Solid polycrystalline potassium ion conductor having a β″-Al2O3 structure, its production and the preparation of potassium metal using this potassium ion conductor
AssigneeBASF SE
InventorsKerstin Schierle-Arndt, Günther Huber, Stephen Nicholas Heavens, John Stuart Blackburn, Ivor Wynn Jones
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Abstract
A solid polycrystalline potassium ion conductor having a β″-Al2O3 structure, its production, and the preparation of potassium metal using this potassium ion conductor.
Claims9
A solid polycrystalline potassium ion conductor having a β″-Al2O3 structure and being free of chlorine and comprising at least 90% by weight of potassium β″-Al2O3, obtainable by means of ion exchange of the alkali metal ions of a polycrystalline alkali metal β″-Al2O3 moulding, in which the alkali metal ions are sodium ions or a mixture of sodium and potassium ions and the molar ratio M2O (M=alkali metal) to Al2O3 is 1:x, x being an integer or non-integer number within the range 5 to 11, for potassium ions, the ion exchange being effected by a process wherein neither chloride-containing nor liquid potassium ion sources are used, the process comprising the steps of:
- embedding the polycrystalline alkali metal β″-Al2O3 moulding in an oxidic powder containing potassium and aluminium of a molar K2O to Al2O3 ratio within the range 1:(x−1) to 1:(x+1), the weight of oxidic powder amounting to at least two times the weight of the moulding;
- heating the embedded moulding at a rate of at least 100° C. per hour to at least 1100° C.;
- and
- further heating to at least 1300° C., this temperature being maintained for at least one hour prior to cooling.
A process for the production of a solid polycrystalline potassium ion conductor having a β″-Al2O3 structure by ion exchange of the alkali metal ions of a polycrystalline alkali metal β″-Al2O3 moulding, in which the alkali metal ions are sodium ions or a mixture of sodium and potassium ions and the molar ratio M2O (M=alkali metal) to Al2O3 is 1:x, x being an integer or non-integer number within the range 5 to 11, for potassium ions, neither chloride-containing nor liquid potassium ion sources being used, comprising the steps of:
- embedding a polycrystalline moulding of alkali metal β″-Al2O3 in an oxidic powder containing potassium and aluminium of a molar K2O to Al2O3 ratio within the range 1:(x−1) to 1:(x+1), the weight of oxidic powder amounting to at least two times the weight of the moulding;
- heating the embedded moulding at a rate of at least 100° C. per hour to at least 1100° C.;
- and
- further heating to at least 1300° C., this temperature being maintained for at least one hour prior to cooling.
Dependencies are inferred from the claim text.