The maximum service temperature of diatomite brick varies with the specific composition and production process. According to the search results, the following information is relevant:

I. General diatomite brick:

Usually used for thermal insulation below 900℃. The fire resistance of this kind of brick can reach about 1280℃, but in practical use, it is generally recommended that the temperature should not exceed 1000℃.

II. High-purity diatomite brick:

If pure diatomaceous earth is used as raw material and sintered at a higher temperature, its maximum service temperature can be increased to above 1000℃. Under some special conditions, its fire resistance may be close to 1600℃, but this situation is rare.

III. Specially treated diatomite bricks:

By adding binder such as lime and mineralizer, the transformation of phosphorus and Shi Ying during firing can be promoted, which can further improve the heat resistance of brick and make it shrink and deform less at high temperature.

To sum up, the maximum service temperature of ordinary diatomite bricks is generally about 900℃, while the maximum service temperature of diatomite bricks with special treatment or high-purity raw materials can reach above 1000℃.