Common Types of Thermal Insulation for the Industrial Sector

Industrial sectors use different thermal insulation types to keep equipment safe. These help protect machines that get very hot. Refractory materials work well in tough places. They are good when heat and chemicals can cause problems. Refractories keep furnaces, boilers, and reactors safe. A study from insulation.org showed a big problem. Not enough insulation causes about 8.3% of energy loss in factories. This usually happens when temperatures are between 150 and 600°F. This shows thermal insulation is important for saving energy.

Some common refractory materials are:

• Refractory ceramic fiber (alumina-silica blend, works up to 2300°F)

• Low biopersistent fiber (biosoluble, good up to 2190°F)

• Polycrystalline fiber (works up to 3000°F)

Other popular insulation types are:

• Fiberglass

• Stone wool

• Foam

• Wood fiber

Refractories are important in hot processes. They last a long time and protect against heat and chemicals.

Key Takeaways

• Refractory materials keep machines safe from very high heat, chemicals, and harm. They help save energy and make machines last longer.

• Picking the right refractory type—acidic, basic, or neutral—depends on the chemicals and heat levels. This keeps things safe and strong.

• Other insulation types like mineral wool, ceramic fiber, calcium silicate, foam glass, and aerogel have different good points. They help with heat, weight, and chemical safety.

• Important features like thermal resistance, chemical resistance, mechanical strength, and thermal shock resistance help choose the best insulation for each job.

• Choosing, putting in, and caring for insulation the right way saves energy, stops machine damage, and cuts costs over time.

Refractory Materials Overview

Definition of Refractory

Refractory materials are very important in factories. They stop heat from hurting equipment. These materials do not melt easily. Their melting points are very high. This makes them good for places with lots of heat. Refractories include fire bricks, castables, ceramic fibers, and insulating bricks. Each type has its own job.

Refractory materials do not melt even at 1,200°F (650°C). They keep their shape and strength when it is very hot. The fusion temperature puts refractories into three groups: normal, high, and super. Normal refractories melt between 1,580°C and 1,780°C. High ones work from 1,780°C to 2,000°C. Super refractories can handle over 2,000°C. The pyrometric cone equivalent (PCE) value shows how much heat a refractory can take before it gets soft.

Refractories are different in how they move heat. Some, like silicon carbide, let heat pass through. Others, like silica and alumina, do not. Insulating refractories like calcium silicate and kaolin keep heat inside. Their tiny closed pores trap heat. This helps furnaces and kilns stay hot.

Key Properties

Refractory materials have many important features. These features help them work well in tough places.

Ordered List of Key Properties:

1. High thermal resistance: Refractories can handle up to 1,800°C. This lets them work in furnaces, kilns, and reactors.

2. Chemical resistance: They fight off acids, alkalis, and melted metals. This keeps equipment safe from rust and chemical harm.

3. Mechanical strength: Refractories can take pressure and heavy loads. They do not break down easily.

4. Thermal shock resistance: These materials can handle quick changes in heat. They do not crack or break when the temperature jumps.

5. Porosity and permeability: Refractories control how gas moves. Their small closed pores trap air and slow heat loss.

6. Abrasion resistance: They do not get damaged by melted stuff or strong forces.

7. Forms: Refractories come as fire bricks, castables, ceramic fibers, insulating bricks, and refractory cement. Each form works best for different needs.

8. Functions: Refractories hold heat, protect furnace walls, stop thermal shock, fight chemicals, and make things safer.

The way refractory materials are built changes how they work. Low bulk density, between 0.6 and 1.2 g/cm³, makes them lighter but still strong. High apparent porosity, above 45%, means more closed pores. These pores trap air, which does not move heat well. This helps refractories stop heat from escaping.

A table below shows how refractory materials compare to other insulation types for max temperature:

Refractory materials work at much higher temperatures than mineral wool or glass wool. Their high melting points make them great for very hot jobs.

