What is lining?

Furnace lining. Lining materials

The firebox is the “heart” of a brick kiln, its most important section. In the combustion section, the material comes into contact with an open flame, is exposed to temperatures of about 1000⁰C and thermal shocks.

Furnace sections of furnaces are not made of ordinary brick, since ordinary brick will, under these extreme conditions, lose natural moisture, burn, and as a result, crumbling and rapid destruction of ceramic bricks is very likely.

In order for a brick oven to serve for a long time and operate without accidents, operational safety is ensured by lining, or separating ordinary red ceramic bricks from direct contact with the flame.

It’s not just the brick oven that needs to be protected with lining. Metal stoves and solid fuel boilers have steel walls and firebox elements. The connections of such elements are welded. Both steel and, to an even greater extent, welded joints are subject to fairly rapid burnout. Only cast iron fireboxes do not require lining, and the metal structures of stoves do not last long without protection.

If the design of a stove or solid fuel boiler involves steel welded parts, then, as a rule, the manufacturer also develops lined protection using fireclay products or kaolin wool. There are other lining materials, but not many.

But a factory-made steel furnace is not always made with a lining of the combustion chamber, and in this case the owner has to do this work.

Lining is the lining of the inner surface of the furnace sections located in the zone of direct contact with the flame in order to protect against thermal shock and prolonged exposure to high temperatures, as well as from mechanical and chemical influences. The term lining is used not only in the context of household stoves, fireplaces and boilers, but also for furnaces in the metallurgical industry.

The lining has another function, in addition to protection - a significant reduction in heat loss from the internal surfaces of the firebox.

It is important to accurately calculate the thickness of the lining so that the furnace heats up sufficiently; if you protect the furnace section of the furnace too much, you can achieve the opposite effect - the heating time of the thickened walls of the furnace will increase too much, more fuel will be required, and heat loss through the chimney will be constant, and the room will be warm doing is not enough. That is, both the efficiency and overall efficiency of the heating unit will be reduced. The thickness of the heat-resistant lined layer cannot be exceeded.

Basic lining methods

The method is selected based on the furnace materials and operating time - simultaneously with laying the furnace or as a modernization.

1. A method suitable both for lining a completely finished heating structure and for one under construction is to line the internal surfaces of the firebox with heat-resistant material with low thermal conductivity.
2. Heat-resistant material in the form of a solution is applied to the inner surface of the combustion chamber of the finished heating unit. A brick oven can be protected with heat-resistant mortar only during construction.
3. For a metal sauna stove, an effective lining method is to install a heat-reflecting screen. For other models of stoves, shielding does not make sense, since the thermal energy will be reflected inside the combustion chamber and go into the chimney instead of heating the walls of the stove.

Types and classification of materials for lining

The raw materials for protective materials are clay and rocks with special properties. Classify materials according to a basic basis.

• A - silica as a base
• B – refractory fireclay clay as a base for lining composition, bricks or panels
• C – combined base composition

The most popular and popular materials for linings are group B: products made of chamotte (chamotte), which can be in the form of bricks, panels and dry mixtures for preparing mortar. To produce these products, fireclay powder is used, which is obtained by grinding special refractory fireclay clay (white kaolin, blue Cambrian) fired at high temperatures - up to 1550⁰C.

With the addition of fireclay powder - the main component of lining materials, with the addition of mineral powders of hard rocks such as sandstone and quartz - fireclay products are produced. The powder is also sold in dry form for solutions. Fireclay brick is the most popular material for lining, mainly due to its quite affordable price. The main thing when choosing fireclay bricks is the emphasis on quality.

When purchasing, you need to be careful, since low-quality fireclay will not provide the effect of protecting the stove.

Another, slightly less popular lining material is kaolin wool (group A). Raw materials are quartz sand, aluminous cements, refractory clays and liquid (silicate glass). The technical name of viburnum wool is mullite-silica wool (MCRR -130).

Wool is produced in electric furnaces and converted into fibrous structures using the blowing method, resulting in a material with excellent heat resistance. Visually – white insulating material for padding and surface insulation. thermal insulation for conditions up to 1250⁰С.

More expensive fire-resistant wool - high-alumina and zirconium - is suitable for insulation under extreme thermal conditions up to 1600⁰C.

Kaolin wool is used as insulators for expansion joints in furnaces of all types, for filling expansion joints, and for surface insulation on walls and vaults. This is a highly efficient material, used for household furnaces and boiler units, and in metallurgy, since it is inert even to molten metals. MKKR not only resists thermal influences, but is also a perfect electrical insulator with constant properties in operating modes up to 800⁰C. In addition, it has the following properties:

• Excellent sound insulation and vibration resistance
• Thermochemical resistance
• Plasticity and easy installation due to the elastic, tight fit of the wool texture to almost any structure and surface
• Not wetted by liquid metals
• Resists aggressive environments from acidic to alkaline, mineral oils
• Inert to water, moisture, water vapor

In furnaces, roll, slab and sheet kaolin wool are used as gaskets between the heat-resistant layer and the outer brickwork, as an addition to fireclay products.

Cardboard and mats for linings are made on the basis of kaolin and basalt wool, vermiculite (a material based on volcanic rock) and binders based on white clays. Kaolin cardboard is designed to work at temperatures up to 1400⁰С.

Lining is also done by coating with a solution. Special heat-resistant solutions from ready-made dry mixtures are used both for applying coatings to the surfaces of the walls of the combustion chambers of the finished furnace, and for laying the chimney ducts of the furnace made of refractory bricks.

Dry mortar powders (a refractory mixture made from Cambrian or blue clay) are also used for filling technological cavities, gaps and gaps in masonry, as well as free seams intended for compensatory thermal expansion in metal parts of heating unit structures.

In addition to mortar (MP-18 mortar, thermal operating mode up to 1600⁰C), the dry mixture can be produced from fireclay powders and enriched cements. refractory self-expanding cements, for example RPC grade M500, are also used in household ovens.

But mortar is much more environmentally friendly, and is preferable for stoves intended for cooking.

In Russian ovens or national clay ovens such as tandoors, of course, only environmentally friendly materials should be used, for example, based on blue clay.

The lining adhesive is easy to use and dries quickly. In practice, the oven can be used within 24 hours after being coated with fire-resistant aluminosilicate glue (for example, Anker 1600 glue). High-temperature refractory adhesive compositions based on aluminosilicates are intended for laying refractory bricks and for coating the walls of furnaces made of ordinary red brick.

