SX technology has existed for more than 50 years, and is considered an economical route for the production of high-quality cobalt cathode.

Solvents extract and upgrade metal ions from leached solutions through various stages and tanks, which then become a concentrated electrolyte, and deposits pure cobalt onto cathodes by using an electrolytic process in the electrowinning phase.

South African company MC Process developed the Luita SX plant and is contracted to supply processes and process equipment to Camec’s copper/cobalt operations in the DRC.

Because cobalt only plates when no other metal impurities are present in the solution, MC Process designed a ‘constant velocity impeller’, which is a unique design for the mixers, as well as a new tank design that mirrors the shape of the impellers.

“In keeping with our philosophy from day one of the copper/cobalt project in the DRC, Camec has taken the road less travelled by identifying small, innovative companies, that think out of the box and have been able to come up with efficient new ways to apply old technologies in record time,” says Camec subsidiary Boss Mining MD Laurent Décalion.

Boss Mining is managing the DRC mining operations.

Luita is the first plant that will employ this technology worldwide.

Camec started copper winning at the Luita plant in February, which is ten months after the start of the project. Camec expects the plant to produce 30 000 t of copper cathode this year.

The company says, “It would normally take two to three years for a project like this to move from the design phase to live copper winning, and such rapid deployment of a plant of this size in such a remote location is an achievement.”

By 2009/10 copper cathode production will have ramped up to Camec’s target of 100 000 t/y.

Camec notes that a key factor for this achi-evement is rapid access to raw copper, which is made possible through the heap-leaching process.

“Our heap-leaching process is a major departure from the way other mining companies in the DRC are doing its extraction. They are approaching it in the traditional way by using flotation or tank leaching.

“We opted for heap leaching for a number of reasons. The heap-leaching process allows for the production of 99% copper cathodes without using SX technology to increase the grade. Our ore is ideal for this approach, because it is extremely pure and, therefore, acid consumption is very low. Another reason is that heap leaching allows us to move rapidly from extraction to production, compared with traditional methods. Costs associated with heap leaching are also moderate,” he adds.

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