气浮工艺中气载絮体尺寸分布及其浮力效率研究

Size Distribution and Buoyancy Efficiency of Microbubble-flocs in Dissolved Air Flotation Process

针对气浮工艺中气载絮体微观特性对上浮性能的影响,基于气浮工艺对蒙脱石和二氧化硅无机悬浊体系的处理特性,通过构建模拟絮体动态观测系统,探究了不同絮体尺寸条件下,气泡尺寸和气泡数量的分布规律,揭示了微气泡与絮体的结合特性。结果表明,混凝剂的投加量会影响气载絮体的尺寸,进而改变气浮处理效果;在最佳混凝剂投加量条件下,气载絮体尺寸主要分布在350~1500μm。基于上述气载絮体尺寸分布规律,采用玻璃球作为模拟絮体,探究了不同尺寸模拟絮体与微气泡的结合特性,发现模拟絮体黏附的微气泡尺寸主要分布在100~300μm,且絮体上附着的微气泡数量随反应时间逐渐减少,而微气泡尺寸逐渐增大。通过计算模拟絮体浮力效率发现,气载絮体的浮力效率与絮体粒径整体上成反比,且随时间呈现先增长后稳定的状态,在30~40min达到最大值。

This paper constructed a simulated floc dynamic observation system,explored the distribution of bubble size and bubble number under different floc size conditions,and revealed the binding characteristics of microbubbles and flocs based on the characteristics of dissolved air flotation process for treating montmorillonite and silica inorganic suspension,so as to investigate the influence of micro-characteristics of microbubble-flocs on flotation performance of dissolved air flotation process.The dosage of coagulant affected the size of the microbubble-flocs,and then change the air flotation treatment performance.Under the optimal dosage of coagulant,the size of the microbubble-flocs was mainly distributed in the range of 350-1500μm.Based on the size distribution of microbubble-flocs,the binding characteristics between simulated flocs(glass particles)with different sizes and microbubbles was explored.The size of the microbubbles adhered to the simulated flocs mainly distributed in the range of 100-300μm,and the number of microbubbles attached to the flocs gradually decreased with the reaction time.However,the size of microbubbles gradually increased.According to the calculation of the buoyancy efficiency of the simulated flocs,the buoyancy efficiency of microbubble-flocs was inversely proportional to the floc size,and it increased first and then remained stable with the reaction time,which reached the maximum value in 30-40 minutes.