| 摘要 |
<p>1. Process for reclaiming rare-earth metallic oxide and/or rare-earth metallic oxysulphide phosphors from a phosphor mixture which, apart from these, also contains at least one chalcogenide phosphor, namely a sulphide and/or selenide of zinc and/or cadmium, by suspending in water, mixing with a hypohalide and acidifying, characterized in that, - first, there is added to the phosphor suspension approximately 1 to 2% of the amount of hypohalide which would be necessary for converting the whole of the chalcogenide phosphor present into a sulphate and/or selenate, - thereafter, the suspension is acidified up to a pH value ranging between 1 and 6.5 in such a way as to produce elementary sulphur and/or selenium which accumulates on the granules of the chalcogenide phosphor causing these phosphor granules to sediment, - after the sedimentation, the excess aqueous rare-earth-phosphor suspension is decanted and the rare-earth phosphor is centrifuged from this, washed and then dried.</p> |
