新型煤泥浮选促进剂的研究

STUDY OF NEW PROMOTERS FOR FINE COAL FLOATATION

本文从煤的基本结构和表面活性剂的分子结构特点出发,通过动电位测定、红外光谱半定量分析和热力学分析计算,对三种典型的表面活性剂与煤表面的作用机理做了详细研究,结果表明:非离子型表面活性剂FCA能压缩煤-水界面双电层和减少弱酸性基的解离,使煤柱表面动电位减小(接近零电点)。FCA在整个煤表面产生了特性吸附,在亲水性部分为P型氢键吸附,在疏水性部分为π型氢键吸附。FCA在煤表面吸附的自由能和吸附平衡常数最大,它的吸附能明显减少煤表面含氧官能团对可浮性的影响,增强煤粒表面的疏水性,因此,非离子型表面活性剂FCA是最佳的煤泥浮选促进剂;阴离子型表面活性剂DSS也能与煤表面亲水性部分产生P型氢键吸附,其在煤表面吸附的自由能和平衡常数居中;而阳离子型表面活性剂OT在煤表面完全是物理吸附,其吸附强度最小。 FCA乳化M_2油-M_4浮选剂在两个选煤厂的生产试验结果表明:M_4浮选剂具有浮选速度快、药剂用量少和精煤产率高等优点,并具有一定的技术经济效益。

Based on the basic structure of coal and the molecular structure of surfactants, the interactive mechanism between three typical surfactants and coal surface has been studied in detail by measurement of Zeta-potential of coal particles, semi -quantitative FT-IR examinstion, and thermo-dynamic analysis and calculation. The results indicate that the non-ionic surfactant FCA can compress the double electric layer of coal-water interface and reduce the ionization of weak acid radicals and Zeta -potential of coal particles close to PZC.FCA molecules adsorb coal particles on the whole surface, i.e. P H-bond adsorption occurs at hydrophilic zone of surface, and π H-bond adsorption at hydrophobic zone of the surface. Gibbs free energy and equilibrium constant of FCA are the largest among the three surfactants, and adsorption of FCA can decrease considerably the effect of oxygen functional groups of coal surface on floatability, and increase the surficial hydrophobicity of coal particles. Therefore, non-inonic surfactant FCA is the bast promoter for floatation of fine coal; anionic surfactant DSS can also adsorb at the hydrophilic zone of coal surface through P H-bond adsorption, however, gibbs free energy and equilibrium constant for DSS are moderate; and cational surfactant OT has physical adsorption capacity only, and the adsorption is the weakest among the three. The demonstration results of the emulsified M_2 oil by FCA-M_4 floatation reagent at two coal preparation plants show that M_4 has the advantages of high rate of floatation and high yield of combustible, and low consumption of reagent, and some techno-economic benefits.