Electricarc furnaces are relatively simple in operation. Massive electrodes are lowered into the furnace pot which is filled with the solid metal to be melted. Just at the point of contact an arc strikes between the electrodes and the metal, heating the metal to a liquid. The process is very power hungry - consuming 60 megawatts or more for a large furnace - but is often the preferred method for recycling scrap metal into new products.
The plasma cutting process (shown at the right) is a fast and efficient way to cut thick or very hard pieces of metal without the friction and wear that a mechanical process would have. A jet of inert gas or air is blown through a nozzle onto the work piece. The nozzle acts as one electrode and the work piece acts as the other. The jet of gas conducts the current, ionizing into an extremely hot plasma. The plasma jet then melts the metal and also blows it away, leaving the cut opening.
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