Adhesive compositions are also used for gluing sheet, roll or panel refractory material. The parameters of heat-resistant adhesive compositions vary slightly among different manufacturers, but are always designed for operating conditions of at least 1400⁰C, which is acceptable for protecting the brick walls of the firebox in contact with open fire.

The main advantage of adhesives is the speed of installation and the oven is ready for use within 24 hours.

Adhesive compositions are offered by the market in a wide range, both one-component and two-component, in the form of pastes, mastics and coatings. These compounds are applied both to finished heating units and during the construction of a furnace and arrangement of a firebox. These materials contain fireclay powders, micro-reinforcing fiber, mineral additives and additives to strengthen the protective heat-resistant layer.

The most commonly used linings are made from the following materials:

Specific gravity, kg/m3	Thermo modes not exceeding temperature
fireclay bricks, fireclay mortars	1900-2000	1300⁰С
kaolins sheet and slab	2450-2500	1400⁰С
mullite mats	3050	1800⁰С
basalt wool	110	750⁰С
ceramic red brick	1550	700⁰С
vermiculites	150-260	1100⁰С
fire-resistant aluminosilicate adhesive compositions	—	1600⁰С

Source: https://stroyfora.ru/p/post-306

Lining - what is it?

Surely many have heard the word “lining”. What it is? This is the name of the internal protective finishing of heat engines and their parts (mills, furnaces, ladles, pipes, furnaces, hogs, etc.), pickling baths, chemical apparatus and much more.

Mill protective lining

In the past, drum mill linings were made from steel, but recently it has become apparent that rubber is much better. This material has many advantages.

The rubber lining demonstrates excellent performance. This primarily concerns ball mills, namely units of the third and second stages of grinding. But that's not all. Rubber lining is also an excellent choice for regrind mills.

This is the best option for them. For ball units of the first stage of grinding, it is recommended to use a mixed rubber-metal lining, which is very resistant to abrasion and corrosion. It lasts really long.

Mill lining is a serious matter, and you need to approach it responsibly.

Lining device

In rubber protective linings, the most popular is the “slab-lifter” scheme. Together with it, plates are used for lining the wave profile, consisting of one element. The strength of the protective cladding and the performance of the unit largely depend on the parameters of the interior finishing - the thickness of the slabs, as well as the profile and length of the lifters. By the way, they depend on the size of the drum, the rotation speed of the mill, the processing environment, the characteristics and size of the material.

To prevent the discharge grid from clogging, the effect of elastic shear in its design should not be neglected.

When choosing the configuration of the optimal protective lining, it is necessary to pay attention to the technical features of the mill’s operation (torsion speed, size of grinding media, loading level, etc.). Everyone who works with a mill should know not only the meaning of the word “lining”, but also basic information about it.

Why is rubber better than metal?

Rubber has many unique qualities: it does not corrode, has good shock-absorbing properties, and excellent anti-friction properties. Based on this, it can be argued that this material is superior to metal in almost all respects. What other benefits does rubber have?

• It remains in excellent condition for a long time, which means it can serve for a long time. Rubber protective lining can be used 1.5-2.5 times longer than metal. That's how good this lining is. Many people working in production know what it is.
• This lining is very easy to install and disassemble. This means that the availability of the unit is high. The time allocated for assembling and dismantling the rubber protective lining is 3-4 times less. Impressive, isn't it? The duration of repairs and inspections is also reduced.
• The rubber lining vibrates and makes less noise, and this is very important. The noise level is reduced by 2-3 times. Of course, under such conditions it is much easier for workers to fulfill their duties.

Bucket protective lining

Lining buckets is the main method that significantly increases their service life. In most cases, it is simply necessary.

Protective lining is applied to the exterior and interior of attachments to protect them from heat. We are primarily talking about ladles used to pour steel. The lining also protects equipment from mechanical damage. Buckets of bulldozers and excavators especially need this.

Immediately after applying the protective lining to the attachment, it becomes clear how effective it is. This is especially noticeable in the example of buckets of machines working with stones.

Economic necessity

From an economic point of view, a protective lining must be applied to all attachments.

After all, not only does the lining help to increase the service life of the bucket, but it also allows you to significantly reduce the time spent on repair work.

What does it mean? It turns out that the lining indirectly affects, among other things, an increase in the duration of continuous operation. It really has a lot of advantages. Every bucket needs a good liner. What it is is known to everyone who works with attachments.

What material is suitable for the bucket liner?

It is very important to choose the most suitable lining material, which will be durable and strong. The reliability of the protective lining itself and the service life of the bucket will depend on its wear resistance. It's important to remember this.

The best options for ladle linings include CDP boards. They are very durable and reliable. In addition, they have the following advantages:

• simple and quick fastening;
• selection of slabs of different sizes;
• ease of rolling;
• the opportunity to purchase them in our country, which is much faster and more profitable than ordering from abroad.

These are the many advantages of high-quality lining. What it is, some, unfortunately, become aware of quite late.

Source: https://FB.ru/article/142257/futerovka-chto-eto-takoe

Why is furnace lining needed in Suvorov and Suvorov-M boilers?

Lining buckets is the main method that significantly increases their service life. In most cases, it is simply necessary.

Protective lining is applied to the exterior and interior of attachments to protect them from heat. We are primarily talking about ladles used to pour steel. The lining also protects equipment from mechanical damage. Buckets of bulldozers and excavators especially need this.

Immediately after applying the protective lining to the attachment, it becomes clear how effective it is. This is especially noticeable in the example of buckets of machines working with stones.

Polymers/PE

The advantages of polymer lining include:

• speed.
• lightness of the material.
• eliminating sticking.
• surface tightness.

And the safety of the material allows it to be used to create tanks for the food industry.

It is applied for:

• body structures of transporting vehicles.
• various containers and pools, septic tanks.

Polyurethane/PU

Due to its high durability, it is used for gumming anti-corrosion surfaces in metal structures and brick buildings (as waterproofing).

After lining with PU, the structure becomes insulating due to the non-porous properties of the material. In addition, the substance has the following properties:

• strength,
• elasticity,
• resistance to UV rays.

It is used for boxes and chutes, buckets of loading machines, dump truck cabins, skips, concrete mixers, pipelines, hydrocyclones and scrubbers, electric centrifugal pumps, screen bottoms in:

• production of military and naval equipment;
• mining, oil and gas industries;
• approved for use in food industry factories.

Polyethylene/PE

If the main problem is not equipment failure, but the sticking of raw materials, then PE will be an excellent choice for gumming.

Due to the perfectly smooth plane of polyethylene sheets, as well as the low adhesion and good fastening, the material slides without difficulty and sticking becomes impossible.

