Allied Chemical Corporation

Win-Sow Ho

Kang-Jen Liu

Lester T Lee

A system utilizing membrane extraction is provided to recover metal values. The system may be used to separate metal ions from an aqueous solution through the membrane by an organic liquid containing a chelating agent. This invention also contemplates the recovery of metal values from an organic phase, containing the metal complexed with a chelating agent, by an aqueous phase using membrane extraction. In the former case, the metal ion is passed through the membrane from the aqueous phase to the organic phase where it forms a complex with a chelating agent present in the organic phase. In the latter case the metal is extracted from the organic phase into the aqueous phase through the membrane. In both cases a chelating exchange reaction is involved at the interface between the membrane and one of the two phases. This hydro-metallurgical process employs membranes with metal ion diffusivity in the range of about 10.sup..sup.-5 to about 10.sup..sup.-8 cm.sup.2 /sec. and has advantages over conventional metal extractions and may be applied as the mechanism is pollutant removal and recovery as well as for metallurgical separations.

Membrane hydro-metallurgical extraction process

A membrane solvent extraction system is utilized to separate two substantially immiscible liquids and extract a solute through a solvent swollen membrane from one solvent liquid phase to the extracting solvent liquid without direct contact between the liquid phases. The membrane extraction method has advantages over conventional solvent extraction and may be applied as the mechanism in separation, purification, pollutant removal and recovery processes.

Membrane solvent extraction

Novel membrane compositions are prepared from polymers comprising tertiary amine containing polyamideamine functional groups. The membranes are durable, highly selective and have excellent homogeneity and high diffusivity. Asymmetric membranes can be prepared by solution casting or melt processing techniques can be used to produce homogeneous, high performance, symmetric membranes. The specific compositions of the membranes can be adjusted so as to achieve a membrane possessing a required degree of hydrophilicity and porosity. These membranes may be used in a variety of separation applications, particularly in two-phase solvent extraction.

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Wharton, NJ, United States of America

Win-Sow Ho