Recovering luminescent materials - by solubilising impurities in water by addn. of hydrogen peroxide and amine

摘要

Sulphide, oxysulphide or oxide luminescent materials are recovered from compsns. comprising binders e.g. PVA, polyvinyl pyrrolidone, gelatine etc. sensitisers e.g. ammonium (di) chromate etc. and surfactants as impurities by making the pref. already hardened binder water soluble in aq. phase by addn. of hydrogen peroxide and an amine. The amine may be an alkylamine e.g. ethylamine, ethylene diamine or ethanolamine or a mixt. of ethylene diamine and triethanolamine. Ammonia may be added to the aq. phase in addn. The impurities are removed at 10-95 deg.C, pref. room temp. Luminescent materials used in cathode ray tubes can be recovered and reused.