Used for lining:

• bunkers,
• gutters,
• tanks for unloading,
• truck cabins,
• propeller blades,
• funnels in machines, various containers and elevators.

Compared to other facing materials, polyurethane lining lasts on average 5-6 times longer.

Metal furnace lining

The peculiarity of metal furnaces is that the thermal expansion rates of metals are not the same. Therefore, a small space must be left between the combustion and lining layers. This will prevent the protective layer from being destroyed when the size of the metal part changes.

In this space, special materials with non-flammable properties, such as asbestos or basalt wool, are usually placed. The use of asbestos is permissible only for structures located in non-residential premises. But there shouldn't be any air there.

To make a metal furnace as safe as possible, the boiler is often lined on both sides at once. Through this step, the best heating is achieved. But this point of view is partly correct. This is explained:

• High heat capacity of brick;
• Low thermal conductivity of brick.

This combination of properties is a guarantee that the heat will not escape beyond the firebox, and will subsequently be removed with the escaping smoke. But with double-sided lining of the furnace wall

begin to burn out due to lack of air necessary to remove thermal energy.

Therefore, a double-sided lining for a metal furnace is a measure for thermal insulation, not thermal protection. But cooled air masses must be able to flow to the combustion chamber.

The furnace lining is a necessary component of its long-term and safe operation. But it must be carried out in strict accordance with the basic rules and using high-quality and suitable materials.

Source: https://www.tproekt.com/cto-takoe-i-dla-cego-nuzna-futerovka-peci/

General ideas about furnace lining - Home insulation school

Heating furnacesGeneral ideas about furnace lining

For the construction of furnaces, only fire-resistant materials are used. But even they are not able to withstand high temperatures on their own for a long time, which when burning fuel reach hundreds of degrees. To protect the outer walls near the firebox from radiation, thermal or chemical influences, a lining is installed inside.

The first question that an amateur stove maker asks when he hears the word lining is what it is and what its purpose is. This is the shell that covers the inner surface of the combustion chamber. Thanks to its resistance to constant exposure to high temperatures, it allows the structure to last for a long time.

In the chemical-thermal system “medium-lining-material” the lining is a kind of mediator. When starting to lay the central part, it cannot be considered as a separate component.

You can arrange the lining in one of the following ways:

1. Installation of protective screens that reflect thermal radiation, but some of the heat will escape through the chimney to the street
2. Treat the internal surfaces of the combustion chamber with materials that have a low thermal conductivity coefficient

The main purpose of the lining is thermal protection, but not thermal insulation. These two concepts are completely different from each other. If the inner surface is insulated from heat, the heat will be constantly retained inside the combustion chamber and removed outside along with the smoke, significantly reducing the efficiency of the stove.

It is necessary to begin laying the lining after carrying out engineering calculations and deciding on the type of foam installation. In this case, the characteristics of all building materials used are taken into account.

Introductory video

Features of lining for various types of furnaces

For each type of furnace or heating boiler, the lining has certain features. Let's look at the most common options:

• Lining of metal furnaces
• Brick kiln lining
• Steam boiler lining

Lining of metal furnaces

If the combustion furnace is made of metal, the different thermal expansion of the materials must be taken into account. A small gap must be left between the lining and the steel, otherwise the constant fluctuation in the size of the iron walls will destroy the masonry.

The cavity left should not be empty. It is filled with one of the non-flammable materials, for example, basalt wool. Sometimes asbestos is used, but the stove must be located in a non-residential area.

When making the lining of metal furnaces, bricks are sometimes laid on both sides. The answer to the question about the feasibility of such a solution is justified as follows: the heating of the furnace improves and the level of safety increases. However, this approach is wrong:

• Brick has low thermal conductivity
• Brick has a heat capacity

Analyzing the above, we can come to the conclusion that lining metal furnaces on both sides will lead not to thermal protection, but to thermal insulation. Moreover, cooled air will not flow inside the furnace, which can lead to burnout of surfaces.

Read also about how to make a Swedish oven with your own hands

Brick kiln

The opinion that lining a brick kiln is much simpler than a metal kiln is erroneous. Such work also has some features, without taking into account which you cannot count on the long service life of the structure.

It is impossible to lay the lining close to the bricks that are elements of the outer walls. The reason for such consequences is the pushing out of the outer layers by the expanding inner layers. Cracking can be aggravated by the fact that clay has low adhesion rates and expands more than brick.

If the lining is of poor quality, this will lead to unpleasant consequences:

• Overheating of external surfaces will result in cracking of seams and the formation of cracks
• The latter, in turn, will cause carbon monoxide leaks into the room, but not into the chimney

In addition to the high-quality lining made from fireclay bricks, special attention is paid to the quality of the seams and the clay used. It is necessary to glue 2-3 bricks together and burn them at high temperatures. This action will allow you to clearly determine how the assembled structure will behave. If the results are not satisfactory, you will have to experiment with the composition and repeat the tests.

Steam boiler

Sometimes the lining needs to be laid not for classic fireplaces and stoves, but for combustion steam boilers. In this case, choose one of its 3 varieties:

• Heavy
• Lightweight
• Natrubnaya

Heavy lining and what it means is one of the exciting questions. They resort to it when boilers have weak shielding. Sometimes the temperature inside the furnace can exceed 1200 degrees, causing fires in external materials. It is necessary to lay out heavy lining from 2-3 layers of fireclay bricks. Such protection allows you to reduce the temperature outside to a safe 60-80 degrees.

If the brick is laid in just one layer, the lining is called lightweight. However, each of the belts must be supported by an intermediate beam or boiler frame. Then the surface of the heating installation is wrapped in non-flammable materials and covered with a metal sheet. Thanks to this combination, it is possible to reduce the outside temperature and increase the efficiency of the boiler room.

The simplest is the pipe lining. To arrange it, it is necessary to prepare a viscous non-flammable mass and apply it to the pipes in 2-4 layers. To make the structure better resist thermal expansion, a reinforcing mesh is laid.

Household lining: answers to common questions

More often, the lining is a laying of fireclay bricks, which will be in direct contact with the burning surface. However, a novice builder, faced with such a task for the first time, will ask himself a number of questions:

1. What is the best way to lay bricks?
2. How thick should the furnace lining be?
3. What should be the gap between the bricks and is it necessary at all?

When constructing classic stoves and fireplaces, it is enough to lay only one layer of lining. In this case, products measuring 25x15x6.5 cm are used - such a brick is considered standard.

Laying is usually done vertically. Nobody forbids making it horizontal, but most of the internal usable area will be lost.

