The paper discusses the effects of reaction kinetics on differential thermal analysis (DTA) patterns, focusing on reactions of the type solid → solid + gas. It explores how the rate of reaction, which varies with temperature, influences the position of the DTA peak. The study uses analytical methods to construct curves of reaction rate vs. temperature for constant heating rates, demonstrating the effect of varying reaction orders. The results are applied to analyze the DTA patterns of magnesite, calcite, brucite, kaolinite, and halloysite. The findings agree with isothermal results except in specific cases. The paper extends a previous method for determining the activation energy of first-order reactions to reactions of any order, proposing a method to determine the reaction order from the shape of the DTA peak. It discusses the temperature distribution in DTA specimen holders and the heat flow equation governing the temperature change. The analysis shows that the peak differential thermal deflection occurs when the reaction rate is maximum, assuming a constant heating rate. The paper presents an equation describing the reaction rate as a function of temperature and discusses the integration of this equation to determine the extent of reaction as a function of temperature. It shows that the amount of undecomposed reactant at the peak temperature decreases with decreasing reaction order, leading to increasingly asymmetric DTA peaks. A "shape index" is proposed to quantify the asymmetry of the DTA peak, defined as the absolute value of the ratio of the slopes of tangents to the curve at the inflection points. The shape index is shown to be a function only of the reaction order, n. The paper also describes an experimental procedure using a DTA apparatus to measure the peak temperature and reaction rate constants, and compares the results with isothermal weight-loss measurements. The results show that the activation energy and reaction order obtained from DTA agree with isothermal measurements for magnesite but differ for calcite and brucite. The differences are attributed to factors such as reaction reversibility and diffusion rates. The paper concludes that DTA can provide information about the kinetics and reaction order of simple decomposition reactions, with the reaction itself being the dominant factor controlling the shape and position of the DTA peak.The paper discusses the effects of reaction kinetics on differential thermal analysis (DTA) patterns, focusing on reactions of the type solid → solid + gas. It explores how the rate of reaction, which varies with temperature, influences the position of the DTA peak. The study uses analytical methods to construct curves of reaction rate vs. temperature for constant heating rates, demonstrating the effect of varying reaction orders. The results are applied to analyze the DTA patterns of magnesite, calcite, brucite, kaolinite, and halloysite. The findings agree with isothermal results except in specific cases. The paper extends a previous method for determining the activation energy of first-order reactions to reactions of any order, proposing a method to determine the reaction order from the shape of the DTA peak. It discusses the temperature distribution in DTA specimen holders and the heat flow equation governing the temperature change. The analysis shows that the peak differential thermal deflection occurs when the reaction rate is maximum, assuming a constant heating rate. The paper presents an equation describing the reaction rate as a function of temperature and discusses the integration of this equation to determine the extent of reaction as a function of temperature. It shows that the amount of undecomposed reactant at the peak temperature decreases with decreasing reaction order, leading to increasingly asymmetric DTA peaks. A "shape index" is proposed to quantify the asymmetry of the DTA peak, defined as the absolute value of the ratio of the slopes of tangents to the curve at the inflection points. The shape index is shown to be a function only of the reaction order, n. The paper also describes an experimental procedure using a DTA apparatus to measure the peak temperature and reaction rate constants, and compares the results with isothermal weight-loss measurements. The results show that the activation energy and reaction order obtained from DTA agree with isothermal measurements for magnesite but differ for calcite and brucite. The differences are attributed to factors such as reaction reversibility and diffusion rates. The paper concludes that DTA can provide information about the kinetics and reaction order of simple decomposition reactions, with the reaction itself being the dominant factor controlling the shape and position of the DTA peak.