轴对称电场与流体场作用下电解制取金属锰的基础研究

Manganese is an important basic material for economy development. China has the absolutly largeset share for the prouction, export and consumption of manganese metal. Electrolytic manganese production is a high energy consumption industry. Energy saving determines whether a manganese production enterprise can survive in the future competition. Manganese nuddles will occur on the surface of cathode due to the uneven deposit of manganese. Lead anodes have shortcomings of high energy consumption and introduction of lead impurities in manganese dioxide. Ti anodes tend to be passivated and are only suitable for use in electrolysis at low current density. To solve these problems, a high energy efficiency electrolysis method of manganese under symmetrical electric and fluid fields around central axis is advanced. A new electrochemical reactor is designed based on the electrolytic cell with symmetrical electric and fluid fields and the Ti/TiO2 nanotube-based nest structure composite anode (TNCA). Electrochemistry on reduction of manganese and behaviors of the anodic constituents during the electrolysis under the symmetrical electric and fluid fields are investigated. This research aims to reveal influence of the symmetrical electric and fluid fields on the reduction/oxidation behaviors of manganese and other ions and its mechanism, and to establish the design law, relationship between the structure and electrochemical properties of the TNCA, and then obtain an energy-saving technology for preparation of metallic manganese under the symmetrical electric and fluid fields. This will provide a new method for decreasing energy consumption of metallic manganese production and utilizing anodic manganese dioxide with high efficiency, and develop the theory for electrowinng manganese and related metals.

金属锰是支撑经济建设与发展的重要基础原料。我国是全球的最大电解锰生产国、出口国和消费国。电解锰属于高耗能行业，节能降耗关系到电解锰企业的生存问题。项目针对电解阴极锰因非均匀沉积易结瘤、阴极电流效率低；铅阳极电势高，且使阳极二氧化锰副产物含铅而无法经济利用；传统钛阳极易钝化、适用电流密度低等问题，提出轴对称电场与流体场作用下电解制取金属锰的新方法。通过轴对称性电场与流体场设计、嵌布结构钛基复合阳极设计，构建新型电化学反应器，研究并阐明该新型电化学反应体系下锰的阴极还原电化学、阳极过程组元行为与调控机制，揭示轴对称电场与流体场对锰离子及杂质离子还原/氧化行为的影响规律和作用机制，嵌布结构钛基复合阳极的构-效关系与调控原理，建立高效低耗电解制备金属锰的新方法和基础理论。项目成果将为电解锰工业节能降耗和高效利用阳极副产物提供一种新思路，并丰富和发展锰及相关金属的电解冶金理论。

本项目针对传统方法电解金属锰过程中存在阴极效率低，易结瘤，阳极过电势高，阳极泥无法综合利用等问题，提出轴对称电场与流体场作用下电解制取金属锰的新方法。通过轴对称性电场与流体场设计、钛基复合阳极设计，构建具有轴对称电场与均匀流体场的新型电化学反应器。首先，研究开发了新型钛基复合阳极，并将其首次应用于电解金属锰体系中。研究发现相较于传统的铅阳极，新型钛基复合阳极不仅具有较高的析氧催化活性，较低的阳极电势，而且使用新型钛基复合阳极会降低阳极泥的生成量，同时阳极液不会被阳极泥恶化。基于此，提出并验证了钛阳极上二氧化锰反应的机理，完善了电解金属锰的基础理论，阐明了钛基复合阳极中钛氧化物、二氧化锡、氧化钌等组元对钛基复合阳极的电催化特性及阳极副产物性能的作用规律及其调控原理。其次，设计加工了立式圆柱形电解槽，分别研究了轴对称电场和均匀流体场对电解沉积金属锰的影响。结果表明，相较于传统的平板电解槽，在轴对称电场作用下，所得的电解金属锰致密平整，结瘤现象得到明显抑制。更进一步地，在轴对称电场的基础之上，通过旋转阴极和循环阴极电解液，研究了流体场作用下的锰电解规律。结果表明，在合适的流体场作用下，阴极表面吸附的气泡量减少，抑止了金属锰晶核的过度生长，进一步抑制了结瘤，强化传质，降低浓差极化，提高阴极效率。最后，我们研究了综合利用阳极副产物直接合成锰基锂离子电池正极材料，阐明了新型阳极对体系组元以及阳极氧化行为对正极材料的影响规律和作用机制。项目成果形成了新型轴对称电场与流体场作用下电解金属锰的技术原型，对我国电解锰行业提供了节能降耗，综合利用锰资源提供了新思路。