Evaluation of crystalline structure and SO₂ removal capacity of a series of MgAlFeCu mixed oxides as sulfur transfer catalysts

A series of MgAlFeCu mixed oxides with different Mg/Al atomic ratios derived from hydrotalcite-like compounds were prepared and tested for SO₂ removal under the conditions similar to those of FCC units. The crystalline structures, the surface areas and the chemical compositions of the catalysts were investigated through the XRF, XRD, and N₂ adsorption analysis. And spinel, spinel and Mg(Al)O, or Mg(Al)O was produced by changing the Mg/Al atomic ratios. The results of SO₂ adsorption-reduction tests showed that the activities of the catalysts were strongly affected by the Mg/Al atomic ratio, structure and surface area. The sulfur transfer catalyst LDO6 (Mg/Al = 6) showed the excellent SO₂ oxidative adsorption and reductive capacity, its total amounts of adsorbed SO₂ reached 1.62 g SO₂/g Cat, which was also remained at constant after eight cycles.