New or unused resin beads.

Resin beads after many cycles of use.

The AuGMENT process is compact and efficient and can be fitted into most existing plants in an uncomplicated and environmently friendly manner.

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Technology to recover copper, gold and cyanide

Bateman Engineering Inc. has an agreement with AuGMENT Technologies to promote AuGMENT’s patented technology for the recovery of copper, gold and cyanide through BATEMAN’s worldwide marketing network. AuGMENT Technologies is a joint venture between E. I. DuPont de Nemours and Co. with Newmont Mining Co.

The AuGMENT process is applied to cyanide leach liquors and involves extracting copper and cyanide on a commercially available resin. It works with copper-gold ores or concentrates, in either heap leach or mill applications. It can be applied to enhance the economic viability of several processes involving the treatment of copper- and gold-containing materials in cyanide solutions.

The technology is based on the recovery and recycling of 95 % of the cyanide and typically reduces the cyanide discharge levels in the tailings stream to between 5 and 50 ppm. This minimises the cost of replenishing the cyanide and also the cost of producing a tailings stream which meets environmental requirements by eliminating the need for detoxification or by reducing the cost of cyanide destruction.

The AuGMENT process works as follows. A commercial strong-base ion exchange resin is used to selectively extract both copper cyanide and cyanide (as free cyanide ion and weak acid dissociable cyanide) from the solution or slurry. This is accomplished in one or more stages, depending upon the cyanide concentration in the feed solution.

Copper recovery is facilitated by pairing the elution column with a patented electrowinning step during which copper is plated onto starter sheets or stainless steel plates. The oxidation of cyanide during electrowinning is prevented by the use of a Nafion TM membrane at the anodes, enhancing cyanide recovery and safety.

Contact with dilute sulphuric acid then regenerates the resin and recovers the cyanide which is immediately allowed to react with lime slurry to produce a calcium cyanide solution for recycling to the process plant. As a result no gaseous cyanide emissions occur.

The process parameters are flexible and can be selected to handle the type of feed solution to the AuGMENT plant, the type of copper product required and the concentration of the cyanide stream needed to make up the water balance of the plant. Process testing is done by means of preliminary testing of ores and analysis of process solutions and permits an evaluation of the potential economics. The process capital and operating costs can be accurately estimated by pilot plant studies.

For further details, please contact Dr Peter Spencer, General Manager, Gold, on +61-9316-6905 or e-mail gold@batemanengineering.com.

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