Lightweight and high strength refractory castables are amorphous thermal insulation materials prepared from lightweight aggregates, heavy fine powders, binders and additives. Compared with thermal insulation materials such as lightweight bricks and refractory fibers, the refractory castable has the advantages of simple production process, convenient construction, good integrity, energy saving, low cost, no pollution to the environment, and no harm to the health of construction workers. hazards, etc. Lightweight and High Strength Refractory Castables have high-strength wear resistance, alkali resistance and musk corrosion resistance. So what are its own advantages? Where are they often used? Today, I will introduce the performance advantages and applications of lightweight and high-strength refractory castables.
Performance advantages
1. The addition of silicon micropowder improves the flow properties of the castable. When the silicon micropowder is added at 5%, the lightweight castable has better flow properties.
2. The addition of silicon micropowder improves the strength of the lightweight castable, but when too much is added, the shrinkage of the castable after high temperature treatment will increase;
3. The developed lightweight castable has good flow performance, high strength and fast hardening speed, which meets the requirements of customers and is successfully applied to the casting of the thermal insulation layer of the heating furnace.
4. Small expansion line parameter, good thermal shock resistance, high thermal conductivity and thermal shock resistance. In addition, the particle composition, density, pore size and degree of dispersion of the casting material, as well as the shape of the product, all affect the thermal shock resistance of the casting.
5. The particle size synthesis, density, pore size and distribution, and product shape of the castable all affect its thermal shock resistance. In view of different refractory castables, their thermal shock resistance detection methods are also different, mainly including water quenching method and oxygen quenching method.
6. Lightweight and high-strength refractory castables have strong cohesion, long initial setting time and construction operation time, rapid strength growth, strong impermeability, no need for acid treatment, and easy to ensure the dense and full masonry ash joints, which can significantly improve The air tightness and integrity of the chimney lining wall and the anti-corrosion ability of the lining make it an ideal cementing material for the lining of high chimneys, high temperature flues and air ducts. Slots and other acid-resistant engineering.
Application
Lightweight castables are widely used in the insulation of shells and pipes of blast furnaces, hot blast stoves, chimneys, catalytic cracking units, etc. The use of lightweight castables reduces the heat loss during the operation of the thermal kiln, improves the efficiency of the thermal kiln and the equipment used, and contributes to energy saving and consumption reduction.
In order to save energy and improve operation efficiency of steel rolling heating furnace, ramming material is generally used on the top of the furnace. A layer of lightweight thermal insulation castable is poured on the upper layer, but because of the blocking of anchor bricks and steel beams on the top of the heating furnace, it brings inconvenience to the construction. Therefore, the construction party puts forward the following requirements for the lightweight castable: good flow performance, high strength, no water separation, fast hardening, and can meet the requirements of use.
In certain temperature stages where the above changes occur rapidly, the temperature should be raised slowly or even kept at an appropriate time. If it is not baked properly or it is put into use immediately with rapid heating without baking, serious cracks or even collapse are very likely to occur, and even explosions may occur in thick parts. The baking speed of the hardened body varies depending on the binder and the cross-sectional size of the structure.
The above is an introduction to the performance advantages and applications of lightweight and high-strength refractory castables. From the perspective of the use process, the actual water content of the lightweight castable during construction is 24%, and the material flow performance is very good. With only a little vibration, the castable can quickly flow and fill the low-lying parts; the lightweight castable can be filled within 12 hours. Afterwards, higher hardening strength can be produced, which has been recognized by the construction unit. Silicon micropowder can greatly improve the flow properties of the castable. When the mass fraction of silicon micropowder is 5%, the overall performance of the lightweight castable is better. After testing by the user unit, its performance fully meets the customer’s requirements, so it can be used.
