混合药剂对浮选柱中气泡性质及其分散特征的影响

Effect of reagent blend on characteristics and dispersion of bubbles in a flotation column

  • 摘要: 为研究十二胺和仲辛醇对浮选柱内气泡性质及其分散特征的影响,利用图像分析法测定了气泡的粒径分布,分别采用表面张力仪和量筒法测定了表面张力和充气量,并进一步分析了气泡的吸附密度和表面积通量。研究表明,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后分别稳定在0.6303和0.6020mm,其中气泡粒径衰变程度为99%时,十二胺和仲辛醇的浓度分别为0.081 1和0.0703mmol/L,相同药剂浓度时,十二胺溶液中的气泡尺寸大于仲辛醇溶液的;溶液的表面张力随着药剂浓度的增大而线性减小,相同药剂浓度时,十二胺溶液的表面张力低于仲辛醇溶液;充气量随着药剂浓度的增大而逐渐增大,相同药剂浓度时,十二胺溶液的充气量大于仲辛醇溶液。在临界兼并浓度时,十二胺和仲辛醇在气泡表面吸附密度分别为0.9662和0.2827μmol/m2,仲辛醇的气泡表面积通量大于十二胺。随着仲辛醇溶液中十二胺添加量的增大,气泡临界兼并浓度和稳定粒径均逐渐减小,其中十二胺添加量为0.0324mmol/L时,混合药剂溶液的临界兼并浓度达到最小值为0.0216mmol/L,气泡稳定粒径也达到最小值为0.5833mm;表面张力和吸附密度均随着十二胺添加量的增大而逐渐减小,其中十二胺添加量为0.0324mmol/L时,气泡表面药剂吸附密度达到最小值0.1540μmol/m2;充气量和气泡表面积通量均随着十二胺添加量的增大而逐渐增大,当添加量为0.0324mmol/L时,气泡表面积通量达到最大值7.734 s-1。

     

    Abstract: The effects of dodecylamine (DDA) and 2-octanol on the characteristics and dispersion of bubbles in a flo- tation column was investigated in this study. Bubble size distribution was measured using the McGill bubble size analy- zer,surface tension was measured using the surface tensionmeter,and aeration rate was researched using the measuring cylinder technique. Furthermore,bubble adsorption density and surface area flux were analyzed. With the increase in reagent concentration,the bubble size decreased until the critical coalescence concentration ( CCC) to 0. 630 3 and 0. 602 0 mm of DDA and 2-octanol,respectively,and the concentrations (CCC99 ),at which bubble size is reduced by 99% from that with water only,were analyzed to be 0. 081 1 and 0. 070 3 mmol / L for DDA and 2-octanol,respective- ly. The bubble size in DDA solution was found to be larger than that in 2-octanol solution with an equal solution con- centration. Surface tension was found to linearly decrease with the increase in reagent concentration,and the surface tension of DDA was lower than that of 2-octanol under the same concentration. Aeration rate increased as the reagent concentration increased,and the aeration rate of DDA was larger than that of 2-octanol. The adsorption density of DDA and 2-octanol at CCC was calculated to be 0. 966 2 and 0. 282 7 μmol / m2 ,and the bubble surface area flux of DDA was smaller than that of 2-octanol while the concentration was above CCC. With the increase of DDA addition in 2-oc- tanol solution,the CCC,constant D32 ,surface tension and adsorption density decreased,but aeration rate and bubble surface area flux increased. With a DDA addition of 0. 032 4 mmol / L,the minimum CCC,constant D32 and adsorption density were obtained at 0. 021 6 mmol / L,0. 583 3 mm and 0. 154 0 μmol / m2 ,respectively,while the maximum bub- ble surface area flux was calculated to be 7. 734 s-1 .

     

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