起泡剂对浮选气泡特征的影响研究

Study of effect of frother on bubble characteristic in flotation process

为了研究十二胺和仲辛醇对气泡粒径及其运动特性的影响,采用图像分析法测定气泡的粒径分布,利用表面张力仪测定不同条件下的表面张力,并搭建气泡运动测试系统,通过高速摄像技术拍摄分析气泡运动状况。研究结果表明:随着十二胺和仲辛醇药剂浓度的增大,气泡粒径逐渐减小并在达到临界兼并浓度(CCC值)后趋于稳定,十二胺和仲辛醇的CCC值均为0.0432mmol/L;溶液的表面张力则随着药剂浓度的增大而线性减小,相同条件下十二胺溶液的表面张力低于仲辛醇溶液;在仲辛醇溶液中添加十二胺,气泡临界兼并浓度和稳定粒径均减小,溶液表面张力和吸附密度均减小;气泡上升过程中其纵横比随着药剂浓度的增加而逐渐增加并趋于稳定,相同条件下十二胺溶液中气泡纵横比大于仲辛醇溶液;在仲辛醇溶液中添加十二胺有利于提高气泡纵横比;气泡上升速度随着药剂浓度的增加而逐渐减小,相同条件下十二胺溶液中气泡上升速度小于仲辛醇溶液,在仲辛醇溶液中添加十二胺有利于降低气泡上升速度。气泡上升速度与其纵横比呈负线性相关,这种相关性与药剂种类、浓度和混合机制无关。

In order to explore the effect on size and kinetic characteristics of bubble produced by frothers dodecylamine(DDA)and 2-octanol in flotation process,the bubble size distribution,surface tensions under different conditions and bubble motion state are analyzed using image analysis method,tensionmeter and high-speed camera,respectively.As indicated by study results,with the increase of concentration of DDA and 2-octanol,the bubble size decreases gradually and stay stabilized when the critical coalescene concentration(CCC value)which is 0.0432 mmol/L for both DDA and 2-octamol;the surface tension of solution of both agents tends to decrease linearly with increase of concentration of agents,and under identical conditions,the surface tension of DDA solution is lower than that of 2-octanol solution;when DDA is added into 2-octanol,the CCC value,stabilized size of bubble as well as the surface tension of DDA solution and adsorption density are all seen to decrease;the bubble′s aspect ratio during its rising process tends to gradually increase and finally become stabilized with the increase of concentration of reagent,and under otherwise identical conditions,the bubble′s aspect ratio in DDA solution is larger than that in 2-octanol solution;adding DDA in 2-octanol solution can help increase bubble′s aspect ratio;the bubble ascending velocity decreases with increase of concentration of reagents;and under identical conditions,the ascending velocity of bubble in DDA solution is lower than that in 2-octanol solution;addition of DDA in 2-octanol solution can help reduce bubble ascending velocity;bubble ascending velocity is in negatively linear correlation with aspect ratio and such a dependence is unrelated to types and concentrations of reagents and their mixing mechanism.