Consequently, the selective and powerful collectors for the monazite flotation system are important research subjects of related researchers. In this way, the difference in the floatability of monazite and the associated gangues could be enlarged and a basic condition for flotation separation could be created ( Sis and Chander, 2013). According to current research, flotation is the most effective way to concentrate monazite from related gangue minerals compared to the combined gravity–magnetic–electrostatic enrichment process ( Zhang and Honaker, 2018). Monazite mineral belongs to the monoclinic system and is one of the important minerals of mixed light rare earth resources in northern China ( Yang et al., 2007). The ore types of these deposits are the main bastnaesite and monazite ( Mancheri et al., 2019). There is still little value in mining the world's rare earth deposits, and only a few deposits from China and the United States are doing large-scale mining. Rare earth elements (REEs) have important strategic value and are called “the mother of new materials’’ ( Jordens et al., 2013). Rare earth metals are an important input to the development and manufacture of many green and high-tech products. The innovative point of this study is using a simple reagent scheme to float fine mineral particles rather than traditional complex processes. A schematic model was also proposed to explain the mechanism of Fe 3+ for improving surface hydrophobicity and flotation of fine monazite using octyl hydroxamate as a collector. From the XPS results, Fe 3+ reacts with surface O atoms on the surface of monazite to form a monazite–O surf–Fe group that acts as a new additional active site for SOH adsorption.
This can result in the formation of a more uniform and dense hydrophobic adsorption layer, as shown by the fluorescence spectrum and zeta potential results. This is because the addition of Fe 3+ promotes the adsorption of SOH and greatly improves the hydrophobicity of the monazite surface. However, adding a small amount of Fe 3+ to the pulp before SOH can significantly improve the flotation of fine monazite. Flotation tests have shown that fine monazite particles (−26 + 15 μm) cannot be floated well with the SOH collector compared to the coarse fraction (−74 + 38 μm).
XPS PEAK SHIFT CHEMICAL BONDING SERIES
In this paper, the effect and mechanism of Fe 3+ on improving surface hydrophobicity and flotation of fine monazite using sodium octyl hydroxamate (SOH) as a collector were investigated through a series of laboratory tests and detection measurements including microflotation, fluorescence spectrum, zeta potential, and X-ray photoelectron spectroscopy (XPS).
Qingzhu Zheng 1, Yunlou Qian 1,2*, Dan Zou 2, Zhen Wang 1,2*, Yang Bai 3* and Haidong Dai 1