Blast furnace
lastmod 2023-02-17created 2023-02-167 edits
A blast furnace is an industrial furnace used in metalworking for smelting to produce metals and alloys. Because it stands very tall compared to other furnaces (such as open-hearth furnaces), it is also called a shaft furnace.
Blast furnace process
The blast furnace is a method of making steel by melting iron ore in a hot furnace.
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Steel manufacturing via the blast furnace goes through the process of ironmaking (Korean: 제선) → steelmaking → rolling.
Iron ore, coke, and limestone are put into the furnace, and hot air at 1,200℃ is blown in. The process in which the coke burns in the hot air and the iron ore melts into molten iron is called ironmaking. This molten iron is the hot metal. It takes 5–6 hours for iron ore to become hot metal, and the temperature inside the furnace reaches 1,500℃. When the iron ore melts, due to the difference in specific gravity, the molten iron collects at the bottom of the furnace, while the remaining impurities combine with the limestone and float on top of the molten iron. The reason for adding limestone to the furnace is precisely to remove impurities, and this residue is called slag. Molten iron extracted from iron ore is brittle, hard to deform, and contains many impurities such as phosphorus (P) and sulfur (S). Therefore, it goes through the steelmaking process, which removes impurities from the molten iron and reduces the amount of carbon (C) to make steel. Rolling is the process of stretching or thinning the solid, semi-finished steel made from the clean molten iron into steel sheets of the desired thickness, and is divided into hot rolling and cold rolling.
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Because blast furnaces produce with large-capacity facilities, the barrier to entry is relatively high. They mainly produce flat products used in the automotive, shipbuilding, home appliance, and IT industries. They produce high-quality products with higher margins than electric furnaces, but have high construction costs and emit large amounts of air pollutants.
Domestic companies
The domestic (South Korean) companies that produce steel using blast furnaces are:
- POSCO
- Hyundai Steel
These are the two.
Hot-rolled steel sheet
- POSCO
- Hyundai Steel
- Dongbu Steel
- Dongkuk Industries
Cold-rolled steel sheet
- POSCO
- Hyundai Steel
- Dongbu Steel
- Dongkuk Steel
- Hyundai BNG Steel (HYUNDAI BNG STEEL)
Steel pipe
Steel pipe requires a relatively low quality level, so relatively many companies are in the market
- SeAH Steel
- Hyundai Special Steel (Hyundai Steel)
- Husteel
- Dongyang Steel Pipe
- Kumkang Kind
Wire rod
- POSCO
- Kosteel
- Chosun Sunjae
- SeAH Changwon Special Steel
- SeAH Besteel
Heavy plate
- POSCO
- Hyundai Steel
- Dongkuk Steel