Production of SHG Zinc From 100% Recycled Materials
77
LLC (INMETCO) in 2009, adding 70,000 tons per year of specialty steel dust and
nickel waste recycling capacity to produce Ni-bearing pig iron. INMETCO generates
about 6000 tons per year of flue dusts containing over 1500 tons of zinc that are
recovered through the Waelz kilns.
By 2012, the Zinc Corporation of America electrothermic smelter in Monaca,
PA was processing over 140,000 tons per year of calcined Waelz Oxide from the
Palmerton plant, along with about 40,000 tons per year of Waelz Oxide through
its washing plant. These recycle feeds and 50,000 tons per year of purchased zinc
secondaries were processed to produce about 80,000 tons per year of zinc metal (PW,
CGG and SHG grades) and 80,000 tons per year of high-purity zinc oxide.
Increasing environmental pressures, high operating, maintenance and capital
costs, and shrinking markets for Pb-containing zinc metal led Horsehead to make
the strategic decision to embrace environmentally-friendly leach, solvent-extraction
(SX) and electrowinning technology (EW) to replace its 80-year old Monaca smelter.
Horsehead licensed the Leach/SX technology from Tecnicas Reunidas and EW
technology from Asturiana de Zinc to process Waelz Oxide and oxidic zinc secondaries and produce 155,000 tons per year of special high-grade (SHG) zinc metal.
The Mooresboro, NC plant produced its first zinc in May 2014, and the Monaca
smelter shutdown the same month. While the Mooresboro plant continued operating
through January 2016, it was plagued by unit operations capacity and design engineering constraints, which limited throughput to about 40% of design. Horsehead
filed for bankruptcy protection in February 2016 and emerged that September with
new ownership and a commitment to restart the Mooresboro facility.
With the restart of Mooresboro, AZR is the only producer of SHG zinc metal
from 100% recycled feed in the world. With an EAF dust recycling capacity of over
650,000 tons per year, AZR is uniquely positioned among steel scrap re-melters to
close the zinc life cycle loop from galvanized and other zinc-rich scrap, to EAF dust
and WOX, through to production of CGG and SHG metal ready for steel galvanizing
mills. AZR’s four regional facilities ensure uninterrupted recycling of EAF steel
producers’ dust: reclaiming a hazardous waste to produce feed for the company’s
Mooresboro zinc metal facility with minimal need for secondary zinc units (Fig. 2).
Waelz Kiln Process Improvements
The Waelzing process has been operated by AZR as the EPA-preferred Best Demonstrated Available Technology (BDAT) for nearly 40 years, having survived attempts
by as many as 30 other process methods to compete in the EAF dust market. The
combination of a robust technical process and equipment design, modest capital,
low operating costs, and proven environmental performance have enabled the Waelz
process to dominate the world market for recycling of zinc from EAF dust. AZR
now operates eight Waelz kilns, one calcining kiln, and one “swing” kiln in four
regional plants (see location map in Fig. 1). Details of the Waelzing process have
77
LLC (INMETCO) in 2009, adding 70,000 tons per year of specialty steel dust and
nickel waste recycling capacity to produce Ni-bearing pig iron. INMETCO generates
about 6000 tons per year of flue dusts containing over 1500 tons of zinc that are
recovered through the Waelz kilns.
By 2012, the Zinc Corporation of America electrothermic smelter in Monaca,
PA was processing over 140,000 tons per year of calcined Waelz Oxide from the
Palmerton plant, along with about 40,000 tons per year of Waelz Oxide through
its washing plant. These recycle feeds and 50,000 tons per year of purchased zinc
secondaries were processed to produce about 80,000 tons per year of zinc metal (PW,
CGG and SHG grades) and 80,000 tons per year of high-purity zinc oxide.
Increasing environmental pressures, high operating, maintenance and capital
costs, and shrinking markets for Pb-containing zinc metal led Horsehead to make
the strategic decision to embrace environmentally-friendly leach, solvent-extraction
(SX) and electrowinning technology (EW) to replace its 80-year old Monaca smelter.
Horsehead licensed the Leach/SX technology from Tecnicas Reunidas and EW
technology from Asturiana de Zinc to process Waelz Oxide and oxidic zinc secondaries and produce 155,000 tons per year of special high-grade (SHG) zinc metal.
The Mooresboro, NC plant produced its first zinc in May 2014, and the Monaca
smelter shutdown the same month. While the Mooresboro plant continued operating
through January 2016, it was plagued by unit operations capacity and design engineering constraints, which limited throughput to about 40% of design. Horsehead
filed for bankruptcy protection in February 2016 and emerged that September with
new ownership and a commitment to restart the Mooresboro facility.
With the restart of Mooresboro, AZR is the only producer of SHG zinc metal
from 100% recycled feed in the world. With an EAF dust recycling capacity of over
650,000 tons per year, AZR is uniquely positioned among steel scrap re-melters to
close the zinc life cycle loop from galvanized and other zinc-rich scrap, to EAF dust
and WOX, through to production of CGG and SHG metal ready for steel galvanizing
mills. AZR’s four regional facilities ensure uninterrupted recycling of EAF steel
producers’ dust: reclaiming a hazardous waste to produce feed for the company’s
Mooresboro zinc metal facility with minimal need for secondary zinc units (Fig. 2).
Waelz Kiln Process Improvements
The Waelzing process has been operated by AZR as the EPA-preferred Best Demonstrated Available Technology (BDAT) for nearly 40 years, having survived attempts
by as many as 30 other process methods to compete in the EAF dust market. The
combination of a robust technical process and equipment design, modest capital,
low operating costs, and proven environmental performance have enabled the Waelz
process to dominate the world market for recycling of zinc from EAF dust. AZR
now operates eight Waelz kilns, one calcining kiln, and one “swing” kiln in four
regional plants (see location map in Fig. 1). Details of the Waelzing process have