Search results
Results From The WOW.Com Content Network
Anode: Carbon anodes have a specific situation in aluminium smelting and depending on the type of anode, aluminium smelting is divided in two different technologies; “Soderberg” and “prebaked” anodes. Anodes are also made of petroleum coke, mixed with coal-tar-pitch, followed by forming and baking at elevated temperatures.
Primary aluminium smelting is the process of extracting aluminium from aluminium oxide (also known as alumina). The process takes place in electrolytic cells that are known as pots. The pots are made up of steel shells with two linings, an outer insulating or refractory lining and an inner carbon lining that acts as the cathode of the ...
The biogeochemical cycle of aluminum is integral with silicon and phosphorus. For example, phosphates store aluminum that has been sedimented and aluminum is found in diatoms (made of silica). Aluminum has been found to prevent growth in organisms by making phosphates less available. The humans/lithosphere ratio (B/L) is very low at 0.000011.
Aluminium (or aluminum in North American English) is a chemical element; it has symbol Al and atomic number 13. Aluminium has a density lower than that of other common metals, about one-third that of steel. It has a great affinity towards oxygen, forming a protective layer of oxide on the surface when exposed to air.
The Hall–Héroult process is the major industrial process for smelting aluminium. It involves dissolving aluminium oxide (alumina) (obtained most often from bauxite , aluminium 's chief ore, through the Bayer process ) in molten cryolite and electrolyzing the molten salt bath, typically in a purpose-built cell.
A Century Aluminum plant in Kentucky vented tons of perfluorocarbons, or PFCs, which are among the most potent and longest-lasting greenhouse gases on the planet.
The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide) and was developed by Carl Josef Bayer. Bauxite, the most important ore of aluminium , contains only 30–60% aluminium oxide (Al 2 O 3 ), the rest being a mixture of silica , various iron oxides , and titanium dioxide . [ 1 ]
The process consumes the anode at a rate of roughly 450 kg of anode per tonne of aluminium produced. [1] "Spent" anodes have little industrial use and are generally discarded; however, anodes that have been used to process aluminium fluoride may contain some amount of hydrogen fluoride and require hazardous waste disposal procedures. [2]