The minerals used for the production of foundry coatings can be categorized according to its particle morphology into granular and lamellar fillers.
Granular fillers are generally used for high temperature applications where refractoriness and resistance to chemical attack are the key properties. We usually recommend white fused alumina for massive steel & iron casting , and aluminosilicates such as Molochite or andalusite for massive iron casting. White fused alumina fillers are more and more considered as a better performing and cost-effective alternative to zircon silicate for steel and iron casting.
Among the lamellar fillers, mica and graphite plays an important role. In particular, mica offers a very high aspect ratio (ratio between plate’s width and thickness) and therefore plays an important role in enhancing the mechanical barrier properties of the coating as anti-veining.
Due to their platy form, our micas are generally used for coating in aluminum foundry as in automotive iron foundry.
Furthermore, there are minerals that are used as additive for controlling gel properties of the coating. These are clays, kaolin and calcined kaolin, which influence key properties such as rheology, sedimentation and drying shrinkage.
A large number of mineral additives are used in all stages of the foundry process. We supply in particular kaolin and metakaolin which are used as additives in the moulding process as well as components in the new generation of inorganic binders based on geopolymers.