Metso Outotec Research Center hosted two early-stage researchers (Pelin Altinkaya and Ivan Korolev) working on leaching and electrochemical recovery of critical and valuable metals in cyanide-free solutions under supervision of Professor Mari Lundström. The research was focused on leaching kinetics of metal dissolution and selective electrowinning of metals from complex process solutions. Optimal leaching parameters for gold extraction were evaluated using response surface methodology.
Collaboration between Metso Outotec Research Center and Aalto University resulted in several successful research projects. The goal of one of the investigations was to extract gold from mildly refractory ore in cyanide-free glycine agitating leaching media, followed by gold recovery from pregnant leach solution. This study was conducted by Pelin Altinkaya, Zulin Wang, Ivan Korolev, Joseph Hamuyuni, Mika Haapalainen, Eero Kolehmainen, Kirsi Yliniemi and Mari Lundström.
The results of the mentioned research have been published in the peer-review international journal. The study showed two major findings: that the adequate gold extraction (90%) can be achieved in totally cyanide-free glycine media, with intensive agitation in the presence of oxygen within the industrially acceptable timeframe (Figure 2), and that gold can be successfully (88%) recovered from pregnant glycine solution by the electrochemical-redox replacement (EDRR) method.