Method and apparatus for heating and burning cement raw material, containing alkali

Claim 1

A PROCESS OF PREHEATING AND TREATING CEMENT RAW MATERIAL PRIOR TO PASSING SAID RAW MATERIAL INTO A KILN IN COUNTERFLOW TO EXIT GASES ISSUING FROM SAID KILN, COMPRISING THE STEPS OF PASSING HOT EXIT GASES FROM A KILN AND FORCING AT LEAST PART OF SAID EXIT GASES THROUGH A CONTAINER AFTER SAID EXIT GASES LEAVE THE KILN, BRINGING SAID PART OF SAID EXIT GASES INTO CONTACT WITH A FINE GRAINED SOLID MATERIAL IN SAID CONTAINER FOR PRECIPITATION OF ALKALIES CONTAINED IN SAID PART OF SAID EXIT GASES WHILE SIMULTANEOUSLY PASSING SAID FINE GRAINED SOLID MATERIAL THROUGH SAID CONTAINER IN CONTINUOUS FLOW, REMOVING FROM SAID CONTAINER SAID FINE GRAINED SOLID MATERIAL AFTER THE LATTER HAS TAKEN UP THE ALKALIES SO AS TO DECREASE THE ALKALI CONTENT OF THE EXIT GASES USED FOR PREHEATING THE CEMENT RAW MATERIAL, AND THEN PASSING THE CEMENT RAW MATERIAL THROUGH A PREHEATER IN DIRECT CONTACT WITH SAID PART OF SAID EXIT GASES AFTER SAID PART OF SAID EXIT GASES HAS PASSED THROUGH SAID CONTAINER.