Production of anhydrous alumina

Claim 1

A PROCESS FOR OBTAINING FROM ALUMINA TRIHYDRATE, AN ANHYDROUS ALUMINA WHICH IS AT LEAST PARTIALLY CRYSTALLIZED IN THE FORM OF ALPHA ALUMINA, THE PROCESS COMPRISING SUBJECTING ALUMINA TRIHYDRATE TO A PARTIAL DEHYDRATION TO OBTAIN A PARTIALLY DEHYDRATED PRODUCT WHICH CONTAINS SUBSTANTIALLY ABOUT 5% TO 30% OF ITS INITIAL CONSTITUTION WATER, INTRODUCING SAID PRODUCT INTO A STREAM OF INCOMPLETELY BURNED HOT GASES, DELIVERING SAID GASES WHICH CONTAIN SAID PARTIALLY DEHYDRATED PRODUCT INTO A SUBSTANTIALLY CYLINDRICAL COMBUSTION CHAMBER TANGENTIALLY OF THE WALLS THEREOF, BURNING SAID INCOMPLETELY BURNED HOT GASES IN SAID COMBUSTION CHAMBER, FORMING IN SAID COMBUSTION CHAMBER SUBSTANTIALLY HELICALLY DESCENDING FLOWS OF SAID GASES AND IMPARTING TO SAID PRODUCT SUBSTANTIALLY HELICALLY DESCENDING PATHS, COLLECTING SAID PRODUCT IN A LOWER PORTION OF SAID CHAMBER AND THERE FORMING A FLUIDIZED BED OF SAID PRODUCT BY DIRECTING AN AIR STREAM THERETHROUGH, DEHYDRATION OF SAID PRODUCT BEING SUBSTANTIALLY COMPLETED DURING ITS DESCENT TO SAID BED, SAID BED BEING IN CONTACT WITH THE GASES THEREABOVE, MAINTAINING SAID PRODUCT IN SAID BED FOR CONVERTING AT LEAST A PORTION THEREOF INTO CRYSTALLIZED ALPHA ALUMINA TO FORM AN ANHYDROUS ALUMINA WHICH IS AT LEAST PARTIALLY CRYSTALLIZED ALPHA ALUMINA, A HEAT EXCHANGE BEING EFFECTED BETWEEN SAID BED AND SAID GASES THEREABOVE, SAID HEAT EXCHANGE COOPERATING WITH HEAT EVOLVED FROM SAID CONVERSION TO CRYSTALLIZED ALPHA ALUMINA TO MAINTAIN SAID BED AT A TEMPERATURE SUBSTANTIALLY ABOUT 1000*C. TO 1250*C., AND RECOVERING SAID ANHYDROUS ALUMINA WHICH IS AT LEAST PARTIALLY CRYSTALLIZED ALPHA ALUMINA.