Enhanced cobalt recovery from ammoniacally leached reduced ores using cyanide, hydrazine, or hydroxylamine compounds

Claim 2

IN A REDUCED AMMONICAL LEACHING PROCESS FOR THE RECOVERY OF NICKEL AND COBALT VALUES FROM AN ORE WHICH COMPRISES TREATING A SLURRY CONSISTING OF (A) A SOLID PHASE COMPRISING A REDUCED COBALT CONTAINING ORE AND (B) A LIQUID PHASE COMPRISING AN AQUEOUS AMMONICAL SOLUTION HAVING A PH ABOVE 7, WITH A GAS CONTAINING ELEMENTAL OXYGEN IN AT LEAST ONE LEACHING STAGE TO SOLUBILIZE NICKEL AND COBALT VALUES OF THE ORE IN THE LIQUID PHASE OF THE SLURRY, AND THEN WASHING THE SLURRY WITH AN AMMONIACAL WASHING SOLUTION IN AT LEAST ONE WASHING STAGE, WITHOUT PASSING A GAS CONTAINING ELEMENTAL OXYGEN THROUGH THE SLURRY DURING THE WASHING STAGE, TO RECOVER A PRODUCT LIQUOR CONTAINING THE SOLUBILIZED NICKEL AND COBALT VALUES: THE IMPROVEMENT FOR ENHANCHING THE SOLUBILITY OF THE COBALT VALUES OF THE ORE IN THE LIQUID PHASE OF THE SLURRY WHICH COMPRISES PROVIDING IN THE SLURRY, DURING THE WASHING STAGE, A NITROGENOUS COMPOUND SELECTED FROM THE GROUP CONSISTING OF HYDRAZINE AND A SOLUBLE SALT OF HYDRAZINE, WHEREIN THE AMOUNT OF THE COMPOUND IN THE SLURRY IS

Claim 3

In a reduced ammoniacal leaching process for the recovery of nickel and cobalt values from an ore which comprises treating a slurry consisting of (a) a solid phase comprising a reduced cobalt containing ore and (b) a liquid phase comprising an aqueous ammoniacal solution having a pH above 7, with a gas containing elemental oxygen in at least one leaching stage to solubilize nickel and cobalt values of the ore in the liquid phase of the slurry, and then washing the slurry with an ammoniacal washing solution in at least one washing stage, without passing a gas containing elemental oxygen through the slurry during the washing stage, to recover a product liquor containing the solubilized nickel and cobalt values: the improvement for enhancing the solubility of the cobalt values of the ore in the liquid phase of the slurry which comprises providing in the slurry, during the washing stage, a nitrogenous compound selected from the group consisting of hydroxylamine and a soluble salt of hydroxylamine, wherein the amount of compound in the slurry is sufficient to provide a hydroxylamine content, expressed as NH2OH, of from about 0.01 to 10% of the total weight of slurry.

Claim 4

In a reduced ammoniacal leaching process for the recovery of nickel and cobalt values from an ore which comprises treating a slurry consisting of (a) a solid phase comprising a reduced cobalt containing ore and (b) a liquid phase comprising an aqueous ammoniacal solution having a pH above 7, with a gas containing elemental oxygen in at least one leaching stage to solubilize nickel and cobalt values of the ore in the liquid phase of the slurry, and then washing the slurry with an ammoniacal washing solution in at least one washing stage, without passing a gas containing elemental oxygen through the slurry during the washing stage, to recover a product liquor containing the solubilized nickel and cobalt values: the improvement for enhancing the solubility of the cobalt values of the ore in the liquid phase of the slurry which comprises providing in the slurry, during the washing stage, a nitrogenous compound selected from the group consisting of hydroxylamine and a soluble salt of hydroxylamine, wherein the amount of compound in the slurry is sufficient to provide a hydroxylamine content, expressed as NH2OH, of from about 0.01 to 10% of the total weight of slurry.

