Recovery of molybdates from an alkaline leachate of spent hydrodesulphurisation catalyst - proposal of a nearly-closed process

• Type: Article in International Scientific Journal
• Date: 2013

Authors

Isabel S.S.Pinto (Author) Other; Helena Soares (Author) FEUP

Journal

Title: Journal of Cleaner Production

Vol. 52

Pages: 481-487

ISSN: 0959-6526

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 22 Citations

ISI Web of Science

Scopus - 32 Citations

Scientific classification

FOS: Engineering and technology

CORDIS: Technological sciences

Other information

Authenticus ID: P-006-8XX

DOI: 10.1016/j.jclepro.2013.03.021

Abstract (EN): In this work, we developed a simple, effective, low-cost and more environmentally friendly process (with low energy requirements and minimized effluent emissions) to recover molybdenum from an alkaline leaching solution of a spent hydrodesulphurisation catalyst, as a final product with high purity and in high yield. Alkaline leaching of spent Ni-Mo hydrodesulphurisation catalysts results in a solution that mainly contains molybdenum and aluminum. Before recovering molybdenum, previous separation of aluminum from the solution, as a precipitate of aluminum hydroxide, was performed by lowering the pH to 8, at room temperature, with a yield of 99.2%. Recovery of molybdenum was studied by precipitation in the form of a salt of strontium or lead molybdate. The first process allowed a recovery of 96% of Mo at 25 degrees C, as tetragonal SrMoO4, with high purity (99%). Precipitation with lead at 25 degrees C resulted in a maximum recovery of 99.8% of the molybdenum, as tetragonal PbMoO4, with a purity of 99.5%. Finally, the destination of the final solution is discussed and a flow sheet considering the production of strontium/lead molybdate is proposed.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7