Aluminium Holding Furnace With Cast Crucible
fig-1
Silcarb manufactures Aluminum holding Furnace using high-density calcium silicate boards as the metal contact material. These Furnaces use Silicon Carbide heating elements as their main heat source.
These are highly energy-efficient Furnaces and are the preferred choice for Aluminum filtration and holding applications.
Aluminum Holding Furnace with Roof(Top) Heating
One of the basic disadvantages with the crucible type furnace is the expensive ceramic crucible which is a consumable.
Another disadvantage is the limitation of the quantity of aluminum these crucible furnaces can hold as the capacity of the ceramic crucible has a limitation and in general, the reliability of the ceramic crucible drops with an increase in size.
In plants where there is no frequent change in the alloy(the crucible furnace is a better option when the alloy changes often)the monolithic cast crucible furnace that silcarb manufactures is the Ideal choice.
These furnaces can be made from small-hold capacities of 500kgs up to larger capacities 2000 kgs.
Isometric view (fig-2)
Internal view (fig-3)
The furnace construction is typically made of three chambers where the molten metal is poured in the rear chamber, the central chamber holds the liquid to the required temperature and the third chamber allows for drawing out of metal.
Most of silcarb’s furnaces have a filter installed below the liquid level in order to retain all oxides in the central holding area.
An option silicon nitride lance pipe is provided in-between the holding and the tap out area for continues online degassing.
An optional immersion heater is provided in the tap out area to boost the temperature if required which drastically reduces the dross formation in the holding chamber.
The charging door in the rear is typically pneumatically actuated. The central hold zone top cover can be hydraulically lifted to clean all corners of the holding area for dross build up during routine maintenance.
These furnace linings typically achieve a life cycle of 7 years with no expensive consumables.
The refractory linings used by silcarb for these electric/gas-fired holding furnaces are not only “non -wetting” but also insulating in nature, thereby achieving high energy efficiency.
When these furnaces are electric silcarb uses silicon carbide heating elements as its heat source with a radiant tube covering it in order to ensure the heating element has a long life without being affected by fumes coming out of the molten metal. These radiant tubes are made of ceramics that have the highest thermal conductivity, hence having only a marginal effect on energy consumption.
The heaters used would be loaded to the lowest surface load possible to ensure long life and also the heaters which are overhanging are made of a single piece which is non-jointed.
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