuyere in the form of a swirling single vortex stream into the lining through the channels of the shotcrete lining installed along the axis of the lining of the gun; the adhesion of the supplied particles of the shotcrete mixture is simultaneous variably over the entire cylindrical surface of the shotcrete section of the lining and the formation of a shotcrete coating layer on it, while the shotcrete components are fed to the lining from the end nozzle of the shotcrete lance having an outer circular edge and twist into a single vortex flow in the form of a hollow cone with an external opening angle - titium equal to at least 45 °, and the adhesion of the particles of the shotcrete mixture simultaneously over the entire cylindrical surface of the shotcrete lining section is ensured by creating the necessary radial and tangential values Flax components of particle velocity shotcrete mixture by adjusting the degree of twisting of the single vortex flow or components thereof in one direction or another.

A device for implementing this method comprises a container connected to each other with a shotcrete mixture, a pneumatic transport unit, pipelines for supplying shotcrete components, connected to the corresponding channels of the shotcrete lance with a nozzle, a swirl of at least one shotcrete supplied through the channels - lances of the shotcrete component, wherein the shotcrete lance is made with an end nozzle having an outer round edge, with the possibility of feeding from it to the lining of the shotcrete components in the form of a twisted single ihrevogo stream, it is provided with a mechanism of vertical movement, mounted on a mobile chassis and provided protective screen, and the swirler docked at least one channel gunning lance.

The disadvantages of the method include the large dimensions of the device for its implementation. In addition, the creation of a single swirling vortex flow is relevant and possible only when mixing the shotcrete components and ends at the stage when the mixture leaves the nozzle, where rectilinearly directed inertia forces act. Large external angles of the flow of the shotcrete mixture make it possible to apply it on a cylindrical (horizontal) surface of small diameter of the repaired aggregates, however, in the vertical plane, large angles lead to the traditional Losses of the shotcrete mixture due to its rebound. As a result, the known method and device do not have universality of application for lining a variety of metallurgical aggregates and their elements, with the exception of spherical and cylindrical surfaces. It should also be borne in mind that the torch application of the shotcrete mixture is mainly used for hot repair of metallurgical units and is rarely used in the manufacture of linings for newly constructed aggregates, as well as for large-volume linings.

Full automation of the spraying of the sprayed mixture onto the un-cooled, unprepared surface of the unit (the so-called “hot” repair) often leads to unpredictable results.

The problem solved by the group of claimed inventions and the achieved technical result consists in creating a new method of lining metallurgical and other thermal units and its structural implementation, which allows to improve the quality of preparation, uniformity and stability of the composition of the lining mixture, such properties of which swarms, as density, porosity and strength are close to bulk refractory concrete with a density above 2.4 kg / cm ³ while simplifying the design of the lining device and reducing its dimensions. In addition, the lining installation time is significantly reduced to 1, 5-2, 0 times.

To solve the problem and achieve the claimed technical result in a method of lining metallurgical units, including applying to their internal surfaces using a nozzle a stream of prepared composition saturated with compressed air based on a refractory mixture moistened with water, the composition is prepared by wetting dry refractory mixture with water in a turbulent stream of compressed air, after which the stream of the composition is discharged and saturated with a hardener in an additional stream of compressed air, and By applying the prepared composition to the internal surfaces of the aggregates, its flow is compacted.

Besides: - saturation of the air flow of the refractory mixture with water and its subsequent saturation with the hardener is carried out uniformly over the flow cross section;

- the stream of the prepared composition is applied to the inner surfaces of metallurgical aggregates at a distance of 0, 2-4, 0 m and at an angle to the normal not exceeding 60 °;

- the prepared composition is applied to the inner surfaces of metallurgical units in series in several layers, while the composition of the composition has the same or different chemical composition for each layer.

Also, to solve the problem and achieve the claimed technical result in a device for lining metallurgical units, including a nozzle with a housing, the inlet end of which is equipped with a supply pipe for a dry refractory mixture in a compressed air stream and a water supply pipe, the nozzle body contains a vacuum chamber equipped with a nozzle for supplying a mixture of hardener with compressed air, and the outlet end of the nozzle is made narrowing.

