Method of preparing catalysts

Claim 1

IN THE PROCESS FOR PREPARING A CATALYST OF MIXED SULFIDES OF AN ELEMENT OF THE LEFT SUBGROUP OF GROUP VI OF THE PERIODIC SYSTEM AND OF A METAL OF THE IRON GROUP BY TREATING AN AQUEOUS SOLUTION OF A SALT OF A THIOACID OF SAID ELEMENT WITH A SALT OF SAID METAL SO AS TO PRECIPITATE THE SULFIDES OF SAID ELEMENT AND OF SAID METAL FOLLOWED BY A SEPARATION OF THE PRECIPITATE, WHEREIN THE SAID THIOACID SALT SOLUTION CONTAINS SULFIDE IONS IN AN AMOUNT AT LEAST EQUIVALENT TO SAID METAL, THE IMPROVEMENT WHICH COMPRISES ADDING AS SAID METAL SALT A SALT THE ANION OF WHICH FORMS WITH THE CATION OF SAID THIOACID SALT A COMPOUND WHICH DECOMPOSES COMPLETELY INTO VOLATILE CONSTITUENTS UPON HEATING IN AQUEOUS SOLUTION TO TEMPERATURES IN EXCESS OF ABOUT 100* C., MAINTAINING SAID AQUEOUS SOLUTION NON-ACIDIC DURING SAID ADDITION, HEATING SAID SOLUTION ABOVE 100* C. TO EVAPORATE THEREFROM ALL CONSTITUENTS EXCEPT SAID PRECIPITATE AND RECOVERING SAID PRECIPITATE AS PRODUCT CATALYST.