溶气气浮的微气泡影响因素及其与絮体的结合特性

Characteristics of Microbubbles and Microbubble-flocs in Dissolved Ozone Flotation Process

通过微观分析系统对气浮工艺中的气载絮体进行观测,分别研究了气浮过程中微气泡和气载絮体的特性以及Zeta电位对气载絮体平衡接触角的影响。在0.40 MPa和30%回流比的工况条件下,气泡平均粒径较小,其尺寸主要分布在40~110μm之间,占整体数量90%以上。投加混凝剂聚合氯化铝(PAC)后,在0.40 MPa时气载絮体尺寸最大,主要尺寸分布在0.45~0.95mm之间,二维分形维数最小,结构更为松散轻薄。在此基础上通过投加不同浓度的混凝剂控制溶液的Zeta电位来探究其对平衡接触角的影响,发现不同于传统混凝在等电点处达到最优混凝效果,气浮工艺是在Zeta电位为17 m V时平衡接触角达到最大值,此时的气载絮体中气泡与絮体的结合更为理想,更利于提升气浮工艺的分离效果。

In order to study the characteristics of microbubble-flocs and effect of Zeta potentials on microbubble-flocs in the flotation, the microbubble analysis system was developed for microbubble-flocs observation in the dissolved ozone flotation （DOF） process. The results showed that the average micro- bubble size was the smallest with the saturator pressure of 0.40 MPa and reflux ratio of 30% , and the mi- crobubble size was mainly between 40 - 110 μm, accounting for more than 90%. Polyaluminium chloride （PAC） was added to the process in different saturator pressure. It was found that the size of the micro- bubble-floes was the biggest with the saturator pressure of 0.40 MPa, and the main dimensions were be- tween 0.45 mm and 0.95 ram. Meanwhile, because of the smallest fractal dimension, the floe structure was fluffy and thin. Through applying differerlt PAC dosage, the effect of Zeta potential on the contact an- gle was obtained. The results showed that optimal Zeta potential for flotation process was 17 mV in this study because the contact angle reached the highest, which indicated favorable separation performance due to the good contact between microbubbles and floes.