Whether in our personal lives or in business, environmental sustainability is an increasingly high priority. We all must do our utmost to comply with new, more stringent and/or revised regulations in order to leave a healthier plant for the next generation.
Now is therefore the right time to apply products that can reduce the environmental impact of foundry operations.
Foseco has taken the challenge on board with a new water-based coating that helps foundries reduce their FH release emissions at the point in the process where concentration is highest: The exhaust chimney of the core drying plant
This article will discuss water-based foundry coatings that are designed to reduce formaldehyde (FH) emissions. In doing so, they support foundries in achieving compliance with the latest EU regulations of FH release emissions in coating drying processes.
Introduction
All water-based systems are susceptible to the growth of microorganisms, such as bacteria and fungi, which can influence the performance of those systems and lead to significant changes during application. Microorganisms can also impact the health of the operators who use contaminated products.
In order to avoid such effects and protect water-based systems, biocides are included in their composition. In the foundry environment, water-based coatings are the main products that require this type of protection.
Beside the applied coating, there are quite a number of other FH-releasing items in a core shop, such as binders and additives, that contribute to the overall FH emissions. The picture depicts coating colour change on drying
The biocides commonly contain FH, which is a powerful antibacterial and antifungal agent. This FH is released under specific conditions, such as those found in coating drying processes, and therefore contributes to the overall FH emissions of the foundry.
This presents a challenge, however, as FH is considered a harmful substance and regulated as such by the EU. The EU regulation on the emission of harmful substances (2008/50/EG) has recently been revised to further reduce allowable FH emission levels from 20mg/m³ to just 5mg/m³. Even foundries with exhaust gas treatment facilities are required to adopt the new limits.
As an example, the revised directive has been translated for Germany as the new TA-Luft regulation, which requires re-adjustments of emissions levels at old and/or existing plants. In many cases, this would lead to investment in new gas treatment systems. The new limits have been in force since February 2020.
Foseco has taken the challenge on board with a new water-based coating that helps foundries reduce their FH release emissions at the point in the process where concentration is highest: The exhaust chimney of the core drying plant.
This article will not discuss FH levels in Foseco coatings as such, however, but the total FH emissions to which the coating drying process contributes.
After evaluation of different ways to determine FH emissions, we found FTIR (Fourier Transform Infrared) spectroscopy most suitable, being accurate to the necessary standard and because the equipment is compact. The test set up consists of a sealed drying oven containing a fixture to hold the sample, a heated exhaust sampler and heated pipes to avoid any condensation. The heated pipes are connected to the gas analyser, which can then determine different pollutant gas streams, even those that occur concurrently
Foundries applying water-based coatings are following an established trend away from solvent-based coatings in order to better comply with environmental demands. However, these water-based products require protection against microbiological attack:
Water based coating – Bacterial Infection – Effects/Actions/ Solutions
Since the conversion from solvent-based to water-based coatings is happening with increased speed in Europe, it is necessary to direct foundries’ attention to the effects of microorganisms on coating performance, which are not usually well known.
Conclusion
Beside the applied coating, there are quite a number of other FH-releasing items in a core shop, such as binders and additives, that contribute to the overall FH emissions. On top of this, during several process steps, e.g., core blowing, drying and storage, FH can be released by components that reassemble / restructure / convert to different chemicals and set FH free as a step in this alteration process.
During the above FH investigation, it became obvious that the new SEMCO FF generation of coatings is only the very first step for modern water-based coatings that will help foundries to comply with the latest EU regulatory requirements.
The next step for coating development will be to evolve the coating into a FH barrier, where the FH-free coating actually absorbs FH released from the sand binder or additives.
All this is combined with a final opportunity to optimise the drying process by incorporating colour change on drying technology. This quickly and easily allows core shop operators to see when the drying process is complete, optimising energy consumption and hence reducing costs and the carbon footprint of core shop operations.
References and download the full article option
All work mentioned in this paper was undertaken in Foseco laboratories and represents the results of those investigations.
The research, results and discussion are documented in Foseco’s well-known Foundry Practice magazine. References and graphs have been removed from this shortened version of the research paper because of space constraints. A full version of the paper is available BY CLICKING THIS LINK: https://www.vesuvius.com/en/our-solutions/international/foundry/newsletter/foseco/semco-ff.html
The authors of this paper are Christoph Genzler and Rene Roeleveld, both of Foseco
For more information contact Foseco on TEL: 011 903 9500 or visit www.foseco.com
