Modelos matemáticos de transferência de calor e massa: extração de metais por membranas poliméricas e sinterização de materiais cerâmicos

Abstract

The overall objective of this work was to present a mathematical study of multicomponent mass transfer in a metal ion extraction cell through a flat polymeric membrane and to conduct an experimental and kinetic study focused on the production of synthetic aggregate from bauxite residue. In the first part of the work, a mass transfer model for the recovery of metal ions using flat polymeric membranes was developed. Unlike most existing models, which are limited to studying a single component and do not consider the selectivity and effects of multiple components on reaction kinetics, a model capable of simulating the simultaneous extraction of various metals is proposed. This model is based on the mass conservation equation and was solved using the Coupled Integral Equations Approach (CIEA), and validated with experimental measurements and previous simulations. In the second part, an experimental and theoretical study was conducted using a kinetic model for the production of coarse synthetic aggregates from bauxite residue, silica, and clay. The experimental study included the production and characterization of the aggregates in different compositions. To analyze the sintering process of a full-sized pellet, a small electric furnace with an attached balance was built, allowing the monitoring of mass loss measurements as a function of temperature and time. Additionally, a kinetic study was carried out using mathematical models to evaluate the main solid-state reactions and their phase transformations during the sintering process, using experimental data from thermal analysis.