Context, issues and problems

The term iron and steel industry relates to the techniques used to obtain cast iron and steel as well as to the industry implementing these techniques.

It involves a large variety of industries, from integrated sites producing several million tons of steel with dedicated unloading platforms, coking plant, sinter plant, blast furnaces, converters, ladle treatment stations, continuous casting, hot rolling mills and finishing tools, to electric steelworks.

It includes two major categories of finished products:

• flat products: plates (over 10 mm thick), hot sheets, cold rolled sheets or reels, possibly coated, galvanised or lacquered
• and long products: rails, girders, sheet piling, wire rod, concrete reinforcing bars, merchant bars.

There are two major types of iron and steel installations:

• integrated steelworks, producing raw steel from iron ore and coal;
• electric steelworks, producing steel from scrap iron.

French production of raw steel is concentrated on three plants situated in Dunkerque, Fos and Florange.

60% of the French production of raw steel comes from the three large-scale integrated steelworks. The twenty six electric steelworks using recycled scrap iron make up the remaining 40% of this production.

The iron and steel industry uses 20% of the energy consumed in the French manufacturing industry, with 9.5 million tons of oil equivalent in 1999. Iron and steel plants mostly consume solid mineral combustibles (64%) with coal and coke derived from hard coal. They also consume electricity (28%) and natural gas (7%). They consume 84% of the coal used in the manufacturing industry and 11% of the electricity.

This activity is characterised by some of the highest pollutant emissions in France for many parameters. Over half of the raw materials treated end up, at the end of the process, as gas emissions, waste or solid by-products.

Risks of accident:

• Fire (gasometers; coal depots, oxygen, flammable liquids etc.)
• Toxic risks (gases from blast furnaces and steelworks, ammonia, hydrochloric acid etc.)
• Explosion (gases from coke plants and steelworks; combustible dust; contact between the water and molten materials; calcium carbide etc.)
• Air pollution (fumes from fire)
• Water pollution (extinguishing water, chemical spill (ammonia solution, hydrochloric acid, tar, hydrocarbons, metals etc.), fuel depots etc.)
• Soil pollution

Can come under the Seveso directive for the use of toxic substances, gas manufacturing or storage.

Chronic risks:

Air pollution:

• Flying dust from external raw material storage (coal and iron ore)
• Manufacturing units – agglomeration, blast furnaces and rolling mills - emitting dust containing metals, in particular Pb, Cd and Hg, pollutants such as sulphur dioxides, nitrogen dioxides, volatile organic compounds (including benzene) and dioxins. In 2005, dust emissions amounted to an estimated 1.5 kg per ton of steel produced. The implementation of best techniques should limit emissions to 1 kg/t by 2010.
• Odours

Other types of impact:

• Water pollution: large flow rates of cooling water and water used to treat gases contaminated by various chemicals, hydrocarbons and heavy metals
• Noise generated by the scale of the installations and activities
• Health: impact on health mostly due to the amount of air emissions. The main pollutants emitted by the iron and steel industry affecting health are: NOx, SO2, dust particles, PCDD/F, Chromium, Lead, Selenium, Cadmium, Zinc, Arsenic, Nickel, Antimony, HAP, Naphtalene, Acetaldehyde, H2S, HCl, Fluorides, Benzene, Toluene, Xylene, n-hexane – risk of legionella disease due to the presence of a number of powerful air cooling towers. The majority of circuits fail to comply with the annual shutdown for cleaning and disinfection (these tools cannot withstand a rather lengthy annual shutdown).

Prevention and protection measures:

• Dust reduction is achieved by collection and treatment process using electrofilters followed by bag filters. Furthermore, the injection of lime and activated carbon makes it possible to reduce the quantity of metals, dioxins and sulphur dioxides contained in dust. Diffuse emissions are controlled by a lacquering process and mass treatment of external stocks.
• Sulphur dioxide emissions can be reduced by desulphurising coking plant gases.
• Nitrogen dioxides can be reduced by recirculating flue gases.
• For noise control, distancing from housing areas and, if necessary, specific acoustic measures during the design phase.
• Protection of the subsoil and groundwater tables, notably if there are internal landfills treating sludge from washing operations or waste generated by gas dust removal (water tightness of depot areas).
• In terms of risks: preventative maintenance; personnel training; detection resources (sensor network) and resources to control fires and explosions; installations isolated from housing areas; POI / PPI response plans.
• Monitoring of the environment (air, groundwater tables etc.).