| 摘要 |
<p>100 kg of spent catalyst waste (containing 8 % Mo, 1.5 % S and 2 % Co) on a support based on gamma alumina, freed from volatile matter, carbon and part of the sulphur by preliminary oxidising roasting, are mixed with 37.5 litres of aqueous solution of Na2CO3 (400 g/l) at 70 DEG C. An impregnated product is obtained which is heated between 650 and 750 DEG C for one hour. The product thus treated is washed with water so as to obtain a solution of sodium molybdate which is neutralised with a solution of nitric acid in three precipitation operations separated by a clarification. A precipitate of molybdic acid is obtained while the alumina remains in solution. After drying, this precipitate has an apparent relative density of 2 and contains 61.2 % Mo and 0.004 % Al. Molybdenum yield : 85 %.</p> |
