An environmentally friendly process for the recovery of valuable metals from spent refinery catalysts

Waste Manag Res February 7, 2013
An environmentally friendly process for the recovery of valuable metals from spent refinery catalysts
Laura Rocchetti
l.rocchetti@univpm.it
Department of Life and Environmental Sciences, Università Politecnica delle Marche, Ancona, Italy
Viviana Fonti
Department of Life and Environmental Sciences, Università Politecnica delle Marche, Ancona, Italy
Francesco Vegliò
Department of Chemistry, Chemical Engineering and Materials, Università dell’Aquila, Monteluco di Roio, Italy
Francesca Beolchini
Department of Life and Environmental Sciences, Università Politecnica delle Marche, Ancona, Italy
Abstract
Describes the valorization process of exhaust refinery catalysts, including metal extraction by ferric iron leaching and metal recovery by precipitation with sodium hydroxide. In the leaching operation the effects on metal recovery of the concentration and kind of acid, the concentration of catalyst and iron (III) were determined.
The best operating conditions were 0.05 mol L−1 sulfuric acid, 40 g L−1 iron (III), 10% catalyst concentration; almost complete extraction of nickel and vanadium, and 50%extraction efficiency of aluminium and less than 20% for molybdenum. Sequential precipitation on the leach liquor showed that it was not possible to separate metals through such an approach and a recovery operation by means of a single-stage precipitation at pH 6.5 would simplify the procedures and give a product with an average content of iron (68%), aluminium (13%), vanadium (11%), nickel (6%) and molybdenum (1%) which would be potentially of interest in the iron alloy market.
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