Process and device for casting a large-area crystalline salt body
AssigneeSiemens Aktiengesellschaft
InventorThomas Berthold
Life of this patent
Estimating the term…
Abstract
A process and device for producing an optically pure polycrystalline salt body by melting a starting material for the salt and then introducing the melted material into a casting mould having a base which is kept at a temperature of 1.degree. C. to 50.degree. C. below the melting point of the material to form a solid crust on the base and then solidifying the entire melt to form the polycrystalline salt body.
Claims18
A process for the production of a polycrystalline salt body comprising the steps of:
- providing a furnace having a single chamber heated to a uniform temperature for melting a starting material with a composition intended for the salt body;
- providing a melting crucible which is inert to the salt melt,
- providing a casting mould with a base,
- producing a salt melt by inserting the crucible with the starting material and the casting mould into the chamber,
- introducing the salt melt into the casting mould and directly cooling only the base to keep the base at a temperature which is 1.degree.-50.degree. C. below a solidification point of the salt melt to form a solid salt crust directly on the base of the casting mould,
- maintaining the casting mould at a temperature below the solidification point until the supernatant salt melt has solidified completely into a polycrystalline salt body and then cooling the salt body.
Device for the production of large-area polycrystalline salt bodies comprising:
- a furnace having a single chamber,
- a casting mould with an inert lining positioned in the chamber,
- a melting crucible, which is located above the casting mould and has a base region with fine outlet openings for the salt melt,
- the melting crucible forming together with the casting mould a closed system with pressure equalization channels, and
- means for directly cooling the base of the casting mould being placed in said chamber.
A process for the production of a polycrystalline salt body comprising the steps of:
- providing a casting mould having a base with a shape of a hollow cylinder with a longitudinal axis,
- producing a salt melt by melting a starting material with a composition intended for the salt body in a melting crucible which is located inside the mould and is inert toward the salt melt,
- rotating the hollow cylinder on said axis,
- introducing the salt melt into the rotating casting mould while keeping at least the base at a temperature which is 1.degree.-50.degree. C. below a solidification point of the salt melt to form a solid crust directly on the base of the casting mould,
- maintaining the casting mould at a temperature below the solidification point until the supernatant salt melt has solidified completely into a polycrystalline salt body and
- then cooling the salt body.
Dependencies are inferred from the claim text.