Future-proof chemical pre-treatment process for vertical powder-coating lines

A second driver is the ‘chemical strategy of the EU’, which aims to better protect citizens and the environment and encourage innovation in safe and sustainable chemicals. AD Chemicals is at the forefront of the market with chemical pre-treatments that enable companies to reduce their carbon footprint. Key components of this strategy are energy saving, water conservation, reduction of chemical consumption and maintenance costs, while maintaining the highest quality in paint adhesion and corrosion protection.

To reduce the footprint of its production process, AD joined forces with Corialis Group, a major player in the aluminium industry. Together, they conducted an in-depth analysis of the chemical pre-treatment process of the vertical powder-coating lines at two production sites (ALIPLAST BELGIUM N.V./S.A., Belgium and LINGOTE ALUMINIOS S.A., Portugal). The production site in Belgium is Qualicoat Seaside certified and the site in Portugal is Qualimarine certified. This case study shows that when supplier and manufacturer intensify their collaboration, solutions are realised that significantly reduce the carbon footprint. This results in important steps being taken to future-proof the production process.

The project fits within Corialis’s sustainability strategy. Sustainability is central to Corialis’s business model, which is reflected in its product range, as well as in its procurement and production processes. Corialis’s strategy focuses on the following areas: recyclability, longevity, sustainability and good governance. This places Corialis in a strong position to meet the new EU standards for construction and renovation.

Analysis and comparison

The process analysis reveals several focus areas where the footprint can be significantly reduced compared to similar companies in the sector. The figures presented are based on actual performance within Corialis plants compared to other companies with a traditional process. Optimisations were carried out in the following areas: energy consumption and (waste)water usage (preparation for wastewater-free systems).

Energy saving

Many companies in industry still operate with heated process baths for their cleaning and pickling processes (around 50°C on average). Whether these process baths run on gas or electricity, they consume a lot of energy. New chemical technologies make it possible to significantly reduce the temperature of these process baths to 30–35°C. Energy savings of up to approx. 66.7% can be achieved when using these lower temperatures.

(Waste)water saving

Due to a combination of pollution and overconsumption, droughts and water scarcity are no longer considered rare or extreme in Europe. About 20% of Europe’s land and 30% of its population are affected by water scarcity every year. Water scarcity can be expected to be an even greater challenge in the coming years as the climate changes. Regions across Europe are seeing an increase in the frequency of droughts. Southern European areas in particular are expected to experience more water shortages over the next decade, with potentially disastrous consequences for industry (Source: EIT Food, 2023). This underlines the vital importance of water conservation.

In traditional pre-treatment lines, the cleaning and pickling zones often cause negative effects, such as carry-over of chemicals to subsequent process steps and sludge formation in the baths. This leads to unnecessarily large wastewater volumes. AD’s chemical process has an optimised pickling process that significantly reduces (waste)water flows. At the Aliplast line in Belgium, which is Qualicoat Seaside certified, the cleaning and pickling steps are both acidic in nature, reducing the negative effects of carry-over. Moreover, the entire (waste)water flow is more efficient, leading to additional savings on wastewater and fresh water. In Portugal, the pickling process has been optimised in line with the Qualimarine standard.

The challenge is to find the right balance between sufficient water flushing and minimal water consumption. A key element in this ‘sustainable water system’ is the recirculation of water streams in the process, a unique feature of the AD Chemicals process. An added advantage is that this process also reduces chemical consumption and enables energy and maintenance savings.

How much water can be saved? As a benchmark, a cascade line with an output of 11,000 m² of aluminium per day can switch from an average water consumption of 4,000–5,000 litres per hour to 500–900 litres per hour. This results in an 87% reduction in water consumption, in turn reducing the ecological footprint and contributing to water availability in arid areas.

Quality

These optimisations represent important steps in making the pre-treatment process more sustainable for vertical powder-coating lines. The chemical pre-treatment process has proven to be stable through years of experience. The improved cleaning and pickling process, followed by a chromium-free conversion layer, results in an aluminium surface ready for coating, with excellent paint adhesion and anti-corrosion properties. These properties exceed the standards of Qualicoat, GSB and Qualimarine. These labels require 1,008 hours of AASS, while AD and Corialis have shown that quality standards are still met even after 3,024 hours of AASS.

Next steps

In addition to the pre-treatment line optimisations discussed that reduce the carbon footprint, AD and Corialis are investigating further improvements. One theme is the possibility of recycling chemicals. This demonstrates both companies’ drive to innovate and highlights that when companies strive for continuous improvement, sustainability becomes achievable.

By reducing the footprint of the vertical pre-treatment line, AD and Corialis are contributing to a more sustainable construction value chain that meets increasingly stringent carbon requirements. This is crucial during the procurement phase, essential for maintaining competitiveness, and necessary to create long-term solutions that benefit society as a whole.