DEVELOPMENT OF LEACHING ROUTES FOR RECYCLING OF SPENT PETROLEUM CRACKING CATALYSTS FOR THE RECOVERY OF RARE EARTHS

• Grant number: 24/15256-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2024
• End date: October 31, 2025
• Field of knowledge: Engineering - Chemical Engineering - Chemical Technology
• Principal Investigator: Denise Crocce Romano Espinosa
• Grantee: Gabriel Ferreira Zapata
• Host Institution: Escola Politécnica (EP). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 19/11866-5 - Development of innovative processes for the recovery of critical metals, AP.TEM

Abstract

Among the different cracking units, the Fluidized Catalytic Cracking (FCC) unit stands out for its efficiency and productive versatility. This unit subjects vacuum gas oil to high pressures and temperatures combined with a catalytic bed to produce LPG, gasoline, olefins, and other petroleum derivatives. The catalyst used is a zeolite stabilized by rare earth elements, which are employed to enhance its catalytic activity. As it goes through cracking cycles, the catalyst becomes deactivated. Although it can be regenerated, this process is limited, resulting in a global generation of 200 to 400 kt/year of spent FCC catalysts as waste. Disposal of this material commonly occurs through landfilling, leading to the loss of valuable metals. Several research groups have been dedicated to establishing hydrometallurgical routes for recovering these metals, aiming to obtain a secondary source of these elements and reduce the toxicity of this waste. The present project aims to characterize spent FCC catalysts and develop a hydrometallurgical route for the recovery of rare earth elements, evaluating the need for thermal pre-treatments, acid and alkaline leaching, and solvent extraction processes. It is expected to quantify the metals present in the waste through a thorough characterization to assess which metals have the highest recovery value, the rare earths or the contaminant metals. Based on this information, various exploratory leaching processes will be conducted. The key differentiator of this project is the use of solvent extraction and its comparison with classical leaching techniques for catalytic residues.