基于植物采矿的绿色冶镍研究

A considerable amount of Heavy Metal Hyperaccumulator Biomass (HMHB) were generated by phytoremediation to alleviate environmental heavy metal pollution. How to recycle these HMHB harmlessly and safely has become one of the scientific problems that need to be solved urgently. Based on phytomining and green metallurgy, in this project, the nickel hyperaccumulators will be employed to absorb nickel in the soil and transport nickel to the aerial parts of the plant, which are considered as secondary nickel-rich resources. Then nickel-rich bio-ore with nickel concentration roughly 20% can be obtained via incineration. By designing different hydrometallurgical processes, this project propose using sodium sulfide to separate Ni2+ ion to obtain nickel sulfide, nickel hydroxide and nickel sulfamate from the harvested nickel hyperaccumulators. On the above basis, both the preparation of nano-nickel, nickel nanotubes and other nickel nanomaterials from the nickel hyperaccumulators, and the influence of coexistence metals and organic components on the structures and properties of these nanomaterials will be explored, which would achieve environmental, resource and economic benefits. In general, this project will not only solve the problem of environmental nickel pollution, reducing the potential risk of nickel in the environment to humans and other organisms, providing a theoretical basis for how to handle the harvested HMHB, will also alleviate the shortage of nickel resources.

利用植物修复环境重金属污染会产生大量的重金属富集植物生物质，如何安全无害化和资源化地处理这些重金属富集植物已成为亟待解决的科学问题之一。本项目将镍富集植物视为镍资源的二次来源，基于植物采矿绿色冶金理念，利用镍超富集植物将土壤中的镍吸收并转运到植物的地上部分，再进行焚烧获得含镍约20%的“高镍生物矿砂”（Nickel-rich bio-ore）。采用硫化钠一步法分离镍离子，通过设计不同的湿法冶金工艺，从“高镍生物矿砂”中制备硫化镍、氢氧化镍和氨基磺酸镍。在此基础上探索从镍超富集植物中制取纳米镍、镍纳米管等镍纳米材料，探讨共存金属和有机组分对纳米材料结构及性质的影响，实现环境、资源及经济效益。本项目的研究成果将不仅解决环境镍污染问题，降低环境中镍对人类和其它生物的潜在危害，为如何处理大批重金属超富集植物生物质提供理论依据，同时也将缓解镍资源紧缺的重要问题。

利用植物修复技术治理土壤重金属污染产生了大量富含重金属的生物质，基于安全无害化和资源化回收该生物质中重金属的指导思路，本项目首先设计了一种实验室用重金属超富集植物燃烧炉，通过对采集的重金属富集植物样品进行充分焚烧，确保减少生物质燃烧过程中对大气的污染，同时将生物质转为富含重金属的“生物矿砂”；探索出从镍超富集植物Alyssum murale中制备NiSO4的最佳条件为2 mol/L H2SO4在95℃反应2 h；通过分离去除K+,Ca2+,Mg2+等干扰离子后在制得的硫酸镍溶液中添加硫化钠制备出硫化镍；在不添加其它反应试剂条件下，利用水热法以固液比1:25在100℃反应15 min从Alyssum murale植物中制备出苹果酸镍、丙二酸镍和柠檬酸镍等镍产品；利用先焚烧生物质后使用H2SO4酸化继而添加硫化钠的方法，从新乡市本地筛选出的镉富集植物小藜中制备出硫化镉，但由于硫化镉的纯度不高且产品目前应用前景不佳，其他镉产品仍在探索中。我国土壤重金属污染日益严重，目前已逐渐大规模采取植物修复技术治理土壤重金属污染，未来5-10年内将产生大量的富含不同浓度重金属的植物生物质。本项目通过焚烧后湿法冶金制备重金属产品或水热法直接制备重金属产品将为以后大批资源化处理重金属富集生物质提供技术指导。