It can be a complicated process trying to determine the benefits of different types of processing systems. One common dilemma is choosing between electronic arc furnaces (EAF) and blast furnaces.
There are benefits to both, but there can also be challenges with using one specific type of furnace and production method over the other. Understanding the differences is critical when considering changing an existing system or setting up a new plant.
The blast furnace is perhaps the most iconic image and symbolizes the metal industry. The furnace system is very large and involves multiple components that are very open and visible. It is certainly not a new technology and can be dated back to ancient China where the same method was used on a smaller scale in the production of metals.
However, these furnaces work slightly differently than they did 2000 years ago. Today, coke is used to melt the iron ore to create pig iron. Oxygen is then used to further transform the pig iron into steel. This process requires a continual supply of coke as well as very large furnaces that produce high CO2 emissions.
Electric Arc Furnaces
Electric arc furnaces (EAF) tend to be much smaller and more efficient in their operation. They don’t need a constant supply of coke. Instead, they use electricity passed through graphite electrodes to create an arc. These graphite electrodes must be superior quality to ensure correct, current flow through the rods to create the arc.
The metal is placed in a vat or a shell that is also used in forming the arc with the graphite electrodes, raising the temperature to as high as 3000 degrees Celsius for an efficient melting process.
The metal used with EAF is typically scrap metal or iron ore, but there are other possibilities. Controlling the temperature within the system is easier than a blast furnace, something that is important for efficiency. Another advantage of using the EAF process is that all types of steel can be created, including specialized metals and products.
In some operations, carbon electrodes may also be used. These carbon electrodes are also used to carry a high current, so they also have outstanding thermal conductivity. The choice of carbon electrodes is often found when working with calcium carbide, phosphorous, ferroalloys, or in the production of silicon.
For many plants, the lower cost of setup and the lower time to complete the process makes the EAF a very smart choice vs. a blast furnace in many types of processing facilities.