Methods and compositions are provided that utilize high-alumina refractory aluminosilicate pozzolans in well cementing. An embodiment discloses a method of cementing comprising: introducing a cement composition into a subterranean formation, wherein the cement composition comprises; a component selected from the group consisting of cement kiln dust, Portland cement and any combination thereof; a high-alumina refractory aluminosilicate pozzolan; and water; and allowing the cement composition to set.

A porous refractory composition containing a foamed colloidal silica binder, and porous refractory articles made from it, are provided. The foamed colloidal silica binder has a total porosity of about 50% to about 95% by volume and includes a synthetic, non-protein foaming agent mixed with colloidal silica and water. The foamed colloidal silica binder has sufficient durability and integrity to withstand the mixing with dry refractory ingredients to form a porous refractory composition, casting the refractory composition into a refractory shape, and drying the shape to form a porous refractory article having a porosity of about 25% to about 75% by volume. The resulting refractory articles have excellent high-temperature durability and insulating properties.

The present description relates to a method of producing a wet-cast slag-based concrete product particularly where the wet-cast slag-based concrete product is partially or completely set inside a mould, pre-conditioned outside of the mould and then cured with carbon dioxide in a curing chamber. The wet-cast slag-based concrete product is optionally reinforced.

The present description relates to a method of producing a wet-cast slag-based concrete product particularly where the wet-cast slag-based concrete product is partially or completely set inside a mould, pre-conditioned outside of the mould and then cured with carbon dioxide in a curing chamber. The wet-cast slag-based concrete product is optionally reinforced.