Besides:

- the supply pipe in the compressed air stream of the dry refractory mixture is installed coaxially with the nozzle body;

- the water supply pipe to the nozzle body includes a perpendicularly placed collector with a number of holes evenly distributed along the perimeter of the body;

- a nozzle for supplying a mixture of hardener with compressed air to the discharge chamber of the nozzle body includes a perpendicularly placed collector with a number of holes evenly distributed along the perimeter of the body;

- the pipe for supplying the mixture of hardener with compressed air includes a channel for supplying compressed air perpendicular to which the channel for supplying the hardener is located.

The group of inventions is illustrated by drawings, where: - in FIG. 1 shows a general view of the most significant fragment of the design of a device for lining metallurgical and other thermal units — nozzles with a body — in axonometric projection;

- in FIG. 2 shows a longitudinal section of the lining device of FIG. 1 ;

- in FIG. 3 shows a section AA of FIG. 2 - collector design for supplying and evenly distributing water into a stream of a dry mixture saturated with compressed air based on a refractory composition;

- in FIG. 4 is a section BB of FIG. 2 - design of a manifold for supplying a mixture of hardener with compressed air to a stream of moistened refractory composition.

The device for lining metallurgical units includes a traditional, fairly common (commercially available) set of equipment, which includes, for example, most of the equipment of a typical dry shotcrete installation (not shown conditionally), the function of which is to feed into the transport pipeline (highway ) 1 under the action of compressed air of the dry refractory mixture, and further on, the nozzle 2 with the housing 3, to the inlet end 4 of which the nozzle 5 for supplying the dry refractory compressed air in the compressed air stream is suitable for it B b and the water supply pipe, wherein the nozzle body 3 is contained vacuum chamber 7, 8 is equipped with a nozzle for supplying a mixture of a hardener with compressed air, wherein the outlet end 9 of the nozzle 2 is tapered. Since the outlet end 9 is made as a separate part from special wear-resistant materials, such as polyamide, it is called “nozzles”.

The pipe 6 for supplying water to the body 3 of the nozzle 2 includes a perpendicularly placed collector 10 with a number of holes 1 1 evenly distributed along the perimeter of the body 3.

The pipe 8 for supplying the mixture of hardener with compressed air to the chamber 7 of the discharge housing 3 of the nozzle 2 includes a perpendicularly distributed manifold 12 with a number of holes 13 evenly distributed around the perimeter of the body of the pipe. with compressed air is made in the form of a channel 14 for supplying compressed air, perpendicular to which there is a channel 15 for supplying a hardener.

The method implemented by the present device for lining metallurgical units includes applying to their internal surfaces through the outlet 9 of the nozzle 2 a stream of a prepared composition saturated with compressed air based on a refractory mixture moistened with water, the composition being prepared by wetting the dry refractory mixture with water in a turbulent stream of compressed air, after which the stream of the composition is discharged and saturated with a hardener in an additional stream of compressed air, and before applying the prepared composition and the inner surface of compacted aggregates its flow by narrowing the cross section of the outlet end 9 of the nozzle 2.

Saturation of the air flow of the refractory mixture with water and its subsequent saturation with the hardener is carried out uniformly over the cross section of the flow, while the flow of the prepared composition is applied to the inner surfaces of metallurgical aggregates at a distance of 0.2-4.0 m and at an angle to the normal not exceeding 60 °, successively in several layers, while the composition of the composition has the same or different chemical composition for each layer, which is determined by the technological requirements for the quality of the composition of the lining.

We analyze the essential features of the group of inventions.

