A smelting pot is the container used to melt ore and other ingredients into a liquid that can be poured into molds to be given a working shape. Commonly created from very heavy cast iron and lined with brick, ceramic tile or some other type of heat barrier, the pot is able to withstand extreme heat for many smelting cycles without burning through or weakening. Heated in various matters, the smelting pot is often hung from large lugs cast into the sides of the pot. These lugs provide a tipping location that allows the pot to be tilted and poured. The pots often include a heavy lid or cover to aid in the fast heating of the contents.
Some of the smaller smelting pot designs are placed on or above a heating element to melt the contents. Commonly an electric or natural gas heating element will be used to bring the pot up to temperature. Some very small, single-use pots are simply placed on a small burner and heated until the contents can be poured into a sand mold. When using this type of pot, it is extremely critical that no water be in the vicinity of the smelting pot. One drop of water into a very hot pot of molten metal can cause the pot to explode and empty itself on everything and anyone in the vicinity.
Larger, industrial-size designs use a number of methods of heating the contents with electricity in one form or another being the method of choice for many pots. One design uses a coiled electric element to create the required heat to allow the smelting to be accomplished. Alternating electric current (AC) is applied to the heating coils, which begin to heat similar to an element in an electric kitchen oven. Many of these electric-powered smelting pot assemblies use a water-cooled design to eliminate overheating of the heating element.
The most common type of smelting pot in large industrial operations uses carbon rods charged by electric current to create super-high temperatures similar to a carbon arc torch or welder. The carbon rods create heat to the contents of the pot, creating a molten liquid that must have impurities skimmed from the top of the liquid metal prior to pouring the material into a mold. Limestone is commonly added to molten iron to bring the impurities to the surface. Workers use long steel ladles to pull the impurities from the top of the molten liquid.