A method of processing a mineral powder (e.g. a zeolite in powdered form) comprises (a) contacting the powder with (i) water or a solution of sulphuric acid or phosphoric acidor a mixture thereof, or (ii) one or more alkaline earth metal oxides, carbonates or hydroxides, or a mixture thereof; (b) combining the product of (a)(i) with one or more alkaline earth metal oxides, carbonates or hydroxides, or a mixture thereof; or combining the product of (a)(ii) with water or a solution of sulphuric acid or phosphoric acid or a mixture thereof and optionally with further of the alkaline earth metal oxides, carbonates or hydroxides, or a mixture thereof; (c) granulating the combination of (b) to form granules of mass median diameter (MMD) from 1 mm to 10mm; and (d) allowing the resulting granules from step (c) to cure.
