酸浸条件下氧化铜矿岩散体孔隙结构及渗流演化规律

发布时间：2018-01-20 12:05

本文关键词： 氧化铜矿堆浸散体孔隙结构渗透性调控技术　出处：《北京科技大学》2017年博士论文　论文类型：学位论文

【摘要】：保持矿堆良好的孔隙结构和渗透性能是矿物高效浸出的关键,论文以酸浸氧化铜矿岩散体为研究对象,以室内试验、数值模拟、理论分析为技术手段,以强化堆浸渗流、改善浸出效果为目的,开展堆浸过程中孔隙结构及渗流演化规律研究,主要包括:(1)开展了酸浸过程中氧化铜矿石颗粒内部结构成像试验。借助显微CT扫描系统、图像处理技术和三维重构技术,展示了浸出作用下矿粒内部裂隙结构演化过程,运用数字图像分析技术揭示了酸浸氧化铜矿石颗粒内部微裂隙结构演化规律,酸浸作用使矿粒孔隙率、裂隙尺寸和数量分别增加了约40%、3.5%和 25%。(2)完成了硫酸柱浸氧化铜矿岩散体颗粒间孔隙结构演化试验。利用工业CT成像技术获取了柱浸体系孔隙结构参数信息,借助三种不同维度的孔隙率用于散体孔隙结构评价,探明了酸浸条件下氧化铜矿岩散体孔隙率、孔隙尺寸、渗透系数及浸出率随浸矿时间演化规律。(3)探明了氧化铜矿石酸浸体系孔裂隙双重介质渗流演化规律。考察了酸浸氧化铜体系孔裂隙分形演化规律,明确了矿粒内部裂隙分形维数与孔隙率、裂隙尺寸及数量之间的正线性相关关系,确定了散体颗粒间孔隙分形维数与孔隙率、孔隙尺寸及渗透系数间的线性关系,建立了氧化铜矿石酸浸体系孔裂隙双重介质分形渗流演化模型。(4)考察了堆浸散体饱和细观渗流速度场分布特征。利用MRI系统开展了柱浸散体饱和渗流成像试验,实现了堆浸溶液细观渗流速度场的可视化,引入标准偏差、变异系数和均匀性指数用于体系流场均匀性评价,揭示了堆浸散体颗粒间溶液细观渗流规律,基于MRI图像构建了有限单元模型,开展了浸矿散体细观渗流数值模拟,模拟结果与测试结果较吻合。(5)阐明了酸浸氧化铜矿岩散体孔隙结构及渗流演化机理。由氧化铜矿石酸浸反应动力学入手,解析了酸浸作用对氧化铜矿石颗粒内部裂隙的影响机制,探明了酸浸条件下氧化铜矿岩散体渗流演化机理。(6)完善了浸矿过程中矿堆渗流调控技术措施。针对浸矿过程中矿堆孔隙结构及渗流演化特点,分析了堆浸渗流调控技术措施及其作用机理,提出了充气强化堆浸渗流工艺设想,以促进浸出进程、改善浸矿效果。
[Abstract]:Keeping good pore structure and permeability of ore heap is the key to high efficiency leaching of minerals. This paper takes acid leaching of copper oxide as the research object, laboratory test, numerical simulation and theoretical analysis as the technical means. In order to strengthen heap leaching seepage and improve leaching effect, the pore structure and seepage evolution law in heap leaching process were studied. The main results include: (1) the internal structure imaging tests of copper oxide ores during acid leaching were carried out, with the help of micro CT scanning system, image processing and 3D reconstruction technology. The evolution process of the internal fracture structure of ore particles under leaching is demonstrated. The evolution law of micro-fracture structure in the particles of acid leaching copper oxide ores is revealed by using digital image analysis technology, and the porosity of ore particles caused by acid leaching is revealed. The size and number of fractures increased by about 40% respectively. The pore structure evolution test between particles of copper oxide in sulphuric acid column leaching has been completed in 3.5% and 25. The information of pore structure parameters of column leaching system has been obtained by using industrial CT imaging technique. With the help of three different dimensions of porosity to evaluate the pore structure of the bulk, the porosity and pore size of the copper oxide ore under acid leaching conditions are proved. Permeability coefficient and leaching rate with leaching time evolution rule.) the evolution law of pore and fissure double medium seepage in acid leaching system of copper oxide ore is proved. The fractal evolution law of pore and fissure in acid leaching copper oxide system is investigated. The positive linear correlation between the fractal dimension of fracture and porosity, the size and quantity of fracture is determined, and the fractal dimension of pore and porosity among granular particles are determined. Linear relationship between pore size and permeability coefficient. The fractal seepage evolution model of pore and fissure double medium in acid leaching system of copper oxide ore is established. The distribution characteristics of saturated meso-seepage velocity field of heap leaching particles were investigated and the imaging experiments of saturated seepage flow of pillared particles were carried out by MRI system. The visualization of flow velocity field of heap leaching solution was realized. Standard deviation coefficient of variation and uniformity index were introduced to evaluate the uniformity of flow field. The finite element model is constructed based on MRI image and the numerical simulation of mesoscopic seepage of leaching granular is carried out. The simulation results are in good agreement with the test results.) the pore structure and seepage evolution mechanism of acid leaching copper oxide ore are explained. The kinetics of acid leaching reaction of copper oxide ores is discussed. The influence mechanism of acid leaching on the internal crack of copper oxide ore is analyzed. The mechanism of seepage evolution of copper oxide pellets under acid leaching condition has been proved, and the technical measures for controlling the seepage of ore heap in leaching process have been perfected, aiming at the pore structure and seepage evolution characteristics of ore heap during leaching. This paper analyzes on the technical measures and mechanism of seepage control in heap leaching, and puts forward the assumption of aerated enhanced heap leaching process to promote the leaching process and improve the leaching effect.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD862.1;TD313

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