On the territory of Belarus people learned to extract iron in the era of the Iron Age (7th century BC - 5th century AD). Metallurgy of the time was based on the production of local iron (marsh) ores by cheese-making method. Charcoal, dried and crushed ore with limestone was loaded into layers in a special furnace-house. Through a special clay tube nozzle with the help of bellows artificially injected air. A high temperature was created in the combustion chamber - up to 1200 ° C. In the form of fine softened grains, which were sintered among themselves, iron was deposited on the bottom of the furnace. The resulting flash iron was not yet suitable for use, therefore, in the future, it was reheated again and forged with hammers to remove slags and make the metal more dense. The mass of crits depended on the volume of the melting furnace and could reach several kilograms. Under archaeological excavations of settlements and settlements there is often under-processed waste iron - formless solid pieces of metal with slag inclusions. One of the critics was found by Valentin Alexandrovich Bulkin in Polotsk in 1977 during an archaeological study of the Upper Castle. This copy is in the form of a piece of sponge iron scientists refer to the 11-13th centuries. This item is presented in the exposition of the Museum of Local Lore.
