Patent GB-498921-A (GB)
Title: Process and apparatus for vapourising or gasifying metals, metal alloys, metal compounds and other solid mineral substances difficult to vapourise
IPC: C22B5/16
Filed: 1937-06-08
Abstract: <PICT:0498921/III/1> <PICT:0498921/III/2> A method of vaporizing or gasefying metals, metal alloys, metal compounds and other solid mineral substances difficult to vaporize, comprises feeding the substance in individual drops or particles on to a substantially smooth refractory and heat-radiating surface in a closed, highly-heated vaporization chamber, the drops or particles being fed to the surface at such a rate and the temperature of the chamber being maintained so high that vapour is formed around a drop or particle immediately it is fed on to the surface, the entire surface of the material thus being subjected to heat by radiation and being converted into the vapour or gaseous state, in which state it is discharged from the chamber.  A furnace for carrying out such method comprises an iron casing 16 lined with a refractory material in which a crucible 18 is embedded.  Through the cover-plate 19 of the crucible project electrodes 22 surrounded by nonconducting, refractory tubes 20. Current is supplied through electrode holders 21.  An outlet pipe 23 of graphite leads from the crucible and a tube 26 extends through the cover 19 and casing 16, the end of the tube 26 being provided with a transparent cover for purposes of inspection. Material is fed to the crucible through a tube 28 connected to the tube 26.  A graphite overflow tube 29, serving as a safety device and projecting slightly above the bottom of the crucible is connected to a tube 30 extending into an electrically heated container 31.  The furnace is mounted on wheels 41.  The surface of the crucible bottom, consisting of graphite may be porous. When starting up the furnace, the vaporization surface may be covered, e.g. with liquid copper. The pressure may be atmospheric or below or above atmospheric. Specific examples refer to the vaporization of copper, zinc, tin, nickel zinc oxide, tin dioxide, zinc sulphide.  The Specification as open to inspection under Sect. 91 comprises also a furnace, Fig. 2 (Cancelled), having a central vapour discharge tube and inclined electrodes 22 operating on three-phase supply.  The supply may be controlled automatically in accordance with the vaporization.  Iron may be fed in the form of wire. Ores, e.g. of nickel, copper, or zinc may be vaporized, the vapour decomposed and the individual constituents obtained as a fine powder.  Metal vapours leaving the vaporization space may be superheated by means of electrically heated tubes or plates of graphite.  Nitrogen may be used to protect parts of the device against burning.  In other forms of apparatus, (1) a graphite crucible is embedded in a trough filled with coal, the trough and crucible being connected to the secondary of a transformer; (2) an inclined graphite tube serving as the crucible is connected to a transformer; (3) the crucible is formed as a hollow ring of graphite surrounding a leg of a transformer core.  This subject-matter does not appear in the Specification as accepted.