The Process of Steel Production

Have you ever taken a moment to observe the objects around you and wonder what they are made of? Everything that surrounds you is composed of different materials. Have you ever considered the various components that make up these objects? For instance, are the fibers beneath your feet made of carpet? Is the seat you’re sitting on constructed from wood or plastic?

Steel is another commonly used material found worldwide. It can be found in the pots and pans used for cooking, as well as in household appliances, vehicles, bridges, and even buildings. However, steel does not grow on trees—it is a metal derived from beneath the Earth’s surface. Interestingly, steel is not listed as an element on the periodic table of elements, but its primary component, iron, is.

Iron is mined from various locations across the globe. However, iron ore usually contains impurities such as silica, phosphorus, and sulfur, which weaken its structure. To transform iron into steel, these impurities must be removed and carbon must be added to enhance its strength.

Steel is classified as an alloy, which is a combination of two or more metallic elements. Ferrous metals, which contain iron, include steel. On the other hand, non-ferrous metals, such as aluminum, copper, and titanium, do not contain iron.

The process of steel production involves smelting, which is the extraction of metal from ore by heating it to extremely high temperatures until it melts. Historians believe that rudimentary furnaces have been used for steel production for thousands of years. However, advancements in technology during the 17th to 19th centuries, such as the invention of blast furnaces, led to the production of higher quality steel on a larger scale.

Today, most steel plants use a production method called basic oxygen steelmaking (BOS). In BOS furnaces, high-purity oxygen is blown through molten iron ore. The oxygen reacts with impurities to form oxides, which either burn off or become slag, a by-product that can be removed from the surface of the molten iron. Additionally, other chemical cleansers known as fluxes are added to eliminate impurities. Furthermore, various elements can be added to create specific types of steel. Carbon, for example, is commonly added to produce high-strength carbon steel. Chromium is another popular additive that enhances the rust resistance of stainless steel.

Steel is widely used in construction due to its strength and relatively low production cost. Annually, steel plants produce over 1.3 billion tons of steel, which is utilized in the construction of buildings, ships, vehicle frames, bridges, appliances, weapons, and machinery.

Give It a Try

We trust that this Wonder of the Day has helped develop a SOLID understanding of steel! Make sure to explore the following activities with a companion:

  • Wouldn’t it be fascinating to witness steel being manufactured in person? Actually, it would be extremely hot! Steel factories are not suitable for children, so instead, watch this online Steelmaking Video to gain more knowledge about the process!
  • Which items do you possess in your house that are made of steel? Find out! Take a pen and paper and search for steel objects around the house. Create a list of all the steel items you discover. Don’t forget to check the garage if you have one! Share your list with a companion. Can they come up with any items you missed?
  • Stainless steel is a popular material because it doesn’t corrode. But what exactly is corrosion? And why do materials corrode? To learn more, explore the experiments in The Chemistry of Rust online. Make sure to seek assistance from an adult companion.

Sources of Wonder

  • http://science.howstuffworks.com/iron4.htm
  • http://www.keenovens.com/articles/steel-furnance.htm
  • http://sciencewithkids.com/science-facts/facts-about-steel.html

FAQ

1. How is steel made?

Steel is made through a process called steelmaking, which involves the extraction of iron from iron ore and the addition of other materials to create the desired properties. The most common method of steelmaking is the basic oxygen furnace (BOF) process. In this process, iron ore is heated in a blast furnace and the impurities are removed to produce molten iron. The molten iron is then transferred to the BOF, where oxygen is blown through the molten iron to remove impurities and lower the carbon content. Alloying elements such as manganese, chromium, and nickel are added to achieve specific properties. The molten steel is then cast into various forms such as slabs, billets, or sheets, depending on its intended use.

2. What are the raw materials used in steelmaking?

The main raw materials used in steelmaking are iron ore, coal, and limestone. Iron ore is the primary source of iron and is mined from the earth in large quantities. Coal is used as a fuel and a reducing agent to convert iron ore into iron. Limestone is added to remove impurities and act as a flux during the steelmaking process. Other materials such as scrap steel, alloying elements, and fluxes may also be used depending on the specific requirements of the steel being produced.

3. What is the role of the blast furnace in steelmaking?

The blast furnace plays a crucial role in steelmaking as it is where the iron ore is converted into molten iron. The blast furnace is a tall, cylindrical structure made of steel and lined with refractory bricks. It operates at a high temperature of around 1500 degrees Celsius. Inside the blast furnace, iron ore, coke (derived from coal), and limestone are loaded from the top. The coke acts as a fuel and provides the heat needed to melt the iron ore. As the materials descend through the furnace, the coke reacts with the oxygen in the iron ore to produce carbon monoxide. This carbon monoxide then reacts with the iron ore to reduce it to molten iron. The impurities in the iron ore combine with the limestone to form slag, which floats on top of the molten iron and is removed.

4. What are the different types of steelmaking processes?

There are several different types of steelmaking processes, including the basic oxygen furnace (BOF) process, the electric arc furnace (EAF) process, and the open-hearth furnace process. The BOF process, as mentioned earlier, is the most common method and involves the use of oxygen to remove impurities from molten iron. The EAF process uses electricity to melt scrap steel and other raw materials, which are then refined to produce the desired steel. The open-hearth furnace process, which is less common nowadays, involves the burning of fuel in a furnace to melt iron and scrap steel. Each of these processes has its advantages and disadvantages and is used depending on factors such as cost, energy efficiency, and the type of steel being produced.

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