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Arc-furnace Dust Recycling - Technology - Scionix PDF Print E-mail
An electric arc furnace (EAF) is one of the most commonly used methods for the purification of scrap steel. The process generates electric arc furnace dust (EAFD) which contains several metal oxides such as Zn, Pb, Cd, Cu, Fe, Mn and Al. The steel industry worldwide is currently producing several million tonnes of the dust and due to its heavy metal content is regarded as environmentally hazardous. Currently the majority of EAFD is buried in landfill sites.
One of the most common processes used to treat EAFD is hydrometallurgy. The process involves dissolving the metals into an aqueous system (usually in strongly acidic/basic conditions) and precipitate the metals out in an electrowinning process. The current problems with this system is the relatively poor selectivity and the environmental hazards of using strongly acidic/basic conditions of the EAFD dissolution stage, and the extremely poor current efficiency of the electrowinning stage.
Scionix have developed a process in which using Deep Eutectic Solvents (DES), it is possible to selectively extract Zn and Pb from the EAFD. The DES used in the process are environmentally benign and due to the ionic nature of the solvents the current efficiency of the electrowinning is improved over the hydrometallurgy process. The process is currently being tested on the 200 L scale with a view to going to the tonne scale.
Arc-furnace Recycling Plant