Selective stripping process

Claim 2

A process for selectively removing nickel from a water-immiscible organic oxime extractant containing copper and nickel which comprises contacting said oxime extractant with an aqueous acid solution containing an acid of the type which forms a water soluble nickel salt when reacted with nickel, said contacting of said extractant and said acid solution causing nickel ion transfer from the oxime extractant to the aqueous solution and hydrogen ion transfer from the aqueous solution to the oxime extractant in accordance with the equation: (R*2Ni)organic + 2(H )aqueous -> (2R*H)organic + (Ni )aqueous, where R* is the oxime organic moiety, the mole ratio of hydrogen ion in the aqueous solution to nickel ion in the oxime extractant being maintained between about 1.8 and 2.2.

Claim 3

The process of claim 1 wherein the aqueous acid solution contains sulfuric acid as a source of exchangeable hydrogen iOn.

Claim 4

The process of claim 1 wherein the aqueous acid solution contains sulfuric acid, boric acid and nickel and wherein pure nickel is recovered from the aqueous acid solution after contacting the oxime extractant by electrowinning.

Claim 5

The process of claim 1 wherein the oxime comprises 2-hydroxy-4-nonyl-benzophenoxime.

Claim 6

The process of claim 2 wherein the oxime comprises 2-hydroxy-4-nonyl-benzophenoxime.

Claim 7

The process of claim 3 wherein the oxime comprises 2-hydroxy-4-nonyl-benzophenoxime.

Claim 8

The process of claim 1 wherein the oxime extractant consists essentially of a. a benzophenoxime of the formula

Claim 9

The process of claim 1 wherein the oxime extractant comprises an Alpha -hydroxy oxime of the formula:

Claim 10

The process of claim 1 wherein the oxime comprises 5,8 -diethyl -7- hydroxy -6- dodecanone oxime.

Claim 11

The process of claim 2 wherein the oxime comprises 5,8 -diethyl -7- hydroxy -6- dodecanone oxime.

Claim 12

The process of claim 3 wherein the oxime comprises 5,8 -diethyl -7- hydroxy -6- dodecanone oxime.

Claim 13

A PROCESS FFOR SELECTIELY REMOVING NICKEL FROM A WATERINIMMISCIBLE ORGANIC OXIME EXTRACTANT LOADED WITH COPPER AND NICKEL COMPRISING INTRODUCING SAID EXTRACTANT INTO A FIRST OF A PLURALITY OF STRIPPING STAGES AND FLOWING SAID EXTRACTANT THROUGH SAID PLURALITY OF STRIPPING STAGES TO A LAST STRIPPING STAGE, INTRODUCING AN AQUEOUS ACID SOLUTION CONTAINING AN ACID OF THE TYPE WHICH FORMS A WATER SOLUBLE NICKEL SALT WHEN REACTED WITH NICKEL INTO SAID LAST STAGE AND FLOWING SAID AQUEOUS ACID SOLUTION COUNTERCURENT TO THE FLOW OF SAID EXTRACTANT THROUGH SAID STAGES, THE MOLE RATIO OF HYDROGEN ION IN THE AQUEOUS SOLUTION INTRUDCED AT SAID LAST STAGE TO NICKEL ION IN THE OXIME EXTRACTANT INTRODUCED AT SAID FIRST STAGE BEING MAINTAINED BETWEEN THE RANGE OF ABOUT 1.8 TO 2,2, THE MOLE RATIO OF HYDROGEN ION IN THE AQUEOUS SOLUTION TO NICKEL ION IN THE OXIME EXTRACTANT BEING CHOSEN TO CAUSE NICKEL ION IN THE OXIME EXTRACTANT TO TRANSFER TO THE AQUEOUS SOLUTION IN PREFERENCE TO COPPER ION WITH HYDROGEN ION IN THE AQUEOUS SOLUTION TRANSFERRING TO THE OXIME EXTRACTANT TO REPLACE THE NICKEL ION TRANSFERRED THEREFROM.

Claim 14

A PROCESS FFOR SELECTIELY REMOVING NICKEL FROM A WATERINIMMISCIBLE ORGANIC OXIME EXTRACTANT LOADED WITH COPPER AND NICKEL COMPRISING INTRODUCING SAID EXTRACTANT INTO A FIRST OF A PLURALITY OF STRIPPING STAGES AND FLOWING SAID EXTRACTANT THROUGH SAID PLURALITY OF STRIPPING STAGES TO A LAST STRIPPING STAGE, INTRODUCING AN AQUEOUS ACID SOLUTION CONTAINING AN ACID OF THE TYPE WHICH FORMS A WATER SOLUBLE NICKEL SALT WHEN REACTED WITH NICKEL INTO SAID LAST STAGE AND FLOWING SAID AQUEOUS ACID SOLUTION COUNTERCURENT TO THE FLOW OF SAID EXTRACTANT THROUGH SAID STAGES, THE MOLE RATIO OF HYDROGEN ION IN THE AQUEOUS SOLUTION INTRUDCED AT SAID LAST STAGE TO NICKEL ION IN THE OXIME EXTRACTANT INTRODUCED AT SAID FIRST STAGE BEING MAINTAINED BETWEEN THE RANGE OF ABOUT 1.8 TO 2,2, THE MOLE RATIO OF HYDROGEN ION IN THE AQUEOUS SOLUTION TO NICKEL ION IN THE OXIME EXTRACTANT BEING CHOSEN TO CAUSE NICKEL ION IN THE OXIME EXTRACTANT TO TRANSFER TO THE AQUEOUS SOLUTION IN PREFERENCE TO COPPER ION WITH HYDROGEN ION IN THE AQUEOUS SOLUTION TRANSFERRING TO THE OXIME EXTRACTANT TO REPLACE THE NICKEL ION TRANSFERRED THEREFROM.

Claim 15

The process as set forth in claim 12 wherein a nickel rich aqueous solution is flowed from said first stage to a nickel recoveRing zone and the aqueous acid solution is introduced into said last stage after the nickel values therein are removed.

Claim 16

The process as set forth in claim 13 wherein the substantially nickel free organic extractant loaded with copper is flowed from said last stage to a copper stripping stage.

Claim 17

The process as set forth in claim 14 wherein the acid in said aqueous acid solution is an acid selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid and mixtures thereof and wherein said oxime extractant is an oxime selected from the group consisting of 2-hydroxy-4-nonyl-benzophenoxime and 5,8 - diethyl -7- hydroxy -6- dodecanone oxime.