Primary MetalsTable of Contents Industry Overview Steel Making
Industry Ferrous & Non-Ferrous Foundries Aluminum Smelting & Refining |
GlossaryAluminum Dross : Dross is a by-product of primary aluminum melting. It consists of aluminum metal and other impurities and is frequently used in secondary aluminum production.Attrition Sand Reclamation: Attrition sand reclamation technology spins two streams of sand in opposite directions in the presence of heat. The combination of sand abrasion and binder combustion free the sand particles from some binders. Basic Oxide Furnace (BOF): Molten iron from the blast furnace is sent to a basic oxide furnace, which is used for the final refinement of the iron into steel. High purity oxygen is blown into the furnace and combusts carbon and silicon in the molten iron. Alloy materials may be added to enhance the characteristics of the steel. Bayer Process: The process by which alumina is extracted from bauxite ore in primary aluminum production. Cast Making: The process used to make the molds into which molten metal will be poured. Coke: Coke is a solid carbon fuel and carbon source used to melt and reduce iron ore Cokemaking: The processess used to make coke. The process begins with pulverized, bituminous coal. The coal is fed into a coke oven which is sealed and heated to very high temperatures for 14 to 36 hours. After completion, the coke is moved to quenching towers and stored until it is needed. Continuous Casting: A sucessive series of operations that used to produce metal pieces. These operations often replace batch processes which are done in stages, leaving some equipment idle while others are in operation. Cores: Cores are pieces that fit into the mold to create detailed internal passages in the metal piece. Cores must be strong and hard to withstand the molten metal, and collapsible so they can be removed from the metal piece after it has cooled. To obtain these properties, resins or chemical binders are usually added to sand mixtures. Cupola Furnace: Cupola furnaces are tall, cylindrical furnaces used to melt iron and ferro alloys in foundry operations. Alternating layers of metal and ferro alloys, coke, and limestone are fed into the furnace from the top. Direct Iron Ore Smelting (DIOS): The DIOS process is a cokeless ironmaking procedure. Molten iron is produced from coal and previously melted ores. In this process, coal and other ores can produce enough heat to melt ore, replacing coke completely (USEPA, 1995). Dry Sand Reclamation: Dry sand reclamation relies on mechanical and pneumatic scrubbers to remove lumps and binders from sand. Mechanical scrubbing moves each sand grain through a sand-to-metal or sand-to-sand interface to remove impurities. Pneumatic scrubbers use air to propel sand between baffles. These scrubbers are particularly good for removing clay from molding sands and binders in systems that are not baked. Electric Arc Furnaces (EAFs): Electric arc furnaces are often used in large steel foundries and steel mills. The metal is charged into the furnace, with additives to make recovery of slag easier, and heat to melt the metal is produced with an electric arc from three carbon or granite electrodes. Frequently mills producing steel with EAF technology are called mini-mills. Energy Optimizing Furnace (EOF): EOF was developed to replace the electric arc and other steelmaking furnaces. The EOF is an oxygen steelmaking process. Carbon and oxygen react to preheat scrap metal, hot metal and/or pig iron. Foundries: Foundries specialize in melting and casting metal into desired shapes. Foundry products are most often used in automobiles, plumbing fixtures, train locomotives, airplanes and as metal pieces in other kinds of equipment. Green Sand Molds: Green sand molds, used in 85% of foundries, are a mixture of sand, clay, carbonaceous material and water. The sand provides the structure for the mold, the clay binds the sand together and the carbonaceous materials prevent rust. Water is used to activate the clay. Hall-Heroult Process: The process by which aluminum oxide from the Bayer Process is reduced to aluminum metal. Hearth Furnaces: Hearth furnaces are used in batch melting of non-ferrous metals. The hearth can be heated by either electric or natural gas methods. Hearth furnaces are used to produce small quantities of metal, usually for art and similar industries. HiSmelt Process: The HISmelt process, named after the HISmelt Corporation of Australia, is another cokeless iron melting process being tested. In this process, ore fines and coal are manipulated to melt iron ore. Induction Furnaces: Induction furnaces are the most widely used type of furnace for melting iron and are increasingly popular for melting non-ferrous metals (USEPA, 1992). They are popular because they provide excellent metallurgical control and are relatively pollution free. Ingots: Convenient shapes into which newly refined, molten metal is poured for storage. The ingots are then remelted and cast into desired molds. Integrated Steel Mills: Integrated steel mills produce steel by refining iron ore. They produce very high quality steel with well controlled chemical compositions. Investment Molds: Investment molds are made from ceramic substances called refractories. They are used in high precision metal castings. Iron Carbide Production Plants: Iron carbide production plants can be an alternative to the Basic Oxide Furnace. These plants use iron carbide, an iron ore that contains 6% carbon rather than 1.5-1.8% of regular iron ore . The additional carbon ignites in the presence of oxygen and contributes heat to the iron melting process, reducing energy requirements (Ritt, 1996). Ironmaking: During ironmaking, iron ore, coke, heated air and limestone or other fluxes are fed into a blast furnace to produce molten iron that is free from impurities. Mini-Mills: Steel production plants that rely on steel scrap as a base material rather than ore. Products do not have the tight chemical composistion of integrated plants and have narrower product lines. Non-Recovery Coke Battery: In non-recovery batteries, coke oven slag and other by-products are sent to the battery where they are combusted. This technique consumes the by-products, eliminating much of the air and water pollution. Permanent Molds: Permanent molds are made from metal or other resistant material. The molds are used multiple time by industries that produce large numbers of the same piece. Primary Metal Industries: Industries that produce ferrous or non-ferrous metal products from metal ore and / or scrap metal. Plants may refine metals, cast molten metal into desired shapes, or produce the inputs for the refining or casting process. Pulverized Coal Injections: Pulverized coal can be substituted for coke at nearly a 1:1 ratio and can replace 25 - 40% of coke traditionally used in furnaces (USEPA, 1995). Pulverized coal injections are used to reduce pollution by reducing the volume of coke production. Refractory: Hard, heat resistant substances such as fire clay, bricks or blocks. The refractory protects a furnace shell from abrasion, heat and oxidation. Sand Reclamation: "the physical, chemical or thermal treatment of a refractory aggregate to allow its reuse without significantly lowering its original useful properties as required for the application involved" American Foundrymen's Society. Sintering: Sintering is a process in which solid wastes are combined into a porous mass that can then be added to the blast furnace. These wastes include iron ore fines, pollution control dust, coke breeze, water treatment plant sludge, and flux. Shell Molds: Shell molds use chemically bonded sand to make the molds into which molten metal will be poured. Slag: Impurities in the iron ore that have been captured by limestone or other fluxes. Steel: Steel is an alloy of iron usually containing less than 1% carbon which is used most frequently in the automotive and construction industries or is cast into bars, strips, sheets, nails, spikes, wire, rods or pipes as needed by the intended user. Thermal Sand Reclamation: Thermal reclamation uses heat in a rotary kiln, multiple-hearth furnaces, or a fluidized bed to combust binders and contaminants. Wet Sand Reclamation: Wet reclamation uses water to remove sand binders. The process uses on the different water solubilities of sand and binders to separate the two. Clay bonded systems work well with water reclamation processes because the clays are very soluble in water. Sodium silicate sand binders can also be removed using wet reclamation. Other less soluble binders may not be as effective. After the sand is soaked in a water bath it is dried and reused. |