Bateman Engineering markets the Galvanox copper-leach technology

Bateman Engineering N.V. has been granted the exclusive rights by the University of British Columbia (UBC) to market, in about 20 countries, its Galvanox technology, which offers several potential advantages over existing copper-leach processes.

With this novel atmospheric leaching process, copper recoveries of 98 % or greater can be achieved at 80°C under atmospheric conditions, thus obviating the need for high-cost pressure-leach autoclaves. With a residence time of as little as four hours, the processing capacity of the leaching circuit is also increased. The process is selective for chalcopyrite over pyrite, making it applicable to low grade or bulk concentrates, and thus offering a distinct recovery advantage over smelting. Furthermore, it generates near-quantitative levels of elemental sulphur in less than 24 hours, and is fully compatible with conventional solvent extraction and electrowinning of pure copper (LME Grade A) cathodes.

In the Galvanox process, ferric sulphate is used to leach copper from concentrates containing a mixture of copper sulphides, but particularly those containing chalcopyrite (CuFeS₂). The process takes advantage of the galvanic couple between pyrite and chalcopyrite to ensure rapid oxidation of chalcopyrite under mild conditions in the acidic iron (ferric sulphate) solution, without the need for microbes, ultrafine grinding, or chemical additives such as chloride, nitrate or surfactants.

Normally the surface of the chalcopyrite becomes passive in ferric-sulphate solutions and this has limited its use in copper leaching circuits. The inventors of the Galvanox technology, Dr David Dixon and Mr Alain Tshilombo, however, found that this passivation may be overcome by the addition of a pyrite catalyst to the leach liquor so that near complete dissolution of the copper can be achieved many times faster than has been possible up to now.

The process offers several other potential advantages over existing processes including the fact that the leach liquor is a pure sulphate medium with a relatively low propensity to corrode the process vessels, equipment and piping. Elemental sulphur rather than sulphate is generated, facilitating waste treatment, and the process also operates below the melting point of sulphur and therefore requires no surfactants

As part of the programme to assist UBC commercialise the Galvanox technology, for which patents have been filed in several countries, Bateman Engineering is commissioning pilot-plant studies on batches of chalcopyrite concentrate sourced from several of the existing producers of concentrate.

Under the terms of the marketing agreement, Bateman Engineering will also develop a business plan for the Galvanox technology and actively promote and pursue opportunities for commercial application within the nominated exclusive territories. Bateman Engineering will prepare all the technology-supply packages for proposed projects and in each case will assist UBC and the end users to negotiate licenses for project-implementation services at end-user sites.

Further information about the agreement between UBC and Bateman Engineering may be obtained from Steve Burks, Chief Technology Officer, Bateman Engineering, on +27-11-899-9111 or email technology@BatemanEngineering.com.

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