Unlike classic brick, the thermal expansion of fireclay products is minimal. Therefore, there is no need to leave a large gap between them. A clay solution is used as a connecting link and a metal spike is installed. The use of cement-sand mortar is prohibited.

If the lining comes into contact with metal products, for example, a grate, a gap should be provided between them. Metal under the influence of heat will constantly change in size and can be pushed out, bend over time and even burst.

Materials used

Having learned what a lining is, it is necessary to take a closer look at the materials for its construction. The materials used for lining furnaces and boilers can be divided into three main classes:

• Class A - artificial or natural materials based on silica
• Class B - classic materials based on clay
• Class C - this includes all remaining options and various fire-resistant solutions

Specific examples

You can protect the inner surface of the combustion chamber using a variety of methods:

• Fireclay brick masonry
• Application of non-flammable mixtures
• Installation of protective screens

It is recommended to install screens when installing metal sauna stoves. In other cases, it is not effective, as it will lead to wasteful leakage of thermal energy.

When choosing brickwork, it is not recommended to use classic brick - it quickly collapses and requires replacement. Before the advent of fireclay materials, products of the M-300 brand were used. They are relatively reliable and durable, but still inferior in efficiency.

How to prepare the solution

It was previously mentioned that it is necessary to experiment with the mortar for laying the lining. To minimize the number of tests, it is recommended to prepare several options at once and fire them under the same conditions. Don't forget to label.

A solution prepared on the basis of brick dust and fireclay clay is considered widely popular. However, if only wood is burned in the stove, you can use a classic clay mixture with a small sand content.

Lining for stucco stoves

Classic stone or metal heating structures in baths are gradually being replaced by more modern and beautiful stucco stoves. They are built using the adobe method. For them, the lining can be made of fireclay bricks, but craftsmen recommend resorting to special mixtures:

• Mullite
• Fireclay
• Corundum

To use these compounds, it is enough to dilute them in warm water on site. The solution is applied to fire-resistant surfaces. After drying, the monolith will not crack.

About repairs

Nothing lasts forever, including the furnace lining. Before the start of the next heating season, it is recommended to inspect surfaces and restore damaged areas.

It is recommended to use a mixture based on aluminous cement and fireclay powder as patches. First, the mass is applied to the damaged areas, and then dried with an open flame. The last stage should begin after a week. If you rush, the renewed surface can quickly collapse again.

A little about industrial lining

The main difference between industrial and household linings is the structure of the fireclay bricks used. In the first case, it will be exposed to high temperatures, and therefore requires additional pressing during the production process. They are much more expensive, but can withstand thermal shock.

Let's consider the most optimal ratios of such characteristics as material-density-temperature:

Material	Density kg/m3	Maximum operating temperature °C
Chamotte	1800-2000	1300
Kaolin is dense	2400-2500	1400
Vermiculite	150-250	1100
Basalt wool	100	750
Clay brick	1600	700

In industry, linings perform much more practical functions than in everyday life:

• Reduces the temperature of external surfaces
• Protects furnace walls from thermal destruction
• Reduces heat loss
• Does not allow furnace materials to come into contact with chemical compounds or molten metals

Let's sum it up

Having familiarized yourself with the various features of arranging linings for various types of furnaces, you can safely get to work. However, neglect of the considered rules can significantly affect the reliability and durability of heating structures.

Source: https://v-teplo.ru/fyterovka-pechi.html

Do-it-yourself furnace lining and cladding

To understand what the furnace lining is, it is necessary to understand the physical processes occurring in the furnace during fuel combustion. High temperatures generated during combustion can lead to changes in the properties and structure of surrounding materials. Although the materials used to make stoves are usually fireproof, they need to be protected from overheating.

DIY furnace lining

It is the lining that is designed to protect the furnace materials from the undesirable consequences of overheating.

The furnace lining is the brick shell that is placed on the inner surface of the firebox. It is characterized by high fire resistance, which allows the equipment to be used for a longer time.

note

The furnace lining is one of the main elements of the chemical-thermal system “material-lining-environment” and should be considered only in conjunction with other components. It interacts closely both with the materials from which the stove is made, and with the environment inside the firebox, where the combustion process itself occurs.

The lining can be represented not only by brick lining, but also by other types. Depending on the chemical properties, there are three types of refractory substances that can be used as lining materials: acidic, neutral and basic.

The separation is due to the different reactions of different substances to the substances formed during the combustion of fuel.

Furnace lining is carried out only after engineering calculations and selection of materials for it. The calculation allows you to achieve the greatest effect with all the characteristics of the materials and the furnace itself. Another function of the lining, in addition to thermal protection, is to protect furnace elements from mechanical and chemical influences.

Providing heat protection for the furnace

There are two ways to protect the inner surface of the firebox:

• treat the inner surface with a material with low thermal conductivity;
• use protective screens that will reflect thermal radiation. In this case, the heat from this radiation will leave the furnace along with the smoke.

With the first method, do not confuse thermal insulation and thermal protection. With thermal insulation, the heat generated in the furnace remains in the working area. Thermal protection only protects a certain area of ​​the surface from thermal radiation, without retaining heat inside the work area. It is for this purpose that when lining furnaces, heat-protective rather than heat-insulating materials are used.

Source: https://teploizolyaciya-info.ru/teploiz_sidebar/obekt-teploizolyacii/dom/futerovka-pechi-i-oblicovka-svoimi-rukami.html

Lining work - technology and features of the work

Lining work is directly the work of laying and strengthening various structures, depending on the purpose of these structures. The lining provides protective properties of structures from all kinds of mechanical and physical damage.

As a rule, lining work is mainly carried out in metallurgical production, where the main element is blast furnaces. Additional parts of blast furnaces, such as ladles, pipes and furnaces, are also lined.

Lining work for these elements is necessary, since its implementation improves the quality of metallurgical equipment such as fire resistance and increases resistance to various types of mechanical influences. After lining work, the furnaces can withstand impacts such as increased friction quite steadfastly, they are protected from various types of adhesion and are able to serve for a longer period.

Lining technology

Lining work is carried out by applying a special product made on a vermiculite basis to the inner surface of the product. This substance has many qualities that are necessary to extend the life of products.

These qualities include the following, such as increasing the fire resistance of the material and its heat resistance. This material tolerates all kinds of chemical influences well and is a good insulating material.

Thus, this material is also minimally electrically conductive.

To carry out lining work on blast furnaces, refractory materials such as fireclay bricks are used. This material is of very high quality. Also used are carbon-type blocks, bricks containing an increased amount of alumina material. In some cases, silicon carbide bricks are used to line blast furnaces.

