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The specific electrical resistance of the coke-type anodes is higher than that of the graphitized ones, but they have higher compressive strength and lower porosity. [ 10 ] Soderberg electrodes (in-situ baking), used for the first time in 1923 in Norway, are composed of a steel shell and a carbonaceous mass which is baked by the heat being ...
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.
Hall–Héroult process – Aluminium oxide (Al 2 O 3) is smelted with coke (C) in a high-temperature electrolysis reaction, yielding the desired pure aluminium (Al) and a mixture of CO and CO 2. Al 2 O 3 (s) + 3 C(s) → 2 Al(s) + 3 CO(g)
Efforts to find industrial use for spent anodes have led to proposals to use the anodes as a cost-effective alternative for coke in small-scale foundries that lack a ready supply of coke, and cannot afford modern electric furnaces.
Gas emission. Coke oven interior: detail (1942, USA). The coke oven is the central element of a coking plant. Horizontal ovens, which are the most commonly used (they are suitable for monitoring the various extraction stages), take the form of narrow compartments (approx. 50 cm wide), but several meters high and several meters deep.
The electrolysis reaction will produce molten pure iron as a main product and oxygen as its by-product. Because this process does not add coke in the process, no CO 2 gas is produced. So no direct greenhouse gas emission. Moreover, if the electricity to run such cells comes from renewable sources, this process may have zero emissions.
The Cowles process was the immediate predecessor to the Hall-Héroult process—today in nearly universal use more than a century after it was discovered by Charles Martin Hall and Paul Héroult and adapted by others including Carl Josef Bayer. Because of the patent landscape, the Cowles companies found themselves in court.
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