基于FBRM和PVM技术的尾矿浓密过程絮团演化规律
- 1. 北京科技大学土木与资源工程学院
- 2. 北京科技大学土木与环境工程学院
- 3. 北京科技大学
- 4. 北京科技大学土环学院
摘要: 在初始泥层高75cm时耙架转速为0rpm、0.1rpm、1rpm和10rpm条件，以及耙架转速为0.1rpm时初始泥层高度为75cm、45cm和25cm条件下，采用FBRM和PVM实时在线监测技术，对动态浓密系统泥层脱水过程絮团结构演化进行原位连续观测，获得了泥层脱水过程中，絮团尺寸、分布特征和实时图像。研究结果表明，尾矿浓密过程中絮团尺寸和数量随剪切时间呈现先增长后降低，再保持稳定状态，絮团密实化过程可分为絮团生长期、絮团重构期和絮团破碎期3个阶段。合理的剪切速率有利于絮团尺寸生长和絮团快速破裂重构，有利于絮团密实化，但过高的剪切速率作用相反。初始泥层高度大条件下絮团的生长阶段时间更长，絮团尺寸峰值更高，重构期较长。剪切速率的增加造成絮团尺寸减小，絮团尺寸减小的速率随剪切速率上升而增大，絮团尺寸随初始泥层高度增加而增大。尾矿絮团分形维数逐渐上升反映了絮团封闭水释放排出，孔隙率降低，密实化程度提高的过程。根据絮团直径观测和分形维数计算，分析了流体动力应力和絮团强度对絮团破裂程度的影响，解释了尾矿浓密过程中的絮团密实化规律。
Aggregate evolution rule in tailings thickening based on FBRM and PVM technology
- Available Online:
2020-07-07
Abstract: The real-time online monitoring technology of FBRM and PVM were used to continuous analyze the aggregate structure evolution, during the process of dynamic thickening system. The tailings dewatering studies were taken under the condition that the rake rotation speed is 0 rpm, 0.1 rpm, 1 rpm and 10 rpm while the initial mud bed height is 75 cm, and the initial mud bed height is 75cm, 45 cm and 25 cm while the rake rotation speed is 0.1 rpm. The characteristics of aggregate diameter, distribution and real time images of the tailings thickening process were obtained. The results show that the diameter and quantity of aggregate increased at the early stage of shear, then decreased with shear time, and stabled at the final stage of shear. The process of aggregate evolution can be divided into three stages of growth, reconstruction stage and densification stage. Reasonable shear rate is beneficial to the aggregate growth, accelerate the structure breaking and reconstruction of aggregate, and improve the rate of aggregate densification, but the effect of high shear rate oppositely. The longer growth period of aggregate, the larger maximum aggregate diameter, and the longer reconstruction period was observed at higher initial mud bed height. The aggregate diameter decreased with the increase of shear rate, and rate of aggregate diameter decrease was raised with the shear rate increase. The diameter of aggregate increased with the increase of initial mud bed height. The increasing fractal dimension of tailings aggregate reflects the process of bondage water releasing, porosity decreasing and rate of aggregate densification. According to the observation of aggregate diameter and the analyze of aggregate fractal dimension, the hydrodynamic stress and aggregate strength was used to estimate the rate of aggregate structure breaking, which explained the law of aggregate densification in the process of tailings thickening.
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