微乳型捕收剂的稳定性和浮选性能的试验研究

Experimental study on stability and flotation performance of micro-emulsion collector

微乳型捕收剂(Micro-emulsion Collector,MEC)在煤浆中的分散性能优于柴油和乳化柴油,可以有效降低煤泥浮选药剂的用量。MEC的稳定性是影响其工业应用的重要性能指标,国内外学者通常采用静置观察法研究乳化柴油和微乳化柴油的稳定性,难以直观并定量表征微乳液的稳定性和液滴粒径。笔者借助多重散射光稳定性分析仪研究了乳化剂配方和用量、超声波功率及作用时间对MEC稳定性和液滴粒径大小的影响,通过煤泥浮选试验考察了MEC的浮选性能。研究结果表明:制备MEC的最佳工艺条件为,乳化剂用量为柴油质量的5%,含水量为柴油质量的5%,表面活性剂配方为Span80∶Tween40∶Octanol=7∶3∶4,磁力搅拌10 min后用200 W超声波强化处理5 min;乳化剂配方和用量影响MEC的稳定性和液滴粒径大小。乳化剂用量越多,MEC越稳定。乳化剂用量为3%时,液滴易发生聚集,放置一段时间后液滴粒径会超过100 nm。乳化剂用量为7%时,MEC最稳定,液滴初始粒径为69 nm,并随放置时间延长缓慢变大。乳化剂用量为5%时,MEC稳定性好,液滴粒径随放置时间的延长基本不发生变化,保持在37 nm左右;超声波功率低于 600 W 时,功率越小,MEC越稳定。功率大于600 W时,功率越大,液滴粒径越小,MEC稳定性越好。超声波处理时间为20 min时,MEC的稳定性动力学指数(Turbiscan Stability Index,TSI)值随放置时间延长快速变大,MEC很不稳定;MEC用于煤泥浮选时,能显著提高煤样的接触角,增加煤粒表面疏水性,提高煤粒的可浮性。在相同的捕收剂用量下,浮选精煤产率更高,灰分更低,浮选完善指标更好。

Micro-emulsion Collector (MEC) has better dispersion performance in coal slime than diesel and emulsified diesel,which can effectively reduce the amount of coal flotation agent.The stability of MEC is an important performance index affecting its industrial application.Domestic and foreign scholars usually use static observation method to study the stability of emulsified diesel and micro-emulsified diesel,which is difficult to visually and quantitatively characterize the stability and droplet size of micro-emulsion.In this paper,the effects of emulsifier formulation and dosage,ultrasonic power and duration of action on MEC stability and droplet size were studied by means of Multiple Light Scattering Stability Analyzer.The flotation performance of MEC was investigated by coal slime flotation test.The results showed that the optimum process conditions for the preparation of MEC were:the consumption amount of emulsifier was 5% of diesel,the water content was 5% of diesel,the formulation of the surfactant was Span80∶Tween40∶Octanol=7∶3∶4 and the duration of 200 W ultrasonic action was 5 minutes after stirring for 10 minutes.The emulsifier formulation and amount affected the stability of the MEC and the droplet size.The more the emulsifier was used,the more stable the MEC was.When the amount of the emulsifier was 3%,the droplets were likely to aggregate,and the droplet size would exceed 100 nm after being left for a while.When the amount of emulsifier was 7%,the MEC was the most stable,and the initial droplet size is 69 nm,which gradually increased with the increase of the standing time.When the amount of emulsifier was 5%,the stability of MEC was good,and the droplet size did not change with the increase of the standing time,which remained at about 37 nm.When the ultrasonic power was lower than 600 W,the smaller the power,the more stable the MEC was.When the power was greater than 600 W,the greater the power,the smaller the droplet size was,and the better the MEC stability was.When the ultrasonic treatment time was 20 minutes,the Turbiscan Stability Index (TSI) of MEC increased rapidly with the increase of standing time,and MEC was very unstable.When MEC is used for flotation of coal slime,it can significantly increase the contact angle of coal samples,increase the hydrophobicity of coal particles,and improve the floatability of coal particles.With the same amount of collector,the yield of flotation clean coal is higher,the ash content is lower,and the flotation improvement index is better.