Steel Mill Operation

How Does a Steel Mill Work?

A steel mill, sometimes referred to as a steelworks plant, is where the steel alloy is created from carbon and iron. This production is done in two different stages and requires a number of specialized equipment. While steel production evolved over the years, once the steel mill became commonplace, the techniques used became the primary form of steel production and haven’t changed as radically as steel production techniques did in the prior years.

Step One

The first step in the two-step process requires iron ore. The ore is smelted in a blast furnace with limestone and a fuel called coke that is created from coal. This fuel is very high in carbon and has been used as far back as the 4th century in China. In the U.S., coke has been used since the 1800s.

Step Two

Now that the iron ore has been smelted, one of two things can be done with it. It can be made into pig iron, which is an intermediate product. Pig iron is very high in carbon and is very brittle. Because of this, it can’t really be directly used for anything. However, it can be saved and later melted down to be used in making steel. This is basically a way of creating a raw material for transport or for making large batches of steel later. If the iron is left molten, it can be directly used to create steel. In this phase, impurities like the large amount of carbon, phosphorus, and sulfur are removed from the alloy and other elements like nickel, vanadium, chromium, and manganese are added. The steel is then cooled and turned into ingots, blooms, sheets, and slabs through a variety of different techniques.

Integrated Steel Mills

Some steel mills simply take the processed pig iron and transform it into steel. These dedicated steel mills produce only steel, but an integrated steel mill can do everything in one space. These mills create iron, transform it into steel, cast the liquid steel into various forms, and then prepare the final product for shipment. Today, more and more mills are full integrated steel mills.

A Minimill

A mimimill is the term given for a secondary steel producer. These minimills acquire steel scraps from a number of places (automobiles, rubble from demolished buildings, etc.). They then recycle the steel by melting the scraps using an electric arc furnace. Once done, they recycled steel is cast into ingots or sheets.