We recycle hazardous electric arc furnace dust and convert it into a valuable commodity. But that’s an easy way to talk about a complex process.
The Origin of Electric Arc Furnace Dust
Since the invention of electric arc furnaces in the 1880s, melting scrap steel in electric arc furnaces (EAF) produces EAF dust, a hazardous waste byproduct. In the past, steel producers disposed of EAF dust in hazardous waste landfills. Today, EAF dust is recycled and recovers valuable metals.
EAF dust contains valuable non-ferrous metals, especially zinc, nickel, and iron. It also contains smaller amounts of lead, chromium, and cadmium which can be harmful to human health and the environment.
At our five recycling facilities, EAF dust is recycled and valuable metals are reclaimed for downstream use in a variety of markets.
Carbon Steel EAF Dust Recycling
EAF dust from carbon steel producers is shipped to one of our four Waelz kiln recycling facilities, where valuable metals are reclaimed as Waelz Oxide product, more commonly known as Crude Zinc Oxide (CZO) or Waelz Oxide (WOX).
At our recycling facilities, EAF dust is fed along with coke or coal into a Waelz kiln, which is a large, rotating metal tube. In the kiln the EAF dust is tumbled and heated to a temperature where certain non-ferrous metals are vaporized. Air is drawn through the kiln and the metal vapors are oxidized to form solid metal oxide particulates which, once collected, is WOX. Air from the kiln passes through a product collector where the WOX is gathered. WOX is a light gray metal oxide powder, that contains 60% zinc oxide. Other metal oxides recovered in WOX include lead oxides, cadmium oxides, and chromium oxides.
The remaining portion of EAF dust that exits the kiln is Iron-Rich Material, referred to as IRM. IRM contains 40% iron oxide and other minerals, and once tested to ensure hazardous metals have been removed, can be sold to asphalt, cement, or aggregate companies, and it can even go back into the steel production process.
WOX is a product that is shipped to the company-owned American Zinc Products facility, or it can be sold to other zinc metal producers as feedstock for zinc metal production.
Stainless Steel Dust Recycling
Zinc Metal Production
The WOX shipped to our zinc refining facility, American Zinc Products in Rutherford County, North Carolina, enters a state-of-the-art solvent extraction and electrowinning (SX/EW) process. Through this proprietary SX/EW technology, zinc metal is produced that is 99.995% pure. Our facility is one of only four facilities in the world using the SX/EW technology.
Other metal bearing products produced at the American Zinc Products facility are sold as feedstock to metal production facilities. From there, our zinc can be used to make hundreds of items that can be used every day, including galvanized steel, automobile parts, health and beauty products, and more.
At our INMETCO facility, we recycle various types of used industrial and consumer batteries, including alkaline and nickel-cadmium to reclaim nickel and other valuable metals. The facility is capable of recycling large industrial battery packs from aircraft and batteries used by railroads, electric utilities, military and telecommunication companies for back-up power. Used batteries of various smaller types from transceivers, portable power tools and appliances, as well as medical equipment and emergency lighting systems, are also recycled at the facility.
Nickel Alloy Production
INMETCO provides waste recycling services to stainless customers, similar to what AZR does for electric arc furnace facilities. Inmetco processes mill scale, swarf, and flue dust, reclaiming Nickel, Chromium, Iron and Molybdenum to produce a remelt alloy (Ni-Cr-Fe or Ni-Cr-Fe- Mo) that is used as feedstock in the production of stainless steel.
As part of our processes, we create several co-products that meet the demand for various applications. Our Co-Products typically include:
- Iron-Rich Material – used as an iron source in aggregate processing, as well as passive treatment of metal-bearing and acid rock drainage water.
- Gypsum – potential uses include wallboard, fertilizer, and waste material treatment.
- Zinc-Cadmium Cake – often reclaimed for the contained metals.
- Lead Carbonate – valued for the lead and silver-containing elements.
- Metallic Dross – often reclaimed for the metallic content.
Our recycling facilities provide the highest quality EAF dust recycling services, through which we produce the following products:
Special High-Grade Zinc
We produce high purity zinc slabs and ASTM jumbos for a variety of uses. The slabs use a unique interlocking design for sturdy bundle integrity in transit. All slabs conform to LME standards. For full chemical composition and other specifications, download our product spec sheet.
High Moly Remelt Alloy
We produce high molybdenum remelt alloy at our INMETCO facility. For full chemical composition and other specifications, download our product spec sheet.