Metallurgical and Materials Engineering doctoral student Joseph Grogan has developed an environmental friendly dezincing process that recycles the galvanized steel in its entirety. While the steel component of galvanized steel is mostly recycled nowadays, the zinc component is often not. This technology produces a zinc sulfate that could be marketed as fertilizer and the remaining steel used as an alternative feed material to a foundry.
Due to issues including health and safety concerns at facilities that would recycle this type of steel, Grogan has created a simple hydrometallurgical (water based process) method with lower costs for removing the zinc coating on galvanized steel scrap.
“For reasons including environmental stewardship and sustainability, the reuse of metals in society is a good thing,” Grogan said. “This de-zincing process has zero waste discharge – minimizing environmental impact while completely recycling the zinc and steel.”
Galvanized steel has a lower market price compared to regular scrap metal, but is problematic to recycle as zinc vaporizes at lower temperatures than iron. Facilities that recycle this type of steel require gas and dust collection systems to capture the zinc. The dust can be recycled at a significant cost, but it is often landfilled, dependent on the jurisdiction.
“As commodity prices rise with increased demand and mine supply constraints, resources from recycling are frequently a more viable and significant supply for many metals,” Grogan said. “These increasingly complex recycling streams will require a host of new processes to recycle them economically. Extractive metallurgy is a field which specializes in developing the techniques and technologies needed to recycle these complex materials.”
Grogan’s research was supported through the Center for Resource Recovery and Recycling, of which Colorado School of Mines is an academic partner.
In the fall, Grogan was the recipient of the 2014 National Scholarship from the Recycling Research Foundation for his research supporting scrap processing and the recycling industry.
Grogan began this research in 2011, along with Department of Metallurgical and Materials Engineering professors Corby Anderson and Gerard Martins. He is studying at the Kroll Institute for Extractive Metallurgy at Mines and will earn his doctorate degree in May.
Contact:
Kathleen Morton, Communications Coordinator / 303-273-3088 / kmorton@mines.edu
Karen Gilbert, Director of Public Relations / 303-273-3541 / kgilbert@mines.edu
