Phosphor powder, size distribution

A series of works have been reported on preparation of YAG based phosphor powders by using spray pyrolysis method, with spray solutions of different fluxes [226-229]. It has been demonstrated that spray pyrolysis method can be used to control the morphologies and sizes of the YAG based phosphor powders in a very feasible way. Highly spherical particles with well controlled size distribution can be readily synthesized by optimizing the processing parameters. 

Cho JS, Jung KY, Son MY, Kang YC (2014) Large-scale production of spherical Y203 Eu phosphor powders with narrow size distribution using a two-step spray drying method. Rsc Adv 4 62965-62970... 

The most common adsorbant used is granular or powdered activated carbon. This material, which is available from almost all forms of organic carbon-containing matter, is a microcrystalline nongraphite form of carbon. The production of activated carbon can be achieved by use of rotary kilns, hearth furnaces, or furnaces of the vertical shaft or fluidised bed type, and each is suitable for the generation of different pore size and the source of carbon. The pore volume and size are influenced by both the carbon source and method of production. The adsorption properties are directly related to the pore volume, pore size distribution and the nature of the functional groups on the surface of the carbon. Activation is achieved chemically, by treatment by dehydration with zinc chloride or phosphoric acid, or by treatment with steam, hot carbon dioxide or a mixture of both. The activated carbon is available in three basic forms, powder, granules or as cylindrical or spherical pellets. For solvent recovery systems the carbon is usually obtained from either wood charcoal, petroleum residues or coconut shells and is often used in the form of pellets. 

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