Removal of Fe from molten Al by filtration in a centrifuge

•The centrifugal force field and Al2O3 CFF were jointed to removing Fe from Al melt.•Continuous purification induced by centrifugal force on aluminum was achieved.•High separation efficiency of purifying aluminum with low-contented Fe was reached.•The nucleation adjacent to coarse wall in Al2O3 CFF can prematurely precipitate. A separation method induced by centrifugal force and combined with alumina ceramic foam filter (Al2O3 CFF) was proposed to remove Fe from molten aluminum. In exploratory the separation, the effect of Al2O3 CFF (pore size (P) and thickness (H)), temperature (T) and gravity coefficient (G) on the separation efficiencies were analyzed. The walls in Al2O3 CFF acting as nucleation sites promoted the formation of iron-rich phase which was either sticked on the wall or intercepted at other place in the inner Al2O3 CFF. Under the condition of P = 80 ppi, H= 35 mm, T = 700 °C and G= 10, the removal efficiency of Fe (RFe) and loss percentage of Si (LSi) were 75% and 58%, respectively. On the basis of exploratory experiment on the separation, a centrifugal separation apparatus combined with Al2O3 CFF was designed for continuously removing Fe element from molten aluminum on an engineering scale and the result obtained from the experiment treating 4 kg molten aluminum were 70% for RFe and 52% for LSi. Results indicate separation induced by centrifugal force and using Al2O3 CFF can be employed as a practical process.