亚熔盐介质中微气泡强化生成活性氧机理及调控规律

Liquid oxidation technologies in sub-molten salt media, based on the critical role of reactive oxygen species (ROS) including oxidative oxygen anions and free radicals in the oxidation and decomposition of amphoteric ores, have gradually become an alternative green approach for the clean chemical-metallurgy production of typical amphoteric metal (such as vanadium, chromium, and manganese) compounds. The key to improve the reactivity of sub-molten salt media is to intensify the formation of reactive oxygen species (ROS). Based on the unique physiochemical phenomena featuring the shrinkage and burst of micro bubbles to generate ROS, the project focused on the interfacial structure characteristics of micro bubbles as well as the formation mechanisms of different ROS. Formation mechanisms and controlling strategies of ROS in sub-molten salt media, intensification effect of ROS formation by micro bubbles, the catalytic oxidation effect of low-valence amphorteric metal oxide by ROS, and the effects of external fields for the generation of ROS will be systematically investigated, to uncover the formation mechanisms and the controlling strategies of ROS and establish the new decomposition method of amphoteric metal mineral in sub-molten salt media strengthened by micro bubbles, providing theoretical development of sub-molten salt media technology, and the promotion of green technology developments on the cleaner utilization of typical amphoteric metal(V, Cr, Mn, etc.) resources in China.

基于亚熔盐介质的液相氧化技术已逐渐成为钒、铬、锰等两性金属清洁生产的绿色替代技术，其核心原理是利用介质中高反应活性的活性氧（氧负离子/自由基）强化低价两性金属矿物的氧化分解。强化亚熔盐介质中活性氧的生成，是提高亚熔盐介质反应活性的关键。亚熔盐介质中微气泡收缩爆裂会生成高活性氧粒子，本项目聚焦于亚熔盐介质中微气泡界面结构及不同种类活性氧生成机理，系统研究亚熔盐介质中活性氧生成机制、微气泡强化生成活性氧机理、活性氧催化氧化低价两性金属氧化物作用机理、外场协同微气泡强化活性氧生成等基础研究内容，揭示亚熔盐介质中活性氧生成机制及定向调控规律，建立微气泡强化亚熔盐介质中两性金属矿物分解新方法，进一步发展亚熔盐清洁冶金理论，为推动我国钒、铬、锰等典型两性金属资源清洁生产技术绿色升级提供理论依据。

活性氧是亚熔盐介质高氧化活性的核心，微气泡爆裂瞬间可极大强化亚熔盐介质中活性氧的生成，提升介质的氧化能力，强化两性金属氧化物的氧化分解。本项目首先系统研究了亚熔盐介质中活性氧的生成机制、量化调控规律以及与两性金属氧化物的作用机理，明晰了亚熔盐介质中存在的主要活性氧种类为过氧氢根，确定了钒铬两性金属氧化物氧化的最优操作温度和碱浓度，建立了亚熔盐介质中宽温全碱浓度界面和体相中活性氧的定量测定方法；采用分子动力学模拟与流场模拟初步建立了微气泡界面结构与活性氧生成的调控关系，并自行设计了3000 mL双层桨自吸式搅拌反应器，大幅提升活性氧的生成能力；采用流场、电场协同微气泡强化亚熔盐介质中活性氧生成以及钒铬两性金属的的氧化溶出，并将微气泡的应用扩展至高铬型钒渣以及铬系尖晶石矿物，铬转化率可达到99%以上。本项目建立了微气泡强化亚熔盐介质中两性金属矿物分解新方法，实现了两性金属氧化矿在温和条件下的高效氧化分解，为推动我国钒、铬等典型两性金属资源清洁生产技术绿色升级提供理论依据。