Selective leaching of molybdenum from spent hydrodesulphurisation catalysts using ultrasound and microwave methods

• Type: Article in International Scientific Journal
• Date: 2012

Authors

Pinto, ISS (Author) Other; Helena Soares (Author) FEUP

Journal

Title: Hydrometallurgy

Vol. 129

Pages: 19-25

ISSN: 0304-386X

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 36 Citations

Scopus - 53 Citations

Other information

Authenticus ID: P-002-3K0

DOI: 10.1016/j.hydromet.2012.08.008

Abstract (EN): Spent hydrodesulphurisation (HDS) catalysts from petroleum refineries, mostly constituted by aluminium (Al), molybdenum (Mo), nickel (Ni) and cobalt (Co), are classified as hazardous wastes and disposal is restricted by environmental regulations; thus, the recovery of valuable metals is the most attractive option in the processing of these residues. Selective Mo leaching from two spent HDS (Ni-Mo or Co-Mo) catalysts, roasted at 500 degrees C, was studied using three different approaches: conventional, ultrasound- and microwave-assisted methods. For the Ni-Mo or Co-Mo catalysts, 77% and 84% of Mo extraction, respectively, was achieved when a conventional (10 g/L NaOH. 80 degrees C, 120 min, S/L = 50 g/L) approach was used. For both catalysts, ultrasound-assisted leaching (pulse 0.5 s and 20% amplitude) with 10 g/L NaOH and S/L = 50 g/L led to 66% Mo dissolution after 10 min. Under microwave-assisted (four cycles of 30 s) conditions, Mo leaching reached 89% and 91% for Ni-Mo and Co-Mo catalysts, respectively. The latter conditions represent the best compromise between Mo extraction and selectivity, since Al dissolution was between 6% and 9%.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7