Impact of Gravity Effect on In Situ Leaching of Uranium

Gravity becomes an important factor that affects the hydrodynamics of the in situ leaching process, when the densities of leaching solution and groundwater are different. Consequently, leaching solution flows in the porous medium are noticeably at a lower rate than expected, which might introduce difficulties for recovering uranium concentrated in the upper parts of the geological layers. Current work investigates gravity effects on the flow regimes by including it in the Darcy equations. Overall, the modelling consists of calculation of the pressure and density distribution and the filtration Darcy velocity with respect to the gravity effect. Increased resource demand when accounting for the gravity effect was managed by numerically solving the fully coupled differential equations using the CUDA (compute unified device architecture) parallel computing technology provided by nVidia. Results show a magnitude of gravity impact on uranium leaching depending on various concentrations of sulphuric acid in the leaching solution. Additionally, the pressure equation which was solved by CUDA on a graphics processing unit significantly accelerated simulation processes when compared with the central processing unit calculations. (author)