Phosphate-bonded refractory materials were routinely shot in cyclone boilers in the 1970s. These phosphate-bonded materials don’t have a cement bond, but achieve a chemical bond when heat is applied. Without knowing the precise formulation of the mixture and grain sizes involved, we cannot tell you definitively that your specific material can be shotcreted. However, there is a long history of successful past experience with phosphate-bonded refractory materials being shot with the dry-mix process. You may want to consider a field trial before construction to verify your specific mixture works with your dry-mix shotcrete equipment.