高含沙紊动系统中泥沙铜的相互作用及其垂向浓度分布

Sediment-copper Interaction and Vertical Distribution in Hyper-concentrated Turbulent System

采用谐振式紊动模拟装置 ,通过格栅以一定振幅、不同频率的往复运动 ,在水体中形成均匀紊动场 ,研究紊动对高浓度固液两相系统中泥沙 (黄土 )与铜的相互作用及其垂向浓度分布的影响 ,投沙量 (S)范围为 5kg/m3～80 0kg/m3.结果表明 ,在均匀紊动条件下 ,黄土对铜的吸附量在S =1 0kg/m3 处出现峰值 ,而后随着投沙量的增加而快速下降 .这可能是铜的专性吸附、马兰黄土富含碳酸钙而导致铜的碳酸盐和氢氧化物沉淀 ,以及泥沙浓度效应等过程的共同作用所致 .水相铜浓度随S从 5kg/m3增加到 2 0 0kg/m3时快速下降 ,在S >2 0 0kg/m3 的高含沙条件下继续下降趋于 0 .高浓度泥沙紊动水体中 ,水相铜浓度和泥沙吸附铜量的垂向分布分别表现出均匀和波动的不同特点 ,实际含沙量的垂向分布在S <1 0 0kg/m3时比较均匀 ,在S >2 0 0kg/m3时自上而下逐步增加 .

This paper presents a special problem on vertical distribution for sediment and copper in hyper concentrated turbulent solid liquid system that is essentially different from the ordinary lowconcentrated turbulent system.A resonance type turbulent simulation equipment is used for the experimental study in which a vertically uniform turbulent field of the mixture of loess and water is produced in a testing cylinder with a grille stirrer that moves up and down harmoniously with varying vibration frequencies.In order to compare the variations of the vertical profiles of sediment and copper in low and hyper concentrated solid liquid system,different scenarios for input sediment content ranging from 5 to 800kg/m 3 was considered in the experimental studies.It was found that solids copper content increases with input sediment content, S ,and reaches its peak as S goes to 10kg/m 3 and then decreases rapidly with increasing input sediment content.Such a behavior is possibly resulted from the joint effect of the specific adsorption of copper on loess,precipitation of carbonate and hydroxide of copper due to high carbonate content in the loess and the so called “particulate concentration effect” due to the present of the sediment variation in water.The vertical sediment concentration distribution resulted from the uniform turbulence is generally uniform,but slight non uniformity does occur as sediment concentration exceeds certain value.However,the vertical concentration distributions of soluble copper seem not affected much by the variation of sediment concentrations.