Thermal Insulation Refractories
Efficient Solutions for Energy Saving and Thermal Resistance
The use of Thermal Insulation materials reduces material consumption, saves fuel, lowers capital investments, and enhances the efficiency of thermal processes. Therefore, this type of product is an essential part of the refractory industry’s portfolio. Thermal Insulation refractories are used in metallurgy, energy, petrochemicals, and other industries for insulating furnaces and high-temperature equipment. These materials are applied in environments where weight reduction and heat retention are critical for improving efficiency and reducing energy costs.
Types of Products
Taking into account the specific requirements of our customers, we offer the manufacturing and supply of refractory products in various shapes and configurations. Our advanced production capabilities and technological expertise enable us to handle projects of any complexity, ensuring high quality and precision in every delivery.
Technical Description
Thermal Insulation materials include a wide range of materials with different compositions, characterized by high porosity, low apparent density, and low thermal conductivity.
Thermal conductivity depends not only on overall porosity but also on the size, shape, and distribution of pores, as well as the mineral composition. The lowest thermal conductivity is observed in materials with pore sizes smaller than 0.1 mm.
The primary performance characteristic of thermal insulation materials is their maximum operating temperature, which serves as the basis for their classification into the following groups:
- High-temperature – above 1200°C;
- Medium-temperature – 900-1200°C;
- Low-temperature – up to 900°C.
For low-temperature insulation, materials such as diatomite, asbestos, and vermiculite products are used. For medium- and high-temperature insulation of furnaces, various types of lightweight refractories are applied.
Thermal Insulation refractories are also an essential component in industrial processes where it is necessary to combine high operating temperatures with low thermal conductivity.
Erbau Industrial Group offers for delivery Thermal Insulation Refractories, which corresponds to the following quality indicators:
Table 1. Physical and chemical parameters of lightweight products
| Properties | Value for product grades | |||||
| Silica | Mullite-silica | Mullite | Corundum | |||
| SL-1,2 | SL1-1,2 | MSL-0,8 | MLL-1,3 | CL-1,3 | CL-1,1 | |
| Mass fraction, %: | ||||||
| min | 91 | 90 | 50 | 63 | 95 | 90 |
| max | – | – | 1,0 | 1,4 | 0,5 | 1,0 |
| Apparent density, g/cm, max | 1,2 | 1,2 | 0,8 | 1,3 | 1,3 | 1,1 |
| Additional linear shrinkage (growth) at 2h exposure, %, max, | 1,0 | 1,0 | 1,0 | 1,0 | 0,8 | 1,1 |
| at temperature, °C | 1550 | 1550 | 1250 | 1550 | 1550 | 1550 |
| Compressive strength, N/mm, min | 4,5 | 4,5 | 2,5 | 3,0 | 3,5 | 2,5 |
| Thermal conductivity, W/(m*K), max, at average temperature, °С: | ||||||
| 350±25 | 0,60 | 0,60 | 0,35 | 0,50 | 0,80 | 0,55 |
| 650±25* | 0,70 | 0,70 | 0,40 | 0,60 | 0,80 | 0,55 |
| Density, g/cm, max | 2,39 | 2,39 | – | – | – | – |
| * To be determined at the request of the consumer. | ||||||
Table 2. Physical and chemical parameters of lightweight products
| Properties | Fireclay | |||||||
| FLA-1,3 | FKL-1,3 | FL-1,3 | FL-1,0 | FL-0,9 | FTL-0,6 | FL-0,4 | FL1-0,4 | |
| Mass fraction, %: | ||||||||
| min | 36 | – | – | – | – | – | – | – |
| max | – | – | – | – | – | 1,6 | – | – |
| Apparent density, g/cm, max | 1,3 | 1,3 | 1,3 | 1,0 | 0,9 | 0,6 | 0,4 | 0,4 |
| Additional linear shrinkage (growth) at 2h exposure, %, max, | 1,0 | 1,0 | 1,0 | 1,0 | 1,0 | 0,7 | 1,0 | 1,0 |
| at temperature, °C | 1400 | 1400 | 1300 | 1300 | 1270 | 1150 | 1150 | 1150 |
| Compressive strength, N/mm, min | 4,5 | 3,5 | 3,5 | 3,0 | 2,5 | 2,5 | 1,0 | 1,2 |
| Thermal conductivity, W/(m-K), max, at average temperature, °С: | ||||||||
| 350±25 | 0,60 | 0,50 | 0,60 | 0,50 | 0,40 | 0,25 | 0,20 | 0,20 |
| 650±25* | 0,70 | 0,60 | 0,70 | 0,60 | 0,50 | 0,30 | 0,25 | 0,25 |
| Density, g/cm, max | – | – | – | – | – | – | – | – |
| * To be determined at the request of the consumer. | ||||||||
Table 3. Physical and chemical parameters of diatomite and diatomite foam products
| Properties | Value for product grades | ||||||
| PD-350 | PD-400 | D-500 | D-600 | PD-350 | PD-400 | D-500 | |
| Highest grade | |||||||
| Density (volumetric mass), kg/m, max | 350 | 400 | 500 | 600 | 350 | 400 | 500 |
| Thermal conductivity, kcal/(h-m-°C), max, at average temperature: | |||||||
| 25±3 °С | 72 | 82 | 90 | 100 | 68 | 78 | 85 |
| 300±5 °С | 105 | 115 | 135 | 145 | 100 | 110 | 130 |
| Compressive strength, kgf/cm, min | 6 | 8 | 6 | 8 | 8 | 9 | 8 |
| Linear temperature shrinkage at 900 °C, %, max | 2 | 2 | 2 | 2 | 1,5 | 1,5 | 1,5 |
To receive the best service and quality
How the Production Process Works
Thermal insulation refractories are produced to combine high thermal insulation with low density and can be fireclay, silica, high-alumina, and other types. The low density of these materials is achieved through specialized technologies that create a porous structure.
