GB469347A - Method of re-melting and refining magnesium and light metal alloys containing magnesium - Google Patents

Abstract

Magnesium and light alloys containing magnesium are first melted with a thinly fluid non-inspissated flux and when both the metal or alloy and the flux are completely molten, the melt is stirred and an inspissating agent added. The inspissating agent may be added as such or as a flux containing a sufficient proportion of inspissating agent for the latter to have an inspissating effect on the thinly fluid flux. Thereafter, a protective cover of inspissated flux may be applied over the metal or alloy and the latter heated to substantially above pouring temperature, i.e. to above 800 DEG C. The thinly fluid flux may be anhydrous carnallite or mixtures still richer in potassium chloride or anhydrous magnesium chloride with or without additions of chlorides other than potassium chloride and tending to lower the melting point. The inspissation may be effected by mixtures of magnesium chloride with magnesium fluoride, calcium fluoride and/or magnesium oxide or of calcium chloride with magnesium fluoride. The fluxes may be merely mixtures of the ingredients or the ingredients may be preliminarily melted down together and the mass crushed after solidification. The fluxes may also comprise additions which are reduced by the melt to enter the metal or alloy, or, when an alloy is treated, salts of a metal already present in the alloy. Specifications 219,287, [Class 82 (i)], and 459,912 are referred to.