Refractory composition and process for forming article therefrom
A refractory composition and processes for manufacture are provided where the compositions possess improved refractory alkali resistance and superior handling properties. Compositions and processes for their manufacture may include a plurality of ceramic particles and a binder sintered to the particles wherein the binder includes crystalline aluminum orthophosphate distributed as the result of an in situ reaction of aluminum metaphosphate with alumina. Kits provided according to the invention provide materials for use in manufacture of a composition where the kit includes aluminum metaphosphate and a nonfacile additive.
1. A refractory composition comprising:
a plurality of aggregate ceramic particles;
a binder sintered to said plurality of aggregate ceramic particles, said binder comprising crystalline aluminum orthophosphate distributed in said binder as the result of reaction of aluminum metaphosphate with alumina; and
a nonfacile additive of calcium aluminate cement, sodium silicate, polyphosphate, or organic salts.
2. The composition of claim 1 wherein said plurality of aggregate ceramic particles comprise bauxite particles.
3. The composition of claim 1 wherein said plurality of aggregate ceramic particles includes at least one of silicon carbide, fumed silica, or mullite.
4. The composition of claim 1 wherein said crystalline aluminum orthophosphate has a crystal structure of berlinite.
5. The composition of claim 1 wherein said crystalline aluminum orthophosphate is devoid of an amorphous glass phase.
6. The composition of claim 1 further comprising steel fiber filler.
7. The composition of claim 1 wherein the composition has a density greater than or equal to 90% of theoretical and a cold crush strength of greater than 100 N/mm 2 .