Chemical Treatment to Recover Molybdenum and Vanadium from Spent Heavy Gasoil Hydrodesulfurization Catalyst

Alma Delia Rojas-Rodríguez, Orlando Flores-Fajardo, Fabiola Selene Alcántar González, Néstor Noé López Castillo, Modesto Javier Cruz Gómez

Chemical Engineering Department of the Faculty of Chemistry, Universidad Nacional Autónoma de México (UNAM), Coyoacán, México.
Faculty of Engineering, Universidad Anáhuac México Norte, México City, México.

DOI: 10.4236/aces.2012.23050                

Abstract

Large quantities of spent hydrodesulfurization (HDS) catalysts are available from petrochemical industry. Disposal of spent catalyst is a problem as it falls under the category of hazardous industrial waste due to its vanadium concentration. Most of these catalysts are usually supported on alumina containing a variable percentage of elements such as nickel or molybdenum. Hence these catalysts contain environmentally critical, and economically valuable metals such as molyb denum, vanadium, and, nickel. In this paper, a spent HDS catalyst was treated with caustic soda solution. Parameters such as temperature, time, and NaOH solution concentration have been studied thoroughly, in order to settle the appropriate conditions for the maximum recovery of molybdenum and vanadium. Under the best leaching conditions (20 %w NaOH, room temperature, 2 h) about 95% recovery of Mo and V was achieved, and the recovery of nickel obtained was of 99% in the form of NiAlO₄.

Keywords

Spent HDS Catalyst; Vanadium; Molybdenum; Metal Recovery

Conflicts of Interest

The authors declare no conflicts of interest.

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