Pre-water-based suspension alumina coated phosphor treatment process

DETAILED DESCRIPTION In accordance with one aspect of the present invention, a new and improved method for the treatment of an alumina coated phosphor and having a particle size of about 10-12 microns comprises the following steps: Step 1--A phosphor having an alumina protective coating is fluidized in an isothermal fluidized bed to form a fluidized phosphor powder.
Step 2--The fluidized phosphor powder from Step 1 is heated at a temperature from about 700.
degree.
C.
to about 850.
degree.
C.
and for a period of time sufficient to preclude adversely affecting the alumina protective coating on the phosphor during subsequent water-based suspension processing and to preclude detrimentally altering the phosphor to form an annealed phosphor powder.
Step 3--The annealed phosphor powder from step 2 is cooled to form a cooled annealed phosphor powder.
Step 4--The cooled annealed phosphor powder from step 3 is added to a water-based suspension.