Kinetic analysis of retention of SO₂ using waste ulexite ore in an aqueous medium

This study was carried out under atmospheric pressure and examined the kinetics of retention of SO₂, a toxic gas, by waste ulexite ore (WUO) from a boron concentration plant, as well as the kinetics of passing B₂O₃ content of WUO to solution. The parameters of temperature, solid-to-liquid ratio, particle size, gas flow rate, and stirring speed were selected for the experiments carried out in a jacketted cylindirical glass reactor. The data on retention-dissolution and an XRD graph showed that SO₂ had been captured as CaSO₃·0.5H₂O, and that the B₂O₃ content of WUO had almost completely passed into the aqueous medium. A kinetic evaluation, performed with the retention-dissolution data using kinetic models for heterogenous reactions, found that the kinetics model for SO₂ retention fitted diffusion through product layer control. In addition, the kinetics model for the B₂O₃ dissolution fitted the diffusion through product film control. Activation energies for SO₂ retention in solid waste and B₂O₃ dissolution were 6196 J mol^-1 and 15436 J mol^-1 respectively.