Fremgangsmåde til genindvinding af gruppe vi-b-metaller fra brugte katalysatorer

The invention relates to a process for recovering Group VIB metals from a catalyst, in particular a spent bulk catalyst, comprising one or more Group VIB metals and one or more Group VIII metals. Further, the invention relates to a solid Group VIB metal compound obtainable by the process according to the invention having the general formula H 2 XO 4 , wherein X = W 1-y Mo y , wherein y is between 0 and 1 and to its use in a process for the manufacture of a fresh catalyst. The process comprises the steps of: a) oxidizing the one or more Group VIB metals to one or more Group VIB metal oxides; separating the one or more Group VIB metal oxides from the one or more Group VIII metals; dissolving the one or more Group VIB metal oxides in water to produce an aqueous solution of one or more Group VIB metal oxides; d) precipitating the one or more Group VIB metal oxides from the aqueous solution by adding alkaline earth metal (Group IIa) ions to the aqueous solution; e) optionally filtering and washing the precipitate; and f) transforming the precipitate by adding an acid to form a solid metal compound comprising one or more Group VIB metals.