Recycled Steel: An environmental success.
Consider our modern world. It is a long list of records being broken. We consume, travel, exercise, read, watch TV, drive and do a multitude of other activities at rates never imagined in the history of man. In the midst of this record breaking pace we have also become environmentally aware. We sympathize with movies about environmental heroes that curb pollution and protect the innocent. We stall and finally stop massive industrial projects in the name of small animals that decades ago would likely have been given no consideration. We have become so environmentally aware that we now even separate our garbage before placing it on the curbside. We are concerned about landfills and streams, water quality and smog, we worry about having enough natural resources so that our children will have a better life. We have truly become environmentally aware.
There is likely not one among us unaware of the “printed on recycled paper” notice on government letterhead. We sort our garbage into different types of recyclable materials. Some even insist on recyclable containers when making our purchases. We all have recognized that the best way to conserve is to recycle. Yet in the frenzy to recycle we often are blissfully blind to the greatest recycling success story in the environment: Steel.
Many years ago, a fledgling steel recycling industry was born, based not on environmental reasons, but solely upon strong economic potential. This industry was the Electric Arc Furnace Industry (EAF). The concept was simple: use scrap metal as the feedstock and melt it with electrical energy. The world was awash in scrap yards where once useful automobiles, appliances and demolition material now slowly rusted into oblivion. While the motivation was purely economic, the result was a boon to the environment and a new highly efficient steel industry. The economics were simple: plentiful, cheap raw materials combined with a much smaller melting and rolling process, capped off with a growing economical and reliable energy system. The scaled down size provided the setting for what would be called the mini mill or as we know it now, the steel recycling mill.
In its infancy, the mini mills were supposed to be little operations that produced low end materials used as rebar and small structural components. With large quantities of scrap metal available for use, the mini mills quickly developed into new markets and learned to exploit the advantages of their technology. In less than a decade the mini mill recycling process began competing directly with the old school of steel making-the integrated mill.
Unlike most recycling processes that depend on environmentally aware purchasers to pay a premium for the recycled products, steel recycling at the mini mills was competing directly with virgin steel and winning the battle. Recycled steel from a mini mill quickly became cheaper to buy than virgin steel from an integrated mill. With such great economic advantages, no one really noticed the tremendous environmental gains inherent to the process. As the mini mill industry refined its process and reached into new markets, their raw material became more and more valuable until people stopped thinking of steel as garbage and started thinking of it as an economically valuable commodity. Steel recycling had finally come of age.
Steel as a recycled material, was quickly removed from the landfills of this country as the mini mills (recycling centers) began to compete with each other for scrap metal. Unlike so many other recycling options, it actually paid to recycle steel. It paid the original product owner, the scrap yard owner, the broker and finally the recycler. Amazingly, the story doesn’t end there, after steel is recycled the process simply starts over again-the potential recycles of steel are infinite. As a leader of the Recycling Coalition of America once stated “Steel is one of our biggest success stories”. While the success of recycling with respect to keeping material out of landfills is truly impressive (approximately 64% of all steel produced is now recycled 1), even more impressive benefits can be found in the environmental gains achieved through recycling. To truly understand this message the environmental impact of recycled steel must be compared with the impacts of producing virgin steel at an integrated mill.
Integrated steel production facilities first mine and concentrate the iron ore. The ore is then combined with coke (made from heated coal) in a blast furnace. The iron is tapped and moved to the basic oxygen furnace where carbon, lime and some scrap are added. The product of this process is carbon steel. Each of these processes consumes large quantities of electrical and chemical energy.
The mini mill or recycling method of steel production takes scrap metal and places it in an Electric Arc Furnace. Carbon and lime are also used in this furnace. The material is melted using electrical and chemical energy similar to the last process in the integrated method.
A quick comparison of these processes on average indicates that recycling a ton of scrap metal conserves 2,500 lbs of iron ore, 1,400 lbs of coal, 120 lbs of limestone 2,2a and about 1705 kwh of electrical energy 3. Considering that in 1999 in the United States about 48 million tons 4 of scrap metal was recycled in mini mills this amounts to 60 million tons of ore, 34 million tons of coal and 3 million tons of limestone saved annually. Even more significant is the amount of electrical energy saved: enough to power 18 million homes 5,2a for one year.
In a period of national concern over energy conservation, the contribution of the steel recycling industry is impressive. In the year 2000, about 47% of the steel produced in the United States was from recycled scrap metal 6 produced in electric arc furnaces by consuming only17% of the total electrical energy used by the entire steel industry 7. If the entire steel production in the United States could be converted to this recycling process it could conceivably conserve enough electricity to power an additional 20 million homes each year. At an average population of 4 persons per residence the total potential savings from recycling steel amounts to providing power for 152 million people to live.
Source: Department of Energy 8
Source: Department of Energy 8
While conservation of our natural resources is alone a major environmental contribution, it pales in comparison to the reduction in criteria pollutants that is achieved through the recycling of steel. While integrated and recycling steel mills all perform at various rates of efficiency, average values for each can be compared. When emission rates for criteria pollutants are compared for an average integrated mill and an average recycling mill the following environmental benefits can be identified:
PM-10 SOx NOx CO VOC
(#/ton) (#/ton) (#/ton) (#/ton) (#/ton)
Integrated Mill 9 39.8 5.0 0.4 44.0 1.4
Recycling Mill 9 0.3 0.7 0.1 4.0 0.4
In most cases the difference between the recycling mill and the integrated mill are between one and two orders of magnitude (factor of 10). Using the same rate of difference per one ton of steel results in the following comparison. On average, producing a ton of steel at an integrated mill will result in an additional 39.51 lbs of particulate, 4.3 lbs of SOx, 0.3 lbs of NOx, 41.0 lbs of CO, 1.07 lbs of VOCs and consume an additional 1,705 kilowatt hours of electricity3. When this is compared with the production of the 49.5 million tons of recycled steel in 199910 the following average reductions in air pollution can be claimed:
PM10- 948,000 tons per year
SOx- 102,930 tons per year
NOx- 7,200 tons per year
CO- 960,000 tons per year
VOC- 25360 tons per year
Electrical Energy 81.5 billion kwh per year
The total annual average reduction of criteria pollutants resulting from mini mill steel recycling is 2,043,490 tons per year. This means that recycling a ton of scrap steel keeps an average of 85 lbs of criteria pollutants from entering the atmosphere when compared with producing the same ton at an integrated shop.
In the world of recycling there are few choices that are as simple and clean. By simply returning a ton of scrap metal to a recycling center a person can receive between $40 to $80 in revenue while conserving ore, limestone and coal; all valuable natural resources. They minimize mining waste and help preserve the earth’s natural beauty. They stop 85 lbs of criteria pollutants from entering the atmosphere and save enough electricity to power their home for over a month. A simple act with far reaching environmental consequences.
Footnote references cited:
(1),(2),(5) U. S. Geological Survey Minerals Yearbook, 1999, Iron and Steel Scrap, Michael D. Fenton, page 40.1
(2a) Steel Recycling Institute-Fact Sheet & web site
(3),(7),(8) U. S. Department of Energy, Energy and Environmental Profile of the U.S. Iron and Steel Industry, July 1996, pages 26,38,47,55
(4) U.S.G.S. Minerals Yearbook, 1999, Table 4
(6) International Iron and Steel Industry, Crude Steel Production by Process,
2000
(9) Bender Corporation, Manfred Bender, P.E. Beverly Hills, CA
(10) Steel Manufacturers Association, Washington, DC, -Fact Sheet & Web site