Abstract

In this work, we explore the impact of heat transport on chloride heap-leaching process through several case studies. The scenarios covered different operational conditions for both irrigation (flow rates and temperature ranges) and gas injection (flow injection and temperature ranges). We solved a three-dimensional reactive transport model for different species in a non-saturated porous media, coupled with energy balance. The energy balance equation considers convective, radiative, and evaporative heat transfer mechanisms, and the interaction between the environment and the heap. The fluid dynamics was prescribed using a one-dimensional transient model, which solves the Richard's equations and gas dynamics equations. We developed a case study that examines the effect of environmental conditions on heat transport together with changing irrigation rates, gas injection rates, and initial heap temperatures. The heap average temperature shows to be highly sensitive to the irrigation flow rate and heat exchange with the atmosphere. A higher irrigation rate implies a higher average temperature. In contrast, changes in gas injection flows and temperature are of second order importance. Despite attempts to introduce three-dimensional effects, the model results show a mainly one-dimensional behaviour due to the adopted approach for fluid dynamics resolution and the uniform irrigation considered on the surface. The results demonstrate that the model can provide realistics results that it could be used to evaluate more complex scenarios in chloride leaching such as other thermal sources.