Materials
Ferrous metals are mainly composed of iron and have magnetic properties. Steel, an iron alloy containing carbon, is by far the most-recycled material in the world. Total steel production in 2008 reached 1.3 billion tonnes, of which over 500 million tonnes were made from scrap metal. The most commonly recycled items are scrap from industrial processes, end-of-life products such as containers, vehicles, appliances, industrial machinery and construction materials.
The use of scrap metal has become an integral part of the modern steelmaking industry, improving the industry’s economic viability and reducing environmental impact. Compared to ore extraction, the use of secondary ferrous metals significantly reduces CO2 emissions, energy and water consumption and air pollution. At the same time, the recycling of steel makes more efficient use of the earth’s natural resources.
Recycling Processes
In general, metal recycling is a pyramid industry with many small companies at the bottom feeding scrap to large multinationals at the top. Steel recycling involves some, or,all of the following steps:
A shredder in operation
Recovery of aluminium and high value metals
from an aeroplane
- Sorting: Because magnets attract steel, this metal can be easily separated from other recyclables like paper in a recycling facility with magnetic belts. Different kinds of steel do not need to be separated.
- Shredding: Shredders incorporate rotating magnetic drums to extract iron and steel from the mixture of metals and other materials.
- Media separation: Further separation is achieved using electrical currents, high-pressure air flows and liquid floating systems. Other processes may be necessary in cases such as steel cans which have a protective layer of tin that must be removed and recycled separately.
- Shearing: Hydraulic machinery capable of exerting enormous pressure is used to cut thick heavy steel recovered from railways and ships. Other cutting techniques, such as the use of gas and plasma arch, are sometimes employed.
- Baling: Iron and steel products are compacted into large blocks to facilitate handling and transportation.
Applications
Steel is ideal for recycling because it does not lose any of its inherent physical properties during the process, which can be repeated ad infinitum. Steel is 100% recyclable and therefore, recycled steel can be used for the same applications as steel produced from virgin material. Products that are made of recycled steel include:
- Construction materials for roads, railways, infrastructure and buildings
- Electrical appliances
- Cans and containers
- Automobiles and other vehicles
- Office supplies
- Hardware: bolts, nuts, screws, etc.
Recycling Facts
- Almost 40% of the world’s steel production is made from scrap.
- Recycling one tonne of steel saves 1,100 kilogrammes of iron ore, 630 kilogrammes of coal, and 55 kilogrammes of limestone.
- CO2 emissions are reduced by 58% through the use of ferrous scrap.
- Recycling one tonne of steel saves 642 kWh of energy, 1.8 barrels (287 litres) of oil, 10.9 million Btu's of energy and 2.3 cubic metres of landfill space.
- Steel production from scrap uses 24% less energy than making steel from iron ore. Every tonne of steel made from recycled scrap saves enough energy to power 4 homes for a whole year.
- Steel recycling uses 74% less energy, 90% less virgin materials and 40% less water; it also produces 76% fewer water pollutants, 86% fewer air pollutants and 97% less mining waste.
- Steel automobile frames contain at least 25% recycled steel and a typical electrical appliance will usually be made of 75% recycled steel. Steel cans consist of at least 25% recycled steel.
Our Experts
For further information on technical issues, you can contact, via the Brussels secretariat, the following experts, who are board members of the BIR Ferrous Division: