Recovery of sulphuric acid from waste and process solutions using solvent extraction

The optimised TEHA system was used to extracted acid from a synthetic process solution containing a number of metals. It was found that the system only extracted acid with a small amount of metals entrained. After scrubbing the loaded organic solution in a single contact, almost all entrained metals were removed. In the case that the mining waste solution contains low concentration of acid, membrane distillation (MD) technology can be used to recover the water and concentrate the acid and metals. Solvent extraction can be then used to recover the acid and metals. A conceptual process flowsheet has been developed using a combination of MD and SX.