Zinc Recovery From Electric Arc Furnace Dust Using Eggshell
This research shows that levels of zinc, as high as 80%, can be recovered from electric arc furnace dust (EAFD) using a pyrometallurgical treatment with eggshell as a reducing agent. Zinc ferrite is commonly found in EAFD, which isabyproduct from the steel making industry. This waste EAFD was treated with another waste product, eggshell to recover valuable zinc oxide and calcium ferrite. The reduction of the zinc ferrite to zinc oxide and calcium ferrite was achieved by using the calcium oxide, a decomposition product from the calcium carbonate in the eggshell, as a reducing agent. The EAFD was mixed with eggshell and the effects of the molar ratio of zinc ferrite to calcium oxide, temperature and time on the decomposition were studied. It was found that significant recovery of the zinc could be achieved at temperatures as low as 900 C for only 2 hours and a molar ratio of zinc ferrite in EAFD to calcium oxide in eggshellof1:2. In addition, it is shown that the use of a hydrometallurgical process can further increase the amount of zinc recovered.
Index Terms- eggshell, electric arc furnace dust (EAFD), zinc ferrite, zinc oxide, zinc recovery.