Organic binders applied in foundry plants based on synthetic resins,
from the one side influence obtaining the required technological
properties by the moulding sand and – in consequence – obtaining good quality
castings, and on the other side are the source of volatile
organic compounds (VOC). Together with synthetic resins their hardeners, which
although added in very small amounts emit during their thermal
decomposition substances negatively influencing the natural environment,
are also used. Both, resins and hardeners only at the influence of high
temperatures accompanying moulds pouring with liquid metal generate
harmful volatile organic compounds including compounds from the BTEX
group. Investigations of the temperature influence on the kind and
amount of organic compounds formed during the thermal decomposition of
selected binders and hardeners and their mixtures allow to determine
temperature ranges the most favourable for emitting harmful substances
as well as to compare their emission from the selected materials. The
aim of this study was the determination the temperature influence on
formation substances from the BTEX group, during thermal decomposition
of the selected binder, its hardener and their mixture. The BTEX group
emission constitutes one of the basic criteria in assessing the
harmfulness of materials applied for moulding and core sands and it can
undergo changes in dependence of the applied system resin-hardener.
Investigations were carried out on the specially developed system for
the thermal decomposition of organic substances in the temperature
range: 5000 C – 13000 C, at the laboratory scale. The investigations
subject was the furan resin, its hardener and hardened furan resin. The
assessment of the emission degree of the BTEX group in dependence of the
system subjected to the temperature influence was performed, within the
studies. The temperature range, in which maximal amounts of benzene,
toluene, ethylbenzene and xylenes were emitted from tested materials –
was defined. The qualitative and quantitative analysis of the BTEX group
were carried out with using the gas chromatography technique coupled
with the mass spectrometry (GC/MS).