Recycling of Zinc from Galvanized Steel
Scrap
Shafiq Alam, V. I. Lakshmanan and R. Sridhar
Abstract A process flowsheet for zinc recovery from galvanized steel scrap in
alkaline media has been studied. The process includes leaching of zinc by sodium
hydroxide followed by solvent extraction using organic extractants containing oxine
derivatives, such as Kelex 100, LIX-26. Zinc was stripped from the loaded organic
by sulphuric acid, which was then recovered by precipitation as zinc carbonate.
Keywords Zinc · Recycling · Leaching · Solvent extraction · Steel scrap · EAF
dust
Introduction
About 80% of world’s zinc is used for galvanizing steel, which is used for making car
body. New scrap from auto sector and old scrap from auto junk go to steelmakers as
they are cheap source of feedstock for steel manufacturing industries. During making
steel from galvanized steel scrap, zinc is volatilized that goes to air as electric arc
furnace (EAF) dust, which is collected in the baghouse and landfilled. According to
the US Environmental Protection Agency (EPA), this zinc containing dust is classified
as hazardous material. In this work, a hydrometallurgical process has been developed
and patented for recovery of zinc from galvanized coatings [1]. The process flowsheet
includes leaching of zinc from galvanized steel scrap. The zinc-free scarp called
black steel was ready for feedstock to steelmakers for clean steel making. Zinc in
the pregnant leach solution (PLS) was solvent extracted and precipitated as zinc
carbonate to recover zinc as a value added product.
S. Alam (B)
Department of Chemical and Biological Engineering, University of Saskatchewan, 57 Campus
Drive, Saskatoon, SK S7N 5A9, Canada
e-mail: shafiq.alam@usask.ca
V. I. Lakshmanan · R. Sridhar
Process Research ORTECH Inc., 2395 Speakman Drive, Mississauga, ON L5K 1B3, Canada
© The Minerals, Metals & Materials Society 2020
A. Siegmund et al. (eds.), PbZn 2020: 9th International Symposium
on Lead and Zinc Processing, The Minerals, Metals & Materials Series,
https://doi.org/10.1007/978-3-030-37070-1_71
821
Scrap
Shafiq Alam, V. I. Lakshmanan and R. Sridhar
Abstract A process flowsheet for zinc recovery from galvanized steel scrap in
alkaline media has been studied. The process includes leaching of zinc by sodium
hydroxide followed by solvent extraction using organic extractants containing oxine
derivatives, such as Kelex 100, LIX-26. Zinc was stripped from the loaded organic
by sulphuric acid, which was then recovered by precipitation as zinc carbonate.
Keywords Zinc · Recycling · Leaching · Solvent extraction · Steel scrap · EAF
dust
Introduction
About 80% of world’s zinc is used for galvanizing steel, which is used for making car
body. New scrap from auto sector and old scrap from auto junk go to steelmakers as
they are cheap source of feedstock for steel manufacturing industries. During making
steel from galvanized steel scrap, zinc is volatilized that goes to air as electric arc
furnace (EAF) dust, which is collected in the baghouse and landfilled. According to
the US Environmental Protection Agency (EPA), this zinc containing dust is classified
as hazardous material. In this work, a hydrometallurgical process has been developed
and patented for recovery of zinc from galvanized coatings [1]. The process flowsheet
includes leaching of zinc from galvanized steel scrap. The zinc-free scarp called
black steel was ready for feedstock to steelmakers for clean steel making. Zinc in
the pregnant leach solution (PLS) was solvent extracted and precipitated as zinc
carbonate to recover zinc as a value added product.
S. Alam (B)
Department of Chemical and Biological Engineering, University of Saskatchewan, 57 Campus
Drive, Saskatoon, SK S7N 5A9, Canada
e-mail: shafiq.alam@usask.ca
V. I. Lakshmanan · R. Sridhar
Process Research ORTECH Inc., 2395 Speakman Drive, Mississauga, ON L5K 1B3, Canada
© The Minerals, Metals & Materials Society 2020
A. Siegmund et al. (eds.), PbZn 2020: 9th International Symposium
on Lead and Zinc Processing, The Minerals, Metals & Materials Series,
https://doi.org/10.1007/978-3-030-37070-1_71
821