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

Abstract

The present study dealt with the whole 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. The environmental sustainability of the process was also assessed by means of life cycle assessment and yielded an estimate that the highest impact was in the category of global warming potential with 0.42 kg carbon dioxide per kg recovered metal.

Removal of Vanadium(III) and Molybdenum(V) from Wastewater Using Posidonia oceanica (Tracheophyta) Biomass

“…The availability of a mathematical tool that can predict the performance of biosorption in such multi-metal systems is considered very important [56], [57] and there is a real need that new scientific literature goes beyond the very well-known Langmuir/Freundlich sorption models, representative of ideal single metal systems. Future work will be addressed on one hand at real systems coming from refinery catalysts recycling process [58], [59], on the other hand at the upscale of the biosorption process, in order to find a suitable process configuration for the application of Posidonia oceanica biomass at industrial scale.…”

Extraction and Recovery of Metals from Spent HDS Catalysts: Lab- and Pilot-Scale Results of the Overall Process

“…Various methods for recovery of HDS catalysts have been proposed in the literature: acid leaching followed by solvent extraction [11], primary leaching of spent catalyst, and then separation of metals through selective precipitation [12] recovery from biotechnological routes [13,14], carbon adsorption [15], polyelectrolyte extraction [16] and solvent extraction [17][18][19]. To all methods mentioned above, the recovery of metals was at different rates; however, the extraction of metals can achieve around 90% [11][12][13].…”

- Removal of Vanadium(III) and Molybdenum(V) from Wastewater Using Posidonia oceanica (Tracheophyta) Biomass

“…The availability of a mathematical tool that can predict the performance of biosorption in such multi-metal systems is considered very important [56,57] and there is a real need that new scientific literature goes beyond the very well-known Langmuir/Freundlich sorption models, representative of ideal single metal systems. Future work will be addressed on one hand at real systems coming from refinery catalysts recycling process [58,59], on the other hand at the upscale of the biosorption process, in order to find a suitable process…”