Claim 5

In a reduced ammoniacal leaching process for the recovery of nickel and cobalt values from an ore which comprises treating a slurry consisting of (a) a solid phase comprising a reduced cobalt containing ore and (b) a liquid phase comprising an aqueous ammoniacal solution having a pH above 7, with a gas containing elemental oxygen in at least one leaching stage to solubilize nickel and cobalt values of the ore in the liquid phase of the slurry, and then washing the slurry with an ammoniacal washing solution in at least one washing stage, without passing a gas containing elemental oxygen through the slurry during the washing stage, to recover a product liquor containing the solubilized nickel and cobalt values: the improvement for enhancing the solubility of the cobalt values of the ore in the liquid phase of the slurry which comprises providing in the slurry, during the washing stage, a nitrogenous compound selected from the group consisting of hydrazine and a soluble salt of hydrazine, said compound being provided in an amount effective to enhance the solubility of the cobalt values of the ore in the liquid phase of the slurry, without subjecting the slurry to a reductive carbonylation.

Claim 6

In a reduced ammoniacal leaching process for the recovery of nickel and cobalt values from an ore which comprises treating a slurry consisting of (a) a solid phase comprising a reduced cobalt containing ore and (b) a liquid phase comprising an aqueous ammoniacal solution having a pH above 7, with a gas containing elemental oxygen in at least one leaching stage to solubilize nickel and cobalt values of the ore in the liquid phase of the slurry, and then washing the slurry with an ammoniacal washing solution in at least one washing stage, without passing a gas containing elemental oxygen through the slurry during the washing stage, to recover a product liquor containing the solubilized nickel and cobalt values: the improvement for enhancing the solubility of the cobalt values of the ore in the liquid phase of the slurry which comprises providing in the slurry, during the washing stage, a nitrogenous compound selected from the group consisting of hydrazine and a soluble salt of hydrazine, said compound being provided in an amount effective to enhance the solubility of the cobalt values of the ore in the liquid phase of the slurry, without subjecting the slurry to a reductive carbonylation.

Claim 7

In a reduced ammoniacal leaching process for the recovery of nickel and cobalt values from an ore which comprises treating a slurry consisting of (a) a solid phase comprising a reduced cobalt containing ore and (b) a liquid phase comprising an aqueous ammoniacal solution having a pH above 7, with a gas containing elemental oxygen in at least one leaching stage to solubilize nickel and cobalt values of the ore in the liquid phase of the slurry, and then washing the slurry with an ammoniacal washing solution in at least one washing stage, withhout passing a gas containing elemental oxygen through the slurry during the washing stage, to recover a product liquor containing the solubilized nickel and cobalt values: the improvement for enhancing the solubility of the cobalt values of the ore in the liquid phase of the slurry which comprises providing in the slurry, during the washing stage, a nitrogenous compound selected from the group consisting of hydroxylamine anD a soluble salt of hydroxylamine, said compound being provided in an amount effective to enhance the solubility of the cobalt values of the ore in the liquid phase of the slurry, without subjecting the slurry to a reductive carbonylation.

Claim 8

In a reduced ammoniacal leaching process for the recovery of nickel and cobalt values from an ore which comprises treating a slurry consisting of (a) a solid phase comprising a reduced cobalt containing ore and (b) a liquid phase comprising an aqueous ammoniacal solution having a pH above 7, with a gas containing elemental oxygen in at least one leaching stage to solubilize nickel and cobalt values of the ore in the liquid phase of the slurry, and then washing the slurry with an ammoniacal washing solution in at least one washing stage, withhout passing a gas containing elemental oxygen through the slurry during the washing stage, to recover a product liquor containing the solubilized nickel and cobalt values: the improvement for enhancing the solubility of the cobalt values of the ore in the liquid phase of the slurry which comprises providing in the slurry, during the washing stage, a nitrogenous compound selected from the group consisting of hydroxylamine anD a soluble salt of hydroxylamine, said compound being provided in an amount effective to enhance the solubility of the cobalt values of the ore in the liquid phase of the slurry, without subjecting the slurry to a reductive carbonylation.

