x Abu Dhabi, UAEFriday 21 July 2017

The processing of aluminium, from rock to metal

Tom Arnold goes behind the scenes to discover the beating heart of the UAE's aluminium industry.

Rows of kilns filled with a baking-hot powdery substance stand under a 1.2km-long corrugated metal roof on the edge of the desert at Al Taweelah.

This is the nerve-centre of the smelter operated by Emirates Aluminium (Emal).

Pipelines help to fill 576 kilns - known as reduction cells - with alumina, a powder refined from crushed bauxite rocks. As many smelters do, Emal ships its alumina in from Australia and other places where bauxite is abundant.

The alumina comes in on ships docking at the nearby Khalifa Port and is transferred to giant silos for storage.

Firing at more than 900°C, each reduction cell uses electrolysis to yield 2.5 tonnes of liquid aluminium a day, about half the weight of the alumina that goes in.

A short distance from the reduction stage is the next step in the process - casting. In the casting area, newly created molten aluminium is sent into giant cauldrons called crucibles, each holding as much as 12 tonnes. The crucibles are poured into holding furnaces that help mould the metal into the final aluminium products and into various shapes and sizes, as desired by customers.

Stacked in a large open yard are the finished products. They include billet, a piping used mainly in the construction industry. Sheeting, another product, is neatly cut and trimmed into huge slabs weighing up to 30 tonnes. This form of the metal will mainly be used for packaging such as cans and foils.

There is also sow aluminium, large chunks of the metal for general use. That kind of aluminium is typically bought by extruders and casting companies that form it into items including car parts and window frames.

In the final touch, the bulk aluminium products are stamped "Made in Abu Dhabi, UAE". Then they are ready for market.

About 85 per cent of the aluminium is shipped to Europe, Asia and North America. The remainder is trucked to destinations in the UAE, mainly for use in construction.

Operations at the smelter will pick up significantly once plans to double the production capacity at the site are approved in June.

 

tarnold@thenational.ae