Features of lining works

The lining process itself consists of laying out all types of refractory materials in stages. So the lowest part of the blast furnace, called the flange, is lined with brick blocks containing a high level of alumina material.

The space that is formed during such masonry is rubbed with a special putty. Which is made of mortal material, which must be appropriate to the type of brick used in the masonry.

Mortal material is obtained by mixing fireclay, which is crushed into a powdery consistency, and clay.

If this material is used in masonry of a responsible nature, then components such as soda and stillage of sulfite-alcohol composition are certainly added. This substance is added to make the material more sticky and thus to ensure greater adhesion of the brick. Between the blocks, which are carbon, the seam space is filled with another substance. Namely, a special paste-like mass, which is made from substances such as coke and pitch.

Actually, the entire process of lining work consists of laying refractory materials and sealing the seams between these materials. Lining work is not highly complex work, although it is quite labor-intensive. The main condition here is the use of special-purpose materials and composition. It is also important to comply with all work regulations and adherence to all safety precautions.

Source: https://promplace.ru/futerovochnie-raboti-tehnologiya-i-osobennosti-provedeniya-rabot-500.htm

What is furnace lining, why and from what materials is it made, features of the procedure and advice from experts

Furnaces are built from fire-resistant materials. But due to the fact that when burning fuel a very high temperature is formed, reaching several hundred degrees, this material is not able to withstand it. To protect the outer walls, a lining is installed inside the furnace.

The lining is a brick shell that is installed inside the firebox. It is very resistant to even the highest temperatures. This allows the stove to serve for many years because it is protected from overheating.

The lining cannot be considered as an independent element, because it closely interacts with the materials from which the stove is lined, and with the internal environment of the firebox in which the combustion process takes place.

The lining can be made not only of brick, but also of other materials. There are three types of refractory substances that differ in their chemical properties as such materials:

• Sour.
• Basic.
• Neutral.

They have different reactions to substances that arise during the combustion of fuel.

The lining is produced only when all engineering calculations have been carried out and the material for it has been selected. Using this calculation, the maximum effect is achieved, taking into account the characteristics of the material and the furnace itself. In addition, the lining protects various furnace elements from chemical and mechanical influence.

Methods of heat protection of the furnace

The surface inside the firebox can be protected in two ways:

• Using a material with low heat conductivity, which is used to treat the inner surface of the firebox.
• Using protective screens that reflect thermal radiation. In this case, the heat from the radiation is removed from the furnace along with the smoke.

It is worth noting that the first method does not provide thermal insulation, but thermal protection. With thermal insulation, the heat generated by the stove remains inside it. And thermal protection protects a certain area of ​​the furnace structure from radiation, removing heat from it. Therefore, thermal insulation materials are used for lining.

Using fireclay bricks

In the recent past, stoves were made mainly from ordinary bricks, which very quickly became unusable under the influence of high temperatures. Then, for quite a long time, bricks with a denser structure began to be used instead. Fireclay bricks are currently gaining popularity. It is made from clay , which is mixed with baked clay powder and then fired at high temperatures.

Fireclay brick is an ideal option for lining furnace structures. It differs from ordinary bricks in its excellent heat-insulating properties. Lining involves lining the inner surface of the furnace with just such a brick.

Brick kiln lining

The lining of a brick kiln has some features. It should not be laid too close to the bricks, which are elements of the outer walls . The fact is that the stove gets very hot and cracking occurs under the influence of high temperatures.

The hot inner layers push the cold outer layers out of their places. The outer walls, which maintain the shape of the oven, begin to diverge to the sides due to the impact of the expanded inner layers. Bricks become covered with cracks, and some may even collapse.

This may allow carbon monoxide to enter the room.

The situation can be aggravated by the fact that the clay used to connect the outer layer of bricks has little adhesion and, when heated, expands more than the brick itself. As a result of overheating, the seam is destroyed.

That is why, when constructing a furnace structure, a plastic solution is used and then tested. To do this, two bricks are connected to each other using this mortar and fired at high temperature. This tests the solution's adhesion, expansion and cracking. If everything is fine, the solution can be used for the entire structure.

When lining metal furnaces, you should pay attention to the fact that metal, when exposed to high temperatures, expands more than brick .

Therefore, it is necessary to make a gap for thermal expansion between the lining layer and the metal furnace walls, otherwise when the metal is heated, the lining is often destroyed. To seal the gap, use basalt wool in the form of a sheet or strands.

If the stove is not located in a residential building, asbestos can be used instead of basalt wool.

Metal stoves are often lined with brick both outside and inside to improve heating of the stove and its safety. However, this method is considered erroneous because:

• Brick is characterized by low thermal conductivity and high heat capacity, as a result of which the heat arising from the combustion of fuel remains inside the firebox and goes away along with the smoke.
• In this case, the stove surface is deprived of air access to remove heat, which leads to burnout of the walls. As a result, carbon monoxide may enter the room, which is life-threatening.

Thus, the lining of the furnace is done to ensure that it does not collapse due to exposure to high temperatures. The most important thing is to use high-quality material so that the stove can last for a long time.

Source: https://pechi.guru/kladka-pechi/futerovka-pechey-chto-eto-takoe.html

What is a furnace lining and why is it needed?

Furnace lining

To find out what a lining is and why it is needed, you need to understand that in any furnace, when fuel is burned, a high temperature is generated. Exposure to high temperatures leads to changes in the structure and properties of the material. The materials from which the stove is made, although most are fireproof, also need protection.

External, internal protection

Protecting the internal walls of the firebox can be done in several ways:

• Firstly, you can use protective screens that can absorb most of the radiant fluxes. The screens installed inside the firebox affect the heating of the flue gases, so most of the heat will be removed through the chimney.
• Secondly, the inside of the firebox can be lined with fire-resistant, low-thermal conductivity material.

Thermal protection and thermal insulation - there is a difference

There is a huge difference between thermal protection and thermal insulation principles. With thermal insulation , the heat generated in the work area is not removed anywhere. This is what thermal insulation is for.

In contrast, thermal protection is designed to protect a specific area from the thermal radiation of the working area. From all that has been said, it becomes clear that thermal protection is not at all intended to preserve heat.

Fireclay brick

Fireclay brick

If external protection in the form of a screen in heating boilers, the use of this method will be very wasteful, since most of the heat will be spent completely in vain. But this method is perfect for installing sauna stoves.

Previously, under the USSR, most private owners were familiar with simple building brick GOST 530-95 . This brick is intended for the construction of industrial and residential buildings and in no way for use in furnaces and heating boilers. By the way, many still use it to build furnaces and boilers.

