Abstract A process and apparatus for separating scum from molten metal, particularly germanium, and the pulling of single crystals with the use of outer and inner crucibles. The metal is placed in the outer crucible and there melted. In the inner crucible is weighted with a ballast to ensure its penetration into the molten metal and to avoid its flotation on the molten metal. The outer crucible is then lifted and rotated to segregate the scum from the molten metal and to introduce the metal from the outer to the inner crucible through an orifice provided in the bottom of the inner crucible while the scum remains in the outer crucible. The outer crucible is then lowered to empty the inner crucible and again lifted and rotated to reintroduce scum-free metal from the outer to the inner crucible. The steps are repeated until all traces of the scum are separated from the molten metal, which is followed by growing a single crystal of metal from the scum-free metal in the inner crucible.
Apparatus for the separation of scum from a molten metal and for pulling single crystals from the molten scum-free metal, comprising an outer crucible made of a substance resistant to reaction with said molten metal, an inner crucible placed concentrically inside and spaced from said outer crucible, said inner crucible being made of a substance which is inert and noncontaminating to the molten metal said inner crucible having an orifice situated in the bottom portion thereof allowing metal contained in said outer crucible to enter said inner crucible, supporting means to said outer crucible for lifting, lowering and rotating of said outer crucible, means for heating the outer crucible, means for supporting said inner crucible laterally above said outer crucible, said means including a horizontal member located on the top of said apparatus, suspension means fixed to the inner crucible having at least one hook-shaped appendage permitting said inner crucible to bear upon said horizontal member when said outer crucible is lowered and permitting said inner crucible to be lifted from said horizontal member to rotate together with said outer crucible when the upper part of said outer crucible raises said suspension means from said horizontal means, and means for weighting said inner crucible having a weight resting upon said suspension means to facilitate penetration of said inner crucible into the molten metal which is present during the operation of said apparatus.
Claim 2
Dependent Claim
33 words
Apparatus as claimed in claim 2, in which the orifice provided in the bottom of the inner crucible is eccentrically situated and the bottom of the inner crucible is inclined toward said orifice.