Process for preparing alumina trihydrate

Claim 2

IN THE PROCESS OF ALUMINA TRIHYDRATE COMPOSITIONS BY A PROCESS COMPRISING FORMATION OF AN AMPHOUS ALUMINA HYDROGEL, WASHING THE HYDROGEL WITH WATER UNTIL SUBSTANTIALLY FREE OF CONTAMINATING IONS, AND CONVERTING THE AMORPHOUS HYDROGEL TO AN ALUMINA HYDRATE COMPSITION CONTAINING ABOUT 65% TO ABOUT 95% OF CRYSTALLINE TRIHYDRATE, THE METHOD OF HYDRATE CONVERSION WHICH COMPRISES WASHING THE ALUMINA HYDROGEL WITH WATER AT A TEMPERATURE IN THE RANGE DEFINED BY TEMPERATURES LESS THAN ABOUT 60*F. AND FROM ABOUT 75* TO ABOUT 160*F. TO CONTROL THE RELATIVE AMOUNTS OF BAYERITE, GIBBSITE AND RENDOMITE IN THE CONVERTED TRIHYDRATE COMPOSITION.

Claim 3

IN THE PRODUCTION OF AN ALUMINA BASE PLATINUM METAL CAYALYST BY FORMATION OF AN AMORPHOUS ALUMINA HYDROGEL, WASHING THE HYDROGEL SUBSTANTIALLY FREE OF CONTAMINATING IONS WITH WATER AND CONVERTING THE HYDROGEL TO AN ALUMINA HYDRATE COMPOSITION PREDOMINATING IN A MIXTURE OF ALUMINA TRIHYDRATE PHASES, INCORPORATION OF A PLATINUM METAL IN FINELY DISTRIBUTED FORM, DRYING AND CALCINING, THE METHOD OF HYDRATE CONVERSION WHICH COMPRISES WASHING THE ALUMINA HYDROGEL WITH WATER AT A TEMPERATURE FROM ABOUT 75 TO ABOUT 160*F. AND AGING THE HYDROGEL TO OBTAIN A MIXTURE OF CRYSTALLINE TRIHYDRATES AMOUNTING TO 65% TO 95% OF THE HYDRATE COMPOSITION.

Claim 4

IN THE PRODUCTION OF AN ALUMINA BASE PLATINUM METAL CAYALYST BY FORMATION OF AN AMORPHOUS ALUMINA HYDROGEL, WASHING THE HYDROGEL SUBSTANTIALLY FREE OF CONTAMINATING IONS WITH WATER AND CONVERTING THE HYDROGEL TO AN ALUMINA HYDRATE COMPOSITION PREDOMINATING IN A MIXTURE OF ALUMINA TRIHYDRATE PHASES, INCORPORATION OF A PLATINUM METAL IN FINELY DISTRIBUTED FORM, DRYING AND CALCINING, THE METHOD OF HYDRATE CONVERSION WHICH COMPRISES WASHING THE ALUMINA HYDROGEL WITH WATER AT A TEMPERATURE FROM ABOUT 75 TO ABOUT 160*F. AND AGING THE HYDROGEL TO OBTAIN A MIXTURE OF CRYSTALLINE TRIHYDRATES AMOUNTING TO 65% TO 95% OF THE HYDRATE COMPOSITION.