What is the role of refractory aggregate in refractory castables

In the process proportion of refractory castables, the aggregate plays a skeleton role in the castables. The amount of refractory aggregate is generally 60% – 70%, which can improve the strength and wear resistance of castables in use.

The process proportion of refractory castables is mainly aggregate, and then add 15%~25% of powder processed with the same quality as the aggregate, which can fill the aggregate gap and improve the fluidity of materials during construction. Then 6-12% of the binder is added to the castable. Good binding agent, ideal particle grading is that the gap caused by coarse aggregate is filled with fine aggregate, and the gap between them is filled with refractory powder to achieve the maximum bulk density, so as to obtain the best use performance.

Refractory aggregate is divided into coarse aggregate and fine aggregate. Generally, those with particle size greater than 5mm are called coarse aggregates; those with particle size less than 5mm and less than 0.09mm are called fine aggregates. The critical particle size of aggregate depends on the thickness of the lining. If the construction thickness is 30-50mm, 0-5mm aggregate is used. If the thickness is 100-200mm, 0-8mm and 0-10mm aggregate particles are used.

However, the ladle castable and refractory castable for iron trench are mostly made of 20mm – 25mm particles due to special use conditions. The critical particle size of refractory aggregate is different, and the purpose of use will also be different. When preparing refractory castables, the aggregate grain grading will be adjusted from time to time, that is, to meet the grain grading of the finished product and the overall performance of the product, and to consider the actual use of the lining.

In refractory castables, refractory aggregate and powder processed from bauxite clinker are mostly used. For alkaline or acidic furnace lining, aggregates made of siliceous materials and alkaline materials are used, and powders made of the same materials are used. The binder shall also be adjusted under different conditions, and the high-alumina cement in the binder shall also be adjusted. At the same time, the silica powder or aluminum oxide powder shall be adjusted to different degrees. The main purpose of adjustment is to improve the actual use.

For refractory castables used in some special parts, oxidation and construction conditions should also be considered, and different conditions should be adjusted to meet the use needs.