Synthesis of tritium breeder ceramics from metallic lithium

Highlights: ► Ceramic breeders were synthesized from metallic lithium. ► The reactions of lithium with silicon, silica, or titania were investigated. ► The precursor phases were transformed to the desired phases by heating in air. ► The reaction of lithium and silicon is suited for larger quantities. ► Using silicon has the advantage that it is available with a very high purity. - Abstract: For the fabrication of Li-6 enriched ceramic breeder materials for ITER, the availability of Li-6 enriched compounds is limited, and metallic Li-6 is the most widely available compound. As metallic lithium cannot be used directly in ceramic fabrication processes, we investigated different syntheses to obtain lithium orthosilicate or lithium metatitanate directly from molten lithium. In exothermic reactions of molten lithium with silicon, silica, or titania, several intermediate or precursor phases were observed under argon that could easily be transformed to the desired ceramic phases by a subsequent heat treatment under air. The reaction steps and the resulting phases were studied by differential scanning calorimetry and X-ray diffractometry. The synthesis from lithium and silicon seems to be especially suited for the production of larger quantities and has the advantage that silicon is available with a very high grade of purity.