A Circular Solution to Mixed Waste Paint Recycling

Improvements in the sustainability of the coatings industry has been on the agenda for a number of years, particularly in the reduction of volatile organic compounds (VOCs). Environmental and Health legislation regulating the levels of VOCs in coatings and longer-term emissions of other volatiles has driven a major shift in the coatings industry so that more than 80% of decorative paints now sold in the UK and Europe are water-based. The focus for the industry has now expanded to include energy and resource conservation, waste minimisation, improved process efficiency, and the use of renewable and recycled materials for enhanced sustainability. Approximately 90% of the environmental footprint of coatings is shared equally between that generated through raw material manufacture, and through downstream use and disposal.

The most in-demand pigment used in paints and coatings is titanium dioxide (TiO2), found in over 90% of products because of the opacity, aesthetics, durability of colour and protection properties it provides. Production of TiO2 involves high embodied energy, emissions of polluting waste streams, and the extraction of scarce natural resources. Any improvements to the environmental footprint of TiO2 use is to be welcomed, and recycling of pigment from the approximately 56 million litres of waste paint generated in the UK each year, much of which goes to landfill, is one opportunity to achieve this.

Currently, no technology can separate waste paint components to provide a commercially viable recovered pigment product on an industrial scale which does not exhibit significantly reduced performance compared to first-use product. In a previous Innovate UK-supported project, PRA successfully developed a lab-scale process for recovery of TiO2 with similar physical and chemical properties to virgin product for re-use as a high-quality pigment; other mineral components can also be recovered for reuse as pigments, fillers, and extenders.

This industrial research project is a collaboration between three of the most important organisations in the paint and coatings industry in the UK -- PRA World, Crown Paints, and Venator. Successful scale-up of PRA's process, developing the technology from lab to pilot plant will enable local authorities to save costs for waste paint disposal, making recycling financially attractive. This will mitigate the growing environmental burden posed by waste paint disposal/flytipping and will contribute to sustainability in the industry and to UK government recycling and landfill reduction commitments. Successful development of this process presents a step change in waste paint recovery and recycling.