煤泥选择性絮凝浮选中聚丙烯酰胺的作用机制

Mechanism of action of polyacrylamide in selective flocculation flotation of fine coal

  • 摘要: 测试了阴离子型低相对分子质量聚丙烯酰胺PAM A401作用对煤及高岭石絮体表观粒径分布、样品红外光谱以及表面润湿性的影响,并通过浮选速度实验验证PAM A401的作用效果.研究表明,12 mg·L-1PAM A401且循环搅拌11 min时,煤絮体累积粒度分布达到10%、50%和90%时对应的粒径分别是高岭石絮体的6.86、2.22和2.45倍,呈较好的絮凝选择性.吸附PAM A401后,煤的亲水性官能团特征峰增强,疏水性降低;高岭石的亲、疏水性官能团均有增加,疏水性略高.与常规浮选相比,选择性絮凝浮选实验的浮选速率较大,捕收剂用量降低30%.浮选3 min时,选择性絮凝浮选实验的可燃体回收率为81.57%,较常规浮选实验高3.64%,精煤灰分相当.PAM A401虽使煤颗粒的表面润湿性降低,但微细粒煤颗粒表观粒径增大的效应促进微细粒煤泥的分选.

     

    Abstract: The influences of anionic polyacrylamide with low molecular weight(PAM A401) on coal and kaolinite were investigated by the flocs size distribution,FTIR spectra and wettability. Flotation kinetics tests were carried out to verify the effect of PAM A401. By using 12 mg·L-1 PAM A401 and conditioning for 11 min,at the cumulative particle size distributions of 10%,50% and 90%,the particle size of coal is 6.86,2.22 and 2.45 times that of kaolinite flocs,respectively,showing a better flocculation selectivity of coal. After PAM A401 adsorption,the peaks of hydrophilic functional groups of coal are strengthened and the coal particle surfaces become more hydrophilic. For kaolinite,both the hydrophilic and hydrophobic functional groups increase,and the kaolinite is slightly more hydrophobic. Compared with the conventional flotation,the flotation rate of selective flocculation flotation tests is higher,and 30% of collector is saved. The cumulative combustible recovery of selective flocculation flotation is 81.57%,which is 3.64% higher than the conventional flotation experiment,but the ash content of clean coal is similar. Although PAM A401 reduces the wettability of coal particle surfaces,the enlargement of apparent particle size of fine coal promotes efficient separation of fine coal.

     

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