蒙脱石与低灰煤泥对重介质悬浮液稳定性与流变性的影响研究

低密度重介质旋流器分选是实现煤镜质组和惰质组有效分离的可行方法之一。针对低密度时分选体系内固体体积浓度小、悬浮液易沉降并恶化分选效果等问题，论文探讨了细粒级磁铁矿粉、低灰煤泥以及蒙脱石粉末混合调制的重介质悬浮液在重力场中的稳定性及其流变特性，结果表明：在悬浮液密度一定的条件下，配入煤泥可以有效地提高其在重力场中的稳定|仅配入蒙脱石并不能提高延缓沉降趋势|而磁铁矿粉、蒙脱石与低灰煤泥混合配置的重介质悬浮液会因三者的协同作用，形成较显著的结构化，从而获得了最好的稳定性。此外，重介质悬浮液呈现符合幂律方程的假塑性特征，三种物料混合配置的重介质悬浮液在较高剪切率(70.22s-1)下的表观黏度可低至70mPa·s左右，且在更高剪切率(200s-1)下的表观黏度值可低至35mPa·s左右，更为符合重介质旋流器分选的悬浮液黏度低、稳定性好要求，且意味着适度提高重介质悬浮液中煤泥的灰分将有利于分选的稳定。

Effect of montmorillonite and low ash coal slime on stability and rheological property of heavy medium suspension

Due to the similar density of organic macerals in coal, how to effectively separate vitrinite from inertinite has always been a difficult problem in coal processing. Low density heavy medium cyclone is a feasible method to separate vitrinite from inertinite, but because of low density and small solid volume concentration in the system, the suspension is easy to settle and worsen the separation effect. In this paper, the stability and rheological properties of dense medium suspension mixed with fine magnetite powder, low ash slime and montmorillonite powder are discussed. The results show that under the condition of a certain suspension density, the addition of slime can effectively improve its stability in the gravity field, while nearly adding montmorillonite cannot increase the trend of delaying settlement. Due to the synergistic action of magnetite powder, montmorillonite and low ash slime, the heavy medium suspension could form remarkable structure and obtain the best stability. In addition, the heavy medium suspension shows pseudoplasticity in accordance with the power law. The apparent viscosity of the heavy medium suspension mixed with magnetite powder, montmorillonite and low ash coal slime could be as low as about 70 mPa·s at shearing rate of 70.22s-1, and even could theoretically reach as low as 35 mPa·s at shearing rate of 200 s-1, which is more in line with the requirements of low viscosity and good stability of suspension during heavy medium cyclone separation. It means that moderately increasing the ash content of coal slime in heavy medium suspension will be beneficial to the stability of separation.