New technology to process copper without smelting

13th of 11, 2012
A plant is under construction in the once-thriving copper-mining area of the Northern Cape that will make use of a new low-power South African-developed technology that is able to process stranded copper ore concentrates into 98%-pure copper crystals without the need for any smelting.Cuperex’s first plant, under construction, will have a capacity to produce 200 t of copper a month, and on the drawing board is its second plant, planned as a 1,000 t-a-month plant.

The plants can be scaled to match even the smallest of deposits, which are beneficiated to anode-grade copper at the mine site and which means that high-value copper rather than low-value ore is transported.

“Our process of turning concentrate into pure copper is completely new in the industry,” Cuperex CEO Dave Lake explained to the media, which witnessed copper crystals being harvested at the South African company’s demonstration plant, after watching the developer of the technology, Cuperex executive director Dr Gerard Pretorius, growing and harvesting copper crystals hydrometallurgically at desktop scale.

Traditional conversion of concentrate into copper requires significantly more capital expenditure, more electricity and equipment and therefore has to be matched by large resources to recoup the capital cost.In contrast, the Cuperex technology can turn a throughput of as little as 50 t a month to positive account, irrespective of the location.

Cuperex intends elevating itself into a copper producer through the roll-out of the world-patented technology, which is a radical departure from the conventional electro-winning method of copper processing.The simple hydrometallurgical process generates only gypsum as a waste product and has received an environmental thumbs up.It uses scrap metal as a reagent, but without any of the complications commonly associated with cementation, and is equally applicable to sulphide ore and oxide ore.The copper produced has a low oxygen content, which improves its malleability.

A key element of the commercial value of the technology is its modular design, which renders it scalable and quick to construct.With the groundwork of developing, testing and establishing the technology completed, Cuperex is currently working with partners to render its plants mobile so that they can be moved to new resources as existing ones deplete.The company is processing enquiries from copper deposit owners in Zambia, Botswana, Namibia, the Democratic Republic of Congo and Armenia.
Pretorius stumbled on the technology while searching for a way to extract copper from left-over jewellery-grade malachite.He described the process as essentially “tank farming”, making it possible to establish operational plants in six months and allowing the employment of relatively lower-skilled personnel to run the system.He said the copper crystals grown on the scrap metal in tanks were harvested through a pumping action carried out at eight-hour intervals.

Cuperex intends working with mining partners, consultants, joint venture partners and third-party service providers to plan, cost, implement and operate mining operations.The company aims to change the way small, remote copper deposits are viewed, exploited and valued, and is ready to work with ore owners and concentrate producers to convert their ores or concentrates into high-grade copper at the mine face. stablished miners,” a senior official said.

The company is positioned to be a copper maker and it will not be renting or selling its technology.It sees its role as producing copper on site from the many small copper deposits that characterise the Northern Cape and Limpopo and working internationally to provide low-capital solutions to the production of high-grade copper from moderate ore deposits.It expects to be producing copper from dumps, heap leaches, tailings dams and oxides stockpiled on surface by copper producers focused on the deeper copper sulphide ores.

It also intends working with copper exploration companies to use its technology to exploit measured copper resources and sees itself as potentially developing the technology further to replace or supplement the smelter sections of large copper plants, and halving electricity consumption at the same time.

(Edited from an article by Martin Creamer posted at miningweekly.com)
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