The chart below shows max temperatures for different insulation types:

Refractories also stay strong against chemicals. Many can handle pH from 4.5 to 12.0. They work where there are mild acids and alkalis. Some, like MgO-Cr2O3 refractories, help refine copper at up to 1,400°C. These materials fight off attacks from iron, silicon, calcium, lead, and arsenic oxides. Alumina-spinel refractories work well with lead-rich copper slags at 1,300°C.

Mechanical strength tests help pick refractory materials for furnaces. Two main tests are cold crushing strength and modulus of rupture. Cold crushing strength shows how much pressure a refractory can take at room temperature. Modulus of rupture tells how much bending stress it can handle. These tests show how well refractories resist breaking and cracking.

Refractory materials must keep their strength and shape at high heat. High-temperature volume stability stops shrinking or swelling. This keeps furnace linings safe and strong. Refractories also need to fight off slag. They must not wear away from slag, fuel ash, and other stuff at high heat.

A table below lists heat resistance values for refractory materials used in steel making:

The chart below shows heat resistance for different refractory materials:

Industrial Uses

Refractory materials are used in many industries. They keep equipment safe in hot places. Factories use refractories in furnaces, kilns, reactors, and boilers. These materials line steel, cement, glass, and power plants.

A table below shows the global market size for refractory materials in industry:

Refractories are very important in iron and steel making. They line blast furnaces, ladles, and converters. These materials can take high heat and chemical attacks from melted metal and slag. Cement plants use refractories in rotary kilns and coolers. Glass factories use refractory bricks and castables to line melting tanks and regenerators.

Power plants use refractory materials in boilers and incinerators. These materials protect equipment from heat and rust. Non-ferrous metal industries, like copper and aluminum, use refractories in smelting and refining furnaces. Chemical plants also use refractories to fight acids, alkalis, and rough gases.

Refractory materials help save energy by stopping heat loss. Their insulation keeps heat inside machines. This saves energy and lowers costs. Refractories also make things safer by stopping equipment from breaking and causing accidents.

The market for refractory materials is growing. Asia-Pacific makes and uses the most. Big companies sell refractories for many factory jobs. More industries want better refractory materials for longer-lasting equipment.

Refractories come in many shapes for different jobs. Fire bricks give support and insulation. Castables fill spaces and fix broken linings. Ceramic fibers are light and insulate hot equipment. Insulating bricks stop heat loss in kilns and furnaces. Refractory cement sticks bricks and castables together to make strong linings.

Factories need refractory materials to keep high heat and protect equipment. These materials do not melt, fight chemicals, and stay strong. Their toughness makes them needed for safe and good work.

Types of Refractory Materials

Factories use different refractory materials to protect equipment. These materials stop heat, chemicals, and damage. There are several main groups. Each group works best in certain places. Knowing these types helps engineers pick the right one.

Basic Refractories

Basic refractories resist basic slags and strong chemicals. They have lots of magnesium oxide or calcium oxide. Factories use them in steelmaking and cement kilns. They work well where there is a high CaO/SiO2 ratio.

Common Basic Refractory Materials:

• Magnesite bricks (mostly magnesium oxide)

• Chrome-magnesite bricks (magnesia and chromite mix)

• Dolomite bricks (calcium magnesium carbonate)

• Magnesia-carbon bricks

Basic refractories protect furnaces from basic slags and heat. They keep their shape and strength with tough chemicals.

The table below shows main features of basic refractories:

Factories pick basic refractories when basic slags attack other materials. These bricks resist damage and chemical wear. They help furnaces last longer and stay safe.

Performance Characteristics:

• High melting points let them handle very hot jobs.

• Bulk density and porosity affect how well they resist damage.

• Cold crushing strength shows how much pressure they can take.

• Dimensional stability keeps linings from shrinking or swelling.

Basic refractories do not work well with acidic slags. Acidic chemicals can break their structure. Engineers must match the refractory to the slag type.

Acidic Refractories

Acidic refractories have lots of silica and alumina. These materials resist acidic slags and gases. They do not work well in basic places. Factories use acidic refractories in glass furnaces and coke ovens.

