Liquid ion exchange process for the recovery of metals

Claim 2

A CONTINUOUS ION EXCHANGE PROCESS FOR THE SELECTIVE RECOVERY OF COPPER AND ZINC FROM AN AMMONIACAL AMMONIUM CARBONATE LEACH SOLUTION IN WHICH ZINC AND COPPER ARE CONTINUOUSLY ADDED TO THE LEACH SOLUTION AND RECOVERED WITHOUT BUILD-UP OF ZINC IN THE LEACH SOLUTION, THE PROCESS COMPRISING: A. CONTACTING THE LEACH SOLUTION IN AN ION EXCHANGE CIRCUIT FOR COPPER WITH A WATER IMMISCIBLE ORGANIC PHASE COMPRISING A COPPER SELECTIVE ION EXCHANGE AGENT IN AN ORGANIC DILUENT, B. RECYCLING A BLEED PORTION OF THE AQUEOUS PHASE CONTAINING COPPER AND ZINC FROM THE ION EXCHANGE CIRCUIT TO THE LEACH SOLUTION TO MAINTAIN THE CUPRIC-CUPROUS RATIO THEREIN AT AN ACTIVE LEACHING LEVEL, C. RECOVERING ZINC FROM THE REMAINDER OF THE AQUEOUS PHASE AT A RATE SUBSTANTIALLY EQUAL TO THE RATE OF ADDITION OF ZINC TO THE LEACH SOLUTION TO PREVENT BUILD-UP OF ZINC IN THE LEACH SOLUTION. D. RECYCLING THE RAFFINATE FROM STEP (C) TO THE LEACH SOLUTION, AND E. RECOVERING COPPER FROM SAID ORGANIC PHASE.

Claim 3

The process of claim 1 in which said ion exchange extractant is a benzophenoxime.

Claim 4

The process of claim 1 in which said zinc is recovered from said remainder of the aqueous phase by solvent extraction with di 2-ethyl hexyl phosphoric acid.

Claim 5

The process of claim 1 in which zinc is recovered from said remainder of the aqueous phase by boiling off ammonia.

Claim 6

The process of claim 1 in which zinc is recovered from said remainder of the aqueous phase by adding carbon dioxide.

Claim 7

The process of claim 1 in which substantially all of the remainder of copper is removed from said remainder of aqueous phase before removal of zinc therefrom and recycle of the barren raffinate to the leach solution.

Claim 8

The process of claim 6 in which the remainder of copper is removed by contacting said remainder of aqueous phase with barren organic phase resulting from stripping copper from said ion exchange agent.

Claim 9

The process of claim 7 to which is added the following steps: f. stripping copper from said ion exchange agent with a stripping agent for copper, g. recovering copper from the stripping agent, and, h. recycling the barren ion exchange agent from step (f) to step (a) after contacting it with said remainder of aqueous phase.

Claim 10

A continuous countercurrent ion exchange process for the selective recovery of copper and zinc from an ammoniacal ammonium carbonate leach solution in which process the cupric-cuprous ratio of the leach solution is maintained at an active leaching level and the copper is recovered in the presence of zinc without build-up of zinc in the leach solution, the process comprising the following operations performed continuously and simultaneously with the aqueous and organic phases passing countercurrent to each other: a. continuously adding copper and zinc containing feed to the leach solution in a leaching stage to provide an aqueous phase containing copper and zinc ions, b. flowing said aqueous phase to a first copper recovery stage and recovering copper from said aqueous phase by ion exchange by contacting said aqueous phase countercurrently with a water immiscible organic phase comprising a copper selective ion exchange agent in an organic diluent, c. recycling a bleed portion of said aqueous phase from the first copper recovery stage of step (b) to the leaching stage to maintain the cupric-cuprous ratio of said leach solution at an active leaching level, d. passing the pregnant organic phase to a copper stripping stage to strip copper from the organic phase leaving the organic phase substantially barren, e. recycling the barren organic phase to said first copper recovery stage where it is again loaded with copper, f. passing the remainder of said aqueous phase to a zinc recovery stage to recover zinc therefrom at a rate substantially equal to the rate of addition of zinc to the leach solution to prevent build-up of zinc in the leach solution, and g. recycling spent raffinate from said zinc recovery stage to said leaching stage, whereby as zinc and copper are continuously added to said leach solution the cupric-cuprous ratio in said leaching solution is continuously maintained at an active leaching level and zinc is continuously removed from said leach solution at a rate substantially equal to its rate of introduction to prevent zinc build-up in the leach solution.

Claim 11

A continuous countercurrent ion exchange process for the selective recovery of copper and zinc from an ammoniacal ammonium carbonate leach solution in which process the cupric-cuprous ratio of the leach solution is maintained at an active leaching level and the copper is recovered in the presence of zinc without build-up of zinc in the leach solution, the process comprising the following operations performed continuously and simultaneously with the aqueous and organic phases passing countercurrent to each other: a. continuously adding copper and zinc containing feed to the leach solution in a leaching stage to provide an aqueous phase containing copper and zinc ions, b. flowing said aqueous phase to a first copper recovery stage and recovering copper from said aqueous phase by ion exchange by contacting said aqueous phase countercurrently with a water immiscible organic phase comprising a copper selective ion exchange agent in an organic diluent, c. recycling a bleed portion of said aqueous phase from the first copper recovery stage of step (b) to the leaching stage to maintain the cupric-cuprous ratio of said leach solution at an active leaching level, d. passing the pregnant organic phase to a copper stripping stage to strip copper from the organic phase leaving the organic phase substantially barren, e. recycling the barren organic phase to said first copper recovery stage where it is again loaded with copper, f. passing the remainder of said aqueous phase to a zinc recovery stage to recover zinc therefrom at a rate substantially equal to the rate of addition of zinc to the leach solution to prevent build-up of zinc in the leach solution, and g. recycling spent raffinate from said zinc recovery stage to said leaching stage, whereby as zinc and copper are continuously added to said leach solution the cupric-cuprous ratio in said leaching solution is continuously maintained at an active leaching level and zinc is continuously removed from said leach solution at a rate substantially equal to its rate of introduction to prevent zinc build-up in the leach solution.

Claim 12

The process of claim 9 including at least one additional copper recovery stage immediately following said first copper recovery stage and the continuous countercurrent circulation of said remainder of aqueous phase and said barren organic phase therethrough before the organic phase is returned to said first copper recovery stage.