Traditional steel mills typically use a blast furnace-converter production model. However, to achieve environmental protection goals, electric arc furnaces have emerged, eliminating the blast furnace and all processes preceding it, retaining only the processes after steelmaking. This not only reduces carbon emissions but also manpower, and significantly lowers output, making it unsuitable for large-scale production.
In some countries, steel mills, when discussing carbon reduction, immediately think of electric arc furnaces. These furnaces, which smelt steel directly from scrap, save even more energy, eliminating the need for coal and coke. This reduces the consumption of traditional energy sources and, to some extent, carbon emissions. The only requirement is a significant amount of electricity, but electricity can be obtained from a wide variety of sources, so strictly speaking, it is indeed a relatively energy-efficient method.
The traditional blast furnace model (the blast furnace is the main link in ironmaking) involves a long process from raw materials. First, it is necessary to purchase raw materials such as ore, coke, and coal. After these raw materials arrive at the plant, they may need to go through processes such as mixing, sintering, pelletizing, and coking. These investments are huge, the production process is very long, and the number of personnel required ranges from several hundred to several thousand.
The most crucial element of this model, the blast furnace, represents a massive investment. In terms of both investment and operating costs, it constitutes a major portion of a steel plant’s expenses. This is because the blast furnace is a relatively mature production model, and after centuries of development, many blast furnaces still boast excellent economic indicators. As for carbon emissions, these are unavoidable.
However, its advantages are also clear: it can be produced continuously and on a large scale. The volume of blast furnaces ranges from 450 to 6000 cubic meters, and their output is directly proportional to their volume. Moreover, a series of operations of blast furnaces can be automated, making them relatively easy and labor-saving to operate.
However, the fundamental drawback is that with the continuous investment in and construction of new blast furnaces, their volume is constantly increasing, making it difficult to control output and ultimately leading to severe overcapacity. The main reason for this is the unrestricted expansion of blast furnace capacity. As long as the output of molten iron produced by blast furnaces is sufficient, the capacity of subsequent converter steelmaking must also keep up, resulting in a huge increase in output and creating a vicious cycle.
Blast furnaces and electric arc furnaces are essentially the same type of process; blast furnaces are for ironmaking, and electric arc furnaces are for steelmaking. Many people feel that there is no point in comparing them. However, steelmaking does not necessarily require molten iron. The currently touted low-carbon metallurgy directly advocates using electric arc furnaces to smelt scrap steel. In the traditional smelting method, scrap steel was added during the converter smelting process to increase output. Now, molten iron is no longer needed; the scrap steel is directly heated and smelted using an electric arc furnace.
Speaking of electric arc furnaces, they were once ubiquitous, but due to their high power consumption, many were shut down in recent years. Now, with the promotion of low-carbon practices, it seems like it’s time for electric arc furnaces to make a comeback. The reason is that there are now many ways to obtain electricity, such as solar, wind, and hydropower, all of which are relatively clean energy sources. Therefore, electric arc furnaces are now being labeled as low-carbon metallurgy.
Putting all that aside, it’s true that a lot of manpower can be reduced in steel mills. Compared to the traditional blast furnace model, at least the processes before converter smelting are eliminated, which can reduce manpower by at least 80%. If steel mills are keen on reducing manpower, this should be a good option, but output will also have to be reduced.
Currently, using electric arc furnaces for the production of ordinary steel is not actually very cost-effective, because the output is limited and the supply of scrap steel is also a major problem. It is only suitable for small-scale production of a single product and is difficult to reach a scale of millions or tens of millions of tons.
