Recycling Powder

Q: Is it possible to sell or donate used powder from the extractor bins to anyone to recycle? Someone mentioned they may use it in laying new roads, but I also wondered if there may be a market somewhere to use it on metal that wouldn’t be seen.

This is a great question and also a rather misunderstood proposition. There are a few options to consider. One, as you mentioned, is to find a coating requirement that has no color or aesthetic specification and perhaps only a modest durability requirement. Rolled steel joists (RSJs) could be a suitable application, however, one must be careful to be cognizant of any requirements that the finish may need to meet. More on that in a moment.

Another concept is to use the organic-based particles as a filler for a modest quality product. Sanjeev Bagaria, CEO of GBB International, gave a presentation at the 2022 Powder Coating Summit and suggested that surplus powder coatings be used as a filler/binder for garden pavers, patching compounds and entry-level latex paints. His company has done work in these applications and he claims technical feasibility.

Using spent powder as a component of a powder coating is another option that has been explored through the years. InnovaKote, located near Grand Rapids, Michigan, has been recycling surplus powder coatings into new powders for a few years and they report commercial success. They take surplus powder, characterize it, then use it with fresh raw materials to create a new powder coating. I have seen a very similar process at SBS (Steel Belt Systems) at their facility in Villafranca, Sicily.

Surplus powder coatings can also be used as a binding agent for fibrous insulation. A continuous matte of fibers is conveyed horizontally, then sprinkled with organic powder. The powder-laden fibers are then compressed and heated, creating a tough batting that can be used as an insulative sound deadener.

And now for the misunderstood aspect. Assessing the quality of spent or surplus powder coatings is an inexact science. Unless rigorous compositional analysis is performed, you can’t be certain of what’s in the formula and hence what performance to expect. Consequently, high-quality end uses such as structural concrete must be avoided. The composition and quality of materials used for bridges, roads and building structures is strictly regulated; therefore, introducing a relatively unknown filler is not allowed.