Method of manufacture of alkaline - earth metals in the cylindrical oven, which is movable in the vertical plane that is heated by the joule effect in the bars of the graphite seats in the notches made in the crucible made of refractory concrete

摘要

Calcium or other alkaline earth metals are fabricated from tablets, formed by a homogeneous mixture of powdered metal oxides and granules of aluminum and sometimes silicon. Tablets in a furnace under vacuum with a horizontal axis and an outer cylindrical metal carcass (6) are carried rapidly to an elevated temperature of about 1350 deg C in the case of calcium because it is the container (3) containing the compounds that is the heating element, so only the volume of the compounds is heated, such that the surface of contact of the heating container with the compounds is greatly elevated and the thickness of the compounds to be heated is low, e.g. 300 to 600 mm. Transfer of heat from the heating container to the tablets is carried out very rapidly despite the poor thermal conductivity of the compounds. The heating elements within the heated container are graphite bars (1) using the Joule effect for heating. Vapors of metal formed within the heated container are aspirated by a vacuum pump and then condensed to the solid state (13) in the closing cover of the furnace on a water cooled condenser (10).