Holding furnaces are used for a combination of continuous and batch type pyro-metallurgical processes in non-ferrous metals production lines, basically acting as a buffer for liquid metal.
The molten metal is transferred via launders or ladles into the furnace. The holding furnace can also be used as a settling furnace to separate the metal or matte and slag, which is separately tapped through two different tap holes. Feed ports for additives such as pig iron or silica and purging systems can be applied to enhance the process reactions. The furnaces are typically equipped with natural gas - or oil - oxygen burners to heat the furnace, which reduce the off gas volume and energy consumption compared to cold air burners. The burners are further used to adjust the furnace atmosphere to create an oxidizing or reducing furnace atmosphere. At the furnace door and tap holes hoods are optionally installed, which rotate together as part of the furnace structure to capture emissions in all relevant process positions.
To allow a save and reliable operation the furnaces are rotated into the different casting positions using an electric main drive acting via a pinion onto the main gear ring. in case of a power failure the furnace can be prated using either electrical, pneumatic or hydraulic emergency drives.
Holding furnaces allow to combine batch type processes with continuous operating production lines.
The units are equipped with tailor-made lining to assure a long lifetime. Each furnace is connected with an efficient off-gas treatment.