Iron and Steel

Summary

Steel is a crucial material, with an annual production of 600 million tonnes, used across various industries, from transport to construction. The process begins with extracting iron from ores using coke and limestone in a blast furnace. Molten iron is then refined into steel in the basic oxygen steelmaking process, where impurities are removed through oxygen injection. The steel is shaped into products either through molding or continuous casting and is further processed by rolling into final forms. Essential raw materials like iron ores, coal, and limestone play a vital role in this process.

Takeaways

• 😀 Steel is the most important metal globally, with an annual production of about 600 million tonnes.
• 😀 Steel is used in a wide range of products, playing a fundamental role in transportation and construction.
• 😀 Iron is extracted from its ores in a blast furnace by heating with coke and limestone.
• 😀 The basic oxygen steelmaking process (BOS) converts molten iron into steel by reducing carbon and impurities.
• 😀 Iron is processed in four blast furnaces on site, where coke is made in ovens and sintering occurs.
• 😀 The essential raw materials for iron production are iron ores, coal, and limestone.
• 😀 Coke is produced by heating coal for 18 hours, driving off gases, tar, and ammonia, leaving carbon.
• 😀 Sintering blends iron ore, coke, and limestone, and creates sinter, which enhances furnace efficiency.
• 😀 In the blast furnace, a mixture of coke, sinter, ore, and limestone is heated to produce molten iron and slag.
• 😀 Slag, a byproduct of iron production, is used in cement and road building after solidification.
• 😀 In the BOS process, molten iron undergoes oxygen injection to reduce carbon and impurities, forming steel.
• 😀 Steel can be cast into ingots or continuous forms, with rolling processes shaping the final steel products.

Q & A

What is the primary metal used in various industries, and how much is produced annually?

Steel is the primary metal used across various industries, with an annual production of about 600 million tonnes.

Why is steel considered fundamental to transport and construction?

Steel is essential for transport and construction because it is one of the basic building materials used for both interior and exterior applications.

What are the main ingredients used in the process of making steel?

The primary raw materials used in steel production are iron ore, coke, and limestone.

How is iron extracted from its ore in the blast furnace?

Iron is extracted from its ores in a blast furnace by heating the ores with coke and limestone, where carbon monoxide reduces the iron oxide in the ore to molten iron.

What role does coke play in the blast furnace process?

Coke serves as both a fuel and a reducing agent in the blast furnace. It burns to produce heat and carbon monoxide, which helps reduce the iron ore to molten iron.

What is the purpose of limestone in the blast furnace?

Limestone decomposes to calcium oxide in the blast furnace, which reacts with impurities in the iron ore to form slag, helping to purify the molten iron.

How is molten iron transported after being produced in the blast furnace?

Molten iron, referred to as hot metal, is tapped from the blast furnace into torpedo ladles, which can hold up to 300 tonnes of molten iron.

What is slag, and what is its use after steel production?

Slag is a byproduct of the steelmaking process, consisting of impurities like calcium silicate. It floats on top of the molten iron and is tapped out. Once cooled and solidified, it can be used in cement production and road building.

What happens in the Basic Oxygen Steelmaking (BOS) process?

In the BOS process, molten iron is refined by injecting a high-speed jet of oxygen to reduce its carbon content, along with the addition of lime to help form slag and remove impurities.

How is steel solidified after the Basic Oxygen Steelmaking process?

After the BOS process, the steel is solidified either by pouring it into molds to form ingots or through continuous casting, where it is cooled and shaped into various forms.