真空法从铟矿中制备铟的机理研究

Carbothermal reduction mechanism of indium ore in vacuum

在真空条件下,本文采用热力学分析方法计算真空下铟矿碳热还原反应过程中发生的反应的吉布斯自由能以及起始反应温度。结果表明,当压力为10 Pa、温度高于380 K时,In2O3与C的反应满足反应发生的热力学条件。在同一体系压力下,物料In2O3:C摩尔比为1:3时,反应生成单质In所需的温度是最低的。在碳量充足条件下In2O3可直接被还原生成单质铟,随着碳的消耗,In2O3的碳热反应会生成中间产物。由此,推算在真空碳热反应过程中,碳热还原In2O3的顺序首先生成In,随着碳耗及升温生成In2O,最后生成In O。In2O3热分解生成In2O,随着体系压力的降低,反应起始温度降至423 K;中间产物In2O热分解生成单质In,当体系压力降至10 Pa时,起始温度降为781 K;In O与生成物CO反应,随着体系压力降低,吉布斯自由能增加,因此,降压不利于In O与CO反应。本文从热力学角度探讨真空制备铟热力学可行性,为下一步实际生产提供相应的理论基础。

The Gibbs free energy and initial reaction temperature during indium carbothermal reduction process were investigated by thermodynamic analysis. The results show that the pressure of 10 Pa and temperature of 380 K meet the reaction thermody- namic conditions. Under pressure from the same system,when the In2O3：C mole ratio is 1：3, the temperature needed to generate elemental in reaction is the lowest. When the amount of carbon is sufficient, the In2O3 first generate indium, as the carbon con- sumption and heating to generate In2O, then generate the InO. In2O3 generated In2O by thermal decomposition, with the decrease of the system pressure, the initial reaction temperature decrease to 423 K; Intermediate In2O pyrolysis generating elemental In, when the system pressure drop to 10 Pa, the temperature decrease to 781 K; InO reacted with products CO, as the system pressure is reduced, the Gibbs free energy increase, therefore, the pressure decrease is adverse to InO reaction with CO. This study is to provide experimental evidence for preparation of indium by carbothermic reaction of indium ore in vacuum.