Castable refractory compositions comprising zeolithic microstructures and uses thereof

A dry refractory particulate composition comprising:

• 5% to 95% by weight of an aggregate,
• 1% to 8% by weight of a silica fume,
• 0.1% to 1.5% by weight of a hydratable alumina,
• 0.1% to 1% by weight of a calcium source, and
• 0.01% to 1% by weight of a dispersant,
• wherein the aggregate is not a hydratable alumina or a silica fume;
• wherein the calcium source is selected from calcium aluminate cement, Portland cement, hydrated lime, calcium sulfate, calcium acetate, calcium chloride, calcium chlorate or mixtures thereof;
• wherein the calcium aluminate cement and Portland cement have a particle size of up to 80 microns, and the hydrated lime, calcium sulfate, calcium acetate, calcium chloride, calcium chlorate have a particle size of up to 200 microns,
• wherein the calcium oxide content is no greater than 0.3% by weight, and
• wherein all percentages by weight are based on the total dry weight of the dry refractory composition.