低温氢等离子体重构对赤铁矿表面特性和可浮性的影响研究

Study on the influence of low-temperature hydrogen plasma reconstruction on the surface properties and floatability of hematite

  • 摘要: 低温等离子体技术作为一种新型绿色环保的表面改性技术,因其操作简单、安全指数高、反应速度快、功率消耗低等优良特点而备受人们关注. 低温等离子体技术目前多应用于煤炭和硫化矿的处理上,对氧化矿的处理鲜有报道. 本文通过对赤铁矿表面进行了低温氢等离子体处理,对赤铁矿表面特性进行重构,以降低抑制剂淀粉的用量,并实现赤铁矿与石英的高效分离. 单矿物试验结果表明:在最佳处理条件功率240 W,气体流量400 mL·min−1,时间20 min下,玉米淀粉对赤铁矿的抑制效果有了明显提高. 人工混合矿试验结果表明:在最佳处理条件下和淀粉用量4 mg·L−1时,选择性指数提高了3.3784. 通过原子力显微镜和扫描电镜得知,赤铁矿表面被低温氢等离子体刻蚀,X射线光电子能谱(XPS)和能谱仪(EDS)分析出赤铁矿表面元素发生变化,氧元素有所降低,通过紫外分光光度计得知经低温氢等离子体处理后赤铁矿表面淀粉的吸附量有所提高,而处理对石英表面的结构与性质影响较小. 根据上述机理分析得知,低温氢等离子体处理导致了矿物表面活性点位发生变化,从而影响了矿物表面的药剂吸附与作用.

     

    Abstract: Low-temperature plasma technology, a novel and environmentally friendly surface modification technique, has garnered significant attention for its simple operation, high safety, fast reaction speed, and low energy consumption. While widely used in the treatment of coal and sulfide ores, its use on oxide ores remains largely unexplored. Plasma technology also shows potential for flotation reagent pretreatment but is still in the laboratory stage in mineral processing engineering. Its application is mainly focused on mechanism research, hindered by the limited scale of equipment, which makes large-scale ore treatment unfeasible. This study investigates the surface modification of hematite using low-temperature hydrogen plasma pretreatment to enhance its separation efficiency from quartz by minimizing the use of the inhibitor corn starch. Experiments were conducted to determine the optimal conditions for mineral flotation with particles sized −0.074 mm to +0.038 mm, as well as for low-temperature hydrogen plasma pretreatment. The low-temperature hydrogen plasma pretreatment method involved placing the ore powder in a TS-VPR05 type plasma generator, with parameters such as gas flow, treatment time, and power adjusted accordingly. To ensure uniformity, the ore was spread evenly in a thin layer, and a consistent amount was treated each time. For mixed ore tests, individual minerals were treated separately before being combined to maintain consistent proportions. Flotation tests were carried out immediately after treatment to avoid sample degradation. Comparative analyses of recovery rates between treated and untreated samples were performed using single mineral flotation and artificially mixed ore flotation. Surface changes were assessed using atomic force microscopy, scanning electron microscopy-energy dispersive spectrometer, X-ray photoelectron spectrometer, and ultraviolet spectroscopy. The single mineral flotation experiments revealed that under optimal conditions of 240 W power, 400 ml·min−1 gas flow, and 20 min of treatment, the inhibitory effect of corn starch on hematite was significantly improved. For artificially mixed ore, the selectivity index improved by 3.3784 when combined with a starch concentration of 4 mg·L−1. Atomic force microscopy and scanning electron microscopy analyses showed that low-temperature hydrogen plasma etched the surface of hematite, while X-ray photoelectron spectroscopy and energy dispersive spectroscopy results indicated reduced oxygen content on the hematite surface. The ultraviolet spectrophotometer confirmed increased starch adsorption after low-temperature hydrogen plasma treatment. The treatment had a small effect on the structure and properties of quartz. The study concludes that low-temperature hydrogen plasma treatment modifies the active sites on the mineral surface, thereby affecting the adsorption and action of the mineral surface agents.

     

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