Anotace:
Sulphur trioxides are common toxic gaseous pollutants which can be produced from alternative routes via calcination of aluminum sulfate derived from kaolin clay. Its demand increases geometrically, thus the need to optimize the yield of SO3 from the calcination of alum is essential. The rate of alum decomposition was monitored by the formation of SO3 via thermogravimetric analysis and X-ray fluorescence analysis. This study aimed to evaluate the effect of calcination temperature and curing time on the SO3 conversion and yields using Face Central Composite Design and optimize the process conditions to evaluate the maximum yield of SO3 using response surface methodology and its effects and interactions were investigated between 800–900 °C at 60-180 minutes. Results indicated that experimental data satisfied second order polynomial regression model for SO3 conversion and SO3 yield from TG analysis while XRF analysis satisfied first order model respectively. An increase in SO3 conversion and yields was observed as the calcination temperature and time were increased both independently and simultaneously. The calcination temperature was found to have a stronger influence compared to the calcination time. Validation indicated agreement between experimental and predicted values with a regression value of 97.8 %, 97.77 % and 97.67 % for SO3 conversion, SO3 yield via TG and XRF analyses respectively. Based on the ANOVA, the SO3 yield via XRF produced the best model with R2pred of 91.98% while SO3 yield via TG analysis and SO3 conversion had R2pred of 79.99% and 78.01% respectively. Optimization of the production of SO3 was carried out and the optimal condition for SO3 conversion, SO3 yield via TG and XRF analyes were 90.11 %, 91.67 % and 75.81 % respectively at an optimal calcination temperature of 877.43 oC and time of 155.04 minutes respectively.