The production of thermal insulation refractories involves three main methods:
- Incorporation of burnable additives, which decompose during firing, leaving behind a porous structure;
- Use of foaming agents, which create air pockets within the material;
- Chemical introduction of reactive additives into a mixture of clay and chamotte, which interact to release gaseous byproducts, forming pores.
The simplest and most common method is the use of burnable additives. When using the burnable additives method, solid combustible materials such as sawdust, coal, coke, and others are added to the ceramic mass. During the firing process, these additives burn out, creating a large number of irregularly shaped pores within the material.
Foaming method allows for the production of materials with a porosity of up to 80-85%. The process involves mixing finely ground refractory material with a stable and strong foam. The foam mixture, with a moisture content of 40-45%, is poured into molds. After drying and firing, the final products contain a large number of small, evenly distributed pores. Compared to materials produced using the burnable additives method, foamed refractories have higher porosity and lower thermal conductivity. However, their mechanical strength is lower.
Chemical method creates pores through the release of gaseous byproducts resulting from the reaction of dolomite and gypsum with sulfuric acid. This process forms a large number of evenly distributed pores throughout the material.
Fibrous materials have gained widespread use in thermal insulation due to their lightweight nature, low thermal conductivity, high thermal resistance, and excellent chemical stability. The most commonly used products are kaolin wool and materials based on it. Kaolin wool is produced from refractory clays, kaolins, or synthetic mixtures of kaolin and high-alumina compositions. Today, more than 50 types of products are manufactured, including roll materials, dense felt, boards, mats, paper, and cardboard. Lining industrial furnaces with fibrous refractories significantly reduces capital investment in thermal equipment construction and lowers labor costs.
Requirements for Insulation Materials
- Low thermal conductivity coefficient;
- Ability to withstand high temperatures to which the internal refractory layer is exposed;
- Sufficient structural strength to prevent destruction under the weight of the insulation layer;
- Low specific heat capacity to minimize heat losses due to heat accumulation in the masonry.
Flexible Formats
Lightweight refractories can be manufactured in various shapes and sizes, enabling their use in diverse structures and applications. This flexibility makes them suitable for a wide range of industrial processes where material adaptability is essential.
Quality Control
Checking the physical and chemical properties: Strength, thermal conductivity, porosity, chemical resistance, and other parameters are tested in accordance with the required standards.
Sample selection: Samples are taken from each batch of products for laboratory testing.
Packaging and Transportation
Product Protection: Finished products are packaged on pallets or in boxes, and if necessary, they are additionally layered with paper or other materials. To protect against damage and moisture, packaged products are wrapped in film, while external corners and edges are reinforced with protective corner guards.
Historical Background of Thermal Insulation Refractories
The history of thermal insulation refractories dates back to the early 20th century when researchers began actively exploring the possibility of creating refractory materials with low density for use in metallurgy, the chemical industry, and other sectors that required not only heat-resistant but also lightweight materials.
The first attempts to create lightweight refractories were made in the 1920s when the technology for producing refractory materials became more advanced. Materials such as pumice, vermiculite, and other natural porous materials were used to manufacture these materials, which had high thermal resistance while being much lighter than traditional refractories made from chamotte or refractory clay. These materials were not only lightweight but also had good thermal insulation properties, making them popular in industrial applications.
In the mid-20th century, based on the developed technologies for producing lightweight refractories, synthetic materials such as alumina oxides, silicates, and other specialized components began to be used. These materials allowed the creation of lightweight and high-performance refractories with enhanced thermal insulation and mechanical properties. During this period, new production methods were developed, including the use of expanded polystyrene and other organic compounds, which enabled the production of materials with a porous structure capable of withstanding temperatures of up to 1600-1700°C.
