Effect of leaching aid in heap leaching of copper ores – column test study

Abstract

Solution percolation is critical in heap leaching applications. The use of leaching aids has been proven to improve the percolation of solution due to their effects on the surface tension. The introduction of leaching aids reduces the solution surface tension and ultimately improves the flow of solution through small pores or hard-to-flow areas. This study focused on determining the effect of the BASF leaching aid, LixTRA 118, on the solution dynamics through narrow and wider particle size distributions within heaps, as well as evaluating its effect on the acid consumption and metal recovery. The hydrodynamics of the solution were studied through drainage tests. The effect of the leaching aid was evaluated by comparing columns with and without a leaching aid. The same approach was used to evaluate its performance in terms of acid consumption and metal recovery. The effect of the leaching aid was found to be more pronounced at wider particle size distribution ranges. This was found to be associated with the solution holdup inside the particle bed and the capillary actions. The latter was also responsible for the increase in metal recovery and acid consumption. Further work is recommended to ascertain the effect observed with the consumption of leaching aid and the selectivity of copper over certain other metals.