Main Acidic Refractory Materials:

• Silica bricks (over 93% silica)

• Fireclay bricks (alumino-silicate, with 25-45% alumina)

• High alumina bricks (over 48% alumina)

• Quartzite-based products

The table below compares chemical resistance of refractory types:

Silica bricks have a high melting point, above 3,100°F (1,700°C). They keep their shape in glass furnaces and coke ovens. Fireclay bricks work well in moderate heat. High alumina bricks handle higher heat and resist slag better.

Key Features of Acidic Refractories:

• High silica content resists acidic slags.

• Alumina makes them stronger and helps with heat changes.

• High melting points let them work in glass and ceramic jobs.

• Poor resistance to basic slags and fluxes.

Factories use acidic refractories where acidic gases or slags attack the lining. These materials protect equipment from rust and heat loss. They help keep furnaces at steady temperatures.

Typical Applications:

• Glass tank furnaces

• Coke ovens

• Ceramic kilns

• Acidic gas environments

Silica and alumina are important for these refractories. Silica bricks resist high heat but can crack with quick temperature changes. Alumina-rich bricks handle heat changes better.

Neutral Refractories

Neutral refractories work between acidic and basic types. They resist both acidic and basic slags. Factories use them where chemical conditions change or both acid and base attacks happen.

Common Neutral Refractory Materials:

• Chrome bricks (chromium oxide)

• Carbon bricks (carbon or graphite)

• High alumina bricks (over 48% alumina)

• Silicon carbide bricks

Neutral refractories give balanced protection. They work in furnaces with both acidic and basic slags.

The table below lists common neutral refractories and uses:

Neutral refractories use alumina, carbon, chromium oxide, or silicon carbide. These materials resist damage from both acid and base slags. They also handle quick temperature changes well.

Key Features of Neutral Refractories:

• High resistance to chemical attack from acids and bases.

• Good resistance to heat changes.

• High melting points, often above 2,800°F (1,540°C).

• Strong mechanical strength and abrasion resistance.

Factories use neutral refractories in steelmaking, glass, and chemical industries. These materials line furnaces, kilns, tanks, and reactors. They protect equipment from many chemicals and heat.

Industrial Applications:

• Blast furnace linings

• Electric arc furnaces

• Glass melting tanks

• Chemical reactors

• Waste incinerators

Neutral refractories help factories handle changing chemicals. They keep equipment safe and last longer.

Main Categories and Forms of Refractory Materials

Engineers sort refractory materials by chemical type, source, and job. The main groups are:

• Alumino-silicate raw materials (fireclay, high alumina bricks)

• Basic raw materials (magnesite, chromite)

• Insulating raw materials (lightweight, high porosity)

• Specialty types (zirconia, silicon carbide)

Factories use different forms for each job:

• Fired products: bricks, castables, mortars

• Non-fired products: monolithic refractories, plastic refractories

• Functional bricks: shaped for high melting points

• Casting materials: used in monolithic linings

A list of common refractory products includes:

• Fireclay bricks

• High alumina bricks

• Silica bricks

• Magnesite bricks

• Chromite bricks

• Zirconia bricks

• Insulating bricks

• Monolithic refractories (ramming, patching, castable, plastic, mortars)

Insulating materials have lots of tiny holes and low heat flow. They help keep heat inside furnaces and save energy.

Tip:
Factories should always match the refractory type to the job. Using the wrong type can cause fast damage or safety problems.

Chemical Resistance and Melting Points

Chemical resistance depends on the main parts of the refractory. Acidic refractories resist acids but fail with bases. Basic refractories do the opposite. Neutral refractories handle both. Melting points are different for each type:

• Silica bricks: melting point above 3,100°F (1,700°C)

• High alumina bricks: melting point above 3,400°F (1,870°C)

• Magnesite bricks: melting point above 2,800°F (1,540°C)

• Chrome bricks: melting point above 3,000°F (1,650°C)

• Silicon carbide bricks: melting point above 2,700°F (1,480°C)

Silica and alumina help refractories handle heat and chemicals. High melting points mean longer life and better protection.

Summary Table: Types of Refractory Materials

Factories need these refractory materials to keep equipment safe. They help save energy and improve production. Picking the right type means better performance and less repair.

