Research on Bound Liquid Membranes for Hydrometallurgical Processing.

摘要

This study was conducted to provide proof of principle for hydrometallurgical membranes based on Poroplastic technology and to assess the practical utility of such membranes for mineral resource recovery. In such membranes a strongly retained ion exchange liquid is used to purify and concentrate aqueous minerals. This represents the next logical step beyond present liquid-liquid extraction technology and solves many problems. Bound liquid membranes force the flow of target ions against a concentration gradient by the charge-coupled transport of some counter-ion down a larger reverse gradient. This phase has demonstrated such transport for nickel and tungstate,two poorly utilized domestic resources,through strong thin Poroplastic membranes impregnated with conventional ion exchange liquids. Transport rates three times those of Celgard are achieved,and liquid retention is far superior to that of Celgard. An engineering study has confirmed that spiral wound Poroplastic membrane modules would be highly effective for extracting dilute tungstate from western lake brines with pay-back periods as short as a few months. These modules reduce mechanical liquid losses,lower ion exchange liquid inventories dramatically,require simpler equipment than liquid-liquid processing,and show numerous advantages over hollow fibers. Charge-specific membranes which distinguish only between anions and cations are also considered,and a new method of hydrometallurgical processing is suggested in which complex brines are made to concentrate their own valuable trace minerals.