Bao Ren,Mingkang Xu,Jiaqiang Zhu,Zichang Xia,Chunfu Liu,Fanfei Min
The hydration characteristics of fine particles significantly influence the settling and dewatering of tailings. However, the current limited understanding of the micro-mechanisms governing the interactions between hydrophobic flocculants and fine particles hinders the optimization of tailings treatment technical. Through a combination of MD simulations, flocculation settling, and adsorption capacity analysis, the hydrophobic adsorption mechanism of P(AM-MAPTAC-TEMAc6) at the kaolinite/water interface was elucidated. Results suggested that hydrogen bonding and non-bond interactions synergistically drive the adsorption of P(AM-MAPTAC-TEMAc6) onto the kaolinite surface. As the mass concentration of P(AM-MAPTAC-TEMAc6) increased, the hydrophobic and associative interactions between the molecular chains enhanced the adsorption amount on kaolinite particles, leading to a notable decrease in the solution residual amount and the supernatant turbidity. P(AM-MAPTAC-TEMAc6) improved the dewatering performance of concentrated tailings by reducing the hydration film density on kaolinite surfaces, thus decreasing the compression layer thickness. The fluorocarbon side chains of P(AM-MAPTAC-TEMAc6) enhance the hydrophobic adsorption capacity of cationic side chains in the surface water region. Simultaneously, the associative interactions of the molecular chains in the bulk water region promote enhanced diffusion and migration, thereby strengthening the bridging mechanism between P(AM-MAPTAC-TEMAc6) and kaolinite particles, ultimately improving the settling and dewatering efficiency of the suspensions.
The intractable mineral processing wastewater poses severe challenges to ecological environments and resource utilization. Developing novel flocculants for efficient treatment of complex mineral processing wastewater is an urgent problem that demands immediate resolution. In this study, a novel cationic polyacrylamide flocculant with hydrophobic modification, designated P(AM-MAPTAC-TEMAC 6 ), was synthesized via low-pressure ultraviolet (UV) -initiated polymerization using methacrylamido propyl trimethyl ammonium chloride (MAPTAC), acrylamide (AM), and perfluorohexyl ethyl methacrylate (TEMAC 6 ) as comonomers, with irgacure 2959 as the photo-initiator. The synthesis conditions were systematically optimized through single-factor experiments, culminating in optimal parameters: total monomer concentration of 35%, TEMAC 6 content of 10 wt%, photo-initiator dosage of 0.3 wt%, surfactant dosage of 0.8 wt%, UV irradiation time of 4 h, and urea dosage of 0.3 wt%. The successful synthesis of the copolymer was confirmed by ¹H nuclear magnetic resonance (¹H NMR) and Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) revealed a well-developed porous structure, while thermogravimetric analysis (TG/DTG) demonstrated enhanced thermal stability. Flocculation and dewatering tests showed that P(AM-MAPTAC-TEMAC 6 ) exhibited superior turbidity removal and moisture reduction compared to three commercial flocculants in kaolinite, quartz, and montmorillonite suspensions. At a dosage of 50 g/t, residual turbidity values reached 99.63 NTU, 110.5 NTU, and 63.35 NTU, respectively, while the increments in moisture content of filter cakes consistently lower than that achieved by three commercial flocculants.
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