低阶煤颗粒-气/油泡间的诱导时间研究

为表征低阶煤颗粒-气/油泡间矿化过程的差异,通过Sutherland理论下固体颗粒进入泡沫产品的总概率(E)和浮选速率常数(k)之间关系,并结合低阶煤颗粒-气/油泡的浮选速率试验,求得了低阶煤颗粒-气/油泡间的诱导时间。浮选实验研究表明,在相同的捕收剂消耗量下低阶煤-油泡浮选产率均高于低阶煤-气泡浮选产率。诱导时间测试表明,低阶煤颗粒-油泡间的诱导时间(35 ms)要明显低于低阶煤颗粒-气泡间的诱导时间(93 ms)。上述实验结果表明,油泡表面的疏水性要强于传统浮选气泡表面的疏水性。然而,进一步利用Sutherland理论中固体颗粒进入泡沫产品的总概率和浮选速率常数之间的数学关系,并结合低阶煤颗粒-气/油泡的浮选速率试验求得的低阶煤颗粒-气/油泡间的诱导时间分别为9.67和8.46 ms,其与诱导时间测试仪分别测量的诱导时间差异很大。这主要是由于在实际浮选过程中气/油泡的上升速度分别为23.26和22.68 cm/s,其远高于2015EZ型诱导时间仪测试过程中气/油泡碰撞速度(2.0 cm/s)。因此,诱导时间理论计算表明气泡-颗粒间的碰撞速度对颗粒-气泡间的诱导时间影响很大。上述研究结果表明油泡浮选效果优于传统浮选的内在原因在于低阶煤颗粒-油泡间的诱导时间小于低阶煤颗粒-气泡间的诱导时间。

Investigation of the induction times between low rank coal particles and air/oily bubbles

In order to investigate the difference between the low-rank coal particle-air/oily bubbles interaction,the relationship between the total probability(E) and the flotation rate constant(k) of mineral particles entering the foam product by Sutherland theory was introduced.The flotation rate tests of low-rank coal particle-air/oily bub-bles were carried out.Furthermore,the induction times between low-rank coal particle-air/oily bubbles were cal-culated.The results of flotation experiments showed that the maximum flotation yield of low-rank coal particles in oily bubbles(95.69%) was much higher than that of low-rank coal particles in the air bubble(25.99%) with the same collector consumption.Meanwhile,the test results obtained by the 2015 EZ induction timer indicated that the induction time(35 ms) between low-rank coal particles and oily bubble was significantly smaller than that(93 ms) between low-rank coal particles and air bubble.This demonstrated that the hydrophobicity of the oily bubble surface was much stronger than that of the air bubble surface.However,combined with the low-rank coal parti-cle-air/oily bubble flotation rate test,the induction time between the air/oily bubbles and low-rank coal particles obtained by Sutherland’s theory in the relationship between the total probability of solid particles entering the foam product and the flotation rate constant was 9.67 and 8.46 ms,respectively,with little difference between the two.This was mainly due to that the air/oily bubble rising velocity in the real flotation process was 23.26 and 22.68 cm/s,respectively,which was much higher than the air/oily bubble collision velocity(2.0 cm/s) during the 2015 EZ induction timer test.In addition,during the back-calculated process of induction time,it could be found that the rising velocity of air/oily bubble had a significant effect on the back-calculated induction time.Therefore,the intrinsic reason that the oily flotation process was better than the traditional air flotation process was revealed.It also demonstrated that the induction time between the low-rank coal particles and the oily bubbles was smaller than that between the low-rank coal particles and the air bubbles.