Recovering red phosphor from defective colour TV tubes - using hydrogen peroxide soln.

摘要

Recovery of red phosphor based on Y, La or Gd cpds. (pref. oxides, vanadates or oxysulphides) activated with rare earth elements, which is used together with blue and green sulphide phosphors in colour TV tubes, is carried out by loosening the phosphor layer with an aq. soln. contg. 0.1-30 vol. % H2O2, and opt. alkaline accelerators, various stabilisers and complex-forming cpds. By this method, the valuable red phosphor is recovered selectively, because it dissolves in H2O2-contg. solns. more rapidly than the other phosphors.