Comparison between 1000 ° C high-temperature calcium silicate board and 650 ° C low-temperature microporous calcium silicate board

1.Product Overview

Calcium silicate board, as a high-quality thermal insulation material, is widely used in the industrial and construction fields. According to the different temperature ranges of use, it is mainly divided into two types: 1000-degree high-temperature calcium silicate board and 650-degree low-temperature microporous calcium silicate board. Although both of these two materials belong to the calcium silicate series, there are significant differences in raw material ratios, production processes, performance characteristics and application fields.

2.Differences in raw materials and production processes

1.1000-degree high-temperature calcium silicate board

Main raw materials: High-purity quartz sand (with SiO₂ content ≥96%), high-quality lime (CaO), and reinforcing fibers (such as asbestos substitute fibers) are adopted

2.Production process:

Dynamic hydrothermal synthesis method, reaction temperature 200-220℃

High-pressure forming (10-15 mpa)

High-temperature sintering (800-900℃)

Crystal structure: Mainly forms hard calcium silicate crystal (xonotlite, 6CaO·6SiO₂·H₂O) 2. Low-temperature microporous calcium silicate board at 650 degrees

Main raw materials: Common siliceous materials (SiO₂ content ≥85%), lime and organic fiber reinforcing materials

3.Production process:

Static hydrothermal synthesis method, reaction temperature 180-200℃

Forming under normal or low pressure (3-5 mpa)

Medium-temperature drying (300-400℃)

Crystal structure: Mainly tobermorite crystals (5CaO·6SiO₂·5H₂O) are formed.

3. Comparative Analysis of Thermal Performance

1.High-temperature resistance:

The crystal structure of the high-temperature plate remains stable at 1000℃ and will not undergo phase transformation

When the temperature of the low-temperature plate exceeds 650℃, tobermullite will gradually transform into hard calcium silicate, resulting in a decrease in strength

2.Thermal stability:

After 50 thermal cycles (1000℃→ room temperature) of the high-temperature plate, the linear change rate is less than 2%

Low-temperature plates are prone to microcracks when subjected to repeated thermal cycles above 650℃

3.Heat insulation efficiency

The thermal conductivity of low-temperature plates is lower below 500℃ (the micro-porous structure is more effective in blocking thermal convection).

The radiation heat transfer suppression effect of the high-temperature plate is better when the temperature is above 600℃

4.Processing performance:

Low-temperature plates are easier to cut and drill (with a high content of organic fibers).

The edge strength of high-temperature plates is better and they are less prone to damage

4. Comparative Analysis of Thermal Performance

1.High-temperature resistance:

The crystal structure of the high-temperature plate remains stable at 1000℃ and will not undergo phase transformation

When the temperature of the low-temperature plate exceeds 650℃, tobermullite will gradually transform into hard calcium silicate, resulting in a decrease in strength

2.Thermal stability:

After 50 thermal cycles (1000℃→ room temperature) of the high-temperature plate, the linear change rate is less than 2%

Low-temperature plates are prone to microcracks when subjected to repeated thermal cycles above 650℃

3.Heat insulation efficiency

The thermal conductivity of low-temperature plates is lower below 500℃ (the micro-porous structure is more effective in blocking thermal convection).

The radiation heat transfer suppression effect of the high-temperature plate is better when the temperature is above 600℃

4.Processing performance:

Low-temperature plates are easier to cut and drill (with a high content of organic fibers).

The edge strength of high-temperature plates is better and they are less prone to damage。

5.Differences in application fields

Typical applications of high-temperature plates:

Petrochemical industry: Insulation for cracking furnaces and reforming furnaces (800-1000℃)

Power industry: Insulation of boiler furnace walls and flues

Metallurgical industry: Steel ladles, tundish permanent layers

Industrial kilns: Lining of ceramic kilns and glass kilns

Typical applications of low-temperature plates:

Construction field: Fireproof partition walls, ceilings (50-150℃)

Hvac: Pipe insulation (<300℃)

Shipbuilding: Fire and heat insulation of cabins

Low-temperature equipment: Insulation for storage tanks and reaction vessels (200-500℃)

5.Selection Suggestions

The following factors should be given priority consideration when making a choice:

Operating temperature range (whether it frequently operates beyond the temperature limit)

Thermal shock frequency (intensity of temperature change)

Mechanical load requirements (whether load-bearing is needed)

Budget constraints (initial investment and long-term maintenance costs)

Space limitations (requirements for insulation layer thickness)

For working conditions where the temperature frequently fluctuates between 600 and 800℃, even if the maximum temperature does not reach 1000℃, it is recommended to use high-temperature plates to ensure long-term stability.

6.Future Development Trends

High-temperature plates: Developing towards higher temperature grades (1200℃) while reducing density

Low-temperature board: Enhance fire resistance (reaching A1 non-combustible level) and improve water resistance

Common development: nano-modification, addition of composite phase change materials, intelligent thermal management

With the increasing requirements for energy conservation and emission reduction, both products will continue to optimize their thermal conductivity and develop more functional products (such as sound-absorbing, radiation-resistant and other composite functional boards) to meet the growing energy conservation and environmental protection demands of various industries.