School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia; School of Chemical Engineering and Technology, China University of Mining & Technology, Xuzhou, Jiangsu 221116, China.
School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia.
Adv Colloid Interface Sci. 2018 Apr;254:56-75. doi: 10.1016/j.cis.2018.03.005. Epub 2018 Mar 27.
Diasporic bauxite represents one of the major aluminum resources. Its upgrading for further processing involves a separation of diaspore (the valuable mineral) from aluminosilicates (the gangue minerals) such as kaolinite, illite, and pyrophyllite. Flotation is one of the most effective ways to realize the upgrading. Since flotation is a physicochemical process based on the difference in the surface hydrophobicity of different components, determining the adsorption characteristics of various flotation surfactants on the mineral surfaces is critical. The surfactant adsorption properties of the minerals, in turn, are controlled by the surface chemistry of the minerals, while the latter is related to the mineral crystal structures. In this paper, we first discuss the crystal structures of the four key minerals of diaspore, kaolinite, illite, and pyrophyllite as well as the broken bonds on their exposed surfaces after grinding. Next, we summarize the surface chemistry properties such as surface wettability and surface electrical properties of the four minerals, and the differences in these properties are explained from the perspective of mineral crystal structures. Then we review the adsorption mechanism and adsorption characteristics of surfactants such as collectors (cationic, anionic, and mixed surfactants), depressants (inorganic and organic), dispersants, and flocculants on these mineral surfaces. The separation of diaspore and aluminosilicates by direct flotation and reverse flotation are reviewed, and the collecting properties of different types of collectors are compared. Furthermore, the abnormal behavior of the cationic flotation of kaolinite is also explained in this section. This review provides a strong theoretical support for the optimization of the upgrading of diaspore bauxite ore by flotation and the early industrialization of the reverse flotation process.
分散态铝土矿是主要的铝资源之一。为了进一步加工，需要将铝土矿（有价值的矿物）与高岭石、伊利石和叶蜡石等铝硅酸盐（脉石矿物）分离。浮选是实现升级的最有效方法之一。由于浮选是一种基于不同成分表面疏水性差异的物理化学过程，因此确定各种浮选表面活性剂在矿物表面的吸附特性至关重要。矿物的表面活性剂吸附特性反过来又受矿物表面化学性质的控制，而后者又与矿物晶体结构有关。在本文中，我们首先讨论了一水硬铝石、高岭石、伊利石和叶蜡石这四种关键矿物的晶体结构以及研磨后暴露表面的断裂键。接下来，我们总结了这四种矿物的表面化学性质，如表面润湿性和表面电性，从矿物晶体结构的角度解释了这些性质的差异。然后，我们综述了表面活性剂（如捕收剂（阳离子、阴离子和混合表面活性剂）、抑制剂（无机和有机）、分散剂和絮凝剂）在这些矿物表面的吸附机制和吸附特性。综述了一水硬铝石和铝硅酸盐的直接浮选和反浮选分离，并比较了不同类型捕收剂的捕收性能。此外，还解释了高岭石阳离子浮选的异常行为。本综述为优化浮选升级一水硬铝石矿和反浮选工艺的早期工业化提供了强有力的理论支持。