Many craftsmen at that time managed to get a brick of this GOST, but of a higher grade M - 300 , in the popular expression “kiln”. This brick lined the furnace part of the furnaces to protect against high temperatures.

Later, fireclay bricks GOST 390–96 .

Our information: fireclay materials are made from clay mixed with fired clay powder and then fired at high temperatures.

The use of fireclay is the lining

Due to the fact that all fractions have a homogeneous chemical composition, all fireclay products have a high degree of heat resistance and do not crack when exposed to high temperatures.

Lining the combustion part with fireclay material to protect the heating unit from the effects of high temperature in the combustion part is called lining.

Manufacturing lining and material properties

In production, in metallurgy, the lining of an induction furnace is made using special, pressed fireclay bricks. They are very wear-resistant, do not shrink and withstand thermal shocks well. The use of fireclay bricks made it possible to achieve great cost savings and greatly reduce the cost of the metal production process.

Induction oven

Induction oven

The table shows the properties of some refractory materials

Material	Density kg/m3	Maximum operating temperature °C
Chamotte	1800-2000	1300
Clay brick	1600	700
Vermiculite	150-250	1100
Basalt wool	100	750
Kaolin is dense	2400-2500	1400

Household problems - lining as a solution

In everyday life, people usually have to solve simpler problems. At the very last stage, the burning of the coals, the bottom of the metal stove overheats, sometimes red hot. A man decides to cover the overheating wall from the inside with his own hands.

But even in this case, you have to decide to what level to lining, whether to leave a gap and how to secure the bricks?

Specifically in this situation, the issue can be resolved as follows:

• If the width of the firebox allows, fireclay bricks of a standard size are laid along its perimeter - 250X150X65 mm. In this case, the brick is laid flat against the wall. Can be laid vertically with a height of 250 mm or horizontally with a height of 120 mm.
• In order to securely fix the bricks together, a simple method is used. Using a grinder, a cut is made in part of the joint, and the bricks are held together using an inserted metal spike of a suitable size.

Lining device: temperature and metal

Particular attention should be paid to the fact that the thermal linear expansion of metal is much greater than that of brick. Therefore, all metal parts exposed to heat must have free space for expansion.

Our information: the absence of a gap between the metal wall of the furnace and the lining leads to destruction of the lining.

When installing this lining, the gap is sealed with basalt or kaolin wool, twisted into bundles, cords or in the form of a compressed sheet. Asbestos can be used for this purpose.

Wrong defense. Consequences

This picture occurs very often. The metal stove is lined with bricks using clay mortar, and without any gap. This is motivated by ensuring safety and improving the heating of the furnace.

Metal stove with brick lining

This is completely misleading!

• Firstly, brick is very heat-intensive .
• Secondly, brick has low thermal conductivity . What happens during operation of such a furnace?

The brick simply plays the role of thermal protection.
The main heat generated by the stove simply flies out into the chimney due to excess in the firebox. In addition, the absence of a gap prevents the penetration of cooling air to the metal walls of the furnace, which definitely leads to their burnout, and the expansion of the metal will lead to cracking of the brick protection.

As a result, carbon monoxide will begin to enter the room.

Not always brick: lining mixtures

Recently, “modeled” sauna stoves of various shapes have become very popular. Basically, such stoves are installed in bathhouses made in a stylized “fairytale style”. Such stoves are made using an ancient method called adobe.

After the clay has dried naturally, the oven is fired from the inside using firewood. The outer part is burned using blowtorches until a crust forms. It is very convenient to line such furnaces using special compounds.

These can be dry mixtures:

• Fireclay.
• Mullite.
• Corundum.

These compositions can be perfectly used for the on-site production of various refractory products, including linings. A solid, monolithic lining made from these materials far exceeds in quality seam furnace linings made with fireclay bricks.

On-the-job lining

Currently, there are a number of technologies in which lining or restoration of the lining is carried out without stopping the furnace. The compositions are applied by “spraying” directly onto a hot surface or by gunning.

Our information: shotcrete is a method in which concrete or other mixture is applied layer by layer to a structure using compressed air and a special shotcrete installation.

This method is mainly used in production, which allows lining work to be carried out, if necessary, without stopping the production process.

Brick kiln: problems with overheating

We have already considered the need for lining the combustion part of metal stoves, but what about brick stoves? What happens to brick kilns when they are overheated?

Cracks in a brick kiln

There is a concept - thermal cracking . This phenomenon applies both to the material of the stove itself and to its seams.

• The inner walls of the furnaces, heating up from the hot gases produced by the burned fuel, expand and begin to expand the outer “cold” walls.
• The outer walls of the furnace act as a “bandage”, maintaining the dimensions of the furnace and maintaining its integrity.
• The more the oven heats up, the thinner the “bandage” becomes, which is already under heavy loads, and therefore becomes even less durable.
• When the furnaces “overheat,” the outer walls begin to “move apart” under internal pressure.
• Cracks form and even individual bricks break.

Local solution: main disadvantages

It is worth noting that in a brick kiln clay is used to connect the bricks together. Therefore, either the seams themselves or the contact with the bricks rupture due to low adhesion. In any case, a seam in which a mortar with a high sand content was used will expand significantly more than a brick.

This situation is further complicated by the fact that the thermal coefficients of bricks and joints generally differ greatly from each other. This is understandable, because the bulk of the furnace solution is prepared directly on site. Stove makers primarily strive for the plasticity of the solution to the touch and the absence of cracking when drying and compressing.

Our reference: the correct assessment of the mortar for compliance with the bricks used can be checked as follows. Two bricks are held together with a solution; after drying, the test block is calcined in an oven, followed by an assessment for adhesion, cracking and peeling.

Methods and options for preparing the right solutions

Of course, this method requires a certain amount of time, because it is not a fact that you will get the required solution the first time.

Therefore, if you still decide to use this testing method, prepare several “blocks” for testing with different solutions. Then all you have to do is choose the most optimal one. The main thing is not to confuse and forget which solution is which.

Another good option is to use the most common clays for the solution, mixed with powder made from ground bricks.

If you use only firewood when burning, the use of special fireclay clays with a high content of kaolinite is not entirely advisable, since the temperature of the firewood is not sufficient for kaolin to sinter into mullite. But if you use coal, then this option will be completely justified.

Lining: no more questions

Having considered this issue, we can conclude that the lining of stoves used for domestic purposes mainly represents protection of the stove structure from the destructive effects of high temperatures. This is a kind of screen that prevents the heat flow of an open fire from directly affecting the walls of the stove.

