The technical index of high alumina castables is the main reference in the procurement process, which determines the quality of refractory castables.
There are 7 main technical indexes of refractory castables, which are A2O3 content, bulk density, scheinbare Porosität, normal temperature compressive strength, Erweichungstemperatur der Ladung, and thermal shock stability.
In the following, take high alumina refractory castables as an example and analyze their technical indexes.

1. AI203 Content

A2O3 content is commonly known as the content of aluminum trioxide in high alumina castables, which determines the level of various other properties. daher, it is the main performance index of high alumina castables.

2. Schüttdichte

Bulk density is the ratio between the dry mass of high alumina castables and their total volume in g/c3. Bulk density mainly indicates the denseness of high alumina castables. Normalerweise, the bulk density of high alumina castables has a great connection with its porosity and mineral composition.

3. Room Temperature Flexural Strength

The normal temperature flexural strength is the maximum bending stress that a strip made of high alumina castables can withstand in a test. The chemical composition, mineral composition, organization, and production process of the material have a decisive influence on the flexural strength of the material, especially the high-temperature flexural strength. Normalerweise, the use of high-purity raw materials, controlling the material reasonable particle gradation, increasing the molding pressure, the use of high-quality binding agents, and improving the degree of sintering products, can improve the flexural strength of the material.

4. Normal Temperature Compressive Strength

Compressive strength refers to the ultimate load that the construction body of high alumina castables can bear without being destroyed under a certain temperature per unit area. The compressive strength at room temperature is an indication of the sintering of the material and the properties related to its structure. Zusätzlich, other properties such as wear resistance and impact resistance can be indirectly evaluated by the compressive strength at room temperature.

5. Load Softening Temperature

The load softening temperature of high alumina castables refers to the temperature at which deformation occurs during use. The load softening temperature indicates the ability of the refractory to resist both high temperature and load. To a certain extent, it indicates the structural strength of the product under similar conditions of its use.

6. Alkali Resistance

High alumina castables for cement kilns are often subjected to alkaline gas erosion in the kiln, so it is necessary to test the alkali resistance of the material. Alkali resistance is the ability of refractory castables to resist alkaline attacks at high temperatures.

The above is the key to the technical performance index of high alumina castables. When purchasing and using high alumina castables, they must be selected in strict accordance with the requirements of the actual furnace. Only on the premise of guaranteeing the service life of high alumina castables can we extend the service life and save the maintenance cost.