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Zinc
and its alloys
Engitec built several zinc recycling plants to process the various
types of scrap.
The
Ezinex Process
Metallic Zinc recovery from zinc bearing wastes from galvanising
industry and from unwashed crude zinc oxide.
The
Ezinex Technology
EZINEX, an acronym derived from “Engitec Zinc Extraction”, was
developed by Engitec in Italy since 1983 when a pilot plant
capable of treating 500 tons of EAF dust per year was erected
and operated at a major Italian steel mill- belonging to the
Pittini Group.
The basis of the process is metallic zinc recovery performed
by a hydrometallurgical system. Engitec’s R&D tested various
zinc containing materials from different sources like electric
arc furnace (EAF) dust from steel works, Waeltz oxides, oxides
from converters, zinc ashes.
More
about Ezinex Process
The first plant to commercially introduce the EZINEX process
to treat the full quantity of EAF dust generated by the steel
mill, with a nominal treatment capacity of 12,000 tons per year
was commissioned during February 1996.
The EZINEX process is raising great interest in a number of
EAF Dust collectors in the world, who see in this technology
the most appropriate process to maximize the value of the EAF
Dust by producing High Grade zinc metal.
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The
Indutec Technology
Recovery of crude zinc oxide and pig iron from the EAF Dust.
More
about the Indutec Technology
The INDUTEC Process is design to treat EAFD and oxidised zinc
bearing materials with high Fe content. The INDUTEC Process
is based on a low frequency “coreless” induction furnace where
the zinc bearing material is appropriately fed with coal and
slagging additives. The following results are achieved:
• the reduction of iron oxides to pig iron
• the concentration of zinc and other heavy metals in the
fumes leaving the furnace
• the formation of a glassy inert slag
the pig iron bath, kept at the right process temperature and
vigorously stirred by the inductive current, is the reducing
phase of the process where the heavy meal oxides fed to the
furnace are reduced to metal.
The liquid slag, covering the pig iron melted bath, is the
oxidising phase of the process where carbon is oxidised to
CO while the metals, leaving the melted bath, are converted
to oxides and vented out of the furnace by the gas phase.
A gas filtration unit will provide the separation of solids
from the gas stream leading to the recovery of a mix of metal
oxides, the crude zinc oxide, with a high concentration of
zinc. The final concentration of zinc strongly depends on
the composition of the feed.
As an example, the treatment of 100 t of a typical EAFD according
to the INDUTEC Process the following products are obtained:
• 24-28 t of pig iron
• 32-36 t of crude zinc oxide (Zn=50-60%)
• 32-36 t of glassy inert slag
The slag, that passes the leaching test for non-hazardous
materials, was successfully tested for the use in street building
and in sandblasting.
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