含多金属的铁锰矿矿相重构制备复合铁酸盐磁性吸附材料的机理研究

Composite ferrites magnetic adsorbent can effectively remove the heavy metal ions from the wastewater, and it is of great significance to realize the economical, high-efficiency and large-scale preparation of the high-performance magnetic adsorbent for the wastewater treatment. During the existing comprehensive utilization methods of ferruginous manganese ore, it’s found that the spinel-type composite ferrites with strong magnetism are readily generated from the Mn, Fe, Zn, Co constitutes resulting in the poor stepwise separation of the valuable metals. In current project, the applicant exactly uses the characteristic of easy generation of composite ferrites, and the abundant and polymetallic ferruginous manganese ore resources are used as raw materials directly for the preparation of nanoscale composite ferrites magnetic adsorbent via mineral phase reconstruction. With the main research line of directional regulation of mineral phase, separation process and performance characterization of the as-prepared ferrites, the main research contents include: the phase transformation of the main components under different atmospheres are investigated, and the formation mechanism of the composite ferrites is clarified; the effects of impurity elements on the structure and performance of the synthetic composite ferrites are determined, and the strengthening regulation mechanism of the impurity elements migration by the micro zone liquid silicate phase are revealed in order to establish the good mineralogical conditions for the separation of composite ferrites and gangue minerals; the composite ferrites concentrates are further grinded via “sanding-ultrasonic cavitation” coupling process to prepare the nanoscale magnetic adsorbent and the adsorption-desorption behavior of heavy metal ions by the as-obtained adsorbent are investigated. Eventually, the theoretical foundation for the establishment of the technical prototype for the extraction of valuable components and preparation of composite ferrites adsorbent synchronously from the ferruginous manganese ore by mineral phase reconstruction are provided.

复合铁酸盐磁性吸附材料可以有效去除水体中重金属离子，经济、高效、宏量制备高性能吸附材料对废水治理意义重大。铁锰矿中锰铁锌钴等组元易生成强磁性复合铁酸盐的特性，导致其综合利用过程中有价组元分步分离难度大。项目利用这一特性，直接以储量丰富且富含多金属的铁锰矿为原料，开展铁锰矿矿相重构制备复合铁酸盐磁性吸附材料的机理研究。以矿相定向调控机制-分选过程-材料性能表征为研究主线，主要内容包括：研究不同焙烧气氛下铁锰矿中主要有价矿物组分的相变规律，揭示复合铁酸盐的生成机制；研究主要杂质元素对复合铁酸盐结构和性能的影响规律，开发微区液相强化杂质迁移与性能调控的方法，进而为复合铁酸盐与杂质高效分离创造矿物学条件；探究磨选精矿经“砂磨-超声”耦合磨削制备的纳米级复合铁酸盐磁性颗粒去除废水中重金属离子的性能。本项目旨在为构建铁锰矿矿相重构同步提取多金属组分与制备复合铁酸盐磁性吸附材料的技术原型奠定基础。

复合铁酸盐磁性吸附材料可有效去除水体金属污染物，经济、高效、宏量制备磁性吸附材料对有色金属选冶废水治理意义重大。项目利用铁锰矿中锰铁锌等组元易生成强磁性复合铁酸盐的特性，直接以储量丰富且富含多金属的铁锰矿为原料，开展矿相重构制备复合铁酸盐磁性吸附材料的机理研究，主要包括：多金属铁锰矿高温矿相重构机制、矿相重构过程中各组元的迁移行为与性能调控、矿相重构样品的磨选提纯、磨选精矿产品多用途性能表征、高温矿相重构技术拓展应用等方面。查明了多金属型铁锰矿中主要有价矿物组分的相变规律，揭示了复合铁酸盐的生成机制。氧化气氛下焙烧，MnO2首先分解为Mn3O4，Mn3O4再与Fe2O3反应生成MnFe2O4，反应式为2Mn3O4+6Fe2O3=6MnFe2O4+O2。揭示了矿相重构过程中元素迁移行为与性能调控机制。Ca、Mg、Zn、Na、K元素易进入尖晶石型铁酸锰晶格中（AB2O4）占据四面体空隙（A位）；Al元素进入尖晶石结构中占据八面体空隙（B位）；Si、P、Pb元素不会进入尖晶石结构中，其与锰、铁氧化物反应生成相应的盐类。SiO2可以将占据尖晶石结构中A位、B位中的杂质元素，通过与之反应形成相应硅酸盐所产生的化学驱动力将其迁移出尖晶石结构，从而实现了多金属组元的矿相重构与磁性能强化。通过磨选方式，可以实现磁性铁酸盐的分选；铁酸盐磨选精矿再经纳米砂磨处理，可对阴离子集团型金属离子具有良好的选择性吸附性能。项目查明了纳米铁酸盐颗粒选择性吸附关键金属钨钼铼阴离子行为与机制，为超低浓度相似钨钼铼金属离子的高效分离提供了技术支持。本项目是“资源-冶金-材料一体化”研究的典型案例，开发的多金属型铁锰矿矿相重构技术，拓展应用至高磷鮞状赤铁矿，利用矿相重构扩大铁矿物与磷矿物间的物化性质差异（磁性、熔性、粒度等特性），再通过磨选的方法分离回收铁氧体磁性粉末和含磷尾矿产品，含磷尾矿再经高温活化可制备成磷系土壤调理剂，实现了高磷鮞状赤铁矿的高值材料化利用，也为其它复杂难选冶铁矿资源的增值利用提供技术借鉴。