Process for removing copper deposits from surfaces

Claim 2

A PROCESS FOR REMOVING COPPER AND IRON OXIDE DEPOSITS FROM STEEL SURFACES WHICH CONSISTS ESSENTIALLY OF: CIRCULATING AN AQUEOUS ACID SOLUTION HAVING A PH IN THE RANGE OF ABOUT 1.5 TO ABOUT 5 AND CONTAINING AN HYDROXY CARBOXYLIC ACID, AN ACIDIC SALT OF SAID HYDROXY CARBOXYLIC ACID OR A MIXTURE OF SAID ACIDS AND SALTS INTO CONTACT WITH SAID SURFACES SO THAT THE COPPER AND IRON OXIDE DEPOSITS ARE DISSOLVED THEREIN, SAID HYDROXY CARBOXYLIC ACID OR ACIDIC SALT THEREOF HAVING THE GENERAL FORMULA:

Claim 3

The process of claim 1 wherein the said hydroxy carboxylic acid, acidic salt thereof or mixture of acid and acidic salt is present in said aqueous acid solution in an amount in the range of from about 0.5% by weight to saturation.

Claim 4

The process of claim 2 wherein said aqueous acid solution contains an hydroxy carboxylic acid selected from the group consisting of gluconic acid, glycolic acid, mucic acid, 2-hydroxy-butanedioic acid and citric acid.

Claim 5

The process of claim 2 wherein said aqueous acid solution contains an acidic salt of an hydroxy carboxylic acid selected from the group consisting of monoammonium citrate, monosodium gluconate and monopotassium malate.

Claim 6

The process of claim 2 wherein said substantially immiscible liquid having the property of preferentially extracting copper is selected from the group consisting of: an Alpha -hydroxy aliphatic oxime having the general formula:

Claim 7

The process of claim 5 wherein said substantially immiscible liquid having the property of preferentially extracting copper is further characterized to include a water immiscible organic solvent for said Alpha -hydroxy aliphatic oximes, substituted hydroxy benzophenoximes or mixtures thereof, said organic solvent being present in an amount in the range of from 0 to about 99.5% by weight of solution.

Claim 8

The process of claim 6 which is further characterized to include the step of removing copper from the separated extract liquid containing copper.

Claim 9

The process of claim 7 whErein the step of removing copper from the extract liquid comprises contacting said liquid with an aqueous acid solution so that copper is stripped therefrom.

Claim 10

A process for removing a copper deposit from a ferrous metal surface consisting essentially of: a first step of contacting said copper deposit with an aqueous solvent therefore to thereby produce a copper-containing solvent solution, a second step of contacting said copper-containing solvent solution in a first solvent extraction zone with a substantially immiscible liquid having preference for copper to remove at least a portion of said copper from said coper-containing solvent solution to thereby produce a first extract phase consisting essentially of said substantially immiscible liquid and copper and a first raffinate phase consisting essentially of said aqueous solvent, a third step of separating said first extract phase from said first raffinate phase, and a fourth step of contacting said copper deposit with said first raffinate phase, wherein said aqueous solvent is an aqueous solution containing an hydroxy carboxylic acid, an acidic salt of an hydroxy carboxylic acid or a mixture of said acids and salts, the hydroxy carboxylic acid or acidic salt thereof having the general formula

Claim 11

A process for removing a copper deposit from a ferrous metal surface consisting essentially of: a first step of contacting said copper deposit with an aqueous solvent therefore to thereby produce a copper-containing solvent solution, a second step of contacting said copper-containing solvent solution in a first solvent extraction zone with a substantially immiscible liquid having preference for copper to remove at least a portion of said copper from said coper-containing solvent solution to thereby produce a first extract phase consisting essentially of said substantially immiscible liquid and copper and a first raffinate phase consisting essentially of said aqueous solvent, a third step of separating said first extract phase from said first raffinate phase, and a fourth step of contacting said copper deposit with said first raffinate phase, wherein said aqueous solvent is an aqueous solution containing an hydroxy carboxylic acid, an acidic salt of an hydroxy carboxylic acid or a mixture of said acids and salts, the hydroxy carboxylic acid or acidic salt thereof having the general formula

Claim 12

The process of claim 9 further including a fifth step of contacting said first extract phase in a second solvent extraction zone with an aqueous inorganic acid having preference for copper to remove said copper from said first extract phase to thereby produce a second raffinate phase consisting essentially of said immiscible liquid, and a second extract phase consisting essentially of said copper dissolved in said aqueous inorganic acid, a sixth step of separating said second extract phase from said second raffinate phase, and a seventh step of contacting said copper-containing solvent solution in said first solvent extraction zone with said second raffinate phase.

Claim 13

The process of claim 10 wherein said inorganic acid is a mineral acid and is present in an amount in the range of from about 2% to about 30% by weight of solution.

Claim 14

The process of claim 9 wherein said hydroxy carboxylic acid, acidic salt thereof or mixture of acid and acidic salt is present in said aqueous solvent in an amount in the range of from about 0.5% by weight to saturation.

Claim 15

The process of claim 12 wherein said hydroxy carboxylic acid is selected from the group consisting of gluconic acid, glycolic acid, mucic acid, 2-hydroxy-butanedioic acid and citric acid.

Claim 16

The process of claim 12 wherein said acidic salt of said hydroxy carboxylic acid is selected from the group consisting of monoammonium citrate, monosodium gluconate and monopotassium malate.

Claim 17

The process of claim 13 wherein said substantially immiscible liquid having preference for copper is further characterized to include a water immiscible organic solvent for said Alpha -hydroxy aliphatic oximes, substituted hydroxy benzophenoximes or mixtures thereof, said organic solvent being present in an amount in the range of from 0 to about 99.5% by weight of solution.

Claim 18

The process of claim 15 wherein said water immiscible organic solvent is kerosene present in an amount in the range of from about 80% to about 98% by weight of solution.