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Rongsheng Lightweight insulating refractory castable. Lightweight insulating refractory concrete can also be called lightweight insulating refractory castable. Lightweight insulating refractory concrete is an amorphous insulating material made of lightweight refractory aggregate, admixtures, and binder materials. It is usually constructed by pouring, and sometimes by spraying or spraying. Therefore, it is also called lightweight refractory castable, lightweight refractory spray coating, or lightweight amorphous refractory material.

 

Advantages of Lightweight Insulating Refractory castables

 

Because lightweight insulating refractory castables are easy and quick to construct, especially for linings with complex shapes and structures, the construction is relatively easy, and it has many advantages such as energy saving. It is now widely used as an insulation material for many high-temperature projects. Rongsheng lightweight refractory castables are usually named according to the lightweight aggregates used, such as expanded vermiculite castables, expanded perlite castables, lightweight high-alumina castables, alumina hollow ball castables, etc.

 

The Main Raw Material Composition of Lightweight Thermal Insulation Refractory Castables

 

The main raw material composition of lightweight refractory castables is lightweight aggregate and binder.

 

Lightweight refractory aggregate

There are many types of lightweight refractory aggregates. Which lightweight aggregate to choose to prepare lightweight thermal insulation refractory castables mainly depends on the use temperature of concrete. Generally, when used at temperatures below 800 ~1000℃, expanded vermiculite, expanded perlite, or diatomaceous earth are used. When used in the temperature range of 1100~1400℃, lightweight clay aggregate and lightweight high-aluminum aggregate are used. When used at higher temperatures, oxide hollow ball high-grade thermal insulation aggregate is used. The use of temperature range and filling volume density of various lightweight aggregates of Rongsheng manufacturers.

 

Common Temperature Range and Filling Volume Density of Lightweight Aggregate
Types of lightweight aggregate		Commonly used temperature ℃, ＜	Filling volume density g/cm3
Lightweight insulation aggregate	Perlite	1200	0.05 ~ 0.4
Lightweight refractory aggregate	Lightweight clay clinker	1400	0.5 ~ 1.0
	Lightweight high-alumina clinker	1500	0.5 ~ 1.2
	Foamed silica	1500	0.2 ~ 0.35
	Hollow alumina spheres	1500	0.5 ~ 0.8
Melting material	Zirconia hollow spheres	2200	1.6 ~ 3.0
	Silica hollow spheres	1200	–

 

Binder

Lightweight thermal insulation refractory castables usually use aluminate cement, water glass, and phosphate as binders. The properties of the binder have a great influence on lightweight thermal insulation refractory castables.

 

Performance Indicators of Lightweight Insulating Refractory Castables

 

Composition and Properties of Lightweight Insulating Refractory Castables
Items	Maximum operating temperature ℃	Bulk density after drying kg/m3	After sintering at 500 ℃		Thermal Conductivity W/(m·K)
			Compressive strength MPa	Line change rate %
Expanded vermiculite castable	1000	1050	3.4	-0.14	–
Expanded perlite castable	1000	1200 ~ 1300	7.4 ~ 8.3	-0.21	0.308(600℃)
Lightweight clay castable	1300	1465	6.7	-0.11	0.611(30 ~ 357℃)
Lightweight high alumina castable	1300	1340	8.6	-0.07	0.673(30 ~ 357℃)
Alumina hollow ball castable	1600	1600	20.1(800℃)	0.11(800℃)	0.889(1200℃)

 

Factors Affecting the Performance of Lightweight Insulating Refractory Castables

 

The ingredients and properties of various lightweight insulating refractory castables used under different temperature conditions are different. The factors affecting the main properties of lightweight insulating refractory castables are briefly described below.

(1) Bulk density is an important indicator of lightweight insulating refractory castables and has a great influence on other properties. The bulk density of lightweight insulating refractory castables mainly depends on the bulk density of the lightweight aggregate used. Obviously, the smaller the bulk density of the lightweight aggregate, the smaller the bulk density of the lightweight refractory concrete prepared thereby. In addition, the proportion of ingredients also affects the bulk density of lightweight refractory castables. The more the amount of binder and fine powder used, the greater the bulk density of the lightweight refractory castable.

The relationship between the bulk density and compressive strength of lightweight insulating refractory castables: When the aggregate, binder, and admixture are the same, the greater the bulk density, the higher the strength. However, it will increase the thermal conductivity of the lightweight refractory castable, affecting its thermal insulation performance.

(2) Strength. In addition to the binder, another major factor affecting the strength of lightweight insulating refractory castables is the strength of the lightweight aggregate itself. Generally speaking, the higher the strength of the lightweight aggregate itself, the higher the strength of the lightweight insulating concrete prepared.

(3) Thermal conductivity. The thermal conductivity of lightweight insulating refractory castables depends on factors such as the type of lightweight aggregate, binder material and bulk density. The relationship between thermal conductivity and temperature of various lightweight insulating refractory castables. In practical applications, due to the temperature gradient on the cross section of the lining of lightweight insulating refractory castables, different physical and chemical changes occur in different parts, thus affecting the thermal conductivity.

(4) Volume stability. Lightweight insulating refractory castables can be directly heated to high temperatures in the kiln without pre-burning. However, excessive shrinkage after drying and heating will cause cracks and damage. The general trend of the linear change of lightweight insulating refractory castables with different bulk densities during heating is that the heating linear shrinkage rate decreases with the increase of bulk density. In order to reduce excessive shrinkage during heating, an appropriate amount of kyanite concentrate powder can be added to compensate for part of its shrinkage.

 

Rongsheng Lightweight Insulating Refractory Manufacturer

 

Rongsheng Refractory Material Manufacturer is a powerful manufacturer and seller of refractory materials. Rongsheng Factory is committed to providing high-quality refractory lining materials for high-temperature industrial furnaces. In addition, our refractory insulation materials can also help companies reduce energy consumption and save production costs. Rongsheng lightweight insulating refractory castables, lightweight insulating refractory bricks, including lightweight high-alumina castables, alumina hollow ball castables, lightweight high-alumina bricks, lightweight silica bricks, mullite insulation bricks, alumina hollow ball bricks, Rongsheng high-strength nano insulation bricks, insulation boards, etc. If you need insulation castables, insulation bricks, lightweight high-alumina castables, alumina hollow ball castables, alumina hollow ball bricks, lightweight high-alumina bricks, or lightweight clay bricks, please contact Rongsheng. Get free samples and quotes.