The Electric Arc Furnace – Advantages & Deficiencies
This article is transferred from The Graphite Network
There is a lot of material covered. After reading the posts, you will be expert in the following topics:
- Advantages vs Disadvantages of EAF-use (part 1)
- history and UHP concept (part 2)
- Operation mode (part 3)
- EAF vs other furnaces (part 4)
- Construction (part 5)
Industrial arc furnaces range in size from small units of approximately one ton capacity (used in foundries for producing cast iron products) up to about 400 ton units used for secondary steelmaking) (average is 80 to 120 MT).
Arc furnaces used in research laboratories and by dentists may have a capacity of only a few dozen grams. Industrial electric arc furnace temperatures can be up to 1,800 °C (3,272 °F), while laboratory units can exceed 3,000 °C (5,432 °F).
The electric arc furnaces are the most widely used steel furnace around the world. It can be used to smelt high-quality steel and other special steels.
- capabable of producing the full range of steel grades
- not dependent on a particular type of charge (scrap, sponge, iron, pig iron, hot metal),
- low capital outlay,
- melting process can be programmed and automated
- high efficiency and flexibility
Another benefit is flexibility: while blast furnaces cannot vary their production by much and can remain in operation for years at a time, EAFs can be rapidly started and stopped, allowing the steel mill to vary production according to demand.
Although steelmaking arc furnaces generally use scrap steel as their primary feedstock, if hot metal from a blast furnace or direct-reduced iron is available economically, these can also be used as furnace feed.
As EAFs require large amounts of electrical power, many companies schedule their operations to take advantage of off-peak electricity pricing.
A typical steelmaking arc furnace is the source of steel for a mini-mill, which may make bars or strip product. Mini-mills can be sited relatively near to the markets for steel products, and the transport requirements are less than for an integrated mill, which would commonly be sited near a harbour for access to shipping.
The supply and the price of electricity become stable, which makes it possible to generalize the arc furnace;
- The arc furnace tends to be larger and more powerful;
- Less investment, quick to construct and fast cost recovery;
- The temperature and the component of the molten steel can be controlled with accuracy. The arc furnace can also smelt various kinds of different steels.Compared with others, the arc furnace also has several obvious advantages:
- The arc can heat the furnace and the steel up to 4000-6000℃directly and smelt special steels that contain refractory elements like W and Mo.
- The arc furnace could remove the toxic gases and the inclusions while deoxidizing and desulfurating.
- High flexibility. The arc furnace is capable of engaging production continuously or intermittently.
- Currently, owing to the development of related technologies, the electric arc furnaces could be well -integrated with traditional steel-making processes. But there are also several deficiencies
- The arc can only generate point-like heating sources, which will cause uneven heat distribution in the furnace.
- The arc will react with the furnace gases and vapor and release large quantities of H 2 and N 2.