Effect of cationic-anionic surfactant synergistic non-polar oil on low-rank coal flotation
XIE Zhixuan,ZHANG Lei,GUO Jianying,LI Bao,YANG Zhichao,ZHANG Suhong,LIU Shengyu
为提高低阶煤中有机质与无机质之间润湿性差异,从而提高低阶煤浮选效率,采用阳离子表面活性剂十二烷基三甲基溴化铵(DTAB)、阴离子表面活性剂十二烷基醇聚氧乙烯醚硫酸钠(AES)和非极性捕收剂煤油进行复配得到复配捕收剂。通过测定复配体系的表面化学性能并计算协同作用参数研究表面活性剂的吸附和聚集特性;采用浮选实验研究不同配比的复配捕收剂对浮选效果的影响,以及通过浮选动力学实验研究单一使用煤油捕收剂与使用复配捕收剂的浮选速率和浮选选择性;采用Zeta电位测定实验,润湿热测定实验以及接触角测定实验研究复配捕收剂提升低阶煤泥可浮性机理。实验结果表明:DTAB与AES复配体系在降低表面张力效率和能力方面具有协同作用。与单一使用煤油作为捕收剂相比,使用复配捕收剂浮选精煤产率由18.64%提升至69.86%,浮选完善度由7.79%提升至18.00%,精煤灰分增加2.89%。复配捕收剂相较于煤油可以明显提升低阶煤的浮选速度,浮选速率常数由0.010 0提升至0.034 5,选择性也有所增加。复配捕收剂(煤油+ DTAB+AES)中药剂不同配比对有机质疏水性改善程度从大到小排序为n(DTAB)∶n(AES)=1∶1、0∶1、1∶0;对有机质与无机质之间润湿性差异的扩大效果从大到小排序为n(DTAB)∶n(AES)=1∶1、1∶0、0∶1。复配捕收剂中DTAB+和AES-缔合后形成离子对,其含有的乙氧基(—CH2—CH2—O—)能与含氧官能团产生氢键,牢固的吸附在低阶煤表面;缔合后形成的离子对和少量游离的DTAB+离子吸附后会将表面活性剂的疏水链暴露出来,从而掩盖低阶煤表面的极性位点;非极性煤油不仅可以吸附在低阶煤表面本身的疏水位点,还吸附在药剂掩盖极性位点后暴露出的非极性位点,从而促进了煤油在有机质表面的铺展,大幅提升浮选效果。
In order to improve the wettability difference between organic matter and inorganic matter in low-rank coal, thereby improving the flotation efficiency of low-rank coal, cationic surfactants
dodecyl trimet hylammonium bromide (DTAB) and anionic surfactants dodecyl alcohol polyoxyethylene ether sodium sulfate (AES) and non-polar collector kerosene are compounded to obtain a compound collector. Study the adsorption and aggregation characteristics of surfactants by measuring the surface chemical properties of the composite system and calculating the synergistic parameters; using flotation experiments to study the effect of different composite collectors on the flotation effect and through the flotation kinetics experiments to study the flotation rate and flotation selectivity of a single-use of kerosene collector and use of compound collector; Zeta potential measurement experiment, wetting heat measurement experiment, and contact angle measurement experiment to study the improvement of compound collectors floatability mechanism of low-rank slime. Experimental results show that:DTAB and AES compound system has a synergistic effect in reducing surface tension efficiency and ability. Compared with the single use of kerosene as the collector, the flotation yield of the combined collector increased from 18.64% to 69.86%, the flotation perfection increased from 7.79% to 18.00%, and the ash content of clean coal increased by 2.89%. Compared with kerosene, the compound collector can significantly increase the flotation speed of low-rank coal. The flotation rate constant is increased from 0.010 0 to 0.034 5, and the selectivity is also increased. In the compound collector (kerosene+DTAB+AES), the improvement degree of organic hydrophobicity by different ratios of agents from large to small is n(DTAB)∶n(AES)=1∶1, 0∶1, 1∶0. The order of enlarging the difference of wettability between organic matter and inorganic matter from large to small is n(DTAB)∶n(AES) = 1∶1, 1∶0, 0∶1. In the compound collector, DTAB and AES are combined to form ion pairs, and the ethoxy group (—CH2—CH2—O—) contained in it can form hydrogen bonds with oxygen-containing functional groups and firmly adsorb on the surface of low-rank coal; after association the formedion pairs and a small amount of free DTAB ions will expose the hydrophobic chain of the surfactant after adsorption, thereby masking the polar sites on the surface of low-rank coal; non-polar kerosene can not only adsorb on the hydrophobic sites on the surface of low-rank coal itself, it is also adsorbed on the non-polar sites exposed after the agent covers the polar sites, thereby promoting the spreading of kerosene on the surface of organic matter and greatly improving the flotation effect.
low-rank coal; ionic surfactant; synergy; compound collectors; flotation
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会