活性炭在低品位钼精矿加压氧化过程的催化机理研究

China annually produced a large number of low-grade molybdenum concentrates, which are difficult to be treated by traditional processes. Research and development of environmental friendly technology for treatment of low-grade molybdenum concentrate is significant owing to the depletion of high-grade molybdenum concentrates as well as the increasingly strict environmental protection requirements. Pressure hydrometallurgy is one of the important methods of treatment of low-grade molybdenum concentrate owing to its advantages of short technological process, environmental friendliness and high metal recovery ratio. In previous studies, we found that addition of activated carbon could improve decomposition of molybdenum concentrate and decrease reaction temperature and pressure during the pressure oxidation of molybdenum concentrate. However, the underlying mechanism of activated carbon on the pressure oxidation of molybdenum concentrate is unclear. In view of the problems such as high energy consumption, high pressure and passivation effect, the study proposes a novel pressure oxidation technology for low-grade molybdenum concentrate with activated carbon as catalyst. Thermodynamics, dynamics, electrochemical analysis and process mineralogy were employed in the study research the outfield intensifying effect theory of pressure leaching of low-grade molybdenum concentrate, migration rules and oxidation mechanism of sulfur during the pressure oxidation process, multiphase transmission dynamics and controlling steps of chemical reactions, and functional mechanism of activated carbon. This study aims at providing theoretical guidance for efficient utilization of low-grade molybdenum concentrate through explaining interface behavior and migration regularity of mineral components of the low-grade molybdenum concentrate during pressure leaching and evaluating catalytic mechanism of activated carbon on the pressure oxidation of low-grade molybdenum concentrate.

我国每年产出大量低品位钼精矿，采用常规工艺难以处理。随着高品位钼精矿的日益匮乏和环保要求的日趋严厉，开发低品位钼精矿环保处理技术具有重要意义。加压湿法冶金因具有流程短、环境友好、金属回收率高等优点，成为低品位钼精矿环保处理的重要方法。前期研究中，我们发现钼精矿加压氧化过程中添加活性炭可提高钼精矿分解效率，降低反应温度和压力，但是活性炭对矿物氧化分解的具体作用机理尚不清楚。本项目针对钼精矿加压氧化过程存在能耗高、设备操作压力大、反应钝化等问题，提出活性炭催化氧化低品位钼精矿新技术，运用热力学、动力学、电化学和工艺矿物学等冶金方法和现代测试手段，进行钼精矿浸出过程外场强化作用、硫的迁移规律和氧化机制、多相传质和反应控制、活性炭催化作用等研究，揭示低品位钼精矿加压湿法冶金过程的界面行为和迁移规律，阐明活性炭在钼精矿加压氧化过程的催化机理，为实现低品位钼精矿资源高效开发提供理论指导。

我国每年产出大量低品位钼精矿，采用常规工艺难以处理。随着高品位钼精矿的日益匮乏和环保要求的日趋严厉，开发低品位钼精矿环保处理技术具有重要意义。加压湿法冶金因具有流程短、环境友好、金属回收率高等优点，成为低品位钼精矿环保处理的重要方法。本项目针对钼精矿加压氧化过程存在能耗高、设备操作压力大、反应钝化等问题，提出活性炭催化氧化低品位钼精矿新技术，运用热力学、动力学和工艺矿物学等冶金方法和现代测试手段，进行钼精矿浸出过程外场强化作用、硫的迁移规律和氧化机制、多相传质和反应控制、活性炭催化作用等研究，揭示了低品位钼精矿加压湿法冶金过程的界面行为和迁移规律，阐明活性炭在钼精矿加压氧化过程的催化机理，为实现低品位钼精矿资源高效开发提供理论指导。.开展了钼中矿加压氧化浸出速度变化规律的研究，建立了加压浸出动力学模型，揭示了加压浸出过程的反应机理。浸出动力学研究表明，钼中矿加压氧化浸出速率1-(1-x)1/3与时间呈线性关系，浸出过程受界面化学反应控制，反应遵循收缩核模型，反应表观活化能为E=112.24 kJ•mol-1。.研究发现添加活性炭可加快辉钼矿浸出，辉钼矿与活性炭混合加压氧化浸出本质是一个电化学腐蚀强化过程，提出了原电池效应模型。当辉钼矿与活性炭颗粒接触时，两者组成的原电池可使辉钼矿腐蚀电位降低，腐蚀电流升高，原电池效应增强，促进阳极辉钼矿的氧化溶解加速，提高了钼的浸出率，进而降低反应温度和压力。