粘土颗粒表面纳米气泡与聚体结构水对其夹带行为的影响研究

Clay minerals are hydrous aluminium or magnesium phyllosilicates. Due to their colloid sizes (<2 µm), clay particles being entrained follow the water between gas bubbles into the froth phase diluting the concentrate grade. When it comes to the entrainment of clay particles, the researchers tend to consider them as normal fine particles, overlooking the existence of nanobubbles on the their surface and that they can associate with each other in different modes forming aggregate structures with some trapped water inside. The effect of surface nanobubbles and aggregate water on the entrainment behaviour of clay particles has never been studied. This project is based on the coal and chalcopyrite flotation systems and it is expected that, by adapting the advanced cryo-SEM technique to examine the clay surface nanobubbles and the association of clay particles as well as trapped aggregate water inside their aggregate structures in the pulp and froth phase together with developing an accurate aggregate water measurement method, the extent to which the surface nanobubbles and aggregate water affect the entrainment of clay particles and the underpinning mechanisms can be revealed. This project, which will identify the key factors affecting the surface nanobubbles and aggregate water and improve the existing theoretical entrainment models, will provide theoretical guidance in manipulating the entrainment of clay particles.

粘土矿是一些含铝、镁等为主的含水硅酸盐矿物。由于其粒度细（<2µm），在浮选过程中粘土颗粒容易跟随气泡间的水以夹带的形式进入泡沫层降低精矿品位。现阶段学术界在研究粘土矿物的夹带问题时趋向于将其当成普通微细颗粒处理，而忽视了其表面附着有纳米气泡且颗粒间能够以不同形式相互聚集并挟裹住一部分水在聚体结构中的独有特性，这些表面纳米气泡和聚体结构水对粘土颗粒夹带行为的影响有待研究。本项目以煤和黄铜矿浮选系统为研究体系，借助先进的冷冻扫描电镜技术直接观测矿浆相和泡沫相中粘土颗粒表面的纳米气泡和颗粒间的聚集形态以及聚体中的结构水，开发一种能够准确测定聚体结构水量的方法，通过试验确立表面纳米气泡与聚体结构水对粘土颗粒夹带行为的影响程度及机理，找出在浮选环境下影响粘土颗粒表面纳米气泡与聚体结构水的关键因素并对现有的夹带理论模型进行完善，为粘土矿夹带调控提供理论指导。

粘土矿是一些含铝、镁等为主的含水硅酸盐矿物。由于其粒度细（<2μm），在浮选过程中粘土颗粒容易跟随气泡间的水以夹带的形式进入泡沫层降低精矿品位。现阶段学术界在研究粘土矿物的夹带问题时趋向于将其当成普通微细颗粒处理，而忽视了其表面附着有纳米气泡且颗粒间能够以不同形式相互聚集并挟裹住一部分水在聚体结构中的独有特性，这些表面纳米气泡和聚体结构水对粘土颗粒夹带行为的影响有待研究。本项目：1）以高岭石为目标矿物，揭示了纳米气泡对粘土颗粒在浮选过程中夹带行为的促进作用；研究了在矿浆相动态环境下和泡沫相静态环境下纳米气泡对粘土颗粒聚集行为的影响；发现了粘土颗粒聚集形态与其夹带程度之间的紧密联系，并进一步阐释了纳米气泡通过诱导粘土颗粒端面—端面聚集加剧粘土矿物夹带的机理。2）以煤—高岭石浮选体系为研究对象，首次揭示了纳米气泡对粘土颗粒在浮选过程中罩盖行为的抑制作用；利用动态光散射、BET比表面积、沉降等手段揭示了纳米气泡对粘土颗粒自聚集行为的促进现象，并基于此解释了纳米气泡能够抑制粘土颗粒在煤表面形成罩盖的作用机理。3）将高岭石颗粒聚体结构水和蒙脱石层间水与浮选（夹带）总水进行了分割，研究了二者对粘土矿物夹带行为的影响。4）以高岭石为目标矿物，研究了十二胺体系下改性纳米气泡对粘土类硅酸盐矿物浮选行为的促进作用并分析了其机理；以煤和高岭石浮选体系为研究对象，探讨了通过对纳米气泡进行改性来抑制/消除其对粘土矿物夹带行为影响的可行性，为粘土矿物在纳米气泡浮选过程中的夹带调控找到了突破口。