Barium sulfide has been widely accepted as a useful barium compound in many fields. To reduce the emission of CO2 through tail gas during the current industrial production of barium sulfide by the black ash method, a new clean process for barium sulfide preparation by barite reduction using elemental sulfur is proposed. Herein, we report a study on the kinetics and thermodynamics of the thermal decomposition of barium sulfate by elemental sulfur. The mechanism of this complicated gas-solid reaction was investigated under non-isothermal conditions, at different heating rates. Four isoconversional methods were used to determine the activation energy. The mechanism model of the barium sulfate decomposition was confirmed using the double equal-double step method. The results suggested that the barium sulfate decomposition followed the Dander D3 spherical symmetry model; the order of the reaction (n = 1.06) was determined using the Came equation. (C) 2019 Elsevier B.V. All rights reserved.