Other Industrial Insulation Types

Mineral Wool

Mineral wool is also called stone wool or rock wool. It is made by melting rock and spinning it into fibers. You can find it as blankets, boards, or pipe covers. This insulation works from 0°F to 1800°F. Factories use it on hot pipes and tanks. It also helps block noise. Mineral wool keeps heat inside because it does not let heat pass easily. It does not burn and can stop fires from spreading. Workers like it because it is light and bends easily. It does not have asbestos, so it is safer than some old insulation. Mineral wool is good when refractory is too heavy or costs too much.

Ceramic Fiber

Ceramic fiber insulation is great for very hot jobs. It can take heat up to 1600°C (2912°F) and keeps its shape. This material is much lighter than old refractory bricks. Factories use ceramic fiber in furnaces, kilns, and boilers. It comes as blankets, boards, and even paper. Ceramic fiber helps stop heat loss and saves energy. It can handle quick heat changes and shaking, so it lasts longer. Some advanced ceramic fibers, like polycrystalline types, work at even higher heat. They are used where other insulation cannot do the job.

• Ceramic fiber insulation gives:

• High heat resistance (up to 2300°F and more)

• Low heat flow for better energy savings

• Light, bendy forms for easy use

• Strong against wear and heat shock

Calcium Silicate

Calcium silicate insulation uses lime and silica with fibers. It is made into hard boards or blocks. This material works from 80°F to 1200°F. Factories put it on hot pipes and surfaces. Calcium silicate does not get hurt by acids or alkalis. It does not burn and keeps its shape when wet. Workers must cover it because it can break if hit. It is heavier than mineral wool but fights chemicals better. It is used when refractory is too heavy and mineral wool is not strong enough.

Calcium silicate boards stay strong in tough chemical places. They protect equipment from heat and rust.

Foam Glass

Foam glass insulation is made from recycled glass that is heated and foamed. It forms blocks with tiny closed cells, so water cannot get in. This makes it great for pipes underground or in wet places. Foam glass works from -450°F to 900°F. It does not burn and fights off chemicals. Its strength ranges from 1.2 MPa to 7.8 MPa, depending on how it is made. Most foam glass in factories has about 3.9 to 4.3 MPa, which can hold heavy things.

Factories use foam glass when refractory is too thick or when water resistance is needed.

Aerogel

Aerogel insulation is one of the most advanced kinds. It looks like a soft, spongy blanket. Aerogel has the lowest heat flow of any industrial insulation, about 0.017 to 0.020 W/m·K. This means it stops heat better than mineral wool, foam, or most refractory products. Aerogel works up to 1400°C and is very light. Factories use it when space is small or when saving energy is most important. Aerogel can do the same job as thicker insulation but takes up less space.

Aerogel helps factories cut heat loss without adding much weight or thickness. It is often used with refractory linings in the hottest places.

Comparison of Key Properties

Thermal Conductivity

Thermal conductivity tells us how fast heat moves through a material. If the number is lower, the insulation works better. Factories want insulation that keeps heat inside machines. Aerogel is special because it has about half the thermal conductivity of mineral wool. This means aerogel keeps heat in better, even if it is thin. Mineral wool is used as the main material to compare others. Ceramic wool can handle much higher heat, but its thermal conductivity is not always given. Still, ceramic wool works well when things get very hot.

Ceramic fiber insulation, like ceramic wool, is used where it gets very hot. It keeps heat from leaving, even in furnaces. Aerogel helps factories save energy because it stops heat loss better than other materials. When picking insulation for hot jobs, thermal conductivity is very important.

Chemical Resistance

Factories need insulation that does not get ruined by chemicals. Mineral wool has a neutral pH and does not catch fire. It works well where there is salt or chemicals in the air. It can take heat up to about 1038°C. Refractory fiber insulations, like ceramic fibers made from alumina and silica, can handle quick heat changes. They also work at temperatures up to 1649°C. These materials do not burn and can resist damage from strong chemicals.

