Fundamental research on recovering metals from hot-dip Zn–Al–Mg dross by supergravity separation

The dross generated in the hot-dip Zn–Al–Mg coating process is a valuable co-product, since it contains high quantities of recyclable alloy. A new method to recover Zn–Al–Mg alloy from the industrial Zn–Al–Mg dross was proposed using supergravity separation. The separation efficiency was analyzed as a function of gravity coefficient ( G ), separation time, and separation temperature. The separation of Zn–Al–Mg alloy from the dross can be achieved at G > 100. The alloy content in the dross decreased gradually with an increase in the gravity coefficient, the separation time, and the separation temperature. The alloy ratio in the enriched dross decreased almost linearly as the gravity coefficient increased, and the recovery of Zn–Al–Mg alloy from the dross exceeded 78%; these results were consistent with the results of the FactSage software calculation. The purified alloy can be in-situ used in the hot-dip Zn–Al–Mg bath for production. The feasibility of supergravity separation as a promising process for efficiently recovering Zn–Al–Mg alloy from Zn–Al–Mg dross was thus demonstrated.