Papers by Author: Li Feng Zhang

Abstract: Removal of Na by an “active” AlF3 filter seemed to be so efficient that all the sodium was removed in the present experiments. The removal of Na is considered to be limited by the resistance in the melt boundary layer only. However this is not the case for calcium. For calcium to be transfered into the AlF3, resistance in the filter grains has to be taken into account in addition to the resistance in the melt boundary layer. This was indicated by the total mass transfer coefficient of only 4x10-5 m/s. A kinetic model was derived that can describe the removal of Ca from molten aluminum in an “active” AlF3 filter by deep bed filtration following first order kinetics.

Abstract: In order for magnesium to continue to grow, all forms of magnesium scrap need to be recycled – for both economic and environmental reasons. This paper extensively reviews the techniques for the refining and recycling of magnesium. Removal of inter-metallic elements and inclusions through gas fluxing, filtration and other methods are summarized. Flux refining technology is the old but most common method to purify magnesium metal. Fluxless refining technologies are under development, such as salt furnace technology, inert gas and filter refining, vacuum distillation refining, and hydrometallurgical methods. Magnesium scraps recycling is discussed, techniques to protecting Mg (or Mg alloy) melt with protective atmosphere and salt flux are briefly introduced.