STUDY OF THE INFLUENCE OF THE LEVEL OF THE DEGREE OF PROTONATION ON THE USE OF ORGANIC ACIDS AS LEACHING AGENTS IN HYDROMETALLURGICAL PROCESSES.

• Grant number: 24/20879-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2025
• End date: February 28, 2026
• Field of knowledge: Engineering - Chemical Engineering - Chemical Technology
• Principal Investigator: Denise Crocce Romano Espinosa
• Grantee: Mariana Munhos Frare
• 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 techniques for recovering metals from primary and secondary sources, hydrometallurgy stands out. This group of techniques is efficient in recovering metals with low grades or from sources that have several associated metals. The hydrometallurgical process consists of extracting metals from their dissolution and separation, including three main stages, which are leaching, purification, and healing. In the leaching process, metal is solubilized by a leaching agent - usually an acid. In a more recent approach, organic acids have been used as agents due to lower environmental impact in their production and the generation of waste that is less aggressive to the environment. To understand how the reactions between the organic acids and the metal occur, the study of the nature of organometallic complexes is gaining more prominence. Some studies already sought to characterize organometallic complexes formed in the extraction process, in addition to understanding how factors such as temperature, pH of solutions, and acid concentration influence the formation of these complexes. However, there is still not much available literature that explains the complexation itself in residuals due to the multi-element characteristic that makes the characterization more difficult. This project aims to characterize the formation of organometallic complexes in leaching and understand the importance of that in the process efficiency based on the degree of protonation of the acids considered. Initially, the study will be carried out with mono- and multi-element synthetic compounds and in a second moment with real residues. The pH will be varied, and therefore the degree of protonation, and the complexes formed as well as their influence on the leaching process will be evaluated.