Steel is one of the most recyclable products and scrap is recycled steel waste. This is mainly used in Electric Arc Furnaces and Induction Furnaces. Main sources for scrap are America, Europe, Australia and certain parts of Africa and Asia and about 470 – 520 million tonnes of scrap is used annually.
Pig iron is the intermediate product of smelting iron ore with a high-carbon fuel such as coke, usually with limestone as a flux. Charcoal and anthracite have also been used as fuel. Pig iron has a very high carbon content, typically 3.5–4.5%, which makes it very brittle and not useful directly as a material except for limited applications.
Traditionally pig iron would be worked into wrought iron in finery forges, and later puddling furnaces, more recently into steel. In these processes, pig iron is melted and a strong current of air is directed over it while it is being stirred or agitated. This causes the dissolved impurities (such as silicon) to be thoroughly oxidized. An intermediate product of puddling is known as refined pig iron. Pig iron can also be used to produce gray iron. Pig irons are useful to dilute all elements in a ductile iron charge (except carbon) which may be harmful to the ductile iron process.
Direct-reduced iron (DRI), also called sponge iron, is produced from direct reduction of iron ore (in the form of lumps, pellets or fines) by a reducing gas produced from natural gas or coal. The reducing gas is a mixture of hydrogen (H2) and carbon monoxide (CO) which acts as reducing agent. This process of directly reducing the iron ore in solid form by reducing gases is called direct reduction. Direct Reduced Iron is consumed primarily by mini steel mills (which can melt only rich sources of metal, such as steel scrap, but not iron ore) to improve the quality of their steel.
Hot Briquetted Iron (HBI), is a high density steel industry raw material containing 90-94% total iron (Fe) in a nearly pure form.
Used as a supplement for pig iron and scrap which are used in various types of furnaces for iron making and foundry applications.