Influence of calcination temperature on the properties of titanium oxide sulfur recovery catalysts.

To study the effect of calcination temperatures on the sulfur recovery catalysts, titanium oxide (TiO2), as sulfur recovery catalysts, were treated at four calcination temperatures of 300 degrees C, 500 degrees C, 700 degrees C and 900 degrees C. The structure of the catalysts were characterized by X-ray powder diffraction (XRD), Raman, transmission electron microscopy (TEM), Scanning electron microscopy (SEM), temperature thermogravimetry (TG) and differential scanning calorimetry (DSC). The results showed that with the calcination temperature increasing, the particle size of the TiO2 catalysts increases but the surface area and total pore volume decrease. The extent of reduction was more serious after calcination at 500 degrees C. Rutile phase were formed at calcination temperature about 700 degrees C. On the basis of these results, a scheme for the change of TiO2 with increasing calcination temperatures was proposed. The Claus catalytic activity of the TiO2 catalysts was evaluated in the traditional conditions. It was found that the Claus catalytic activity, which decreased a little when the calcination temperature was no more than 500 degrees C but much once the calcination temperature was more than 500 degrees C, was not only related to the surface area and pore volume, but also the phase of the TiO2. The activity of rutile was less than the anatase and a possible reaction pathway to reveal this mechanism was proposed.