超声预处理对低阶煤浮选的影响

Effect of ultrasonic pretreatment on low rank coal flotation

低阶煤亲水性强,天然可浮性差,使用传统的浮选方法很难达到满意的效果。为提高低阶煤的浮选效果,对低阶煤浮选矿浆进行超声预处理,采用粒度分析、接触角分析和红外光谱分析来表征煤样在超声处理前后性质的变化。试验结果表明:当超声波频率为20k Hz,功率为135W时,矿浆经过超声预处理5min之后,浮选精煤产率提高了5.41%,灰分基本保持不变;超声处理使煤样中的粒度组成发生明显变化、煤样的接触角增大、含氧官能团数量减少。因此,超声预处理增强了低阶煤的疏水性,明显地提高了浮选效果。

As the low rank coal is of poor flotability clue to its strong hydrophilicity, the floatation effect is often dissatisfying. Ultrasonic pretreatment on the low rank coal was carried out to enhance its flotation performance. The particle size analysis, contact angle analysis ancl infrared spectrum analysis was conducted to characterize the change of coal sample properties before and after ultrasonic treatment. The results showed that, the yield of clean coal increased by 5.41% while the ash content was almost unchanged after ultrasonic pretreatment of 4min ultrasonic treatment with frequency of 20kHz and power of 135W. The particle size distribution of the coal sample changed significantly, contact angle increased and the amount of oxygen-containing functional groups decreased after ultrasonic pretreatment. Therefore, ultrasonic treatment can enhance the hydrophobicity of low rank coal and improve the flotation effect dramatically.