煤泥浮选过程中六偏磷酸钠对蒙脱石分散行为影响

通过测定润湿接触角和Zeta电位分析了蒙脱石颗粒对煤泥浮选的作用，考察了六偏磷酸钠对煤和蒙脱石浮选行为的影响。依据扩展DLVO理论的计算，分析了分散剂影响煤和蒙脱石浮选行为的作用机理。结果表明：蒙脱石颗粒严重抑制了煤泥浮选，使精煤可燃体回收率从44.11%降至11.68%；六偏磷酸钠可改善浮选效果，使精煤可燃体回收率提高2个百分点；六偏磷酸钠增大煤和蒙脱石颗粒表面电位绝对值，从而提高颗粒间静电斥能，同时六偏磷酸钠附着在煤颗粒和蒙脱石颗粒表面，增强颗粒间的亲水作用能，并且六偏磷酸钠水解形成的长链分子吸附于颗粒表面后，使颗粒相互靠近时产生较强的空间稳定化作用，增大颗粒之间的空间斥力。

Influences of sodium hexametaphosphate on dispersion of fine montmorillonite in coal flotation

The influences of montmorillonite on coal flotation and the effects of sodium hexametaphosphate on the dispersion of fine clay mineral in coal flotation were investigated by wet contact angle and zeta potential measurement.Based on the theoretical calculation of EDLVO,the mechanism of montmorillonite and coal flotation in the presence of dispersant was analyzed.The results show that montmorillonite significantly inhibites coal flotation,and lower the combustible recovery of clean coal from 44.11% to 11.68%.Sodium hexametaphosphate can improve the performance of flotation by increasing 2 percentage of the combustible recovery.By adhering to the surface of coal particles and montmorillonite mineral particles,sodium hexametaphosphate increases the absolute value of zeta potential of the mineral to enhance the electrostatic repulsion,and it improves the hydrophilic polarization effect,strengthening the hydrophilic repulsion.Moreover,long-chain molecules formed from sodium hexametaphosphate hydrolysis adsorb on the particle surface,generating dimensional stabilization effect and increasing the steric hindrance when the particles approach to each other.