Polycrystalline alkali or alkaline earth fluoride balls of high apparent density (approaching theoretical density) useful for the preparation of the equivalent monocrystalline compounds

摘要

The preparation of the polycrystalline products involves a process for increasing the apparent density of the materials initially in powder form. This enables the optimisation of the volume of the crystallisation crucible. Polycrystalline alkali or alkaline earth fluorides in the form of balls of diameter equal to or greater than 100 mu (preferably 100 mu - 2 cm) and apparent density of at least 60%(preferably 90%) of the theoretical value, are claimed. Independent claims are also included for the preparation of the materials and their use in the manufacture of the equivalent monocrystalline compounds.