Method for recovering metals contained in spent catalysts from ferro-alloys

A method for treating a spent catalyst containing at least one refractory mineral oxide, one or more metals in the form of sulfide(s) chosen from the following metals:

• molybdenum, nickel, cobalt, tungsten, vanadium, as well as carbon compounds, this method comprising the following successive steps:
• a) in a smelting furnace of a rotary converter type, preparing a melt of cast iron in the melted state above which there is a layer of slag;
• then
• b) introducing into the furnace said spent catalyst and placing it in contact with the slag and the melt of cast iron in the melted state, while maintaining the furnace in rotation and while injecting an oxidizing gas containing oxygen into the furnace, above the mixture of catalyst, slag and cast iron, in such a way as to cause the combustion of the carbon and/or sulfur compounds which are released from the catalyst in contact with the slag and the liquid cast iron;
• then
• c) extracting from the furnace by sequential castings the slag formed in step b) in such a way as to on the one hand recover in the furnace a cast iron melt enriched with metal or metals, and on the other hand recover a slag containing the components of the catalyst other than metals, with the exception of vanadium which, when the spent catalyst contains vanadium, ends up in the slag.