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介绍了真空碳热还原制备Mg-Sr合金新思路,研究了其还原反应的反应式、吉布斯自由能及临界还原温度。结果表明,真空碳热还原MgO,SrO的混合物可以得到Mg-Sr合金;其他因素不变的情况下,还原反应吉布斯自由能随反应温度的提高而减小,随系统气压的降低而减小,随反应生成的Sr,Mg混合蒸气中Sr摩尔分数的减小而减小;反应温度的提高、系统气压的降低和Sr摩尔分数的减小均有利于还原反应的进行;当系统气压为10 Pa,Sr摩尔分数为0.1时,临界反应温度为1353 K;相同系统气压下,碳热还原制备Mg-Sr合金的临界反应温度低于真空碳热炼锶、炼镁的临界温度,反应更易于进行;常规真空硅热还原制备金属镁(皮江法)的反应温度1473 K,气压13.3 Pa下,无论反应生成的Sr,Mg混合蒸气中Mg,Sr相对比例如何,真空碳热还原制备Mg-Sr合金的反应均具备热力学可行性。
The new idea of preparing Mg-Sr alloy by vacuum carbothermal reduction was introduced. The reaction equation of Gibbs free energy and critical reduction temperature were studied. The results show that the Mg-Sr alloy can be obtained by vacuum carbothermal reduction of MgO and SrO. When the other factors are constant, the Gibbs free energy of reduction decreases with the increase of reaction temperature and decreases with the decrease of system pressure Is smaller than that of Sr and Mg mixed vapor generated by the reaction. The increase of the reaction temperature, the decrease of the system pressure and the decrease of the molar fraction of Sr all contribute to the reduction reaction. When the pressure of the system is Under the same system pressure, the critical reaction temperature of Mg-Sr alloy prepared by carbothermal reduction is lower than that of strontium in vacuum carburization and the critical temperature of magnesium refining, the reaction is more Easy to carry out; conventional vacuum silicon thermal reduction of magnesium metal (Pidgeon) reaction temperature 1473 K, pressure 13.3 Pa, regardless of the reaction of Sr, Mg mixed vapor Mg, Sr relative proportions, vacuum carbothermal reduction of Mg -Sr alloy reaction with thermodynamic feasibility.