Wetting a dry refractory mixture with water in a turbulent stream of compressed air is known from the “dry” shotcrete method. However, in the claimed method, the flow of the resulting mixture is not applied to the surface of metallurgical units, but discharged in a conditionally closed volume (chamber 7) of the housing 3, which results in a more complete and uniform wetting of the dry refractory mixture. A similar, but more pronounced discharge of the wetted mixture can be observed with the “dry” method of shotcrete at the exit of the nozzle, only this process is associated with an unnormalized redistribution of the amount of water over the cross section of the wetted stream, which, in particular, fluidity of its local fragments provided by the lining technology And the cops. After discharge in a closed volume of the casing 3 of the water-saturated stream of refractory mixture moistened with water, a hardener is introduced into it in the form of an independent stream of a mixture saturated with air bubbles. Unlike the final stage of the “wet” shotcrete method — saturation of the dense airless stream of the wet refractory mixture with air bubbles, the turbulent flow of the dry refractory mixture moistened with water does not require additional preparation, it naturally saturates with the hardener. After this, a composition of the required chemical composition and physical properties is obtained, ready for application on the surface of metallurgical aggregates. Further, the flow of the prepared composition is forcibly compressed by moving it towards the tapering outlet end 9 of the nozzle 2. As a result, the flow rate increases and a compact stream of uniformly mixed refractory mixture, water and hardener is formed from the nozzle 2, which is saturated with small air bubbles. The discharge discharge occurring at the outlet condenses the working composition, freeing it from the now unnecessary air bubbles. On the surface of the aggregate lies a layer of composition similar in properties to bulk concrete.

Obtaining a similar result becomes possible as a result of successive saturation of the air flow of the refractory mixture with water and its subsequent saturation with the hardener evenly over the cross section of the flow, which is facilitated by its forced turbulence.

The flow of the prepared composition is recommended to be applied to the inner surfaces of metallurgical units at a distance of 0.2-4.0 m and at an angle to the normal not exceeding 60 °. Distances shorter than 0.2 meters do not fully ensure the removal of air bubbles; the lining is more porous, which reduces its performance. A distance of more than 4.0 meters promotes the formation of unreasonably large conglomerates during the flight of particles of the composition, which create irregularities on the surface of the aggregate - unnecessary protrusions (ripples) and, as a result, sagging and sagging, which require blowing and / or calibration after blowing. This is also facilitated by applying to the inner surfaces of metallurgical aggregates a stream of the prepared composition at an angle to the normal exceeding 60 °. Significantly large 60 ° angles of attack contribute to the rebound of part of the composition and its transition to waste.

The prepared composition is applied to the inner surfaces of metallurgical aggregates in one layer or sequentially in several layers, while the composition of the composition has the same or different chemical composition for each layer. It is obvious that, depending on the type of metallurgical equipment — blast furnaces, blast furnaces, electric furnaces, casting ladles, casting troughs, oxygen converters, reheating furnaces, etc. — lay the lining thickness, the number of layers for its formation and the project - they structure the composition, including for each layer. For example, in a blast furnace, the outer layer of the lining should have greater wear resistance than the inner layers, which is ensured by the corresponding composition of the applied refractory mixture.

As a result, the claimed lining method provides the ability to work with a wide range of geometrical dimensions of metallurgical units, similar to the method of “dry” shotcrete, but with the quality of the lining obtained, which is inherent in the “wet” method and, as can be seen from the above information, with significantly lower implementation costs and simpler design.

A typical device for lining metallurgical units includes a nozzle 2 with a housing 3, to the inlet end 4 of which there is a nozzle 5 for supplying a dry refractory mixture in a stream of compressed air and a nozzle 6 for supplying water. However, in the claimed device, the housing 3 of the nozzle 2 contains a discharge chamber 7 (i.e., a guaranteed cavity, the length of which conditionally reaches the outlet 13 of the collector 12 inside the housing 3), which contributes to additional turbulence in the flow of the moistened refractory mixture and creates favorable conditions for its additional mixing and saturation with hardener. After the openings 13, the flows are summed up, and the turbulence mode is weakened and maintained due to forced mixing of the mixtures through a plurality of openings 13 evenly distributed around the circumference, similar to water supply through openings 1 1 of the collector 10.

It should be noted that the hardener is introduced into the stream of wetted mixture in the form of a pre-prepared air mixture. This is served by the corresponding pipe 8 on the housing 3, which includes a channel 14 for supplying compressed air, perpendicular to which there is a channel 15 for supplying a hardener. Preliminary preparation of the air mixture with a predominantly liquid hardener is ensured by the fact that the hardener stream is brought perpendicularly or close to the air stream and, due to, inter alia, the ejection mode, they are pre-mixed. A thoroughly mixed air mixture of the refractory mixture, water and hardener continues along the body 3 to the nozzle 2, the outlet end 9 of which is made tapering. The narrowing of the nozzle 2 smoothly seals the flow of the prepared composition and increases its speed, which is formed into a compact working stream at the outlet. Thus, the implementation of the claimed method is ensured by fairly simple structural means.

