Recycle Electric Arc Furnace Dust

The zinc content of EAF dust can be removed by sulphating, using iron sulfate derived from a waste product in some steelmaking processes, pickle liquor residue, as the main 

Other promising processes for zinc recovery are examined in Morris (1985). 

Many different chemical treatment systems have been developed to reduce the leachability of lead and cadmium compounds in flue dust. These systems usually rely on stabilization/solidification, adsorption, chemical reduction, or pH control. Chemical reduction employing the use of metallic iron has been successful in reducing the leachability of lead to below EP-Toxicity levels. Adding a 5 percent by weight dose of iron filings to cupola furnace emissions control sludge, for instance, reduced lead leaching from 28.6 mg/1 to less than 0.1 mg/1 (Stephens 1984). 

Systems which control pH normally employ slaked lime, Ca(OH)2, to precipitate lead and cadmium as insoluble hydroxides. A potential problem with this method is that when excess lime is used, creating a high pH environment, lead can resolubilize. To avoid this problem, the use of magnesium hydroxide, Mg(OH)2, to precipitate lead has been suggested (Turpin 1985). Magnesium hydroxide provides a buffering effect so that the potential of dissolving 

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