Effect of ore size and heap porosity on capillary process inside leaching heap
(1. Key Laboratory for High-Efficient Mining and Safety of Metal Mines, Ministry of Education,
University of Science and Technology Beijing, Beijing 100083, China;
2. School of Civil and Environment Engineering, University of Science and Technology Beijing, Beijing 100083, China)
University of Science and Technology Beijing, Beijing 100083, China;
2. School of Civil and Environment Engineering, University of Science and Technology Beijing, Beijing 100083, China)
Abstract: The capillary process coexists with gravity flow within leaching heap due to the dual-porosity structure. Capillary rise is responsible for the mineral dissolution in fine particle zones and interior coarse rock. The effect of particle size and heap porosity on the capillary process was investigated through a series of column tests. Macropore of the ore heap was identified, and its capillary rise theory analysis was put forward. Two groups of ore particles, mono-size and non-uniform, were selected for the capillary rise test. The result shows that particle size has an inverse effect on the capillary ultimate height, and smaller particles exhibit higher capillary rise. Meanwhile, the poorly graded group exhibits small rise height and velocity, while the capillary rise in the well-graded particles is much greater. The relationship between porosity and fitting parameters of capillary rise was obtained. Low porosity and high surface tension lead to higher capillary height of the fine gradation. Moisture content increases with the capillary rise level going up, the relationship between capillary height and moisture content was obtained.
Key words: heap leaching; capillary process; ore size; heap porosity