Additional design solutions for the lining of metallurgical units reinforce the effect. These solutions include a coaxial technological arrangement of the nozzle 5 for supplying a dry refractory mixture to the body 3 of the nozzle 2 in the compressed air stream and the presence of a discharge on the body 3 and in its chamber 7, preferably two collectors 10 and 12 perpendicularly arranged , one of which is an element of the branch pipe b of the water supply, and the other is an element of the pipe 8 of the supply of the mixture of hardener with compressed air. Both collectors 10 and 12 are provided with rows of holes 1 1 and 13 evenly distributed around the perimeter of the casing. These design features contribute to obtaining a working composition on significantly shorter length of the casing 3 of the nozzle 2, in contrast to the brushless design. This is also facilitated by the implementation of the pipe 8 for supplying a mixture of hardener with compressed air in the form of a channel 14 for supplying compressed air, perpendicular to which there is a channel 15 for supplying a hardener, although this is not necessary. However, the best effect and maximum equipment versatility can be obtained by using all the design features of the device.

Of course, the adjustment of such a device requires special knowledge and practical experience, characteristic for the adjustment of the well-known commercially available equipment for shotcrete.

It should be noted that the result of the implementation of the group of inventions is the creation of a new class of special equipment - shotgun installations for shotgun-cretting. The etymology of the new term comes from English. "Gunning" - "dry" shotcrete and English. “Shot” - shotcrete (“wet” shotcrete). The result is “Shotgun (shotgan)”, a technology and installation, consisting mainly of items of equipment for dry shotcrete with the properties and the resulting effect of equipment for wet shotcrete.

The implementation of the group of inventions can be illustrated by the following examples:

Example 1. Creating an original device for lining metallurgical units.

It should be noted that for the manufacture of the device it is possible to use elements of standard lining equipment, mainly for dry shotcrete. Thus, the shotgun installation includes, for example, part of the equipment of a typical shotcrete machine (not shown conventionally) with a receiving hopper for a dry refractory mixture, a revolving rotor equipped with many portion chambers, a unit for their sequential unloading with air supply for unloading, exhaust chamber, equipped with air supply for transportation and main pipeline. Additionally mounted a pressor (in case there is no transport pneumatic supply) and a container for a hardening additive is hung.

The transport pipeline (line) 1 ends with a pipe 5 for supplying a dry refractory mixture in the compressed air stream. This pipe 5 is connected to the housing 3 of the nozzle 2 through its inlet end 4.

In addition, the shotgun installation is equipped with a set of supply pipes and hoses for the refractory mixture, curing additive, air and water.

A working body according to the invention is connected to the main pipeline and includes, in particular, a nozzle 2 with a housing 3, to the inlet end 4 of which there is a nozzle 5 for supplying a dry refractory mixture in a compressed air stream and a nozzle 6 for supplying water, while the case 3 nozzle 2 comprises a vacuum chamber 7 equipped with a nozzle 8 for supplying a mixture of hardener with compressed air, and the outlet end 9 of nozzle 2 is made tapering.

To achieve the maximum technical result, the nozzle 2 with the casing 3 are equipped with all or part of the essential design features:

- a supply pipe 5 for supplying a dry refractory mixture in the compressed air stream is installed coaxially with the nozzle body 3;

- the pipe 6 for supplying water to the casing 3 of the nozzle 2 includes a perpendicularly placed collector 10 with a number of holes 1 1 evenly distributed along the perimeter (perpendicular to the longitudinal axis) of the casing 3, the axes of which, for example, are inclined to the axis of the housing 3 nozzle 2 and away from it (although this is not necessary);

- the pipe 8 for supplying the mixture of hardener with compressed air to the chamber 7 of the discharge chamber 3 of the nozzle 2 includes a perpendicularly distributed manifold 12 with a number of holes 13 evenly distributed along the perimeter of the housing 3, the axes of which are also, for example, inclined to the axis of the nozzle body 3 2 and away from it (although this is also not necessary);

- pipe 8 for supplying a mixture of hardener with compressed air you- it is filled in the form of a channel 14 for supplying compressed air perpendicular to which there is a channel 15 for supplying a hardener, which makes it possible to realize the mode of its ejection, and, therefore, to obtain a better finely dispersed mixture of hardener with air.

