Turning copper waste into valuable raw material

Sustainable management encompasses many aspects. A key task is to use limited resources sparingly. To this end, AT&S is developing processes to recover valuable copper and gold from production waste – at the same time reducing the consumption of chemicals, waste and emissions.

By Helmut Spudich

In ancient times, copper was the first metal that boosted people’s productivity. While gold and silver were first discovered and highly attractive, but were used practically only for jewelry, copper and its alloys were the first material to replace stone in the manufacture of implements, tools, and weapons.

Today, in the digital age, copper is the material from which digitization is woven. Copper is an indispensable raw material in the production of printed circuit boards. AT&S processed 4066 tons of copper in 2020, explains Theresa Gruber, Specialist Corporate Sustainability at AT&S, in an interview with the AT&S blog. Every gram of metal counts during processing: the more efficiently the raw material is used, the lower the costs, less waste, and lower emissions in manufacturing and transportation.

AT&S has launched its own copper recycling project for a resource-saving production. Many chemicals are involved in the manufacture of printed circuit boards: This results in copper-containing sludge, which must be disposed of with extreme care. This is where the “hunt” for the remaining usable copper begins. The goal: “We want to move away from linear production to a circular economy,” says Gruber.

Reclaiming 75 percent of copper used

The result of waste recycling is considerable: After implementing recycling processes 75 percent of copper used can be reclaimed. This also has several positive side effects, describes Gruber: “We have to use significantly fewer chemicals in the production process. And since fewer raw materials and chemicals must be transported to our plants, we reduce the CO2 emissions associated with the transport considerably. ” In the future 75 tons of hydrochloric acid less will be used, in turn saving 2.5 tons of CO2 during transport. The recovered copper in turn reduces the CO2 emissions during transport by 24 tons.

So far, copper recycling has been carried out in a pilot plant that is due to go into regular operation in the near future. In the medium term, these investments in circular production should pay off and not only result in a more economical use of raw materials and less waste, but also reduce production costs.

Another AT&S project will bring savings in the use of gold. Gold and palladium are used for surface treatment in the electroplating processes involved in the manufacture of printed circuit boards. There is a large amount of chemicals used, which in turn means rinsing has to be carried out continuously with pure water in various production steps – with gold not only ending up on circuit boards but also in the wastewater.

Sustainability will become a competitive factor

In the future this process should also take place in a largely closed cycle, explains Gruber. As with copper recycling, the benefits are obvious: lower energy consumption, fewer chemicals, less waste and more efficient use of gold. In numbers of the pilot project: Once this production cycle is running stable it will avoid 17 kilograms of potassium gold cyanide and 320 kilograms of chemicals. 250 cubic meters of ultrapure water and 250 cubic meters of wastewater will be saved compared to the current production mode.

Gruber is convinced that production that is proven to be sustainable will be a prerequisite for surviving in international markets over the next few years. Corporations are under increasing pressure to give their customers an account of how they use valuable resources and their ecological “footprint”. That is why R&D and corporate sustainability work hand in hand on a large research and development project to draw up a life cycle assessment of product groups.

“Just as the ÖBB, Austria’s Federal Railroads, shows you on your train ticket exactly how much CO2 was saved on this journey compared to using a car, we want to give our customers precise information about the environmental balance of a product,” Gruber describes. In relation to a location – Hinterberg will be first – the exact balance is given of the environmental impacts of the production facility, which resources are used, which CO2 emissions and water consumption arise, which land use is associated with it, and much more. “This is an extremely complex process and boundaries between systems are very difficult to draw. But only if such data is available along the entire production and supply chain can a statement really be made about the sustainability of products.”


Published On: 9. December 2021

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