机械搅拌式浮选装置中气泡粒径分布规律

摘要

为研究机械搅拌式浮选装置各可变操作参数对气泡分布特征的影响规律,选择仲辛醇作为起泡剂,利用图像分析法测定了不同条件下气泡的粒径分布,同时采用表面张力仪测定了不同条件下的表面张力.研究表明,随着药剂浓度由0.011 mmol/L逐渐增大到0.154 mmol/L,表面张力由73.577 mN/m线性减小到72.544 mN/m,气泡粒径逐渐减小,当达到临界兼并浓度0.103 mmol/L时,气泡粒径稳定于0.593 mm,仲辛醇的吸附浓度约为0.255 μmol/m2.气泡粒径随着叶轮转速(1494 ～2 494r/min)的增大而线性减小,且药剂浓度越大,气泡粒径降幅越小.随着吸气量由0.1 L/min增大到0.9 L/min,气泡粒径逐渐增大,且药剂浓度越低,气泡粒径增幅越大.气泡上升过程中其粒径随着取样高度(0～20 cm)线性增大,但药剂浓度越高,气泡粒径增幅越小.在各操作参数的研究范围内,药剂浓度小于等于临界兼并浓度时,取样高度对气泡粒径影响最显著,药剂浓度高于临界兼并浓度时,吸气量对气泡粒径影响最显著,而叶轮转速对气泡粒径影响最不显著.%The influence of operating parameters on bubble distribution in a mechanical flotation device was investigated using 2-Octanol as the frother.Bubble size distribution was analyzed using the image analysis technique,and surface tension was measured using the surface tension meter.While the reagent concentration increases from 0.011 to 0.154 mmol/L,the surface tension decreases from 73.577 to 72.544 mN/m.Meanwhile,the Sauter mean diameter (d32) decreases up to the critical coalescence concentration (CCC) of 0.103 mmol/L above which the d32 is constant at 0.593 mm.The adsorption density is calculated at 0.255 μmol/m2.With the increase in impeller rotate speed from 1494 to 2494 r/min,the d32 linearly decreases and more slowly with higher concentration.The d32 increases with air intake from 0.1 to 0.9 L/min and more with lower concentration.The d32 is also found positively and linearly related with the sampling height from 0 to 20 cm,but it increases more slowly with higher reagent concentration.In the studied range of all the operating parameters,the sampling height reflects the most significant effect on the d32 when the reagent concentration is lower than CCC,but that of the reagent concentration higher than CCC is inspiration capacity.The rotate speed of the impeller is found as the least significant operating parameter influencing the d32.