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Metal Casting Technologies : December 2007
METAL Casting Technologies December 2007 49 ■ Study of the physical and chemical characteristics of additives and their decomposition by-products and their effects on Greensand. ■ Study of how carbonaceous additives improve surface finish and minimize the occurrence of certain casting defects. These and other studies have shown that the main volatile organic compounds (VOCs) emitted from carbonaceous additives are Benzene and Toluene and that the levels of their emission can be reduced by blending sea coal with other materials such as lignite [11, 12] and cellulose . Lignite consists of complex naturally occurring organic acids and has the highest humic acid content of coal type materials. The lignite as a sand additive is used in a causticized form that is produced by treating the lignite with caustic soda to alter its pH from the acidic range to around 6 to 8. The treated material is then dried and ground for supply as a free flowing powder . In production tests on grey iron (FC) castings it has been shown that substitution of sea coal with causticized lignite can reduce the total volume of HAPs and VOCs emissions given off during pouring, cooling and shakeout by up to 45% [11, 12]. Figure 1 illustrates this effect in respect of emissions of benzene and toluene . (a) Reduction in benzene emission (b) Reduction in toluene emission Emissions can also be reduced by replacing petroleum or vegetable oil mould release agents with a water based release agent containing graphite. The graphite ensures good surface finish and the need for lustrous carbon formers in the sand is reduced enabling cellulose to replace sea coal [2, 13]. A further success in making green sand greener is the development of foundry proven water-based mould coatings that contain no hazardous ingredients, no volatile organics and whose evaporation products do not present environmental problems . PACIFIC RIM FOUNDRY SERVICES Exclusive Representative for Mancuso Chemicals (Canada) in Australia and Southeast Asia Chemical Binder Systems State of the Art Technology at Competitive Prices Furane Resins and Catalysts Phenolic Urethane No-Bake Binders Phenolic Urethane Cold-Box Binders PACIFIC RIM CASTING & PATTERNMAKING SUPPLIES Marketing consumable products for the casting and patternmaking industries in New South Wales. Specialising in epoxies, urethanes and adhesives PACIFIC RIM SAFETY PRODUCTS Marketing safety products from: Paramount Safety, Elliott Australia, Protective Industrial Products, Defender Safety, Australian Safety, Bacou Dalloz, Livingstone International. Safety Equipment Leather Gloves,Cotton Gloves,Terry Cord Gloves, Welding Gloves & Aprons, Ear plugs, Safety Glasses, Respiratory Masks, Furnace Clothing, High Visibility Clothing, Disposable Overalls, Work Jackets, Safety Boots & Shoes PACIFIC RIM FOUNDRY EQUIPMENT Buying and Selling Second Hand Foundry Equipment Foundry Equipment Asset Liquidations Pacific Rim Foundry Services -- Pacific Rim Casting & Patternmaking Supplies Pacific Rim Safety Products -- Pacific Rim Foundry Equipment Tel: 61 2 8883 2997 Fax: 61 2 8883 2895 Mobile 0419 433 238 Email:email@example.com