Unlike “household” linings, industrial linings, for example, the lining of an induction furnace, are intended to significantly reduce heat losses, protect the furnace casing from direct exposure to high temperatures and protect against direct contact with molten metal.

Having considered this issue, we hope you will draw the right conclusion, which will help you when building stoves with your own hands.

Source: http://SdelaiKamin.ru/uhod-za-pechyu/futerovka-pechi-chto-eto-i-dlya-chego-115

Muffle furnace lining

Furnace lining is a mandatory process carried out during its construction. Footer (from German “futter” - gasket) is a kind of finishing that performs not an aesthetic, but a protective function. Lining is performed for various devices for domestic and industrial purposes that may be at risk of external influences: physical, chemical, thermal.

Additional protection is installed on the side of probable destruction. For example, pipes in a heating plant are lined on the outside to avoid damage from soil pressure, stones and other sharp objects in it.

A laboratory electric furnace is intended for high-temperature processes, so the lining can make up the entire structure or most of it.

Since the heater of the electric furnace is located inside it, the protective lining is installed there too

What is a furnace lining for? After all, it would seem that the walls of the muffle chambers are already constructed from fire-resistant materials. However, the destructive effect of thermal energy released during firing or melting of metals forces us to look for ways to increase the strength of the stove and increase its service life.

The lining of heating furnaces is also carried out in order to improve the thermal insulation functions. Correctly executed cladding will significantly reduce heat loss through the walls of the device. The main thing here is to observe the measure, since an excessive increase in the thickness of the lining can reduce the efficiency of the stove.

Today we will talk about how to make a furnace lining, list the types of linings and tell you what materials are best to use to create them. This information will be useful to those who do not want to buy a ready-made muffle furnace, but are planning to design a heating device themselves.

Types of lining for muffle furnaces

furnace lining presented below gives a clear idea of ​​​​how to create additional protection.

Technologies for forming a lining vary depending on the type of materials used to build the muffle chamber. We list the most common types of linings:

• Invoice . The walls are lined with fireproof materials - piece or sheet. In the first case, it can be molded fireclay bricks, in the second - ShPGT-450 slabs.
• Printed . The masonry is coated with a fire-resistant mixture with a viscous texture. This work is done manually.
• Using shotcrete method . The surface is covered with a flowing heat-resistant compound, which is sprayed under high pressure from a special device.

The lining of muffle furnaces is almost always carried out with an overlay. The filling method is used during minor repair work.

Lining work is carried out directly during the construction of the electric furnace. However, some of their varieties, such as filling, are carried out after construction is completed.

Next, we will consider how to calculate the furnace lining depending on the materials used.

What materials are best used to make a lining for a muffle furnace?

Furnace lining materials are divided into several classes. Their main difference is the characteristics of the ingredients included in the composition:

• “A” – the footer is created from components of natural origin. This also includes synthetic materials with a silicone binder.
• “B” – the main ingredient of the cladding is specially processed clay – fireclay. It is used to create blocks and bricks that are used to build a stove.
• “C” - this class includes materials created on the basis of other components.

B-class raw materials are considered the most popular for lining muffle furnaces, since they are constantly available and are relatively inexpensive.

To increase the heat-resistant qualities of fireclay, quartz sand, crushed sandstone and other rocks that do not change with significant heating are added to it.

Furnace lining with fireclay bricks or ceramics is sometimes carried out in combination with other materials containing white clay. They are produced in the form of rolls, sheets or plates and are laid between layers of masonry made of ceramics or heat-resistant components. Most often used:

• Basalt wool.
• Kaolin.
• Mullite-silica mats.
• Vermiculite.

If the furnace is lined with bricks, then dry mixtures are almost always used. They are used to prepare a solution that is resistant to high temperatures. This composition is coated with the masonry and the cavities and cracks formed during the construction of the muffle are filled.

Semi-liquid formulations help create a cohesive structure and prevent heat loss

Adhesive connection

How rational is it to use glue for lining work? To construct small-sized household and laboratory ovens, a special oven adhesive composition is often used. Its fluid texture allows you to smooth out irregularities and obtain a thin and even seam that does not protrude above the surface of the blocks.

When using basalt cardboard, horizontal sections can be coated with glue diluted with water 12 hours before starting work. Its amount should not exceed 15% of the total mass of the composition

Rules for applying glue to bricks or slabs for lining furnaces:

• The surface is pre-moistened.
• The adhesive solution is applied in a layer up to 3 mm thick.
• Approximately 1-4 kg of glue is consumed per 1 square meter. It all depends on the source material.
• Hardening time: 24 hours at a temperature of 25 degrees or more, 6 hours - from 90°C and above.

If several layers of coating are required, the solution is applied at intervals of 15 minutes.

Pros and cons of different lining materials

In small laboratory structures, refractory materials for lining furnaces occupy the entire space of the working chamber. Let's look at each variety in more detail and list their advantages and disadvantages.

Corundum or ceramics

Dense and hard material, resistant to aggressive chemicals. Very strong and durable. Among the disadvantages of muffle furnaces with a ceramic chamber, we note:

• Significant time costs to achieve the desired heating temperature.
• Increased power.
• The cost is half that of a fiber muffle.

The ceramic stove will serve for many years without compromising the integrity of the chamber

Fiber

Made from aluminum oxide, it heats up very quickly. Disadvantages include the inability to work with samples containing liquids. The vapors and gases released may render the camera unusable. In addition, aluminum fibers are considered very fragile and require careful handling. Once the surface inside the muffle is damaged or worn, further operation is impossible.

Fiber construction price is lowest

Ceramic fiber

Combines the best qualities of the two materials described above. With less power input, heating occurs much faster. The material is also characterized by average resistance to various chemicals.

When using a ceramic fiber muffle, the temperature regime must be strictly observed and not exceeded

Mullite-silica materials

Their strength is similar to fireclay, however, compared to bricks, the weight of mullite-silica is much lighter. External physical influences will not damage the integrity of the camera surface. They interact with chemicals in the same way as ceramic fiber - possible destruction does not occur immediately, allowing the situation to be corrected.

The advantages of this material:

• Accelerated heating.
• Duration of equipment operation.
• Affordable price.

Mullito-silica is sold in rolls, so it’s easy to purchase the right amount without overpaying

As you can see, not a single furnace is built without a lining, since the protective lining is intended both to save heat energy and to prevent damage to the internal chamber. Despite the variety of materials used to create stoves, you can choose a suitable lining for each of them.

Lining a small kiln is not a separate task, since the entire muffle performs a protective function. If all the rules for creating laboratory and household heating devices are followed, their functionality will be at the level of store-bought electric furnaces.

