Tortuosity prediction and investigation of fluid flow behavior using pore flow approach in heap leaching

Abstract

The aim of the current study is to use the pore flow approach in the hydrodynamic modeling of heap leaching. Also, by using this approach and presenting a novel method, the tortuosity of the porous media was predicted. For this purpose, a laboratory scale column with dimensions 20 cm × 20 cm × 45 cm containing copper oxide ore was prepared. Four sides of this ore box were photographed, vectorized and then numerical modeling of the fluid flow was implemented with the pore flow approach. Ore materials were from the first loading lift of a real copper mine, and the irrigation rate was equal to the operational rate of 10 L m−2 h−1 (2.77 × 10−6 m s−1). The average particle diameter was 1.8 cm and the voidage (inter-particle porosity) was about 20%. The modeling results show the velocity and pressure distribution in the media correspond to the pore flow approach. It strongly depends on the shapes of the ore particles and their arrangement. Correlation analysis of inter-particle porosity, velocity and pressure distribution confirm that the average velocity of the fluid is inversely related to the bulk voidage of the bed. Also, the pressure is a function of porosity and how the particles are placed next to each other. In the current research, a semi-empirical function is presented for tortuosity prediction in porous media by using a coupled numerical modeling and image processing approach. This equation predicts the average tortuosity value of the ore box around 1.445. Finally, the pore flow approach was implemented in a heap side wall and the seepage, pooling and fluid flow paths were predicted.