The aim of this study was to investigate the impact of mechanochemical synthesis time on the decomposition of sulfated celestite ore and to understand the reactions, phases, and thermal transformations involved in the formation of strontium carbonate using various characterization techniques. The study found that the conversion rate of celestite ore to strontium carbonate increased with increasing mechanochemical synthesis duration, and that the peak intensities of SrCO3 were highest at 100 minutes but decreased at 200 minutes, indicating that the crystal structure was disrupted beyond a certain duration. The transformation temperatures in DTA curves also decreased with increasing synthesis duration due to the increase in energy of the particles. Overall, this study provides valuable insights into the mechanistic aspects of strontium carbonate decomposition.