Calcination of macrosize alumina hydrate

Claim 1

IN A METHOD FOR ADIABATICALLY CALCINING MACROSIZE PARTICLES OF AN ALUMINA HYDRATE COMPOSITION, SAID COMPOSITION CONTAINING A PREDOMINANT AMOUNT OF TRIHYDRATE AND FROM ABOUT 5 TO ABOUT 50% OF HYDROUS ALUMINA SELECTED FROM THE GROUP CONSISTING OF MONOHYDRATE AND AMORPHOUS FORMS AND THEIR MIXTURE TO OBTAIN CATALYST PARTICLES OF GAMMA-ALUMINA MODIFICATIONS HAVING A SURFACE AREA OF ABOUT 350 TO ABOUT 550 SQUARE METERS PER GRAM (BET METHOD), THE STEPS COMPRISING CONTACTING A FIXED BED OF SAID ALUMINA HYDRATE PARTICLES WITH A HEATED GAS WHICH IS THE ESSENTIAL HEAT SOURCE AND IS ESSENTIALLY CHEMICALLY INERT TO THE ALUMINA HYDRATE TO REMOVE TRIHYDRATE WATER OF CRYSTALLIZATION AT A TEMPERATURE OF UP TO ABOUT 700*F., SAID GAS HAVING A DEW POINT OF UP TO ABOUT 125*F. AND BEING SUPPLIED AT THE RATE OF ABOUT 150 TO ABOUT 1500 STANDARD CUBIC FEET PER CUBIC FOOT OF CATALYST PER HOUR AND AT A SUPERFICIAL VELOCITY OF ABOUT 0.05 TO ABOUT 0.5 FOOT PER SECOND AND THEN COMPLETING THE CALCINATION OF SAID PARTICLES AT A TEMPERATURE FROM ABOUT 750 TO ABOUT 1200*F. BY CONTACT WITH A HEATED GAS WHICH IS THE ESSENTIAL HEAT SOURCE AND IS ESSENTIALLY CHEMICALLY INERT TO THE ALUMINA HYDRATE AT A RATE FROM ABOUT 150 TO ABOUT 1500 STANDARD CUBIC FEET PER CUBIC FOOT OF CATALYST PER HOUR AND AT A SUPERFICIAL VELOCITY OF ABOUT 0.05 TO ABOUT 0.5 FOOT PER SECOND, TO OBTAIN THE CALCINED PARTICLES OF SURFACE AREA OF FROM ABOUT 350 TO ABOUT 550 SQUARE METERS PER GRAM (BET METHOD), SAID GAS EMPLOYED IN COMPLETING THE CALCINATION HAVING A DEW POINT OF UP TO ABOUT 30*F.