堆浸过程中矿岩散体粒间孔隙尺寸的演化规律

Pore size evolution of granular ore media during heap leaching

根据X射线CT技术无损伤地探测细菌浸出前、后矿岩散体介质孔隙结构特征,利用MATLAB环境编写程序对矿岩散体介质颗粒间横向及纵向孔隙尺寸分布进行统计,研究细菌浸出过程中矿岩散体粒间孔隙尺寸演化规律及其对溶浸液渗流特性的影响。研究结果表明:矿岩散体介质孔隙尺寸分布不均匀,分布范围广,基本呈正态规律分布;浸出后顶部区域中等孔隙和大孔隙数量增加,小孔隙数量减少,底部区域中等孔隙也有所增加,但小孔隙数量减少,横向大孔隙数量减少,纵向大孔隙数量变化不明显;浸出后平均孔隙尺寸比浸出前有所增大,大孔隙含量增加,加强了浸堆的渗流各向异性;微细颗粒的运移和沉积对孔隙尺寸演化影响程度最大。

The pore structure characteristics of granular ore media before and after bacteria heap leaching were detected by X-ray computed tomography. Based on MATLAB software, the cross sectional and longitudinal pore size distributions of granular ore media were calculated to investigate the evolution of granular ore media＇s pore size distribution during heap leaching and its influences on permeability. The results show that intergranular pores are inhomogeneous. The pore size ranges widely and assumes a normal distribution. After leaching, the amounts of middle and large pores at top zone increase, while the amount of small pores decreases. The amount of middle pores at bottom zone increases, small pores decrease, cross sectional large pores decrease, and the longitudinal large pores have no obvious change. Average pore size increases after leaching, so the ratio of large pores increases and the permeability anisotropy is strengthened. The transport and precipitation of fine particles is the most critical factor for the evolution of pore size distribution.