By Alec Arbia, Written Communications Assistant
Jack Kaszas, undergraduate materials science and engineering (mse) major, is excited to reveal the results of his independent research project. He was successfully able to recover silver from several computer keyboards.
“Keyboards each contain two thin sheets of silver-plated plastic,” Kaszas explained. “These sheets lie below the keys, and when a key is pressed it causes the two silver-plated sheets to touch. This completes a circuit, and depending on the resistance of the circuit formed, the computer can tell which key is being pressed.”
Kaszas then went on to explain how the silver was recovered. “I first soaked silver-plated sheets from 46 keyboards in dilute nitric acid (HNO3), which caused the silver plating to dissolve as silver nitrate (AgNO3). I then separated the silver from the solution by adding a small amount of hydrochloric acid. Silver compounds form insoluble silver chloride in the presence of chloride ions and precipitate from solution (AgNO3 + HCl -> AgCl +HNO3). Next, I washed the silver chloride (a white solid) with water and added lye to convert it into silver oxide (2AgCl + 2NaOH -> Ag2O + 2NaCl + H2O). I then reduced the silver oxide to silver metal by adding sugar. The sugar molecules donate electrons to the silver oxide to create a finely divided silver powder. After washing with water, I melted the silver powder into a shiny button with a blowtorch.”
Department head Bryan Huey notes: “This is such a great example of how MSE students can align their own passions, apply the concepts they’ve learned in our program, and leverage our amazing undergraduate lab facilities. In this case the work was totally driven by Jack’s creativity, and an interdisciplinary collaboration between Professor Fiona Leek (MSE) and Professor Christian Brückner (Chemistry). It was really surprising just how big of a lump of silver Jack was able to reclaim—I expect that’ll sit on his desk for years to come and impress everyone who asks about it.”
The research project’s primary goal was to explore the recovery of valuable metals from electronic waste. Kaszas chose this topic due to his interest in applying mse to sustainability. “I want to use my engineering knowledge to explore recycling pathways and carbon neutral materials manufacturing.” Kaszas will be graduating in May 2023.
Published: March 23, 2023