Phenolic Binders Based on Resole Resins for the Foundry Industry - Thermal Characteristics

The composition of gases emitted from commercial resin-based binders, under the influence of high temperatures of liquid metal (up to 1500°C), is determined in this summary with a view to assessing the potential harmfulness of these gases to the environment and workers. Mesaurements have been carried out using coupled analytical techniques, such as e.g. HS-GC/MS (Headspace/Gas Chromatography/Mass Spectrometry) or TG/DCS/FTIR (simultaneous Thermogravimetry/Differential Scanning Calorimetry coupled with Fourier Transform Infrared spectroscopy), which allow the simulation of conditions during casting production. A review of the existing literature indicates that the thermal decomposition of commercial resin-based binders is typically characterized by a multi-step process involving a series of sequential reactions, depending on the type of atmosphere. The process of decomposition has been observed to result in the release of various compounds, including water, carbon monoxide, carbon dioxide, phenol, BTEX (benzene, toluene, ethylbenzene and xylenes) and PAHs (polycyclic aromatic hydrocarbons) groups and others, from the tested binders. The composition and quantity of these gases have been found to be contingent on the type of binder, the temperature, and the heating rate of the sample. The decomposition of the binder has been demonstrated to occur through different mechanisms, which depending on the heating rate of the samples.