Abstract: A process for production of vanadium-containing agglomerate, includes the steps of providing a spent, vanadium-containing, iron based hydroconversion catalyst; incinerating the spent catalyst in the presence of an oxidizer until a sulfur content of the spent catalyst is reduced to 2% or less by weight; grinding the spent catalyst to a particle size suitable for a desired use; and mixing the spent catalyst with an iron mineral and a binder to form a vanadium-containing agglomerate; and pyroconsolidating the vanadium-containing agglomerate. Agglomerates so obtained exhibit a solid solution structure of ferric oxide and vanadium pentoxide.