GB558972A - Improvements in or relating to electric furnaces for the electro-thermal production of metallic magnesium - Google Patents

Abstract

558,972. Magnesium production in electric furnaces. SOC., ANON-POUR L'INDUSTRIE DE L'ALUMINIUM. July 30, 1942, No. 10686. Convention date, July 23, 1941. [Class 39 (iii)] In an electric furnace for the reduction of magnesium oxide or burnt dolomite with calcium carbide, ferro-silicon, silicon, aluminium, silicon carbide or calcium silicide which yield non-gaseous products, the heating resistance comprises a graphite tube 1 mounted between graphite cylinders 2, 4, the latter of which is connected by a cap 5 to a metal protecting tube 6. The spaces 8, 9 are exhausted of air to protect the resistance 1, and the cylinder 4 is mounted upon a flexible metallic conductor 3 connected to a supply terminal 18. The other terminal 18<SP>1</SP> is connected through the casing and tube 6 to the upper end of the resistance. The charge 12 is contained in a double walled iron tube 13 surrounded by heat insulation 16, and is under vacuum. Magnesium vapour is condensed in the hood 15. After the reaction, nitrogen or carbon monoxide is introduced, tube 13 is removed. and replaced by a fresh charge. A heating winding may be added between insulation 16 and tube 13. In a modification, Fig. 2 (not shown), the tube 13 is surrounded by an outer tube which separates it from the insulation space and the latter is open to space 8. An additional heating resistance may surround the above outer tube. A uniform heat distribution along the tube 1 may be obtained by tapering the tube at both ends. Specifications 412,417, [Group II], 450,064, 510,196, [Group II], and 526,669 are referred to.