The Iron and steel Industry has significant impact on global environment. Producing steel requires the use of large quantities of energy and minerals, as well as vast mining and waste disposal areas. As a result, steel production generates significant amount of air pollutants, solid by-products and residues, as well as waste water sludge. The pollution can take many forms and impacts do not occur on a local area only but they could spread to regional or global scale, including through atmospheric pollution.
Air pollution from the steel sector is the result of emissions of particulate matter containing minerals (iron, iron oxide), metals (cadmium, lead, chromium, nickel, zinc, copper and arsenic) and other pollutants (polycyclic aromatic hydrocarbons, nitrogen oxides and sulphur dioxide).
Steel plants with electric arc furnace release dust containing heavy metals and some organic compounds. Steel industry is also a source of carbon dioxide (CO2) emissions which is generated during iron and steel making operations, either as a result of the reaction of carbon (coke) with iron oxide in the blast furnace, or from a power plant producing electricity used in the production of steel. According to the International Iron and Steel Institute (IISI), integrated plants can emit between 1.6-2.4 tonnes of CO2 per tonne of steel produced, while electric arc furnace plants which only use iron scrap as raw material are responsible for the emission of approximate 0.7 tonnes of CO2 per tonne of steel produced.
In recognition of the negative environmental impact, the steel industry has in recent years adopted the introduction of efficient processes, pollution control systems and practices which can help to reduce emissions significantly.
China, the largest producer of steel in the world, has witnessed significant growth of steel production in the country and total crude steel output is expected to exceed 500 million tonnes in 2008. The steel industry discharges a lot of pollutants each year. In 2007, steel industry in China discharged 1.73 million tonnes of sulfur dioxide, accounting for 7% of the national total. In the same year, dust discharged by the steel industry in China was 1.07 million tonnes, or 15% of the national total, solid wastes discharge was 228.5 million tonnes, or 13% of the national total, while waste water discharge accounted for 8% of the national total.
Increasing stricter environmental requirements have been a major concern for the iron and steel industry in China in recent years. As a consequence, the industry has started to adopt new production technologies in order to reduce pollution. In 2008, CISA released a report on the environmental protection performance of more than 70 key steelmakers in 2007 and during the first quarter of 2008 (The Chinese Steel Industry, IISI). Key points are listed below:
1. Composite energy consumption was 632.12 kgce/tonne of steel in 2007 and was 627.12 kgce/tonne of steel in the first half of 2008,down 0.39%.
2. Freshwater intensity was 5.31 tonnes/tonne of steel in 2007, and was 4.99 tonnes/tonne of steel in the first half of 2008, down 7.79%.
3. Total SO2 emissions were reduced by 0.51% to 756,368 tonnes in 2007.
4. Dust emissions were reduced by 2.79% to 382,275 tonnes in 2007 and reduced further by 8.93% in the first half 2008.
5. Fume emissions increased by 3.02% to 156,648 tonnes in 2007, but decreased by 1.84% in the first quarter 2008.
6. Chemical Oxygen Demand (COD) was reduced by 8.76% to 59,965 tonnes in 2007 and further reduced by 26.67% in the first half of 2008.
Many key steel companies in China have launched various environmental projects to improve energy consumption in the production process as well as to improve environmental performance. Anshan Steel lately announced that it has launched 11 environmental projects in 2008. The projects focus mainly on energy efficiency and reuse of waste energy in coking, ironmaking, steelmaking and rolling process. The projects are expected to save energy use by 220,000 tonnes a year and reduce energy intensity by 14 kgce/tonne. This may bring Anshan Steel a return of USD62.3 million. Anshan Steel has also signed an agreement on Clean Development Mechanism (CDM) projects with the European Carbon Fund and CAMCO International in early February this year. The deal is expected to bring Anshan Steel earnings of approximately USD 216 million. In May 2008, Wuhan Steel signed a CDM agreement with its Italian partner, ENEL. The projects are expected to reduce CO2 emissions by 3.16 mmt/a. The agreement may bring Wuhan Steel earnings of USD42.9 million a year. In January 2008, Baosteel also signed its first CDM projects with joint buyers Arreon Carbon Ltd and Credit Suisse International.
The Iron and steel industry is without doubt one of the most important foundations of any industrial economy. However, the industry is also a significant contributer to environmental pollution. It would therefore need to adopt more efficient and cleaner technologies to miminize its environmental footprint and ensure the long term sustainability of the industry.