Ferrous metal recycling
Encyclopedia
Ferrous metals are able to be recycled
with steel being one of the most recycled materials in the world,. Ferrous metals contain an appreciable percentage of iron
and the addition of carbon and other substances creates steel
.
The most commonly recycled items are containers, cans, automobiles, appliances, and construction materials. For example, in 2008, more than 97% of structural steel and 106% of automobiles were recycled, comparing the current steel consumption for each industry with the amount of recycled steel being produced (the late 2000s recession
and the associated sharp decline in automobile production explains the over-100% calculation). A typical appliance is about 75% steel by weight and automobiles are about 65% steel and iron.
The steel industry has been actively recycling for more than 150 years, in large part because it is economically advantageous to do so. It is cheaper to recycle steel than to mine iron ore and manipulate it through the production process to form new steel. Steel does not lose any of its inherent physical properties
during the recycling process, and has drastically reduced energy and material requirements compared with refinement from iron ore. The energy saved by recycling reduces the annual energy consumption of the industry by about 75%, which is enough to power eighteen million homes for one year. According to the International Resource Panel
's Metal Stocks in Society report
, the per capita stock of steel in use in Australia, Canada, the European Union EU15, Norway, Switzerland, Japan, New Zealand and the USA combined is 7085kg (about 860 million people in 2005).
Basic oxygen steelmaking
(BOS) uses between 25 and 35% recycled steel to make new steel. BOS steel usually contains lower concentrations of residual elements such as copper
, nickel
and molybdenum
and is therefore more malleable than electric arc furnace
(EAF) steel and is often used to make automotive fenders, tin cans, industrial drums or any product with a large degree of cold working. EAF steelmaking uses almost 100% recycled steel. This steel contains greater concentrations of residual elements that cannot be removed through the application of oxygen and lime
. It is used to make structural beams, plates, reinforcing bar
and other products that require little cold working. Downcycling
of steel by hard-to-separate impurities such as copper or tin can only be prevented by well-aimed scrap selection or dilution by pure steel. Recycling one metric ton (1,000 kilograms) of steel saves 1,100 kilograms of iron ore, 630 kilograms of coal
, and 55 kilograms of limestone
.
Recycling
Recycling is processing used materials into new products to prevent waste of potentially useful materials, reduce the consumption of fresh raw materials, reduce energy usage, reduce air pollution and water pollution by reducing the need for "conventional" waste disposal, and lower greenhouse...
with steel being one of the most recycled materials in the world,. Ferrous metals contain an appreciable percentage of iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
and the addition of carbon and other substances creates steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
.
The most commonly recycled items are containers, cans, automobiles, appliances, and construction materials. For example, in 2008, more than 97% of structural steel and 106% of automobiles were recycled, comparing the current steel consumption for each industry with the amount of recycled steel being produced (the late 2000s recession
Late 2000s recession
The late-2000s recession, sometimes referred to as the Great Recession or Lesser Depression or Long Recession, is a severe ongoing global economic problem that began in December 2007 and took a particularly sharp downward turn in September 2008. The Great Recession has affected the entire world...
and the associated sharp decline in automobile production explains the over-100% calculation). A typical appliance is about 75% steel by weight and automobiles are about 65% steel and iron.
The steel industry has been actively recycling for more than 150 years, in large part because it is economically advantageous to do so. It is cheaper to recycle steel than to mine iron ore and manipulate it through the production process to form new steel. Steel does not lose any of its inherent physical properties
Physical property
A physical property is any property that is measurable whose value describes a physical system's state. The changes in the physical properties of a system can be used to describe its transformations ....
during the recycling process, and has drastically reduced energy and material requirements compared with refinement from iron ore. The energy saved by recycling reduces the annual energy consumption of the industry by about 75%, which is enough to power eighteen million homes for one year. According to the International Resource Panel
International Resource Panel
The International Resource Panel is a scientific panel of experts that aims to help nations use natural resources sustainably without compromising economic growth and human needs...
's Metal Stocks in Society report
Metal Stocks in Society report
The report Metal Stocks in Society: Scientific Synthesis was the first of six scientific assessments on global metals to be published by the International Resource Panel of the United Nations Environment Programme...
, the per capita stock of steel in use in Australia, Canada, the European Union EU15, Norway, Switzerland, Japan, New Zealand and the USA combined is 7085kg (about 860 million people in 2005).
Basic oxygen steelmaking
Basic oxygen steelmaking
Basic oxygen steelmaking , also known as Linz-Donawitz-Verfahren steelmaking or the oxygen converter process is a method of primary steelmaking in which carbon-rich molten pig iron is made into steel. Blowing oxygen through molten pig iron lowers the carbon content of the alloy and changes it into...
(BOS) uses between 25 and 35% recycled steel to make new steel. BOS steel usually contains lower concentrations of residual elements such as copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
, nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
and molybdenum
Molybdenum
Molybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...
and is therefore more malleable than electric arc furnace
Electric arc furnace
An electric arc furnace is a furnace that heats charged material by means of an electric arc.Arc furnaces range in size from small units of approximately one ton capacity up to about 400 ton units used for secondary steelmaking...
(EAF) steel and is often used to make automotive fenders, tin cans, industrial drums or any product with a large degree of cold working. EAF steelmaking uses almost 100% recycled steel. This steel contains greater concentrations of residual elements that cannot be removed through the application of oxygen and lime
Calcium oxide
Calcium oxide , commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline crystalline solid at room temperature....
. It is used to make structural beams, plates, reinforcing bar
Rebar
A rebar , also known as reinforcing steel, reinforcement steel, rerod, or a deformed bar, is a common steel bar, and is commonly used as a tensioning device in reinforced concrete and reinforced masonry structures holding the concrete in compression...
and other products that require little cold working. Downcycling
Downcycling
Downcycling is the process of converting waste materials or useless products into new materials or products of lesser quality and reduced functionality...
of steel by hard-to-separate impurities such as copper or tin can only be prevented by well-aimed scrap selection or dilution by pure steel. Recycling one metric ton (1,000 kilograms) of steel saves 1,100 kilograms of iron ore, 630 kilograms of coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
, and 55 kilograms of limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
.
Types of scrap used in steelmaking
- Heavy melting steel. Industrial or commercial scrap steel greater than 6mm thick, such as plates, beams, columns, channels; may also include scrap machinery or implements or certain metal stampings.
- Old car bodies. Vehicles with or without interiors and their original wheels.
- Cast iron. Cast iron baths, machinery, pipe and engine blocks.
- Pressing steel. Domestic scrap metal up to approx. 6mm thick. Examples - White goods (fridges, washing machines, etc.), roofing iron, water heaters, water tanks and sheet metal offcuts.
- Re-inforcing bars or mesh. Used in the construction industry within concrete.
- Turnings. Remains of drilling or shaping steels. Also known as borings and swarf.
- Manganese steel. Non magnetic, hardened steel used in the mining industry, cement mixers, rock crushers, and other high impact and abrasive environments.
- Rails. Rail or tram tracks.