For any questions, please contact Labor consultants. We will clarify all unclear points.

Source: https://labor-snol.ru/news/futerovka-mufelnoj-pechi

What is Lining

Lining - 1. open
Same as: lining. 2. A facing layer of fire-resistant, chemically resistant and heat-insulating material, which covers the inner surface of metallurgical furnaces, steam boilers, ladles, etc.

Lining in the Encyclopedic Dictionary:

Lining - (from German Futter - lining) - protective internal lining (for example, from bricks, blocks) of furnaces, fireboxes, pipes, containers, etc. There are fire-resistant, chemically resistant and heat-insulating linings, and according to their chemical composition - acidic and main

The meaning of the word Lining according to Ushakov’s dictionary:

LINING
(te), lining, pl. no, w. (those.). 1. Action according to verb. line Furnace lining. 2. Internal lining, lining of chimneys, furnaces for melting metals, made of refractory materials.

The meaning of the word Lining according to the Brockhaus and Efron dictionary:

Lining - Furnaces in which metals are heated during various metallurgical processes are made of materials that ensure their strength and stability - brick, cast iron and iron. But all these materials are not able to withstand the high temperature at which these processes take place, the inevitable temperature fluctuations and the influence of the chemical reactions that accompany them.

In view of this, all working spaces of the furnaces that come into contact with metal or high-temperature gases are lined from the inside with a layer of fire-resistant and chemical-resistant materials, which protect the rest of the furnace from destruction. This internal fireproof clothing of furnaces is called their lining. For F.

Various rocks or clay are used, moreover, either in the form of individual stones (natural or artificial), or in the form of a plastic mass. All lining materials are divided into three classes: A) materials, the main part of which is silica. B) materials the main part of which is clay (hydrosilicate of alumina) and C) mixed materials not suitable for classes A and B.

Class A materials are: 1) natural (in the form of stones hewn from pieces of rock) and 2) artificial (in the form of bricks pressed from pre-crushed rocks). The following are used as natural stones: a) in the form of solid stones—sandstones, quartz, pudding (conglomerate)—for F. blast furnaces. siliceous shale - for fiery furnaces. granite - for stoves that do not develop the highest levels of heat.

b) in crushed form - ganister (quartz grains containing 1-7% Fe 2 O 2 and Al 2 O 3, bound by clay matter), which goes to F. Bessemer converters. Artificial siliceous F. is made in the form of so-called silica bricks.

To do this, finely ground, pure quartz is bound with 1-2% lime or clay substance and pressed into bricks, which are fired to white heat (fuel consumption is three times more than when firing ordinary building bricks). Under the influence of heat, these bricks swell somewhat, but under the influence of sharp temperature fluctuations, they crack easily.

Class B lining materials are used exclusively in their artificial preparation, since natural hydrosilicates of alumina lose water when heated. This type of material includes: a) bauxite brick.

To prepare it, natural alumina hydrate, containing an admixture of iron oxide and known as bauxite, is taken, fired, crushed, mixed with a small amount of water and fresh refractory clay, molded into bricks, which are fired again, and shrink significantly.

b) ordinary refractory (fireclay) brick, consisting mainly of refractory clay with an admixture of lean substance (burnt fireclay), which prevents drying out and cracking, to which clay is very prone. Fresh fireclay mass or ground fireclay bricks that have already been in use are mixed with enough fresh fireclay to form a thick dough.

For the sake of simplicity, sometimes quartz grains (the size of peas) are mixed into it, and in special cases - grains of graphite, coke or charcoal. An admixture of fine quartz flour, iron oxide, alkalis, etc. reduces the fire resistance of bricks. The following refractory materials belong to Class C: 1) basic heels, 2) coal bricks and 3) refractory mortars.

The main are partly iron oxides: ores, hammer scale, slags rich in iron oxide and (in modern times) chromium iron ore in the form of so-called chromium bricks. Practice has shown, however, that the degree of fire resistance does not compensate for the high price of the latter.

Bricks made of lime or magnesia, or both of these substances at the same time, are widely used as the main lining materials. dolomite is used for this purpose which is fired in cupola furnaces until white heat, at which point it begins to float.

After cooling, it is ground, sifted, mixed with 3-8% clay (previously dehydrated by boiling) and molded into bricks, sometimes used directly in the form of a plastic mass. Both the mass and the bricks are, however, subjected to a new firing before being used. Even more durable are magnesite bricks, made from magnesite fired until it melts, ground into flour and pressed on a hydraulic press.

The molded bricks are heavily fired. Magnesite mass (mixed for cohesion with tar, soluble glass, etc.) is used on the F. packing and directly. lime bricks for F. but they turned out to be unsuitable.

Coke turned out to be incomparably better , prepared as follows: dry coke, low in ash content, is ground into flour, mixed with tar or coal tar (up to 20%), stuffed into molds, and after removing from them, dried slowly (over two weeks) on low heat. heat and then fired in hermetically sealed muffles without air access. Taking into account its lightness, coke brick is no more expensive than fireclay and serves very well, except, however, in those cases when, due to the nature of the metallurgical process taking place, it is exposed (at high temperature) to the action of oxidizing gases, iron-rich slag or molten, carbon-poor iron. Refractory mortars used to fill joints when laying refractory bricks belong to the same class of lining materials. They are usually given a composition similar to that of the bricks themselves. For basic phosphorus, solutions are made from calcined dolomite or magnesite, cemented with resin, or from calcined, ground, sifted, and water-moistened magnesite. Sometimes dolomite milk or simply dry magnesite flour is used as a solution. Mortars for non- main stones are mixed with water from ground sand, lime, blast furnace slag, glass, fireclay, etc. The seams should be as thin as possible, for which purpose the bricks are carefully rubbed together before laying. In some metallurgical processes, furnace filtration not only protects the walls, under, and roof of the furnace working space from destruction by heat, but also itself participates in chemical reactions, helping to obtain a product of the desired qualities. V. Knabbe. Δ. .

Definition of the word “Lining” according to TSB:

Lining (from the German Futter - lining, lining)
is a protective internal lining of thermal units and their parts (furnaces, fireboxes, ladles, hogs, pipes, etc.), as well as chemical apparatus, pickling baths, etc.

It is made from bricks, slabs, blocks, concrete, ramming masses, etc. shotcrete mass. Depending on the purpose and type of material, F. can be fireproof, acid-resistant, or heat-insulating. F.

sometimes also called external protective cladding of unit elements, if heat flows, aggressive agents, etc. act on these elements from the outside.

Source: https://xn----7sbbh7akdldfh0ai3n.xn--p1ai/futerovka.html