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Demonstration of environmentally friendly aluminiu.. (INOCAST)
Demonstration of environmentally friendly aluminium engine block Core Package casting (CPS) using an inorganic binder
(INOCAST)
Start date: Jan 16, 2005,
End date: Jul 15, 2007
PROJECT
FINISHED
Background
At the core of every motor vehicle is an engine block, usually made from cast iron or aluminium. Since using aluminium reduces engine weight and thus improves efficiency, 98% of all cylinder heads and 50% of engine blocks in Europe are currently made of aluminium.
The standard Core Package Casting process for casting aluminium engine blocks is the cold-box technique as used before the project at the Hydro Dillingen plant. However, this technique releases substantial amounts of toxic fumes, including aromatic amines, furan, benzopyrene and other organic materials, into the air. Furthermore, the binder used to create the sand mould for the casting also releases organic compounds such as phenol resins and amines into the air when it is burned off the cast at the end.
The process uses significant energy resources, especially during the final stage when the mould and cast are heat treated to make the cast stronger (tempering) and to burn off the organic binder. The heat needed for this tempering stage was responsible for about 56% of total energy consumption of the Dillingen plant (248,600 MWh) in 2005. Finally, the process also generates substantial quantities of waste, including water, filters, sand and sulphuric acid.
Objectives
The LIFE-Environment project Inocast sought to demonstrate the effectiveness of an alternative process to the cold-box technique used by most foundries for casting aluminium. Known as the âInorganic Warm-Boxâ process (or AWB from its German name), it uses a new inorganic binder together with Minsand ® to build core moulds for the production of the engine blocks. These moulds can be mechanically de-cored, which does not release toxic fumes into the air.
In 2003, the Dillingen plant emitted 1,365 tonnes of organic binder, including 700 tonnes of phenol resin solution containing phenol, formaldehyde, naphtha and methanol, 665 tonnes of isocyanide-mixture containing diphenylmethane and aromatic hydrocarbon and 188 tonnes of catalytic converter made up mainly of ethyldimethylamine. It aimed to reduce these emissions to zero.
This process had been refused by automobile manufacturers because of a lack of prototypes which could be quality tested. The project therefore, as well as aiming to demonstrate the environmental advantages of the process in reducing energy consumption, emissions, deposits and waste water, also sought to demonstrate its technical effectiveness.
The Inocast project was to be carried out in a small pilot plant (development centre) at Dillingen next to the two main âproduction streetsâ. The pilot plant was to be located about 30 metres away from the production buildings and exclusively used for testing and demonstrating new technologies in aluminium casting.
Results
The Inocast project successfully demonstrated substantial improvements to the traditional cold-box technique for casting aluminium through the establishment and optimisation of a pilot core production and casting unit using AWB. It was able to lay the foundations for the future use of AWB for the mass production of aluminium engine blocks and cylinder heads with reduced environmental impact. The project was selected by the European Commission as one of the best LIFE-Environment projects completed in 2007.
The beneficiary set up a full-scale pilot core production and casting unit to test and develop the warm-box technology free of organic binders. It was able to reduce inorganic components by 93-99% and the typical foundry emissions of phenols, formaldehyde, naphtha, methanol and amines to below measurable concentrations. It avoided pollution by removing the need to use isocyanide-mixture containing diphenylmethane and aromatic hydrocarbon and a catalytic converter made up mainly of ethyldimethylamine.
The project achieved significant cuts in energy consumption, with the overall energy requirements of the tested AWB process down 37% compared to the traditional technique, equating to a reduction of 25kWh per casting. This was mainly achieved thanks to a reduction in heat treatment after casting of 93% and a halving of the electricity requirement of the cooling water cycle and compressors.
The process also generated 80% less dust pollution and reduced levels of waste materials, such as sand, filters, phenol resin solution, sodium hydroxide and sulphuric acid to zero. For the Dillingen plant alone, this could represent a saving of 4,987 tonnes of quartz sand, 676 tonnes of sulphuric acid and 39.5 tonnes of sodium hydroxide. Tool cleaning can be done with a closed loop water cycle and 100% recovery of the inorganic binder.
After a series of modifications and optimisations, the Inocast project also achieved excellent technical results. Measures included the introduction of micro-wave drying and sand washing and a change of the binder. Laboratory examination showed no deficiencies of the castings compared to those produced with conventional technology. It also achieved a curing time of 70 seconds, which is important for integration into automated assembly lines.
Although the project was not able to reach the stage of mass production, it did deliver proof that the new technology is reliable and ready for market. Such a demonstration is crucial in achieving acceptance from the automotive industry and promoting private investment in the development of the process. Furthermore, the generic production technology demonstrated has already proved highly interesting to other business fields, including bathroom fittings and plastics.
This project has been selected as one of the 21 "Best" LIFE Environment projects in 2007-2008