The use of base/clay composites materials as sorbents for the removal of SO.sub.2 and SO.sub.3 (SO.sub.x) from flue gas and other sulfur containing gas streams is described. The base is either an alkaline earth metal carbonate (eg. CaCO.sub.3) or hydroxide (eg. Ca(OH).sub.2) is incorporated onto the...http://www.google.de/patents/US5334564?utm_source=gb-gplus-sharePatent US5334564 - Method for the preparation of highly reactive clay composites for the removal of SO.sub.x from flue gas streams