GB875827A - Improvements in or relating to the continuous production of magnesium - Google Patents

Abstract

875,827. Electric resistance furnaces. VEREINIGTE ALUMINIUM-WERKE A.G. Dec. 23, 1959 [Dec. 30, 1958], No. 43734/59. Class 39(3). In apparatus for continuously producing magnesium from raw materials containing magnesia by reducing the same with silicon, aluminium, or other substances which form non-volatile oxidation products, in a high vacuum of less than 10 mm. mercury, non- vacuum-tight retorts 4 of silicon carbide or ceramic material are embedded in granular carbon 6 and arranged preferably vertically or nearly vertically inside an evacuable furnace through the wall 2 of which electrodes 9 pass in a vacuum-tight manner for connection to a source of electricity. The reaction material is fed in the form of briquettes through a lock 3 and passes through the retorts 4 to a discharging lock 5. The electrodes 9 are water-cooled and are connected in two groups of four by bus-bars 8 to a transformer 7. The walls of the retorts 4 are perforated, the evolved magnesium vapour passing through the carbon 6 and via an annular channel 14 and an inlet branch 15 to a condenser (not shown) which is connected to a vacuum pump. The furnace is preferably evacuated to a pressure of less than 1 mm. mercury, the arrangement ensuring that the carbon 6 does not burn.