Production of monodisperse, radioactively labelled aluminosilicate glass particles using a spinning top

A technique is described for producing monodisperse (geometric standard deviation, σsub(g), < 1.2) labelled particles of low solubility, needed for experiments on the long term kinetics of clearance of particles from the respiratory tract. Montmorillonite clay in aqueous suspension is labelled with an appropriate radionuclide by ion exchange. An air driven spinning top is used to produce monodisperse droplets of the clay suspension, which are dried, concentrated into a comparatively small air flow and heated to 12000C. The clay melts and on cooling forms a glass in which the label is trapped. Monodisperse particles in the size range 1 to 5 μm can be produced with a yield greater than 10%. The system is relatively inexpensive and is equally suited to producing particles of other materials which require heat treatment in their preparation. (author)