Ways of reducing the use of resources: Metals can be recycled by melting and recasting or reforming into different products. The amount of separation required for recycling depends on the material and the properties required of the final product. For example, some scrap steel can be added to iron from a blast furnace to reduce the amount of iron that needs to be extracted from iron ore.

The idea

Recycling a metal means melting it so it can be recast or reformed into a new product, rather than extracting fresh metal from its ore. How much sorting is needed first depends on the scrap and on what the new product must do: mixed or contaminated scrap gives a poorer alloy, so it may need separating, whereas clean scrap of one metal can be melted directly. For example, some scrap steel can be added to molten iron from a blast furnace, so less iron ore must be extracted. The scrap dilutes impurities and is adjusted to the required composition, then cast or rolled into new steel products.

What earns the marks

• Recycling involves melting scrap metal and recasting or reforming it into different products, so the metal is used again instead of being discarded.
• The degree of separation needed before melting depends on the material being recycled and on the properties required of the final product.
• Scrap that is mixed or contaminated may need sorting or refining because unwanted elements change the properties of the recycled metal.
• Adding some scrap steel to iron from a blast furnace reduces the amount of iron that must be extracted from iron ore.
• Recycling conserves limited metal ores and can use less energy than extracting metal from its ore, though transport and processing still use resources.
• The properties of the final product, such as strength or corrosion resistance, determine how pure or how well sorted the recycled metal must be.

Common mistakes and how to put them right

• Thinking all scrap metal can be melted together without sorting.

  Put it right: In fact separation depends on the material and the properties required of the final product.

• Assuming recycling always needs no energy.

  Put it right: Melting and transport still require energy, even though less ore is extracted.

• Believing scrap steel added to blast-furnace iron is waste.

  Put it right: It is a useful feedstock that reduces the amount of iron ore that needs to be extracted.

Exam tips

• Link the amount of separation to two things: the material being recycled and the properties needed in the final product.
• Use the blast-furnace example precisely: scrap steel is added to iron from a blast furnace, reducing iron ore extraction.
• When comparing recycling with extraction, refer to conserving limited resources and to energy use, not just to litter or landfill.