Sulphide luminescent material recovery - from suspensions arising in the mfr. of screens for colour television tubes

摘要

Recovery of sulphide luminescent matls. from an aq. suspension which also contains chromate-sensitised and/or cross-linked binders such as polyvinyl alcohol, gelatine or polyvinyl-pyrrolidone, and opt. heavy-metal impurities such as Fe, and anti-foaming agents, has bromine-, iodine- or chlorine- water added to the suspension so that the impurities become soluble in water and the sulphide luminescent matls. can then be sepd. by filtration. The process is pref. carried out at room temp. and with the suspension adjusted to pH 3-7. The filtered luminescent matl. is pref. tempered at 100-600 degrees, esp. 300 degrees C for 1/4 to 10 hrs., esp. 2 hrs. so it is fit for re-use. Used with suspensions employed in making screens for colour television tubes, esp. for the recovery of ZnS and/or ZnCdS.