$RS Wear-Resistant Refractory Castables$

Wear-Resistant Refractory Castables

Resist the friction or scouring (impact).
High flexural strength.
High compressive strength.
High-strength refractory castables.
Good high-temperature wear resistance.

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The castable refractory material that can resist the friction or scouring (impact) of high-temperature solid materials or airflow-carrying solid powder is called wear-resistant refractory castable. It is mainly used as the lining of high-temperature cyclone separators, circulating fluidized beds, and the lining of the steel trough of heating furnaces. The flexural strength and compressive strength of wear-resistant refractory castables are relatively high, so they are also called high-strength refractory castables.

Composition of Wear-Resistant Refractory Castables

Wear-resistant refractory castables are composed of high-hardness refractory aggregates and powders, high-strength binders and additives. High-hardness refractory aggregates include: fused corundum (white corundum, brown corundum, etc.), fused zirconium corundum, fused mullite, sintered high-alumina bauxite, fused high-alumina or clay materials, silicon carbide, etc. They can be selected according to actual working conditions. There are two main systems of high-strength binders:

(1) High-strength calcium aluminate cement plus silica powder;
(2) Phosphoric acid or aluminum dioxyphosphate plus hardener. The admixture is mainly a high-efficiency dispersant.

The particle size composition of wear-resistant refractory castables requires the most compact packing as possible. Generally, the ratio of aggregate to powder is (65~70): (30~35), or it can be prepared according to the Andreassen particle size distribution equation with a particle size distribution coefficient q value of 0.26~0.35.

High-Temperature Wear Resistance of Wear-Resistant Refractory Castables

The main performance index of wear-resistant refractory castables is high-temperature wear resistance. However, there is no standard for high-temperature wear resistance determination at present, only the normal temperature wear resistance test method, see standard GB/T18301-2001. This method is measured using a special wear tester. Using black silicon carbide as the wear medium and compressed air (pressure of 448 kPa) as the carrier, black silicon carbide with a particle size of 36 is sprayed onto a test block of a certain size through a sandblasting tube, and 1000g of wear medium is sprayed within 450s. Then the wear amount A of the test block is measured, and the wear amount A (cm3) is calculated according to the following formula

A=(M1- M2)/B= M/B

Where, B is the sample volume density, g/cm3; M1 is the sample mass before the test, g; M2 is the sample mass after the test, g; M is the sample mass loss, g. For wear-resistant refractory castables, the wear volume at room temperature is generally required to be no more than 10 cm3.

Application of Wear-Resistant Refractory Castables

Wear-resistant refractory castables for circulating fluidized bed boilers in power plants are generally prepared with sintered high-alumina bauxite and fused corundum. Some are added with black silicon carbide, and the binder is high-grade calcium aluminate cement plus silicon oxide powder (smoke silicon).
The physical and chemical performance requirements for wear-resistant refractory castables for alumina suspension roasting furnaces are similar to those for wear-resistant refractory castables for circulating fluidized bed boilers, but silicon carbide is not added to the ingredients.
Wear-resistant refractory castables used in oil refining catalytic cracking units use fused or sintered white corundum (or plate-like alumina) as aggregate. High-grade pure calcium aluminate cement plus reactive alumina is used as a binder, and the Fe2O3 content in the castable is required to be less than 0.05%.
The castable used for the steel spout of the heating furnace uses fused corundum (brown corundum or sub-white corundum) as aggregate, and the powder is composed of fused corundum powder, α-Al2O3 micropowder, SiO2 micropowder, Cr2O3 micropowder (or zircon micropowder) and pure calcium aluminate cement. After the castable is prepared, it must be made into prefabricated blocks and used after being roasted at high temperature (greater than 1500℃). After adding a certain amount of SiC to the ingredients of this type of castable, it can also be prefabricated into heating furnace slide rail bricks, which have good high-temperature wear resistance.

Physical and Chemical Properties of Aluminum-Silicon Wear-Resistant Refractory Castables

Physical and Chemical Properties		NM-1	NM-2	NM-3	NM-4
w(Al2O3) %		≥70	＞75	≥80	≥85
w(CaO) %		≤2.5	≤2.5	≤2.5	≤2.5
Bulk Density g/cm3		＞2.6	＞2.75	＞2.8	＞2.9
Compressive Strength MPa	110℃, 24h	＞60	＞65	＞70	＞75
	1000℃, 3h	＞75	＞80	＞85	＞90
	1400℃, 3h	＞90	＞95	＞105	＞110
Flexural Strength MPa	110℃, 24h	＞8.50	＞9.30	＞10.0	＞11.5
	1100℃, 3h	＞10.5	＞11.5	＞12.0	＞13.0
	1400℃, 3h	＞13.0	＞13.5	＞15.0	＞16.0
Wear at Room Temperature cm3		＜9.6	＜8.5	＜7.3	＜6
Load Softening Start Temperature ℃ (0.2MPa)		＞1450	＞1490	＞1530	＞1560
Thermal Shock Resistance /times 900℃, Water Cooling		＞20	＞20	＞20	＞20
Max Operating Temperature ℃		1550	1550	1550	1550
Linear Change Rate after Burning %		＜-0.3	＜-0.3	＜-0.2	＜-0.2

Rongsheng Wear-resistant Refractory Castables Manufacturer

Rongsheng Refractory Castables Manufacturer is a powerful manufacturer and seller of refractory castables. Rongsheng’s environmentally friendly and advanced fully automatic amorphous refractory production line provides reliable guarantee for amorphous refractory lining materials for high-temperature industrial furnaces. For customized wear-resistant refractory castables, please choose Rongsheng. Factory directly sales, reliable quality, preferential prices, and fast delivery. Contact Rongsheng for free samples and quotes.