Studies on removal of petroleum fractions from spent petrochemical catalysts to prepare them for pyrometallurgical recovery of Ni, Mo and V

The article presents a study on the removal of petroleum fractions from reprocessed and decommissioned petrochemical catalysts used in refineries. Petrochemical catalysts are hazardous waste due to their content of petroleum fractions (organic fraction), while also containing high concentrations of Ni, Mo and V. The process of removing petroleum fractions from catalysts was carried out by solvent extraction using hexane. Its purpose was to prepare the catalysts for subsequent steps involving pyrometallurgical processes leading to the recovery of Ni, Mo, V. At the same time, the extraction process was aimed at reducing CO₂ emissions during melting by deriving the oil fraction before the pyrometallurgical step. The realized studies showed that the degree of removal of the petroleum fraction from catalysts depends on temperature, catalyst/solvent ratio and extraction time. The study showed that it is possible to remove > 40% by weight of the oil fraction initially contained in the catalysts. The research presented in this article is being carried out as part of the LIDER13/0133/2022 project funded by the National Centre for Research and Development, which aims to develop a complete technology for the recovery of Ni, Mo and V from spent petrochemical catalysts.