A new thermal transformation process recycles waste toner powder in a sustainable and environmentally friendly manner (Credit: American Chemical Society)That printer cartridge you just threw out still contains some toner powder. To prevent this form of electronic waste from clogging landfills, Australian researchers devised a sustainable and industrially relevant process to transform waste toner powder into a value-added ferrous resource.

About 500 million cartridges out of the estimated 1.1 billion sold each year end up in landfills worldwide, according to the European Toner and Inkjet Remanufacturers Association. These supposedly “empty” cartridges can contain up to 8 percent of unused residual powder by weight and could leach compounds into the soil and underground water sources. Past research has converted residual powder into oils, gases and even an ingredient in asphalt, but the team from University of New South Wales and TES AMM Australia Pty Ltd sought to develop a new reuse technology.

Heating toner powder in a furnace to 1,550 °C converted the inherent iron oxide to a product that was 98 percent pure iron using the polymer resins within the toner powder as a source of carbon. The process delivers an iron recovery of 81.6% and could be ideal for industrial applications because iron and steel are typically made at this temperature. Heating the powder at such a high temperature prevents toxic side products from forming, providing an environmentally friendly way to recycle residual toner.