What are the formula design principles of refractory castables?

1.Design principle of refractory castable formula

The principle of preparation of refractory castable is reasonable selection of particle size, superfine powder and admixture variety and dosage. Refractory aggregate and powder are made from well-calcined clay and bauxite clinker. The maximum particle size of refractory aggregate, according to the thickness of the engineering lining, is generally 10mm. Its particle grading: 10~5mm, 30%~40% : 5~3mm, 20%~30% : 3~0.15mm, 30%~40%. In general, when preparing low cement castables, less bulk is used, but three or four gradations are used to achieve maximum packing density. The amount of refractory aggregate is 68%~72%.
Refractory powder is generally used as raw material of two, one or extra grade high bauxite clinker, powder should be removed after iron treatment, its fineness <0.09mm or <0.044mm should be ≥90%. When preparing, it can be used alone or in proportion. Sometimes high-grade materials such as aluminum oxide powder, white corundum powder or brown corundum powder of the same fineness are added to improve the matrix properties of refractory castables. The amount of refractory powder is 18%~25%. Such as the addition of high-grade materials, the amount of 5% to 10%.

2.The formulation design of refractory castable consists of two parts

application design parameters and material design parameters.  The refractory castable used under the set target conditions needs to consider the combination of raw materials, manufacturing technology, material assembly (construction) and application technology. 

3.Refractory castable formulation design objectives

The goal of formulation design is to find a balance between material properties and application conditions.  Typically, the actual furnace operating conditions (operating temperature, furnace atmosphere and contact state of dust, steam and liquid and/or slag, etc.) and slag characteristics determine the type and quality of the furnace lining refractory material.  If the refractory castable is selected as the target lining, the material suitable for the use conditions, the appropriate bonding system and the additives that can further improve and improve the performance should be selected, so that the refractory castable with better performance can be made.