深锥浓密过程中底流稠化机制及其调控方法

Although the Deep Cone Thickening (DCT) technology has been introduced in already, the underflow concentration is too low or the thickener rakes don't run because of overload, which limits its popularization in China. The reason is that the deep cone underflow densification mechanism is still unclear in DCT, which causes that the control method of underflow concentration is weak. Therefore, it is necessary to commence research on the deep cone underflow densification mechanism, which is a fundamental problem. This project focuses on the analysis of the liquid-solid coupling effect in converse migration process of the two phase flow, starting with the influential factors about tailings thickening, and aiming at improving underflow concentration. Researches will be conducted on the aspects of tailings sedimentation characteristics and its running track, the mechanical constitutive relations, the representation of thickening process, and the control method of underflow concentration. With the aims of quantitative expression of underflow thickening macroscopic compression characteristics, rebuilding the motion tracks of tailings particles, establishing custom function and motion control equation, innovating the numerical simulation method of tailings thickening process, clarifying the mechanism of underflow densification, and establishing an intensive control method for DCT's thickening process, the following methodologies would be adopted: the continuously thickening tests, the online tracing test, the stress analysis and theoretical modeling, and numerical simulation of DCT's thickening process. This project is to explain the complex course of soft-solid thickening under the coupling effect of tailings flocs and closed water, which solve the problem of low efficiency of ultrafine tailings thickening process, and lays technical foundation for the improvement of the tailings thickening effect.

虽然深锥浓密技术已经开始应用，但经常出现底流浓度过低或者浓密机过载停机事故，严重制约了该技术在我国的推广应用。究其原因，深锥底流稠化机制不明了，导致底流浓度调控手段薄弱。因此，有必要研究深锥底流稠化机制这一基础问题。本项目从尾矿浓密的影响因素入手，以提高底流浓度为着眼点，重点剖析两相流逆向运移中的液固耦合效应，围绕尾矿压缩沉降特性及其运行轨迹、尾矿压缩沉降力学本构关系、尾矿压缩沉降过程再现、底流浓度调控方法展开研究。通过尾矿连续浓密实验、在线示踪观测、受力分析与理论建模、数值模拟等方法，定量表达浓密底流宏观压缩特性，还原尾矿在浓密过程中的运动轨迹，建立自定义函数与输送控制方程，创新尾矿浓密数值模拟方法，阐明底流稠化机制，形成底流浓度调控技术手段。本项目将科学诠释尾矿絮团与封闭水耦合作用下软固体浓密稠化这一复杂过程，解决超细尾矿浓密效率低下的问题，为改善超细尾矿浓密效果提供技术支撑。

本项目以超细尾矿膏体充填为研究背景，以改善超细尾矿浓密效果为目的，综合运用室内实验、理论分析及数值模拟等手段，对深锥浓密过程中尾矿絮团运行规律以及底流浓度的稠化机制展开深入研究，取得了以下研究成果：（1）研制了一套尾矿动态浓密模拟装置。鉴于静态量筒沉降实验的局限性，提出并设计了尾矿动态浓密实验模型，可进行非连续/连续动态浓密实验。（2）实现了浓密底流宏观压缩特性的定量表达。基于动态浓密实验装置，分析了非连续/连续动态浓密两种模式下的沉降压缩特性与泥层压力、泥层高度、停留时间等因素之间的关系。（3）建立了深锥过程尾矿运移控制模型。基于有限元方法求解，开展了尾矿浓密过程中的受力分析，实现了尾矿沉降过程中固液两相流混合模型、湍流模型、群体平衡模型的耦合分析；（4）开展了基于停留时间的底流浓度数值模拟。利用Fluent软件开展了深锥浓密过程颗粒分布特征的数值模拟，分析了入料浓度、入料流量、耙架转速等参数对停留时间的影响规律，探明了矿浆停留时间与底流浓度的响应关系。（5）探索了深锥浓密过程底流浓度稠化机理。在物理实验和数值模拟的基础上，分析了静态和动态条件下泥层压力对底流的影响关系，探讨了两种模式下底流浓度稠化机理。（6）提出了深锥浓密过程底流浓度调控方法。以新疆伽师铜矿为工程背景，基于物理实验和相似理论，提出了以底流循环和超声辐照为主的底流浓度调控方法。该项目诠释了重力和机械力耦合作用下超细尾矿底流浓密稠化这一复杂过程，解决了超细尾矿浓密效率低下的问题，为超细尾矿浓密机的有效控制提供理论指导。