South Africa is one of the world’s and Africa’s most important mining countries in terms of the variety and quantity of minerals produced. It has the world’s largest reserves of chrome, gold, vanadium, manganese and PGM’s. South Africa is the Africa's biggest producer of primary aluminium.

The two smelters in Richards Bay - Bayside and Hillside - together with a third
aluminium smelter situated in Mozambique Mozal comprise Aluminium Southern Africa (ASA), the combined aluminium interests of BHP Billiton. Together these three smelters produce in excess of one million tons of aluminium per annum. They are three separate entities belonging to BHP Billiton, the worlds largest diversified resources company.

Hillside, together with Bayside and Mozal, provide primary aluminium for global markets. Hillside produces re-melt merchant product whilst Bayside provides value-added products to downstream manufacturers. Hillside boasts a facility that now produces t-bars and the capacity to produce rim alloy, in addition to its current primary aluminium ingots.

South Africa's potential lies in finished product exports, import replacement and in local niche markets based on a sophisticated industry led by Hulett Aluminium and Hulett-Hydro.

Aluminium Production

Aluminium is produced in reduction plants or smelters, where pure aluminium is extracted from alumina using the Hall-Héroult process.

The Hall-Héroult process is used all over the world, and is the only method of aluminum smelting currently used in the industry. Today, there are two primary technologies using the Hall-Héroult process: Soderberg and prebake. Soderberg uses a continuously created anode made by addition of "pitch" to the top of the anode. The lost heat from the smelting operation is used to bake the pitch into the carbon form required for reaction with alumina. Prebake technology is named after its anodes, which are baked in very large gas-fired ovens at high temperature before being lowered by various heavy industrial lifting systems into the electrolytic solution. In both technologies, the anode, attached to a very large electrical bus, is slowly used up by the process. Prebake technology tends to be very slightly more efficient, but is more labor intensive. Prebake technology is becoming preferred in the industry because of the various pollutant emissions related to the creation of the anode from liquid pitch.

Reduction of Alumina to Form Aluminium

The reduction of alumina into aluminium takes place at around 950 degrees Celsius in a fluorinated bath under very high intensity electrical current. This process takes place in electrolytic cells or pots, where carbon cathodes form the bottom of the pot and act as the negative electrode. Anodes are held at the top of the pot and are consumed during the process when they react with the oxygen coming from the alumina. All potlines built since the early 1970s use the prebake anode technology, where the anodes, manufactured from a mixture of petroleum coke and coal tar pitch, are pre-baked in separate anode plants. In the Soederberg technology, the carbonaceous mixture is fed directly into the top part of the pot, where self-baking anodes are produced using the heat released by the electrolytic process.

Aluminium Alloying and Casting

At regular intervals, molten aluminium tapped from the pots is transported to the cast house where it is alloyed in holding furnaces by the addition of other metals according to the user’s needs, cleaned of oxides and gases, and then cast into ingots. These can take the form of extrusion billets, for extruded products, or rolling ingots, for rolled products, depending on the way it is to be further processed.

Aluminium Extrusion Billet

BHP Billiton is a significant, if not dominating, force in the South African and Brazilian billet market. Production, in total is approximately 50,000 Mt per year, in Brazil (Valesul) and South Africa (Bayside) is almost entirely destined to service the domestic markets. Local marketing teams are in close contact with consumers to supply quality products and services.

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