The degalvanizing process will be tested on shredded auto scrap. This is the largest source of ferrous scrap. The process consists of dissolving the zinc coating from scrap in a hot, caustic solution and recovering the zinc from the solution electrolytically. The zinc-bearing scrap is charged in an electrolytic cell containing a 7090 degrees C sodium hydroxide solution. Applying an electric potential dissolves the zinc into the hot caustic.
Clean scrap is removed, rinsed, and recycled.
The electrolyte is then pumped into a second cell, where the zinc is electrolytically removed from the solution. The zinc can be sold to refiners for purification and resale. This plant has dezinced over 1,000 tons of automotive stamping waste, and tests have demonstrated that the process can remove not only zinc, but also many plastic coatings. Tests continue to evaluate process economics and operation. Future Plans Plans are to provide 1,500 tons of dezinced scrap for a melt test to determine the environmental impact of dezinced scrap on furnace operations.