The assembled shotgun installation is additionally equipped with a control system, it is tested, marked accordingly and delivered to the consumer in this form.

Installation works as follows.

Through the receiving hopper (hereinafter, the work of typical technological stages is not conditionally illustrated), the shotcrete mixture enters the chambers of the revolving rotor. Due to the rotation of the rotor, the chamber with the material enters the discharge point. Using compressed air, the chamber with the material is unloaded. Through the exhaust chamber, the mixture enters the initial section of the line and then using compressed air, i.e. in the air stream (the so-called pneumatic supply), the mixture is transported at high speed to its final section - to the pipe 5 for supplying the dry refractory mixture to the body 3 of the nozzle 2.

Through the manifold 10 of the nozzle 6, the refractory mixture is wetted with water and in this form enters the vacuum chamber 7 on the housing 3, where the moistened mixture is mixed with the hardener through the manifold 12 of the nozzle 8. Further, the prepared composition is compacted by narrowing the nozzle 2 and escapes outward - towards the lined surface of the metallurgical unit.

The composition is applied to the lined surface in one or several layers.

Example 2. Finalization of a commercially available installation for "dry" shotcrete.

A certain enterprise or its specialized service professionally engaged in the lining of metallurgical units has a working shotcrete machine, for example, the AC 1-AC6 series, the SSB series (SSB 02, 05, 14 and 24), MPCS 4 or other installations.

To expand the technological capabilities of the machine adopted the decision to modernize it and bring it to the level of specialized shotgun installations.

Modernization is reduced to the dismantling of its own working body (nozzle) and equipping the machine with a working body, made in accordance with Example 1. If necessary, appropriate changes are made to the control system of the installation.

Example 3. Lining of a blast furnace under construction.

A furnace casing was constructed at the working site, on the inner surface of which tubular heat exchangers were mounted, a forge and shoulders were erected. The latter are covered with technological flooring. There is a connection of energy resources - an electric network of 380 V; 0.64 MPa compressed air network and water supply system. The working pressure in the shotcrete installation, depending on the design of the machine, the distance from the shotcrete installation to the shotcrete surface and the length of material hoses, should be in the range from 0.2 to 0.6 MPa. The pressure in the water tank should be 0.05-0, 1 MPa more than the working pressure in the gunite installation. During shotcrete, the air pressure in the gun installation and the water pressure in the water tank must be constant.

It is necessary to make the lining of the boil, shaft and top of the blast furnace. To do this, develop and draw up the technological regulations of the work performed.

Materials for shotgun-capping are available - a dry refractory mixture, for example, based on silicon carbide (for lining the first layer) and aluminosilicate composition (for lining subsequent layers); potable water and a curing agent, for example, based on liquid glass.

A shotgun installation is delivered inside the furnace casing, which is placed on the technological flooring, connected to the power system and filled with appropriate materials for lining the first layer. The installation is started and, using a special stand, it is brought to the specified operating mode. In accordance with the regulations, the installation operator begins the process of applying the first layer of the prepared lining composition using the nozzle 2 on the inner surface of the furnace casing. For one or more passes to the height of the operator (the so-called lining step), the first layer of the lining is applied along the perimeter of the inner surface of the casing, with which tubular heat exchangers are also walled. After raising the flooring to the next step, the lining process is repeated and so on to the entire height of the casing.

At the end of the application of the first layer of the lining, the flooring is lowered to the level of the shoulders. The equipment is washed and filled with materials for lining the next layer. The installation is started again and, using a special stand, it is brought to the specified operating mode.

Also, in accordance with the technological regulations, the installation operator begins the process of applying with the same nozzle 2 to the first, naturally or force-dried, lining layer of the next layer of the prepared lining composition. For one or several passes, another layer of lining is applied to the height of the operator along the perimeter of the inner surface of the casing lined with the first layer, having, for example, other performance properties compared to the properties of the first layer, for example, more durable, dense, heat-resistant, etc. , and corresponding thickness. After raising the flooring to the next step, the lining process continues. If necessary, in accordance with the regulations, the refractory mixture is changed to a mixture with other operational properties - special, for example, for steamer, shaft and top.

