Synthesis of Fine Particles by Precipitation Stripping using Liftrasound and Monitoring of their Morphology

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Solvent extraction is a widely used process for recovery, separation and purification of metals from minerals or other metal-bearing materials. In conventional solvent extraction, metals are stripped from loaded organic phase into an aqueous phase with mineral acids, then recovered in a following step. Recently, applicability of integrating stripping and metal recovery (as powder) into a single process step has been investigated. Therefore, the direct production of metal powder from metal-loaded organic phase is of interest as a new production method of metal powder. In the precipitation stripping, the droplet size and the reaction rate have a significant effect on the precipitate size and morphology In such a system, ultrasound, because of its compression and expansion, can tear the liquid droplets, increasing the contact area between the immiscible organic and aqueous phases through emulsion and dramatically increasing the rate of stripping. In addition to its emulsifying effect, ultrasonic energy further increases precipitation stripping through enbanced agitation and the removal of stagnant liquid near the interface between the organic and aqueous phases. Therefore, we investigated the utilization of ultrasound for the purpose of controlling the size ad morphology of the powders.In the present study, we found that the possibility of controlling the size and morphology of the powders by using ultrasonic energy ; furthermore, the effect of various conditions of organic and aqueous phases, such as metal concentration in an organic phase, stripping agent concentration and acidity in an aqueous phase, on the size and morphology of the powders was also investigated, Also, we investigated the fundamental process of precipitation stripping and the synthesis of mixed oxalate powders for transition metal and rare earth metal.