Silicates are used to bind particles together in applications such as briquetting, pelletizing, agglomeration, and coatings. The particles can range from very fine powders, such as flyash, to much larger gravel-sized aggregates.
As in paper adhesives, the dehydration of a liquid silicate results in a strong bond, hardening as it dries. Setting agents that react with the liquid silicates may also be used to obtain binders that set faster and are water-resistant. Applied heat will also increase water resistance by driving off excess moisture.
Powdered silicates are also used, although they must be dissolved before they can provide binding power. The powdered silicate can be pre-mixed with a dry setting agent and hydrated to start the reaction. This feature allows the use of a fast-acting setting agent such as calcium chloride without the problems associated with a premature set.