| 摘要 |
<p>Oxidic phosphors, esp. Y or Gd-based colour phosphors activated with rare earths, are freed from impurities such as sensitisers, binders, additives and sulphidic phosphors by: 1) removing sensitisers, binders and additives by treating with water heating to 40-98, pref. 80-95 degrees C; 2) adding organic acid, e.g. acetic, citric and/or tartaric acids, their salts or alkaline reagents, e.g. alkali hydroxides or carbonates, besides strong complexing agents, e.g. gluconic acid, acetylacetone cation, amines or oxidising agent; 3) washing out solubilised impurities; 4) adding another oxidising agent and treating oxidic phosphor, pref. at elevated temp. so that sulphidic impurities are converted to oxides; 5) finally removing resultant oxides. Economical and safe technique permits recovery of very costly red oxidic phosphors from mixtures with green and blue sulphidic phosphors (ZnS, ZnCdS, Ag activated), binders (PVA) and other additives, as used in colour TV tubes.</p> |
