细粒氧化煤表面性质表征与浮选预处理技术研究进展

氧化作用使煤粒表面含氧官能团数量增加,疏水性变差,浮选回收效果降低,而我国氧化煤资源量大,对其分选与利用进行研究具有重要意义。氧化层阻碍了药剂分子和气泡与煤泥疏水部分的有效接触,是细粒氧化煤可浮性降低的主要原因,浮选前对氧化层进行疏水化预处理,成为改善其浮性的主要手段和研究热点。文章对国内外氧化煤表面含氧官能团辨别和定量表征方法进行了总结,对表面疏水化预处理改性技术展开综述。分析表明,红外光谱、拉曼光谱和X射线电子能谱等材料表面分析方法,能够得到含氧官能团不同层面的信息,已经被相关学者广泛应用;研磨、高强度高浓度调浆和超声处理等合适的预处理技术能够实现细粒氧化煤的表面疏水改性。但是,不同的测定和预处理方法均有自身的局限性,研究和工程人员需要根据物料性质、研究目的和可行性等多方面进行选择以及综合运用。

Advances in surface characterization and flotation pretreatment of fine oxidized coal

Oxidation results in an increase in the amount of oxygen-containing functional groups on the surface of coal particles, a decrease in hydrophobicity, and a decrease in the recovery effect of flotation. But oxidized coal reserves are huge, the study on its separation and utilization has important significance. The oxidation layer obstructs the effective contact of collector molecules and bubbles with the hydrophobic part of coal slime, which is the main reason for the decrease of floatability of fine oxidized coal. The hydrophobic pretreatment of fine oxidized coal surface before flotation has become one of the main methods and the research focus to improve the floatability of fine oxidized coal. In this paper, the identification and quantitative characterization techniques and methods of oxygen-containing functional groups on the surface of oxidized coal were summarized, and the methods of surface hydrophobic pretreatment were reviewed. The analysis results show that, some materials surface analysis techniques, such as infrared spectrum, Raman spectrum, and X-ray electron spectroscopy effectively supply the information about the functional groups properties at different levels of fine oxidized coal, and have been used widely by researchers. Suitable pretreatment, such as grinding, high strength and high concentration conditioning, and ultrasonic treatment can achieve the surface hydrophobic modification of fine oxidized coal. However, different measurement and pretreatment methods have their own limitations, so researchers and engineers need to choose and comprehensively apply them according to the properties of materials, research purposes, feasibility and other aspects. This paper provides some references for improving the floatability of fine oxidized coal.