The calcination of the strontium carbonate in the rotary kiln is usually carried out at temperatures as high as 1300 °C in practical applications. During the calcination process, partial melting of powders occurs at about 1150 °C, due to the partial pressure of CO2. Because of adhesion of the melts to the furnace walls, a ring formation can be seen in the progressive stages. Nevertheless, carbon additions to the SrCO3 before calcination can prevent the agglomerations by reducing the partial pressure of CO2. In this study, calcination of SrCO3 is determined by adding metallurgical coke (0–30%) in a laboratory-scale rotary kiln furnace. Experiments were run at the temperatures between 1100 and 1300 °C. The calcined powders were analysed by XRD. The maximum calcination efficiency was obtained with 15% coke addition at 1200 °C.