A process for producing zeolites comprising: a) calcining a clay material to form an amorphous material from clay components in the clay material, b) leaching the material from step (a) in a leaching solution to produce a solution containing dissolved aluminium and dissolved silica and a solid residue, c) separating...

A process for treating a material to remove sulphates or other impurities therefrom comprises a) subjecting the material to a leaching step to selectively dissolve sulphate-containing material or dissolve other impurities from the material and/or to passivate gypsum, b) separating a leach solution generated in step ...