Enriching and Separating Iron Impurity from Galvanizing Dross by Super-Gravity Technology

Hot-dip galvanizing dross is a valuable by-product and contains high levels of zinc and some iron impurities. In this work, the super-gravity technology was applied to removing iron impurities from an industrial galvanizing dross. Firstly, the enriching behaviour of iron phase was investigated in different super- gravity fields. The floatation movement of iron phase was greatly intensified by super gravity, leading to an iron-rich layer in the top area of the sample. Then, the separation of iron impurity from galvanizing dross was further carried out via filtration enhanced by super gravity. The majority of the iron impurities were retained in the upper residue by a filter felt, with the filtered zinc purified significantly. The efficiency of separating increased with increasing gravity coefficient (G). At G = 600, about 99.2 wt% iron was removed and the filtered zinc with a purity of about 99.9 wt% can be directly used as galvanizing zinc.