After applying the lining to the walls of the metallurgical unit, it is kept to dry completely, the formed surface is cleaned (calibrated) and, if necessary, ground.

This technology allows 1, 5-2, 0 times to reduce the time for installation of the lining in comparison with the "wet" method of shotcrete. As a result, construction costs were significantly reduced. After completion of work, the device is washed, purged with air and, as such, left for later use.

Example 4. Reconstruction installation of the refractory lining of the main gutter and the blast furnace transport chutes system (intermediate repair).

Make a technological map of the upcoming repair work.

The installation of the lining begins with the preparation of the surface on which the concrete will be applied. The surface must be cleaned of residues of smelting products (slag, cast iron), oxidized concrete must also be removed. All “unbound”, poorly-held concrete must also be dismantled.

The required amount of refractory material has been prepared at the work site.

Equipment is connected to energy carriers (air, water, electricity) and its testing in idle mode (without load).

Using compressed air to blow the working surface from dust and small external debris.

Depending on the area of work, refractory materials of various densities and for various purposes can be used (from the installation of insulating materials to dense working materials with a density higher than 2.4 kg / cm ³ containing the main material ABO3, SiC).

According to the statement of work, the operator, using the device for lining, namely, the nozzle 2 with the housing 3, starts work on applying (restoring) the refractory lining to the geometric dimensions described in the statement of work.

This technology makes it possible to apply concrete with a thickness of more than 100 mm in one go, as this technology uses binder material. With dry shotcrete, concrete of such a thickness must be applied in layers, which creates a certain, undesirable lamination of the lining.

Today, the main method of restoring the working lining The main gutter is exclusively a dry shotcrete method.

When using the installation technology of refractory lining by the method of shotgun-cracking - “SHOTGAN” (or “SHOTGUN”), the resistance (throughput of the main groove) is increased by 25-30%.

Example 5. Lining of a blast furnace during its overhaul.

There is a need for scheduled repairs of a blast furnace, the lining of which is lined with refractory bricks, partially worn out over time, and the resource of which has not yet been worked out.

The furnace is stopped and its inner surface is blown out to lower the temperature to the level of providing conditions for repair work, including the removal of toxic gases. The shoulders and forge with the remnants of liquid metal and slag are covered with insulating flooring.

The inner surface of the blast furnace is prepared for repair - remove potentially dangerous areas of masonry and clean. The composition of the materials for the lining is selected. A technological map of upcoming repair work is drawn up.

They bring in a shotgun-crating unit, connect it to energy supply systems, deliver materials for the upcoming lining, and charge the unit with them, which they launch and use a special stand to bring them to the specified operating mode.

In accordance with the repair work schedule, the installation operator begins the process of applying, with the aid of nozzle 2, to the internal surface of the furnace or to its separate sections of the refractory composition, which is firmly fixed to the brickwork or to its previous layer. This continues until the desired lining thickness is restored. Thanks to the heated walls, the drying process of the composition is accelerated.

After restoration of the furnace lining, its inner surface, if necessary, is cleaned (calibrated). Further, the internal space of the furnace is freed from the imported equipment and materials. Remove the insulating flooring. Then carry out routine maintenance to launch a blast furnace, in particular, the lining is dried and heated to 700 - 800 ° С.

After completion of work, the lining device is washed, blown with air and left as such for later use.

Thanks to the use of shotgun-capping technology, the repair process of the blast furnace was significantly accelerated, and the costs of its implementation were reduced.

Example 6. The lining of a small metallurgical unit - a typical 50-ton steel pouring ladle.

A feature of the lining of the inner surface of such a bucket is the extremely cramped conditions for work - this is a conditional cone with a height of 2800 mm and diameters of 2620 mm and 2340 mm.

As is known, fireclay bricks, as well as printed or bulk refractory masses are widely used for lining newly constructed or repaired steel-pouring ladles. Their installation is a rather laborious and lengthy process. The durability of the lining of steel casting ladles is usually 7-15 smelts.

