Application introduction of foundry refractory

The foundry refractory should have sufficient refractoriness, small and uniform thermal expansion coefficient, good thermochemical stability, non-toxic, etc. The foundry refractory can be divided into powder used for coating slurry and sanding material used as shell aggregate.

It must be emphasized that the most widely used zircon and aluminum-silicon refractories in my country's precision casting production are both natural mineral materials that have not been deeply processed. In investment casting, factors such as ore source, mining and beneficiation need to be considered.
The foundry refractory manufacturer tells you that because it is a natural mineral, it is normal to contain some organic matter, moisture and other impurities. High-temperature calcination can remove moisture, organic matter, sulfate, etc., and can reduce the activity of many impurities. Therefore, the production of precision casting must use clinker that has been calcined at a high temperature above 1100 °C, and high-temperature calcination should be arranged at the end of all production processes.
The foundry refractory manufacturer tells you that some impurities (especially iron and its oxides, alkali and alkaline earth metal oxides) in the refractory powder may react with the binder or additives, resulting in the change of the pH value of the coating slurry and rapid aging and deterioration . The foundry refractory manufacturer tells you that the magnetic inductors and iron particles mixed in the sanding material may also react with the silica in the shell during roasting or pouring to form low-melting iron silicate, which penetrates from the inside of the shell Ink spots are formed on the surface, which in turn affects the quality of the casting.