Substantiation of using a carbothermal method for processing flotation perovskite concentrate is presented. Results of X-ray structural studies of compacted specimens after two sintering stages are provided. It is shown that titanium carbide is formed in the first stage, and in the second stage calcium carbide is formed followed by dissociation into calcium metal and graphite. A dependence is obtained for the degree of transformation of titanium carbide on isothermal exposure duration and excess carbon in the initial charge. Dependence of degree of calcium extraction on isothermal exposure duration is demonstrated. It is shown that the temperature for the beginning of calcium carbidization at a given pressure is ≈ 1600°C. It is established that briquette compaction pressure has almost no effect on calcium extraction, while it affects briquette mechanical strength. Thermodynamic calculations of equilibrium compositions of phases in contact involved in production processes are performed using HSC Chemistry application software. Results of differential-thermal and thermogravimetric analyses of a charge of a given composition of flotation perovskite and soot are analyzed. In order to study kinetic regularities, correlation coefficients of isothermal exposure duration and reaction rate constant are calculated using kinetic equations of Yander, Gistling–Brownstein, Zhuravlev–Lesokhin–Tempel’man, anti-Gistling, anti-Yander, and Tamman. Apparent activation energy for the first stage of the carbothermal process is calculated using a specific model taking account of results of experiments conducted at different temperatures (Ea = 311.48 kJ/mol). It is established that the dependence obtained for the degree of transformation on isothermal exposure duration is most adequately described by an anti-Yander model formal kinetics equation. Optimum production conditions are selected for the process on the basis of research results: briquette pressing pressure is 8.57 MPa; first stage temperature 1500°C and 1750°C in the second stage; heating rate 17°C/min and 9°C/min respectively. In this case exposure time is 120 min and 60 min in the first and second stages, and residual pressure is 50 Pa and 13.3·10–3 Pa respectively.

中文翻译：

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钙钛矿精矿碳热法制备碳化钛和金属钙工艺研究

介绍了使用碳热法处理浮选钙钛矿精矿的证明。提供了两个烧结阶段后压实试样的 X 射线结构研究结果。结果表明，在第一阶段形成碳化钛，在第二阶段形成碳化钙，然后分解为金属钙和石墨。获得了碳化钛转变程度对等温暴露时间和初始装料中过量碳的依赖性。证明了钙提取程度对等温暴露持续时间的依赖性。结果表明，在给定压力下开始碳化钙的温度约为 1600°C。确定压块压实压力对钙提取几乎没有影响，而它会影响型煤的机械强度。生产过程中接触相的平衡组成的热力学计算是使用 HSC 化学应用软件进行的。分析了浮选钙钛矿和烟灰的给定组成的装料的差热和热重分析结果。为了研究动力学规律，使用Yander、Gistling-Brownstein、Zhuravlev-Lesokhin-Tempel'man、anti-Gistling、anti-Yander 和Tamman 的动力学方程计算等温暴露持续时间和反应速率常数的相关系数。碳热过程第一阶段的表观活化能是使用特定模型计算的，考虑到在不同温度下进行的实验结果 (Ea = 311.48 kJ/mol)。已经确定，通过反Yander 模型形式动力学方程最充分地描述了转化程度对等温暴露持续时间的依赖性。该工艺根据研究结果选择最佳生产条件：型煤压制压力为8.57 MPa；第一阶段温度为 1500°C，第二阶段温度为 1750°C；升温速率分别为 17°C/min 和 9°C/min。在这种情况下，第一阶段和第二阶段的暴露时间分别为 120 分钟和 60 分钟，剩余压力分别为 50 Pa 和 13.3·10-3 Pa。压块压力为8.57 MPa；第一阶段温度为 1500°C，第二阶段温度为 1750°C；升温速率分别为 17°C/min 和 9°C/min。在这种情况下，第一阶段和第二阶段的暴露时间分别为 120 分钟和 60 分钟，剩余压力分别为 50 Pa 和 13.3·10-3 Pa。压块压力为8.57 MPa；第一阶段温度为 1500°C，第二阶段温度为 1750°C；升温速率分别为 17°C/min 和 9°C/min。在这种情况下，第一阶段和第二阶段的暴露时间分别为 120 分钟和 60 分钟，剩余压力分别为 50 Pa 和 13.3·10-3 Pa。