Journal of Petroleum & Environmental Biotechnology

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

2^nd World Congress on Petrochemistry and Chemical Engineering

October 27-29, 2014 Embassy Suites Las Vegas, USA

Helena M V M Soares and Isabel S S Pinto

Accepted Abstracts: J Pet Environ Biotechnol

Abstract:

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 NieMo 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 0 C, as tetragonal SrMoO 4 , with high purity (99%). Precipitation with lead at 25 0 C resulted in a maximum recovery of 99.8% of the molybdenum, as tetragonal PbMoO 4 , 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.