Foundry types

Figure 10.29 shows a VS-Pritit illustrating a complete LVHV system (plan view) for a typical foundry application. This system connects five dustgenerating tools, each with its own exhaust nozzle. This figure also includes recommended nozzle volume flow rates and flexible hose inside diameters for several typical foundry-type operations. 

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... 

Technical molybdic oxide can be reduced by reaction of ferrosiUcon in a thermite-type reaction. The resulting product contains about 60% molybdenum and 40% iron. Foundries generally use ferromolybdenum for adding molybdenum to cast iron and steel, and steel mills may prefer ferromolybdenum to technical molybdic oxide for some types of steels. 

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. 

High-Temperature Coke (1173 to 1423 K or 1652 to 2102°F.) This type is most commonly used in the United States nearly 20 percent of the total bituminous coal consumed is used to make high-temperature coke for metallurgical applications. About 99 percent of this type of coke is made in slot-type recovery ovens. Blast furnaces use about 90 percent of the production, the rest going mainly to foundries and gas plants. 

It was fun to think about how I should dress, speak, move, and touch, to talk of type-foundries and colophons, watermarks and printers patrons, and all the time watch a mans hands, the tilt of his head, the way his mouth moved as he spoke, the way his fingers brushed mine as he put more drinks on the table. It was fun that could fill my head and then my body, that bright, dumb spark in a man s eye that made my skin shiver in response. And we were away from home, after all, it was only a week, and the sun was shining on the Venice canals, or the moon was rising from behind the Rockies, or the coal fire in my rooms was so glowing that it shut out the gray cold and the Lancashire rain, and wrapped us in warmth. 

Induction furnaces are the most common type used by both ferrous and nonferrous foundries. Copper coils heat the metal using alternating currents. The flux reacts with impurities. 

This is the earliest and the most commonly used casting process. It has the advantages of wide metal suitability, low cost, and simple operation. It uses sand as a refractory material. Many types of sand are utilized by the foundry industry. However, because of its wide availability and relatively low cost, silica sand is the one that makes most metal castings. Silica sand is composed of the mineral quartz (Si02), which has a fusion point of approximately 1670°C (3090°F), which is often lowered by the presence of appreciable quantities of minerals with lower fusion points. 

Many toxic pollutants were detected in the process wastewaters from metal molding and casting processes. The toxic pollutants detected most frequently in concentrations at or above 0.1 mg/L were phenolic compounds and heavy metals. The pollutants include 2,4,6-trichlorophenol, 2,4-dimethyl-phenol, phenol, 2-ethylhexyl, cadmium, chromium, copper, lead, nickel, and zinc. Each type of operation in the foundry industry can produce different types of pollutants in the wastewater stream. Also, because each subcategory operation often involves different processes, pollutant concentrations per casting metals may vary. 

Depending on the binder and type of metal cast, the pH of spent foundry sand12 can vary from approximately 4 to 8. As such, it has been reported that some spent foundry sands can be corrosive to metals.14 Spent foundry sand must be monitored to assess the need to establish controls for potential phenol discharges.91516... 

Some end-use applications may prefer the characteristics of foundry solid waste. For instance, spent foundry sand is a uniformly graded fine aggregate containing chemically active iron and organics. Spent foundry sand can be superior to other types of granular materials, such as compacted soils or clays, for hydraulic barriers. In this case, spent foundry sand provides better performance at lower cost. 

Metals, especially the more common iron and steel types, come from the foundry coated with oil, grease and most often a generous layer of oxide formed on the exposed surfaces. All these materials must be removed from the surfaces and from the pores of the metal to ensure that the oils and greases cannot exude under the increased temperature of vulcanisation, when they become more mobile or volatile. Surface oxides also must be removed for they are often only loosely attached to the metal substrate and will detach themselves under duress in service, after bonding. 

It has recently been noted that if copper-induced MEE does occur, it is a very rare event. Despite extensive use of copper in many industries, only a handful of MEE cases are reported in the literature. Further limitations of these reports include possible contamination of the fume by other substances more likely to have caused MFF, atypical symptoms and complaints, and lack of consistency among types of work associated with symptoms. One reason that MFF may have rarely been described after copper exposure is that aerosolized copper particulates formed during welding, thermal cutting, and other hot work are mostly greater than respirable or submicron size. Studies of air in a brass foundry found that only 5% of the total copper exposure was respirable (aerosol less than or equal to 1 )im), whereas 40% of the zinc oxide exposures were to an aerosolized particulate of respirable size. ... 

Silica Refractories. This type consists mainly of silica in three crystalline forms cristobalite [1446446-1]> tridymite [1546-32-3]> and quartz [14808-60-7]. Quartzite sands and silica gravels are the main raw materials, although lime and iron oxides are added to increase the mineralization of the tridymite and cristobalite. Uses include roof linings, refractories for coke ovens, coreless induction foundry furnaces, and fused-silica technical ceramic products. Consumption of silica refractories has declined dramatically since the 1960s as a result of the changes in the steel industry. 

Another alternative would be to visit an automotive repair shop. Internal combustion engines, lifts, levers, and hand tools are only a few of the types of mechanical devices you could see in use. Yet another possibility would be to visit a local manufacturer in your town. Examples include a foundry, a sheet metal fabricator, an automotive manufacturer, or a pump manufacturer. Look in the phone book under manufacturing for possibilities. 

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