AlF(3) reactive Al(2)O(3) foam filter for the removal of dissolved impurities from molten aluminum: Preliminary results

作者：Damoah Lucas Nana Wiredu; Zhang Lifeng^*

来源：Acta Materialia, 2011, 59(3): 896-913.

DOI：10.1016/j.actamat.2010.09.064

• AlF(3) reactive filter
• Filtration
• Aluminum
• Inclusions
• Dissolved impurities

Filters coated with AlF(3) can be used to filter molten aluminum to simultaneously remove nonmetallic inclusions and dissolved alkali and alkaline earth metal impurities. Coating experiments were carried out in which anhydrous HF gas was generated from reactions involving NaF or CaF(2) and concentrated H(2)SO(4), and used in a reaction with Al(2)O(3) ceramic foam filter to produce a layer of AlF(3) coating on the surface of the Al(2)O(3) filter. Samples from these experiments were studied by X-ray diffraction, scanning electron microscopy and electron probe microanalysis. Preliminary results of the coating experiments showed that it is possible to coat Al(2)O(3) filters with AlF(3) by this method. Increasing the pressure of HF gas increased the yield of AlF(3) in the filter. Theoretical evaluation of the removal efficiency of dissolve impurity elements showed that dissolved calcium can be removed up to 99.8% within 30 s of contact time between the filter material and the molten aluminum.

• 出版日期2011-2