节点文献
应力波强化堆浸渗流的理论与试验研究
Theory and Test Study on Seepage Reinforement by Stress Wave in Heap Leaching
【作者】 王贻明;
【导师】 吴爱祥;
【作者基本信息】 中南大学 , 采矿工程, 2008, 博士
【摘要】 矿产资源是我国经济发展的支柱,而溶浸采矿是开发低品位难处理矿石资源的有效途径。由于矿堆的低渗透性问题,制约了溶浸采矿技术的推广应用,因此,开展强化低渗透性矿堆渗流的理论与应用技术研究具有重要意义。论文以国家自然科学基金项目“应力波作用下溶浸液在堆浸散体介质中的流动机理研究”(No.50574099)为基础,结合国家杰出青年科学基金项目“散体多相介质中多级渗流传质的动力学研究”(No.50325415),开展应力波强化堆浸渗流的理论与试验研究。论文通过室内试验、理论分析、数值计算相结合的方法,针对低渗透性矿堆浸出存在的问题,分析渗透性对于矿石可浸性的重要性,以应力波作为改善浸堆孔隙率,提高浸堆渗透性的技术手段,开展应力波在堆浸散体介质中的传播规律、对散体结构的作用机理及其对渗透性的影响规律研究,以德兴铜矿堆浸厂为实例,开展应力波强化堆浸渗流的工程应用技术研究。论文完成主要研究工作如下:(1)系统研究了矿石可浸性的影响因素,根据影响程度,将影响因素划分为决定性的、控制性的和一般性三个等级,建立了以矿石可浸性指数(LI)为评价依据的评价模型,丰富了溶浸采矿理论。(2)将修正的卡曼.科泽尼(Carman-Kozeny)模型引入堆浸渗流机理研究,分析了浸堆渗透性的影响因素,其结果更贴近生产实际。首次建立了微粒渗滤沉积作对浸堆渗透性的影响的数学模型,揭示了微粒渗滤沉积作用对浸堆渗透性的影响规律。(3)首次将激波管试验引入堆浸渗流试验,运用渗流力学原理,研究了应力波对堆浸散体介质孔隙结构和渗流强化的作用机理,结果表明应力波使堆浸散体介质的孔隙结构松散,渗透系数增加3.8~10倍,渗流得到强化,并体现出一定的时效性。(4)以散体动力学为基础,引入双重有效应力模型,阐明了应力波作用下结构有效应力和颗粒问有效应力对浸堆结构的作用,揭示了应力波对浸堆孔隙结构的三重作用机理。(5)以Biot理论为基础,考虑应力波作用下堆浸过程的非线性渗流,建立了应力波作用下的应力场和渗流场耦合控制方程,采用数值模拟方法,验证了耦合模型,探寻了应力波对堆浸渗流的影响,阐明了应力波强化渗流的可行性与有效性。(6)开展了应力波强化堆浸渗流工程应用技术研究。以爆破应力波作为工作媒介,采用松动控制爆破技术作为应力波强化堆浸渗流的手段,研究了浸堆松动控制爆破技术及参数优化方法,并以德兴铜矿废石堆浸场为例,开展了松动控制爆破松堆工业试验研究,进一步验证了应力波强化堆浸渗流的有效性。
【Abstract】 Mineral resources are the backbone of economic advance in China, and solution mining is an effective method to exploit the intractable ore resources or those with low grade. But the application and generalization of the method is restricted badly due to the low permeability of heap. Thus, it is very significant to investigate on the theory and applied technology of seepage reinforced in heap leaching.Based on the National Nature Science Fund Project The Study on the Mechanism of Flow in Granular Media of Heap under Stress Wave (No.50574099), and support by the National Science Fund for Distinguished Young Scholars of China The Study on Dynamics of Multilevel Seepage and Mass Transfer in Multiphase Granular Medium (No.50325415), the classification of ore leachability and the mechanism of seepage reinforced by stress wave in heap leaching were studied in this thesis.Combining the methods of indoor test, theoretical analysis, and numerical simulation, the importance of permeability of heap to ore leachability was analyzed against the heap with low permeability. Then, taking stress wave as technical measure to improve the permeability of heap, the law of stress wave propagation in heap, the mechanism of action to the mesh of granular media, and influencing law to seepage were studied. Taking the heap leaching plant in De-xing Copper Mine as an engineering example, the application technology of seepage enforced by stress wave was researched in this thesis.The main works completed are as follow:(1) The factors influencing ore leachability were studied systematically. They were classified as three grades according to their impact degree, deterministic factors, controlling factors and general factors. An evaluation model, taking ore leachability index LI as basis, was established, which enriches solution mining theory.(2) The modified Carman-Kozeny equation was introduced into the analysis of the seepage mechanism in heap leaching process. Based on it, the impact factors to the permeability of leaching heap were studied widely and systematically, which make the research results be more practical and useful for instructing heap construction. Furthermore, the numerical model describing the influence of fine particles precipitation and filtration on the permeability of leaching heap was established firstly, which disclosed the influencing rules of fine particles precipitation on leaching heap’s permeability.(3) The shock tube was introduced into the seepage experiment during heap leaching initially. Based on seepage mechanics, the action rules of stress wave on the pore structure of granular medium and seepage were studied. The results indicate that stress wave can loose the granular medium and increase seepage coefficient from 3.8 to 10 times, as a result the seepage can be reinforced and presents certain secular properties.(4) Based on the dynamic mechanics of granular media, the double effective stress model was built with structure effective stress and effective stress among particles, and it could reveal the mechanism of triplicate action by stress waves on the structure of granular media in heap leaching process.(5) Based on the Biot theory, the coupled controlling equations of flow and stress under stress wave during heap leaching were set up in the condition of nonlinear flux. With numerical simulation, the coupling model of seepage-stress was verified. The effects of stress wave on seepage during heap leaching were investigated and the feasibility and availability of reinforcing seepage by stress wave were illuminated.(6) The application technology of seepage reinforcement by stress wave was researched. Take blasting wave as stress wave, and employ loosing controlling blast technology to reinforce fluid flow in heap leaching, the loosing blasting technology in heap leaching and the blasting parameters optimization were studied systematically. Moreover, take the dump leaching in Dexing Copper Mine as an example, a commercial test of dump loosing by loosing controlling blast was carried out, which proved the availability of reinforcing seepage in heap leaching by stress wave.
【Key words】 stress wave; granular media; heap leaching; leachability classification; seepage reinforcement;