A New Bubbling Extraction Tower: Toward Liquid-Liquid Solvent Extraction at Large Aqueous-to-Oil Phase Ratios

Abstract

Enrichment and recovery of valuable components in industrial waste waters by traditional liquid-liquid solvent extraction is not economic due to extremely low concentrations of those targets. Large-phase-ratio extraction exhibits potential advantages for recovery of small quantities of target components from large volume of aqueous solutions. A novel bubbling extraction tower is proposed toward performing solvent extraction at large aqueous-to-oil phase ratios in this work. Organic extractants were covered onto surface of gas bubbles to form a layer of organic liquid membrane and the dispersed organic phase in tower could be small enough. The target components are extracted from aqueous feed solution onto the surface of the bubbles, and the enrichment ratios could be extremely high. We develop a feasible methodology to calculate tower height and operation phase ratios of the bubbling extraction tower, which is essential for future industrial scale-up. Experimental results in pilot test are highly consistent with calculations. (c) 2015 American Institute of Chemical Engineer