Ceramic fibers and polycrystalline wools are better at fighting chemical attack than most other types. They stay strong even when acids or alkalis are around. This makes them a great choice for places where chemical resistance is very important.

Mechanical Strength

Mechanical strength shows how much force insulation can take before it breaks. Factories test how much weight, bending, and stretching insulation can handle. These tests help see if a material can hold heavy things or bend without cracking. Ceramic foams are stronger than solid foams or mineral wool if they have the same density. Glass-ceramic foams have compressive strength from 0.3 to 4.5 MPa. If there are more pores, strength can go down, but insulation gets better.

Engineers use crushing and bending tests to make sure insulation will last in hard jobs.

Refractory materials keep their strength even when it is very hot. They do not break from quick heat changes. Foam glass is also strong, so it is good for tough jobs. Mechanical strength helps factories choose the best insulation for each job.

Selection Guide for Industrial Applications

Picking insulation or refractories for factories needs good planning. Every job is different. Engineers think about many things before they choose a material.

1. Find out the highest and usual temperature the equipment will get. Some refractories work above 1,800°C. Others are better for lower heat.

2. See if there are chemicals like acids or alkalis. Many jobs have gases that can cause rust. Refractory materials must fight these chemicals to last longer.

3. Think about shaking, hitting, or quick heat changes. Equipment can vibrate or get hit. Refractories with high thermal shock resistance do better here.

4. Know what the main job is. Some places need insulation to save energy. Others want safety or less noise.

5. Look at how it is built. Refractories come as bricks, castables, fibers, or boards. Each type works for different jobs and ways to put them in.

6. Check how to install it. Some refractory products go in fast with clips or coatings. Others need skilled workers and special tools.

7. Think about the total cost. The best choice balances price, installation, care, and energy savings.

Tip: Always pick a refractory that matches the process heat and chemicals. Using the wrong kind can make it break early.

The table below lists important things for insulation and refractories in chemical plants:

Factories sometimes make mistakes. They may pick the wrong refractory for the heat, use the wrong thickness, or install it badly. Water getting in and damage from hits also make it work worse. Checking and fixing things often helps stop these problems.

Price and how long it lasts matter a lot. Good refractories may cost more but last longer and save money later. For easier jobs, cheaper refractory choices can work fine.

New materials and expert help let factories find the best answer for each job. The right refractory or insulation makes things safer, saves energy, and helps equipment last longer.

Refractories are very important for keeping factories safe. They stop heat, chemicals, and damage from hurting machines. Studies show picking the right refractory saves energy and lowers mistakes. If a refractory can handle quick heat changes and fits well, it lasts longer. Knowing about each type helps pick the best insulation for the job. Experts say to check how hot things get and test materials for safety. Companies make special products and help with support. Their help saves money and keeps equipment working safely.

Refractories with special features and good setup work better and cost less.

• Refractories make factories safer and more dependable.

• Talking to companies helps find the best choice for every job.

FAQ

What are refractory materials used for in factories?

Refractory materials keep equipment safe in hot places. They cover furnaces, kilns, and reactors. These materials help stop heat from escaping. They also protect against chemical harm. Many factories use them in steel, glass, cement, and power plants.

How do refractory bricks differ from ceramic fiber?

Refractory bricks are strong and last a long time. They work well in tough jobs. Ceramic fiber is much lighter and easy to put in. It keeps heat in better at high temperatures. But ceramic fiber can wear out faster in hard jobs.

Can refractory materials resist acids and alkalis?

Yes, some refractory materials fight acids. Others fight alkalis. Acidic refractories work best with acids. Basic refractories work best with alkalis. Neutral refractories can handle both. Engineers pick the right type for each job.

How does Yufeng Refractory ensure product quality?

Yufeng Refractory checks quality very carefully. They test raw materials and finished products. Their team looks at strength, heat resistance, and chemical safety. Customers get good refractory materials for every need.

What is the best way to install refractory materials?

Workers use bricks, castables, or fiber modules. They follow the maker’s instructions. Good installation stops cracks and gaps. Yufeng Refractory gives help and guides for safe and easy installation.