Aluminium Industry and Aluminium Production in Southern Africa
The Hillside Aluminium
Hillside ingot is renowned for its quality. The output of the smelter consists of P1015 and P0610, and a small quantity of P0507.
The Bayside Aluminium
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The use of the Bhp Billiton logo and name in no way implies any endorsement of Ali-tek Aluminium Cylinders by Bhp Billition. The Logo and Name use is only in the context of Bhp Billiton being an international supplier of the highest quality aluminium raw materials and their dominant position in the Southern African Aluminium industry.
South Africa is one of the worlds and Africas most important mining countries in terms of the variety and quantity of minerals produced. It has the worlds largest reserves of chrome, gold, vanadium, manganese and PGMs. South Africa is the Africa's biggest producer of primary aluminium.
The two smelters in Richards Bay - Bayside
and Hillside - together with a third
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 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 users 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.