Ferrous foundries

Ferrous foundries consist of two types steel foundries in which electric furnaces (EAF and induction) are used, and iron foundries in which hot-blast cupolas and/or electric furnaces are used. Electric furnaces use virtually 100% scrap charges. Cupolas are shaft furnaces which use preheated air, coke, fluxes, and metallic charges. Scrap is over 90% of the metallic charge. Cupolas accounted for about 64% of total iron foundry scrap consumption in 1994 and electric furnaces accounted for about 34%. The balance was consumed by other furnaces, such as air furnaces. Iron foundry products have a high carbon content and the scrap charge usually contains a high percentage of cast iron or is used in combination with pig iron. 

FIGURE 4.1 General metal casting flowchart. (From U.S. EPA, Summary of Factors Affecting Compliance by Ferrous Foundries, Vol. 1, EPA-340/1-80-020, U.S. EPA, Washington, DC, January 1981.)... 

Information on occupational exposure to lead is obtained primarily from the National Occupational Exposure Survey (NOES) and industry surveys of workers. While occupational exposure is widespread, environmental monitoring data on levels of exposure in many occupations are not available. OSHA has established a permissible exposure limit (PEL) for lead of 50 pg/m3 for workplace air (OSHA 1991). NIOSH has estimated that more than 1 million American workers were occupationally exposed to inorganic lead in more than 100 occupations (NIOSH 1977a, 1978a). According to NOES, conducted by NIOSH between 1980 and 1983, an estimated 25,169 employees were exposed to tetraethyl lead (not used in gasoline since December 31, 1995) approximately 57,000 employees were exposed to various lead oxides mostly in non-ferrous foundries, lead smelters, and battery plants 3,902 employees were exposed to lead chloride and 576,579 employees were exposed to some other form of lead in the workplace in 1980 (NIOSH 1990). Workers who operate and maintain solid waste incinerators are also exposed to air lead levels as high as 2,500 pg/m3 (Malkin 1992). 

Ferrous castings industry, 21 414 Ferrous chromite, 5 602 Ferrous dititanate, 25 46 Ferrous foundries, types of, 21 412 Ferrous iron salts, in selenium recovery, 22 79-81... 

Stephens, W. A., Oman, D. F., and Stolzenburg, T. R. September 1988. Waste Minimization Options for The Ferrous Foundry Industry. RMT, Inc. Madison, WI. 

Stephens, W.A., Stolzenburg, T.R., Stanforth R.R., and Etzel, J.E. May 1984. "Use of Iron to Render Sludge from Ferrous Foundry Melting Furnace Emission Control Waste Nonhazardous." Presented at the 39th Annual Purdue Industrial Waste Conference. West Lafayette, Indiana. 

OSHA considers Lead to mean metallie lead, all inorganic lead compounds (lead oxides and lead salts), and a class of organic compounds called soaps all other lead compounds are excluded from this definition. The OSEIA PEL (8-hour TWA) is 0.050 mg/m other OSHA requirements can be found in 29 CFR 1910.1025. The OSEIA PEL (8 hour-TWA) for lead in non-ferrous foundries with less than 20 employees is 0.075 mg/m. ... 

In ferrous foundries the shake-out process of casting metal emits PAH, resulting in an emission factor of 7.7 g per ton casting produced (27). 

Foundries melt ferrous and non-ferrous metals and alloys and reshape them into products at or near their finished shape through the pouring and solidification of the molten metal or alloy into a mould. The foundry industry is a differentiated and diverse industry. It consists of a wide range of installations, from small to very large each with a combination of technologies and unit operations selected to suit the input, size of series and types of product produced in the specific installation. The organisation within the sector is based on the type of metal input, with the main distinction being made between ferrous and non-ferrous foundries. 

Figure 1.1 Ferrous foundry productivity data for various European countries the size of the circle represents the total production in the specified country... 

Cmcibles used for holding, transport and metal treatment in ferrous foundries are called ladles. [110, Vito, 2001], [126, Teknologisk, 2000], [225, TWO, 2003]... 

Natural calcium bentonites do not swell or gel when mixed with water. They are rarely used at present, being used only for very special castings. Alternatively, these materials may be "activated" by treatment with soda ash to give "soda activated bentonites". These are used extensively in ferrous foundries throughout Europe their properties proach those of natural sodium bentonites. 

Coal dust is usually added to green sand for cast iron moulding. It is used to a limited extent in some non-ferrous foundries. Coal dust may be mixed with small amounts of resins and oil products. During casting, the thermal degradation produces lustrous carbon , which improves the casting surface finish and shake-out properties. Coal dust is added for three reasons ... 

The general mass stream overview for the foundry process is given in Figure 3.1. This scheme generally applies for ferrous and non-ferrous foundries. Specific aspects of the various process steps and types will be woiked out below. 

Table 3.14 Typical emission data for induction furnace melting in a ferrous foundry [29, Batz, 1986]...

Non-ferrous foundries In as far as when only ingots and internal scrap are melted, the risk... 

Ferrous foundries Depending on the furnace type and metal load the conditions for dioxin formation could occur. Considering the high temperatures in the melting furnace, dioxin emission (if occurring at all) will mainly generate from de-novo s mthesis. The above-mentioned conditions can be used to evaluate the risk of dioxin formation. 

This technique can be applied on any rotary furnace and in the preheating of pouring ladles. Oxybumers do not find implementation in non-ferrous foundries, although they are used e.g. in secondary copper smelting. 

This technique finds wide application in ferrous foundries using rotary furnaces. 

The operational cost of drying is EUR 0.01/kg (non-ferrous foundry in France). 

Operational data from a large series ferrous foundry showed that binder prices for aromatic cold box were around EUR 2/kg (2001) and went up with some 30 %, upon changing to the nonaromatic system. After one year (2003), the price lowered again however, to a level 10 % above the price of the traditional system. 

Table 4.30 Weighted average of yield performances in 82 UK ferrous foundries, 1981 -1987 [45, ETSU, 1990]...

The technique is applicable in all existing ferrous and non-ferrous foundries. 

Table 4.31 Survey of air emissions from different ferrous foundry stages [160, UK Environment Agency, 2002]...

The installation of exhaust capture equipment is applicable to all new and existing induction furnace installations, both in ferrous and non-ferrous foundries. 

Flue-gas cleaning is applied in most ferrous foundries using an induction furnace and in a limited number of non-ferrous foundries. 

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