The raw material of steel

The source of steel is iron ore, that is, the existing form of iron element (FE) in nature. Pure iron does not exist in nature. Iron ore is mainly divided into magnetite, hematite and limonite, these are iron oxides. The difference lies in their oxidation way. The higher iron content in iron ore, the better. Theoretically, the highest iron content in iron ore is about 72%, and the iron content above 60% is called rich iron ore. The iron ore is first reduced into iron (milling iron) in the furnace, and then decarburized and refined into steel in the steelmaking furnace. The scrap can also be recycled in the steelmaking furnace. Generally, iron and steel are made into commodities with different properties and shapes according to their uses, which are called iron and steel products. Usually, iron and steel products are made by reducing iron ore, melting into milling iron (milling), refining milling iron into steel (steelmaking), rolling and processing steel into various iron and steel products. In a broad sense, iron and steel products include cast iron, cast steel, forged steel and steel processing products.
Before we discuss the raw materials of iron and steel, we need to find out what is the difference between steel and iron? Are there different ingredients? In daily life, people always associate steel with iron, which is called 'Steel'. It can be seen that steel and iron should be a kind of material. In fact, from a scientific point of view, steel and iron are slightly different. Their main composition is iron, but the amount of carbon is different. We usually call "pig iron" if the carbon content is more than 2%, and if the carbon content is lower than this value we called "steel". Therefore, in the process of smelting iron and steel, iron ore is first smelted into molten pig iron in blast furnace, and then molten pig iron is put into steel making furnace to refine into steel.
The raw materials needed for the production of iron and steel are divided into four categories to be discussed.