Revolving Furnace
Revolving furnaces consist of horizontal wrought-iron cylinders lined with fire-brick, one end of which communicates with a fireplace and the other to a chimney, which, being revolved on rollers as the flame passes through the interior, permits a thorough mixing of the mass and exposes every portion of the material to the action of the heat. This description of furnace is principally employed for roasting, desulphurizing, and chloridizing ores. The Danks and other furnaces of a rotary kind are used for puddling purposes, and consist of the fixed fireplace and bridge, but, instead of the regular bed, a revolving hearth through which the flames are made to pass to the chimney is used for melting the metal. The molten metal, being spread over the interior by the rotary action of the chamber, is brought in contact with the lining, which, being composed of iron ore, acts in conjunction with the oxygen of the furnace gases to oxidize the carbon and silicon contained in the iron. The spongy mass of malleable iron produced is readily lifted out and conveyed to the squeezers after the movable end has been taken away for this purpose. See PUDDLING-FURNACE; MALLEABLE IRON.