氮杂环化合物协同萃取体系的设计以及对镍钴萃取分离铁铝的研究

Nickel and cobalt are important nonferrous metals for the economical development, which have found a variety of applications. The low-cost and cleaning production is urgently demanded in China. Nickel and cobalt usually co-exist in the ore deposits, such as nickel laterite which is the largest nickel and cobalt resource. Atmospheric leaching is a low-cost and cleaner method for the nickel laterite process. However, nickel and cobalt are difficult to recover due to the presence of large amounts of iron and aluminium, resulting in the limitation of its application. In addition, the difficulty of nickel and cobalt separation from iron and aluminium also limits the recycling of secondary resources of nickel and cobalt scince iron and aluminium are often found in the resources. Therefore, the separation of nickel and cobalt from large amounts of iron and aluminium is the bottlenecking problem for the low-cost and cleaning production of nickel and cobalt. Previous investigations show that nitrogenous heterocyclic compounds based synergistic systems could selectively extract nickel and cobalt from iron an aluminium, providing a potential method to solve this bottlenecking problem. However, no proper commercilised system has been developed at present. The structure of nitrogenous heterocyclic compounds govern the performance of the synergistic systems. In order to develop proper synergistic systems for the separation of nickel and cobalt directly from iron and aluminium, the project focuses on the studies of (1) design of nitrogenous heterocyclic compounds on the basis of program computation; (2) relation modeling of the structure of nitrogenous heterocyclic compounds and the performance of synergistic systems for the extraction of nickel and cobalt and their separation from iron and aluminium; (3) mechanism of the extraction of nickel and cobalt with optimised synergistic systems. The research outcomes will provide an effective way for the low-cost and cleaner production of nickel and cobalt from nickel laterite atmospheric leaching and the recycling of secondary resources.

镍钴是影响国民经济发展的重要有色金属，应用广泛，低成本清洁生产是国家的重大需求。镍钴常在矿物中伴生，其中红土镍矿是最大的矿物资源，常压酸浸工艺是低成本清洁生产的途径。但是，由于浸液中含有大量的铁和铝，镍钴和铁铝分离困难，工艺应用受到限制。另外，镍钴二次资源处理过程中，也常含有大量的铁和铝，镍钴和铁铝分离困难也限制了二次资源的综合利用。因此，镍钴和大量铁铝分离是制约低成本清洁生产的瓶颈问题。前期研究表明，氮杂环螯合物协同萃取体系可以直接萃取镍钴分离铁铝，有望解决镍钴低成本清洁生产的瓶颈问题。氮杂环螯合物的结构决定了协萃体系的性能，为开发适宜的协萃体系，申请课题重点研究：（1）氮杂环螯合物（吡啶基和咪唑基）结构计算设计；（2）氮杂环螯合物的结构与镍钴萃取和分离铁铝的关系模型；（3）协同萃取体系萃取镍钴的反应机理。为低成本红土镍矿常压浸出和二次资源回收搭建平台。

镍和钴是重要的有色金属，在新能源领域发挥了巨大作用。三元锂电材料中，镍和钴是主要的组分，目前尚无法取代。随着新能源电车的快速发展，三元电池材料需要的高纯镍和钴也迅速增加，我国成为镍、钴第一消费大国，电池材料镍钴消费量以100%的年增长率迅速增加。镍红土矿、镍硫化矿以及铜钴伴生矿是三类主要的镍钴资源，其中镍红土矿占了总量的60%以上，由于矿物复杂，提取难度大，湿法冶金工艺成熟度低。我国镍钴矿物资源贫乏，每年进口镍红土矿在5千万吨以上，主要采用火法冶炼工艺制备镍铁供不锈钢企业应用，冶炼过程高价值钴流失在渣中浪费，资源利用率低。我国几家大型企业日，如中冶瑞木镍钴，青山控股集团、华友钴业、励勤环保科技等在巴布新几内亚以及印度尼西亚建立了红土镍矿的湿法冶炼生产线，主要采用较传统的萃取工艺分离提纯镍和钴。另外，二次资源回收在我国逐年增长，尤其三元电池材料回收，目前中国二次资源回收的镍和钴分别约为20万吨和3万吨，达到总产量的约30%，而且还在快速增长。回收过程分离提纯，均采用传统的磷类萃取剂分离提纯。磷类萃取剂分离效果差，对杂质元素，如铁、铝、钙、镁、锰等没有分离，造成镍钴提纯分离困难，工艺流程长，酸碱消耗大，污染严重。新试剂开发可以简化镍钴分离流程，大幅减少试剂消耗和污染物排放，降低运行成本。.本项目研究开发了几种含氮杂环的镍钴萃取剂，与酸性萃取剂组成了新型镍钴协同萃取体系，建立了几种氮杂环萃取剂的合成路线，深入研究了新型萃取体系对镍和钴的萃取和协萃机理，并开发了新型萃取体系适应用于不同镍钴资源的提取分离技术。新型萃取体系可以优先于铁和铝萃取镍、钴分离系数分别达到500及100以上，优于目前文献报道的萃取体系。应用于红土镍矿常压浸出及二次资源回收具有较明显的优越性。项目共发表研究论文6篇，其中SCI论文4篇，申请专利3项，并形成了可以市售的新萃取剂产品3种。