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Some myths about DC arc furnaces
| Content Provider | Semantic Scholar |
|---|---|
| Author | Sager, D. A. |
| Copyright Year | 2011 |
| Abstract | DC arc furnaces are widely used for steel scrap melting as well as for reductive smelting of ore fines. Industrial smelting applications include the smelting of chromite to produce ferrochromium, the smelting of ilmenite to produce titania slag and pig iron, and the recovery of cobalt from non-ferrous smelter slags. A number of myths and misconceptions are widely held, especially regarding: the age of the technology, the use of a hollow electrode, arc stability and shape, arc and bath radiation, interaction between the arc and molten slag, electrical behaviour of arcs and slags, a comparison between AC and DC furnaces, DC reactors, the lifespan of bottom electrodes, and the applicability of DC arc furnaces to various metallurgical systems. DC arc furnaces have been known by various names over the years. In this paper, a 'DC arc furnace' refers to a pyrometallurgical vessel that comprises a cylindrical steel shell with either a domed or flat base, and a roof that is typically conical. It is lined inside with a refractory material in order to contain the molten materials being processed. The furnace usually has a central graphite electrode (maybe more than one, but that is not the specific focus of this paper), and an anode imbedded in the hearth. It is usual that the molten metal in the furnace is in electrical contact with the anode. Energy is supplied to the furnace by means of an open plasma arc that impinges on the upper surface of the molten material. The arc in a DC (direct current) furnace is a sustained high-velocity high-temperature jet, driven by electromagnetic acceleration (the Maecker effect) in the constricted region near the arc's root on the electrode surface. The arc is generated by the interaction between the fluid flow, the thermal field, and the electromagnetic fields. The self-constricting electromagnetic forces keep this supersonic super-heated plasma jet reasonably coherent. A DC reactor is used to stabilize the arc further. Furthermore, the surface of the molten bath (or at least a portion of the surface in the arc- attachment zone) is open, i.e. essentially uncovered by unreacted feed material. |
| Starting Page | 665 |
| Ending Page | 674 |
| Page Count | 10 |
| File Format | PDF HTM / HTML |
| Volume Number | 111 |
| Alternate Webpage(s) | http://www.mintek.co.za/Pyromet/Files/2011Jones1.pdf |
| Alternate Webpage(s) | http://www.scielo.org.za/pdf/jsaimm/v111n10/v111n10a04.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
