GB569472A - Apparatus for manufacture of magnesium metal - Google Patents

Abstract

569,472. Furnaces. NEWTON; E. P. (Marine Magnesium Products Corporation). July 29, 1942, No. 10612. [A Specification was laid open to inspection under Sect. 91 of the Acts, May 5, 1943.] [Class 51 (ii)] [Also in Group II] Relates to apparatus for manufacturing or refining magnesium by thermal treatment of briquettes of a mixture of magnesium oxide and carbon, or impure magnesium powder mixed with a binder such as a heavy petroleum oil. The apparatus comprises a vertical retort 10, Figs. 1 and 2, into which the briquettes are fed through a tube 41 having a branch 42 through which gases evolved from the briquettes during their descent to the retort may be withdrawn. Surrounding the feed tube is a condenser 11 connected to the top of the retort by a liquid - sealed expansible coupling 28. A grid 44 prevents solid material being carried into the condenser with the gases and vapours from the retort. A tube 9 leading from the condenser is connected to a vacuum pump. A division 37 divides the condenser into two zones A. B, in the lower of which, A, magnesium vapour is condensed and drawn off through a pipe 36 while in the upper zone B any accompanying metal, such as sodium, may be separately condensed and drawn off through a pipe 38. Heating units 59, 61 surround the zones. Where a relatively high condensing rate is being maintained, cooling coils surrounding the zones may be employed. The feed tube is in heat-conducting relationship with the condenser, the heat absorbed from the condenser serving to preheat and dry the briquettes on their way to the retort. The retort charge is heated by a central core 47 provided with heating elements 54 and a surrounding heating element 58. The walls of the retort and core are provided with grooves 62, 63, Fig. 3, to facilitate escape of gases and vapours. Small quantities of hydrogen or similar gas is introduced through holes 23 to aid the upward passage of evolved vapours. The feeding of the briquettes to, and the withdrawal of spent residues from, the retort are effected at regular synchronized intervals, without interfering with the maintenance of the desired partial vacuum, by an auxiliary charging unit 71 and discharging unit 72, having pairs of valves 1 and 2, 3 and 4 respectively which are interconnected so as to operate in the desired sequence. The valves have piston-like extensions 87, 88 to avoid crushing the briquettes. Air valves 78, 84 and valves 79, 85 which connect the corresponding chambers to a source of vacuum are connected to operating mechanism, whereby they are operated automatically and in a predetermined sequence.