August 2008

Turning water into gold

New water treatment technologies: upping the ante for environmental sustainability

By D. Kratochvil

ChemSulphide™ treatment plant at Jiangix Copper Dexing mine

With the increasing focus on water management practices, the industry is quickly realizing the need for treatment options that will improve water quality to levels not attainable by technologies commonly in use today. A viable alternative being deployed recently is a new ion-exchange process that incurs comparatively lower capital and operating costs and does not produce a residual product that necessitates special disposal.

Jiangxi Copper Company, China’s largest copper producer, has deployed advanced processing technologies to treat metal-contaminated water at six of its mines. A BioteQ ChemSulphide™ treatment plant was recently commissioned at Jiangxi Copper’s Dexing mine in southeastern China, which produces 120,000 tonnes of copper concentrate annually. The new plant removes copper from mine wastewater, producing a high-grade copper product and leaving behind clean water that can be safely discharged to the environment or recycled into the mining process.

This process not only generates revenues from what has traditionally been considered waste product, but also eliminates the environmental liability associated with alternative processes. The technology has also been successfully deployed at five other plants in Canada, the United States and Australia, with more on the drawing board. BioteQ expects to produce more than 450,000 kilograms of copper annually from wastewater — a number that they expect to grow to approximately two million kilograms over time.

The first commercial-scale plant was built in 2001at the closed Caribou mine site in New Brunswick. Although small compared to today’s deployments, it showcased the commercial application of the technology and led to projects with Falconbridge (now Xstrata) at the active Raglan nickel operation in northern Quebec.

In 2007, the Raglan plant processed 920,000 cubic metres of water and prevented 12,500 kilograms of nickel from entering the pristine Arctic environment. Nickel was removed to less than 0.2 parts per million, well below the 0.5 parts per million required by regulators. Recovered nickel is sold to offset water treatment costs.

The groundswell to new water treatment technologies continues. Last year, for example, BioteQ plants treated 4.46 billion litres of contaminated water — averaging 12.2 million litres daily — enough to fill more than 1,700 Olympic-sized swimming pools. Two plants extracted more than 635,000 kilograms of metals (including copper and nickel) from wastewater within one year.

The move to more sustainable water treatment practices is no short-term experiment. The fact that large-scale operations worldwide are overhauling their treatment systems is a testament to the viability of these new processes.

David Kratochvil is the president and COO of BioteQ Environmental Technologies. He holds a doctorate in chemical engineering and is a specialist in wastewater treatment and chemical processing, with 15 years experience in plant design and operations around the world.

Post a comment


PDF Version