Binders are essential parts of mould materials. They hold the refractory parts of the mould together. Selection is dependent on the temperature you will be using. This also is important in choosing the refractory material to use.
Gypsum plaster - 704C – 816C
Hydrocal cement - 704C – 816C
Hydroperm cement – 760C – 927C
Colloidal silica – 1260C
Colloidal alumina – 1260C
Calcium alumina cement (cement fondu) – 1538C
There are of course, many other factors to take into account when choosing binders and refractory materials for moulds.