配合物碱性体系选择性浸出钢厂含锌烟尘的应用基础研究

There are large amount of zinc containing steelmaking dust in china. Heavy metals such as zinc, lead and cadmum in this dust are difficult to be recovered effectively, which resulting in the latent environment pollution and serious waste of resources. It seems that selective complex-leaching process in alkaline aqueous solution is a new research idea and direction, for its good selectivity and low reagent consumption while treating with zinc containing steelmaking dust. A key issue for current researches of selective complex-leaching in alkaline aqueous solution is the limited ligands which studied. Therefore, we propose to select new ligands and develop new selective complex-leaching process in alkaline aqueous solution for treating with zinc contain steelmaking dust..The project intends to study the basic theories of ligand selection and application of a new selective complex-leaching system. First, through the studies on the evaluation mechanism of combine ability of ligands with metallic ions, regulatory mechanism of ligand selection will be disclosed while using the formation of complex for complex-leaching valuable metals in alkaline system. This regulatory mechanism of ligand selection will provide a theoretical basis for the selection of a suitable ligand, and to form a new complex-leaching system for zinc containing steelmaking dust treatment. Then, based on the thermodynamics studies of L-MaAm-H2O system and the experimental validation works, the behavior and selective separation mechanism of polymetallic components will be revealed during complex-leaching zinc containing steelmaking dust in alkaline system. Finally, the process for selective complex-leaching of zinc containing steelmaking dust in alkaline system can be optimized by means of studies on relevant thermodynamic and kinetic works. This process will provide technical prototypes for selective leaching Zn, Pb and Cd from zinc containing steelmaking dust by complex-leaching in alkaline aqueous solution.

我国钢厂含锌烟尘产量巨大，所含重金属Zn、Pb、Cd难以有效回收，造成潜在的环境危害和严重的资源浪费。配合物碱性体系选择性浸出工艺处理钢厂含锌烟尘具有选择性好、试剂消耗小的特点，是一种新的研究思路和发展方向。针对现有配合物碱性体系所研配体单一的问题，我们提出选择新的配体、开发新的配合物碱性体系处理钢厂含锌烟尘。.本项目拟研究新配合物体系的选型和应用的基础理论。首先，通过研究配体配合能力评价机制，揭示配合物碱性体系中，利用配合物的形成浸出有价金属时的配体选择调控机制，为选择合适配体、形成新的配合物体系用于处理钢厂含锌烟尘提供理论依据；然后，通过L-MaAm-H2O体系热力学研究及实验验证，揭示配合物碱性体系浸出钢厂含锌烟尘过程中，多金属组元行为与选择性分离机理；最后，结合相关热力学和动力学研究结果，优化了浸出工艺过程，为配合物碱性体系选择性浸出钢厂含锌烟尘中Zn、Pb、Cd提供技术原型。

我国钢厂含锌烟尘产量巨大，所含重金属Zn、Pb、Cd等难以有效回收，造成潜在的环境安全隐患和严重的资源浪费。配合物碱性体系选择性浸出工艺处理钢厂含锌烟尘是一种新的研究思路和发展方向。.本项目通过模拟配合物体系中难溶物溶解过程进行建模，揭示了配合物碱性体系中，利用配合物的形成浸出难溶物时的配体选择调控机制，提出了一种通用“粗放型-集约型”两步法评价配体配合能力的方法，为研究新配体、开发新的配合物选择性浸出体系提供了理论指导与技术支持。利用该方法成功地确定了亚氨基二乙酸根离子（Ida2-）和氨基乙酸根离子（Gly-）两种配合能力较强的配体作为研究配体，在其相应配合物体系中浸出钢厂含锌烟尘。热力学研究结果表明，Ida2-和Gly-均对Zn2+有较强的配合能力，对Ca、Mg、Mn和Fe钢铁系统有益金属具有较强的选择性。.实验原料为江苏沙钢电弧炉烟尘，锌含量为16.13%，铁含量为38.35%，为难处理的高含铁酸锌烟尘，其中铁酸锌（ZnFe2O4）75.50%，可溶性氧化锌（ZnO）仅为20.85%，其余为硫化锌。亚氨基二乙酸盐体系和氨基乙酸盐体系常压浸出结果表明，铁酸锌均可以在上述两种体系中溶解，但因为其溶解过程中新生成的铁氧化物固膜阻碍了配合剂与铁酸锌的进一步接触反应，导致铁酸锌溶解不完全，锌浸出率不高。采用加压手段进行强化浸出研究，得到了较好的结果。加压浸出结果表明，氨基乙酸盐体系比亚氨基二乙酸盐体系锌铁分离更彻底，在液固比25∶1，配体总浓度[Gly-]T为3.0 mol·L-1，搅拌速度600 r·min-1，温度130°C，pH值为8.0，反应压力3 MPa，反应时间4 h的优化条件下，锌浸出率为92.31%，而铁的浸出率仅为9.17%，烟尘中Ca、Mg和Mn钢铁系统有益元素基本不溶。这是一个极其有意义的重大发现，该技术应用于锌焙砂的处理将会是颠覆性的，极有可能改变现有的湿法炼锌工艺。