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A furnace smelting lead uses a reduction reaction; it generates an off-gas containing carbon monoxide, similar to blast furnace gas, which needs to be disposed of, usually by flaring. In contrast to a conventional blast furnace used to make iron, lead metal or copper matte and slag were run off more or less continuously.
Smelting involves more than just melting the metal out of its ore. Most ores are the chemical compound of the metal and other elements, such as oxygen (as an oxide), sulfur (as a sulfide), or carbon and oxygen together (as a carbonate). To extract the metal, workers must make these compounds undergo a chemical reaction.
16th century cupellation furnaces (per Agricola). Cupellation is a refining process in metallurgy in which ores or alloyed metals are treated under very high temperatures and subjected to controlled operations to separate noble metals, like gold and silver, from base metals, like lead, copper, zinc, arsenic, antimony, or bismuth, present in the ore.
The pig iron was melted in a running out furnace and then run out into a trough. This process oxidized the silicon to form a slag, which floated on the iron and was removed by lowering a dam at the end of the trough. The product of this process was a white metal, known as finers metal or refined iron.
The advantage of the induction furnace is a clean, energy-efficient and well-controlled melting process, compared to most other means of metal melting. Most modern foundries use this type of furnace, and many iron foundries are replacing cupola furnaces with induction furnaces to melt cast iron, as the former emit much dust and other pollutants ...
In the morning, however, take out the gold and melt it again, hammer it, and put it into the furnace as before. After another day and night take it out again, mix a little red copper with it, melt as before, and put it back into the furnace. And when you have taken it out a third time, wash it and carefully dry it.
The blast furnace was the next step in smelting iron which produced pig iron. [4] The first blast furnaces in Europe appeared in the early 1200s around Sweden and Belgium, and not until the late 1400s in England. The pig iron poured from a blast furnace is high in carbon making it hard and brittle, making it hard to work with.
A metallurgical furnace, often simply referred to as a furnace when the context is known, is an industrial furnace used to heat, melt, or otherwise process metals. Furnaces have been a central piece of equipment throughout the history of metallurgy ; processing metals with heat is even its own engineering specialty known as pyrometallurgy .