Quick Question on "Castable Refractory Products"

What are they? What is the difference between a castable product and a spray-on refactory or insulating-type product?

At last! Someone asks a question in my area of expertise (materials engineering)!

“Casting” is the process of pouring a liquid into a mold and solidifying it to make a part. Usually it refers to liquid metal processes, where you melt the metal, pour it into a refractory mold, and cool it.

“Refractory” loosely means a material with a high melting point or an insulating material. There are “refractory metals,” but when you use the word by itself, it usually means some kind of ceramic.

I would expect that a castable refractory product is a ceramic slurry (solid ceramic particles in suspension in a liquid). You pour it into a mold, and heat it to dry the liquid and probably sinter the particles (bind them together without melting them). It probably makes a moderately porous ceramic part.

A spray-on product is just what it sounds like - a similar ceramic slurry, that you spray onto a surface and dry. For most processes where spraying makes sense, it would be difficult to sinter, so it’s probably mechanically weaker than the castable product.