含铁硅酸盐型铁矿界面溶出离子选择性迁移与强化抑制调控机制研究

Iron ore is an important raw material of iron and steel production enterprise. With the easy to separate iron ore resource in China reducing day by day, high efficient utilization of complex and refractory iron ore is becoming more urgent. However, specularite, aegirite, chlorite and other iron containing silicate in iron oxide ore flotation system have disadvantages such as the high similarity of interfacial properties, the complex interface ions dissolving rule, as well as the poor reagent selectivity. Considering of these disadvantages and taking the reciprocal inhibition mechanism as the starting point, this study proposes to solve theses problems by the following ways. Firstly, the mineral interfacial properties, interface ions dissolving rule and existing form are studied to reveal the interfacial ions release mechanism. Secondly, the internal mechanism of adsorption/conversion reaction and the interactive effect principle of dissolved ions are invested to indicate the reciprocal effect and transformation regulation mechanism of dissolved ions in iron containing silicate type iron ore flotation system. Lastly, strengthening depression and separation of specularite is achieved by mineral interface regulation realizeing the selective migration and conversion of dissolved ions from aegirite and chlorite interface. The research will provide theoretical and technical support for the efficient recovery of iron-bearing silicate type iron ore.

铁矿石是钢铁生产企业的重要原材料，随着中国铁矿资源中易选铁矿资源日益减少，复杂难选铁矿石高效利用问题变得日趋紧迫。针对含铁硅酸盐型铁矿浮选体系中镜铁矿和霓石、绿泥石等含铁硅酸盐矿物的界面性质相似度高、界面离子溶出规律复杂、药剂选择性差等难题，本项目以界面离子溶出和选择性迁移为切入点，首先对矿物界面性质与表面离子溶出规律和存在形式进行研究，揭示界面离子释放机制；再对溶出离子在矿物表面吸附、转化机制及交互影响规律进行研究，探明含铁硅酸盐型铁矿浮选体系中界面溶出离子交互影响与转化调控机制；最后通过矿物界面性质调控实现霓石、绿泥石界面溶出离子选择性迁移与转化调控实现镜铁矿强化抑制与分离；研究成果将为我国含铁硅酸盐型铁矿的高效回收提供理论和技术基础。

我国大型铁矿中大多伴生有含铁硅酸盐脉石，由于氧化铁矿与含铁硅酸盐脉石在密度、比磁化系数和表面物理化学性质方面差异较小，采用重、磁、浮选的分离效果均不理想。含铁硅酸盐型铁矿的分离一直是选矿难点，给我国钢铁生产带来诸多不利影响。本项目通过实验、理论分析和模拟计算等方法，系统研究了霓石、绿泥石和镜铁矿的界面性质、表面组分溶解和迁移转化规律，确立了含铁硅酸盐界面离子的酸-碱强化溶出迁移转化方法，完成了含铁硅酸盐界面溶出离子选择性迁移至氧化铁矿表面的目的，实现了溶出离子的定向迁移和浮选药剂选择性吸附，并利用FTIR、Zeta电位、TOC、XPS和DFT模拟等手段探明了含铁硅酸盐型铁矿界面溶出离子选择性迁移与强化分离的机理。结果显示，三种矿石的解理面种类和含量差别较大，且对于同一种矿石，不同粒级的解理面也不尽相同；镜铁矿表层Fe原子的三维轨道能级的DOS远高于霓石，在阳离子捕收剂体系中，镜铁矿的可浮性高于霓石。对于同一种矿物，三价金属离子的吸附量要高于二价金属离子；对于同一种金属离子，Al3+在镜铁矿表面吸附量最大，在绿泥石表面吸附量最小，Fe3+在镜铁矿表面吸附量最大，在霓石表面吸附量最小；Ca2+和Mg2+在三种矿物表面吸附量相差不大。镜铁矿和霓石表面均能发生一定程度的溶解，且霓石表面溶解程度大于镜铁矿，使用ACPM或ALPM处理后，霓石的可浮性降低，但镜铁矿可浮性不受影响，霓石表面溶出的金属离子通过重结晶生成SiO32-、FeOOH和Fe(OH)3并吸附在镜铁矿表面，阻碍了DDA的吸附，抑制了镜铁矿的上浮。在含铁硅酸盐型铁矿浮选药剂方面，没食子酸丙酯、壳聚糖、谷氨酸二乙酸钠、牛磺酸以及淀粉-聚乙二醇混合物均在一定程度上表现出极好的选择性，有望取代传统抑制剂淀粉。聚氧化乙烯和淀粉依次加入可以实现微细粒石英和赤铁矿的先后选择性絮凝，避免了单一絮凝带来的分选效果差等难题。研究成果对我国含铁硅酸盐型铁矿的高效开发利用具有极大的理论指导价值。