Claim 9

In a reduced ammoniacal leaching process for the recovery of nickel and cobalt values from an ore which comprises treating a slurry consisting of (a) a solid phase comprising a reduced cobalt containing ore and (b) a liquid phase comprising an aqueous ammoniacal solution having a pH above 7, with a gas containing elemental oxygen in at least one leaching stage to solubilize nickel and cobalt values of the ore in the liquid phase of the slurry, and then washing the slurry with an ammoniacal washing solution in at least one washing stage, without passing a gas containing elemental oxygen through the slurry during the washing stage, to recover a product liquor containing the solubilized nickel and cobalt values: the improvement for enhancing the solubility of the cobalt values of the ore in the liquid phase of the slurry which comprises providing in the slurry, during the washing stage, a nitrogenous compound selected from the group consisting of hydrazine and a soluble salt of hydrazine, said compound being provided in an amount effective to enhance the solubility of the cobalt values of the ore in the liquid phase of the slurry.

Claim 10

In a reduced ammoniacal leaching process for the recovery of nickel and cobalt values from an ore which comprises treating a slurry consisting of (a) a solid phase comprising a reduced cobalt containing ore and (b) a liquid phase comprising an aqueous ammoniacal solution having a pH above 7, with a gas containing elemental oxygen in at least one leaching stage to solubilize nickel and cobalt values of the ore in the liquid phase of the slurry, and then washing the slurry with an ammoniacal washing solution in at least one washing stage, without passing a gas containing elemental oxygen through the slurry during the washing stage, to recover a product liquor containing the solubilized nickel and cobalt values: the improvement for enhancing the solubility of the cobalt values of the ore in the liquid phase of the slurry which comprises providing in the slurry, during the washing stage, a nitrogenous compound selected from the group consisting of hydrazine and a soluble salt of hydrazine, said compound being provided in an amount effective to enhance the solubility of the cobalt values of the ore in the liquid phase of the slurry.

Claim 11

The process of claim 5 wherein the washing step employs a plurality of countercurrent washing stages to counter-currently wash the slurry wherein the ammoniacal washing solution is first fed to the final washing stage, in which the nitrogenous compound is provided in the slurry by adding the compound to the ammoniacal washing solution.

Claim 12

In a reduced ammoniacal leaching process for the recovery of nickel and cobalt values from an ore which comprises treating a slurry consisting of (a) a solid phase comprising a reduced cobalt containing ore and (b) a liquid phase comprising an aqueous ammoniacal solution having a pH above 7, with a gas containing elemental oxygen in at least one leaching stage to solubilize nickel and cobalt values of the ore in the liquid phase of the slurry, and then washing the slurry with an ammoniacal washing solution in at least one washing stage, without passing a gas containing elemental oxygen through the slurry during the washing stage, to recover a product liquor containing the solubilized nickel and cobalt values: the improvement for enhancing the solubility of the cobalt values of the ore in the liquid phase of the slurry which comprises providing in the slurry, during the washing stage, a nitrogenous compound selected from the group consisting of hydroxylamine and a soluble salt of hydroxylamine, said compound being provided in an amount effective to enhance the solubility of the cobalt values of the ore in the liquid phase of the slurry.

Claim 13

In a reduced ammoniacal leaching process for the recovery of nickel and cobalt values from an ore which comprises treating a slurry consisting of (a) a solid phase comprising a reduced cobalt containing ore and (b) a liquid phase comprising an aqueous ammoniacal solution having a pH above 7, with a gas containing elemental oxygen in at least one leaching stage to solubilize nickel and cobalt values of the ore in the liquid phase of the slurry, and then washing the slurry with an ammoniacal washing solution in at least one washing stage, without passing a gas containing elemental oxygen through the slurry during the washing stage, to recover a product liquor containing the solubilized nickel and cobalt values: the improvement for enhancing the solubility of the cobalt values of the ore in the liquid phase of the slurry which comprises providing in the slurry, during the washing stage, a nitrogenous compound selected from the group consisting of hydroxylamine and a soluble salt of hydroxylamine, said compound being provided in an amount effective to enhance the solubility of the cobalt values of the ore in the liquid phase of the slurry.

Claim 14

The process of claim 7 wherein the washing step employs a plurality of countercurrent washing stages to counter-currently wash the slurry wherein the ammoniacal washing solution is first fed to the final washing stage, in which the nitrogenous compound is provided in the slurry by adding the compound to the ammoniacal washing solution.