As you know, intermediate repairs of the lining by shotcreting can increase its resistance by 30-50%.

The problem of high-quality and sufficiently fast lining of the mentioned steel-pouring ladle is solved by using the corresponding lining device made according to the invention. Unlike wet shotcrete equipment, the dimensions of the working body of this device — nozzle 2 with housing 3 and nozzle 5 — supplying a dry refractory mixture, is approximately 1 m. Adjusted for the length of the sprayed prepared refractory composition and the bending radius of the supply hoses about 1.5 m of free space is required. The main working equipment is located outside the bucket.

For lining the interior of a new steel-pouring ladle, all actions are performed according to Example 3 by forces, for example measures, one operator.

In order to restore the lining of the steel pouring ladle during scheduled repairs, the actions are carried out according to Example 5, adjusted for significantly smaller dimensions of the ladle and the absence of a bath with molten metal and slag - also by one operator.

The newly lined or repaired steel pouring ladle is dried, heated to 700-800 ° C and transferred to work.

The durability of the mounted lining of the steel pouring ladle made using the shotgun-cracking technology before intermediate repair is comparable with the lining service life, including its restoration, carried out according to the traditional technology - at least 20 melts. Intermediate repairs using the technology of shotgun-cracking can increase the durability of the bucket to 30 heats or more.

The above Examples 1-6 do not exhaust the feasibility of the claimed group of inventions. Other implementation methods are possible, the feature of which will be the use of the essential features of inventions in various combinations and on various metallurgical and thermal units.

As a result of the solution of this problem, a new method for lining metallurgical and other thermal aggregates and a device for its implementation were created, as a result of which the quality of preparation, uniformity and stability of the composition of the lining mixture improved, the density, porosity and strength of which approached the properties of bulk refractory concrete with a density higher than 2 , 4 kg / cm ³ , the design of the lining device has been simplified and its dimensions have decreased. In addition, significantly, to 1, 5-2, 0 times reduced the time for installation of the lining.

Claims

CLAIM

1. A method of lining metallurgical units, comprising applying to the internal surfaces using a nozzle a stream of compressed air saturated with compressed air based on a refractory mixture moistened with water, DIFFERENT THAT the composition is prepared by wetting the dry refractory mixture with water in a turbulent stream of compressed air after which the stream of the composition is discharged and saturated with a hardener in an additional stream of compressed air, and before applying the prepared composition to the inner surfaces of the agr Ghats condense its flow.

2. The method according to claim 1, characterized in that the saturation of the air flow of the refractory mixture with water and its subsequent saturation with the hardener is carried out uniformly over the flow cross section.

3. The method according to claim 1, characterized in that the stream of the prepared composition is applied to the inner surfaces of metallurgical aggregates at a distance of 0, 2-4, 0 m and iodine with an angle to the normal not exceeding 60 °.

4. The method according to claim 1, characterized in that the prepared composition is applied to the inner surfaces of metallurgical aggregates in succession in several layers, while the composition of the composition has the same or different chemical composition for each layer.

5. A device for lining metallurgical units, including a nozzle with a housing, to the inlet end of which there is a nozzle for supplying a dry refractory mixture in a compressed air stream and a nozzle for supplying water, DIFFERENT THAT the nozzle body contains a discharge chamber equipped with a nozzle for supplying the mixture hardener with compressed air, while the outlet end of the nozzle is made tapering.

6. The device according to p. 5, DIFFERENT THAT the inlet pipe in the compressed air stream of the dry refractory mixture is installed coaxially with the nozzle body.

7. The device according to claim 5, DIFFERENT THAT the water supply pipe to the nozzle body includes a perpendicularly placed collector with a number of holes evenly distributed around the perimeter of the body.

8. The device according to p. 5, DIFFERENT THAT the pipe for supplying the mixture of hardener with compressed air to the chamber of discharge of the nozzle body includes a perpendicularly located collector with a number of holes evenly distributed around the perimeter of the housing.

9. The device according to claim 5, characterized in that the nozzle for supplying the mixture of hardener with compressed air is made in the form of a channel for supplying compressed air, perpendicular to which there is a channel for supplying the hardener.