This paper proposes two recycling processes to recover valuable metals and materials from hydrodesulfurization (HDS) and spent fluid catalytic cracking (FCC) catalysts.
The HDS plant, with a 6000 tons/year capacity, is based on a process with pre-treatment thermal stages. The simulations were carried out using lab-scale experimental data. Only wet Ni-Mo catalyst was used as the plant's feedstock, producing 1272 tons/year of V2O5 98%wt, 239 tons/year of MoO3 57%wt, and 227 tons/year of Ni-V-Mo alloy with an approximate composition of 72-25-3%wt, respectively. The investment is highly profitable, with a net profit of around 14.1 MEUR/year, gross margin of 37.2%, return on investment equal to 23.9%, and a payback time slightly greater than 4 years. Regarding FCC catalysts, a recycling process is proposed, aiming to recover cerium (Ce) and lanthanum (La) and reuse the solid leaching residue to produce synthetic zeolites. A profitability analysis was carried out for a 4000 tons/year plant treating spent FCC catalysts: the study showed that the unit production cost is 1.17 €/kg of zeolite. The profitability is achieved with a zeolite price of 1380 €/ton without the disposal fee (NPV 2032 k€). If there is additional revenue of 250 €/ton (disposal fee), the profitability is achieved (NPV 2170 k€) with a selling price of 1150 €/ton.