Bloomery

A bloomery is a type of furnace that was once widely used for smelting oxides. Bloomeries were the first smelters that could smelt iron.  

The result of using a bloomery is a mass of iron and slag called a bloom. This is called sponge iron, because it is porous like a sponge. Sponge iron is usually refined into wrought iron. 

Bloomeries are no longer used in smelting because blast furnaces are better.

 History 
Humans first began to use iron around 1200 BC.

People were using bloomeries in Sub-Saharan Africa before 500 BC.

China appeared not to use bloomeries, seemingly skipping to blast furnaces. Some bloomeries have been found in China, but these were likely brought from other locations, and not built in China.

European bloomeries started very small, smelting about 1kg of iron with each use, but got larger over time. By the 14th century, bloomeries smelted about 14kg per use on average.
 Process 
A bloomery consists of a chimney with heat-resistant walls made of earth, clay, or stone. Near the bottom, pipes made of clay or metal enter through the side walls. These pipes allow air to enter.

To use a bloomery, charcoal is inserted into the chimney, then heated. Then roughly the same volume of iron is inserted. A common byproduct of this process is fayalite, which is created when iron mixes with slag.

Category:Iron