Process for the recovery of metals from used hydroprocessing catalyst particles

摘要

The metals to be recovered are composed of at least one metal of group VIII of the Periodic Table of the Elements and at least one metal of groups Vb or VIb of the Periodic Table of the Elements. The used catalyst particles are initially roasted at a temperature between 400 and 600 DEG C and then contacted with a first aqueous solution of ammonia and an ammonium salt with formation of a first enriched liquid. The once-leached used hydroprocessing catalysts are contacted with a second aqueous solution of sulphur dioxide with formation of a second enriched liquid. The metals from the second enriched liquid are precipitated using hydrogen sulphide and the precipitate is roasted with unroasted used hydroprocessing catalysts. The metals of groups Vb and VIb in the first enriched liquid are transferred into a first organic solution by liquid iron exchange. The first organic solution is stripped by an aqueous stripping solution and the metals are isolated by sequential precipitation. The metals of group VIII are isolated and purified by pure liquid ion exchange.