Emission of organic compounds from mould and core binders used for casting iron, aluminium and bronze in sand moulds

Abstract

Emissions from mould and core sand binders commonly used in the foundry industry have been investigated. Degradation of three different types of binders was investigated: Furfuryl alcohol (FA), phenolic urethane (PU) and resol-CO₂ (RC). In each group of binders, at least two different binder compositions were tested. A test method that provides uniform test conditions is described. The method can be used as a general test method to analyse off gasses from binders. Moulds, containing a standard size casting, were produced and the amount and type of organic compounds, resulting from thermal degradation of binders, was monitored when cast iron, bronze and aluminium was poured in the moulds. Binder degradation was measured by collecting off gasses in a specially designed ventilation hood at a constant flow rate. Samples were taken from the ventilation system and analysed for hydrocarbons and CO content. It is shown how off-gasses vary with time after pouring and shake out. Also the composition of off-gasses is analysed and shown. It is further shown how the composition of off-gasses varies between different types of binders and with varying composition of the binders as well as function of the thermal load on the moulding sand.

Keywords:

• Binder
• emission
• casting
• degradation
• mould production

Acknowledgments

The project was initiated and funded by the Danish Ministry for the Environment, and run by the Danish Foundry Association. Experiments have been carried out at the Technical University of Denmark, Department of Mechanical Engineering in collaboration with the Danish Technological Institute. Chemical analysis was carried out at Danish Technological Institute.