Steel Manufacturing - Electric Arc/Coke
This Industry Profile Fact Sheet is presented by the EPA Region 3 to assist state, local, and municipal agencies, and private groups in the initial planning and evaluation of sites being considered for remediation, redevelopment or reuse. It is intended to provide a general description of site conditions and contaminants which may be encountered at specific industrial facilities. This fact sheet is presented for informational purposes only, and should not be construed as a federal policy or directive.
INDUSTRY, PROCESS, OR SITE DESCRIPTION
Steel is the generic name for a group of ferrous metals composed principally of iron ore, scrap metal, coke, and or limestone (depending on furnace type). Other materials may be added to enhance the engineering properties or appearance of the steel. Historically, most of the steel was made in an open-hearth furnace where scrap metal, processed iron ore and fuel were introduced into the furnace in the presence of heated air to create molten steel. More recently, electric arc furnaces utilizing electrodes have been used to melt scrap into molten steel. Then the molten steel is poured into ingots or casts which are shipped to other plants for fabrication into other steel products.
CHARACTERISTIC RAW MATERIALS
Modern steel making relies primarily on scrap metal. Additives, including molybdenum, nickel, titanium and chrome, are used to improve the engineering qualities and appearance of the steel. Oxidation is used to remove unwanted elements by forming oxides which enter the furnace stack gas or the oven slag.
Older open-hearth furnace systems utilized iron ore, scrap, coke and limestone to manufacture the raw steel. These furnaces included coking ovens where coal was heated in an low oxygen atmosphere to volatilize the impurities into an oven or furnace gas, which was transferred to a by-products recovery plant. Common by-products recovered include natural gas, benzene, toluene, xylenes, phenol, creosols, pyride, anthracene, naphthalene, sulfuric acid, light oils, paraffin and ammonia sulfates and nitrates.
WASTE STREAMS AND POTENTIALLY AFFECTED ENVIRONMENTAL MEDIA
Modern furnaces often have very large scrap yards; older furnaces had iron ore storage areas, coke storage areas, product storage areas, waste piles, and wastewater lagoon areas. Modern plants may generate wastewater, oven slag, oven ash and materials from the air pollution control equipment as waste streams. Waste products associated with older operations may include coal tar, hydrogen sulfide gas, complex cyanide salts, coal fines, quenching wastewater, process still bottoms, slag, and sulfuric acid. The metals concentration in the ash is dependent on the furnace type, plant configuration and content of the original fuel. The most common metals include aluminum, iron, lead, manganese, sulfur, nickel, and chromium. Common waste products encountered at Superfund assessment and remediation projects contain high concentrations of polynuclear aromatic hydrocarbons (PAHs), sulfur compounds, and complex cyanide, volatile or phenolic compounds. Other inorganic compounds are not typically encountered at significant levels.
Large volumes of wastewater are generated in coke quenching and steel processing operations. This wastewater is commonly stored in large on-site surface impoundments. Coal tars, coal fines, sludges and tank bottoms may be encountered in waste piles and large tar pits. Groundwater may be contaminated as a result of leaching or percolation of surface and subsurface contaminants, surface impoundments or leaking process lines and tanks.
Additionally, contaminated buildings and the associated demolition debris may be encountered at abandoned or inactive sites. Associated heat transmission equipment, such as boilers or furnaces, and electrical equipment may contain significant amounts of asbestos and PCBs. Decontamination, asbestos remediation, wipe testing and other analysis of this material may be required prior to off-site landfill disposal or scrapping of process equipment.
All waste materials encountered on site should be visually identified and confirmed using immuno-assay, qualitative indicators, or wet chemistry field screening techniques. It should be noted that many of the waste materials may represent a significant direct contact and/or inhalation hazard to assessment personnel. Visually identified contaminated areas, waste piles and lagoons should be characterized by collecting several samples for laboratory analysis. Surface and subsurface soil sampling should be performed to confirm the extent of the contamination. Once the contaminated areas are established by using field screening techniques, grid or random sampling may be performed to confirm the suspected clean areas. The application of non-intrusive subsurface geophysics should be evaluated to detect subsurface pits, process lines and chemical storage tanks.
On-site and local wells may be sampled if groundwater is an environmental concern. Installation of monitoring wells or other groundwater sampling techniques should be evaluated if it is necessary to fill data gaps.
SUGGESTED ANALYTICAL PARAMETERS
Priority Pollutant Metals Analysis
Priority Pollutant Organics Analysis (volatiles, semivolatiles, pesticide/ PCBs)