Synergie Clean-Tech
Metal Fines Recycling Center
EAFDs are a waste of the steel processing process and may have chemical compositions that vary greatly depending on the type of steel from which they derive, the quality of the scrap and the ferroalloys used, and finally the process conditions; however, in general, the powder coming out of the plants that produce ferritic steels has large quantities of iron oxides, zinc and lead, and in the case of production of stainless steel oxides of iron, nickel, chromium, and manganese, some cases of molybdenum.
EAFDs are a dangerous waste. The quantities of EAFD generated by steelmaking correspond to around 2% of the steel produced.
EAFDs deriving from ferritic steels currently come:
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treated through the so-called Waelz process that recovers a zinc oxide concentrate, generating an equal amount of slag that presents iron oxides and other metals and which is disposed of in special landfills.
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disposed of in special landfills
EAFDs derived from stainless steels currently come:
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disposed of in special landfills
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treated in plasma furnaces
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briquettes and refused in conventional electric arc furnaces
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fmelted directly in electric arc furnaces with Clean Tech arc.
These last three treatment systems recover almost all iron and ferrous metals in the form of ferroalloy ingots, generating secondary fumes with a high concentration of zinc oxide and slag.
Electric Furnace fume dust (Electric Arc Furnace Dusts - EAFD)
Clean-Tech Process: Integrated system with 3 different technologies
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An electric furnace equipped with a fume extraction system (be it a direct current plasma furnace, a traditional alternating current electric oven in which the dust can be charged after briquetting or a "Clean-tech" electric furnace in current alternate where the powder can be loaded as it is) capable of converting the powders into: ferroalloy in which ferrous metals are concentrated, inorganic slag and fume dust in which zinc oxide and other non-ferrous metals are concentrated (CZO).
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A fiber line where the inorganic slag in the liquid state produced by the electric oven is completely converted into mineral wool.
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An "Ezinex" refining line, where the CZO, through a leaching and electrolysis process, is converted into zinc and cement cathodes in which lead and the other non-ferrous metals it contains are concentrated.
Solution to the technical problem:
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The "Clean Tech" process improves the current recycling processes of EAFD both from an economic and environmental point of view as it exploits the interaction between the different technologies used, reducing energy consumption and eliminating the costs of waste disposal.
In particular it improves:
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the melting process of powders because the waste generated by it is processed and enhanced
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the process of zinc refining, since the pre-melting of the powders generates a zinc oxide concentrate free of ferrous metals that would affect the electrolytic phase by not allowing the production of the zinc cathode
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the production of mineral wool, as it directly exploits the slag coming from the furnace, eliminating the melting process normally adopted with a high saving of electricity
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the logistics management of raw materials, eliminating the relative transport cost, for each of the processes downstream of the kiln (production of mineral wool and of the zinc cathode)
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Industrial applicability:
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The "Clean Tech" process can be applied industrially in a systematic manner within recycling centers or in the steel mills themselves, reducing the current disposal costs and generating circular economy, since both the ferroalloy ingot and the resulting zinc cathode can be used as raw material for the production of steel, while mineral wool finds its way into the market of thermal insulation and lead cement can be sold to battery recycling centers.
Announcements:
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To date, there is no integrated system of technologies on the market that allows the total recovery of metals contained in the EAFD without generating waste. The "Clean Tech" process is an absolute novelty in this specific field.
