Investigation of impact recrystallization and migration with using radiotracers

Radiometry, microscopic analysis, and autoradiography have been used for studying migration of the AgCl impurity labelled with sup(110m)Ag into microcrystals and annealed monocrystals of NaCl (1) from a saturated solution of NaCl. Considered is the mechanism of the effect of crystal collisions in the suspension on the transition of the impurity into the solid phase bulk. It has been shown that the migration process is characterized by two stages, viz, fast and slow. The fast phase involves recrystallization caused by breaking off microblocks from crystals of NaCl, dissolution of these blocks and the subsequent reduction of oversaturation from the surface of NaCl crystals. The process is called ''collision recrystallization''. The slow stage involves the formation of defect zones under action of the collisions of the crystals and the accelerated mass exchange of these zones with the solution. This stage is called ''collision migration''. Upon mixing the suspension of NaCl crystals with a stirrer at a rate of about 103 r.p.m., defect zones are formed at a rate of 1-2 s-1 on 1 cm2 of the crystal surface