Extraction of metals with diquaternary amines

A method for recovering Pd and Pt metals from a spent catalyst comprising:

• dissolving the metals into an acidic solution to form metal anion complexes;
• contacting the acidic solution with an iodide;
• separating the iodide from the acidic solution, wherein the Pd anion complex is bound to the iodide;
• contacting the acidic solution with an organic solution including a diquaternary amine, wherein the distance between two diquaternary nitrogens is less than about 10 Å;
• selectively binding the Pt anion complex to the diquaternary amine;
• and
• separating the organic solution from the aqueous solution, wherein the diquaternary amines having the bound Pt anion complex are concentrated in the organic solution.

A method for recovering palladium from an aqueous solution, comprising:

• contacting the aqueous solution with an iodide and an organic solvent;
• allowing the palladium to bind to the iodide;
• and then
• separating the organic solution from the aqueous solution, wherein the iodide having the bound palladium ions are concentrated in the organic solution.

A method for selectively extracting one or more metal anion complex from an aqueous solution, the method comprising:

• contacting the aqueous solution with a diquaternary amine, wherein the distance between two diquaternary nitrogens is less than about 10 Å;
• binding the one or more metal anion complex to the diquaternary amine;
• and then
• separating the diquaternary amine from the aqueous solution, wherein the diquaternary amine is bound to a solid surface of an inert substrate.

A method for recovering valuable metals comprising:

• a. dissolving the metals into an acidic solution;
• b. contacting the acidic solution with an iodide;
• c. separating the iodide from the acidic solution, wherein Pd is bound to the iodide;
• d. contacting the acidic solution with a first organic solution including a first diquaternary amine, wherein the distance between two diquaternary nitrogens is less than about 10 Å and wherein the first diquaternary amine is a selective extractant for a second valuable metal;
• e. selectively binding the second valuable metal anions to the first diquaternary amine;
• and then
• f. separating the organic solution from the aqueous solution, wherein the first diquaternary amine has the selectively bound second valuable metal anions concentrated in the organic solution.
• g. repeating steps d through f, using a second diquaternary amine to selectively extract a third valuable metal.