Classification of refractory castables

Refractory castables can be divided into acidic, alkaline and neutral castables according to their chemical composition and physical properties; classified by density, there are heavy castables and light castables. The main types on the market currently include aluminum silicate castables, magnesia castables, magnesium chrome castables, corundum castables and silicon-based materials.

Key factors in selecting refractory castables

When choosing suitable refractory castables, the working environment, use location, use temperature and corrosion resistance of the material of the kiln should be considered comprehensively.

Work Environment

When selecting castables, the environment of the kiln should be considered. For example, if the working layer needs to be resistant to high temperatures, heavy refractory castables are recommended. If the environment is acidic, castables that resist acid corrosion should be selected; if the environment is alkaline, castables that resist alkali corrosion should be selected.

Use location and temperature

If the castable is to be used in the part in contact with slag, the castable with slag corrosion resistance should be selected; for the part with severe material impact, the castable with high strength and good wear resistance should be used; for the part with frequent temperature changes, the castable with good thermal shock resistance should be selected. For example, clay castable is used for the temperature below 1200°C, high aluminum castable is used for the temperature between 1300°C-1400°C, and corundum castable is used for the temperature above 1450°C.

Casting thickness and construction method

The construction thickness of the castable also affects its selection. If the thickness is less than 50 mm, smear material or spray paint should be used; for maintenance or furnace roof use, plastic is recommended. If the thickness of the castable exceeds 100 mm, large-particle aggregate should be used to improve wear resistance. Generally, the best thickness is 200 mm.

Application of lightweight refractory castables

Lightweight refractory castables are usually used for the insulation layer of kilns. When selecting, the main considerations are its load-bearing structure and reducing the temperature of the furnace shell and reducing heat loss. For example, 1.2 bulk density is a common choice; if there is a weight requirement, you can choose an insulation castable with a bulk density between 0.6-1.0.

Economic cost and service life

When choosing refractory castables, we should not only consider their performance and application occasions, but also pay attention to economic costs and service life. The storage time of castables is between 6-9 months. If it exceeds this period, it may agglomerate or the binder may fail, affecting its service life.

in conclusion

When purchasing refractory castables, it is necessary to conduct comprehensive analysis and decision-making from multiple aspects such as environment, use location, temperature, thickness, etc. Reasonable selection can not only effectively reduce costs, but also ensure the normal operation and service life of the kiln.

In summary, this article explains in detail how to choose appropriate refractory castables in different environments from multiple perspectives such as classification, key selection factors, construction thickness, insulation application, and economic cost, aiming to provide readers with comprehensive knowledge to help them make appropriate decisions.