基于通风强化浸出的矿岩散体孔裂隙双重介质结构演化

Structural Evolution of Porous and Fractured Media of the Ore-rock Granular Based on Aeration Assisted Heap Leaching

为解决羊拉铜矿非生物堆浸中因矿堆渗透性差而导致的铜浸出效果不佳的问题,提出通风强化浸出的新设想,以期从改善浸堆体系渗透特性,提高铜浸出效果。首先,针对羊拉铜矿在堆浸过程中发现的问题及现有堆浸多孔介质渗流理论在分析复杂渗流规律中的不足,提出利用堆浸散体孔裂隙双重介质理论研究强制通风对堆浸体系渗透特性的影响机制;然后,对该矿浸堆的矿石粒级分布情况及其类型进行分析与分类;最后,开展不同通风强度下的室内柱浸试验,利用CT扫描技术分析不同试件的孔隙发育情况,并利用电镜扫描(SEM)与分形几何理论对不同通风强度下散体颗粒表面的分形维数、动态裂隙率及动态渗透系数进行研究。结果表明:羊拉铜矿浸堆的矿石颗粒类型为a型,其浸堆松散细颗粒较多因而密实度较高,矿石颗粒粒级分布不合理;从CT扫描结果来看,引入强制通风虽然降低了堆浸体系的孔隙率,但其可以加剧矿石酸浸反应程度,增加浸堆内矿石颗粒数量,从而大大提高堆浸体系的孔隙数量,促进整个体系的孔隙结构发展并对堵塞的渗流通道形成有效冲破,最终提高铜浸出效果;从SEM扫描与分形几何理论分析结果来看,强制通风能够提高矿石颗粒内部对溶浸液的动态渗透系数与颗粒自身的裂隙率,从而强化浸出液中溶质的渗流性能,最终使得铜浸出效果得以提高。

A comparatively new method of aeration assisted leaching was proposed to solve the bad copper leaching effect of Yangla copper mine（YCM） due to the poor permeability of the heap during abiotic heap leaching,the desideratum of which was improving the permeability of the heap leaching system.Firstly,in view of the problems happening in YCM and the shortage of the present seepage theory in analyzing the complicated seepage laws,a theory of porous and fractured media of the ore-rock granular was proposed to study the impact mechanism of the forced aeration on the permeability of the heap leaching system.Secondly,ore particle size distribution and its type of YCM were analyzed and classified.Lastly,the column leaching experiments with different aeration intensities（AI） were conducted indoors.Pores development of the specimens were analyzed using CT,then SEM and fractal geometry theory were employed to study the fractal dimensions,dynamic permeability coefficient（DPC）and fracture ratio（DFR） of the granular surface when AI was different.The results show that the particles type of YCM belongs to a-type and that particles within the ore heap of YCM are loose and fine with a higher density indicating an improper particle size distribution.From CT analysis,although the porosity is decreased,the acid leaching reaction degree of the ore is intensified to enlarge the ore particles quantities and pore number when air is pumped into the heap leaching system.Therefore,the copper leaching performance is likely to be increased since the blocked seepage channels are effectively broken through.From SEM and the fractal geometry theory analysis,DPC and DFR within the leaching system are increased by the forced aeration.Therefore,the leaching reaction degree and percolation performance of the solutes within the leaching solution may be greatly enhanced to improve the copper leaching effect performance.