PURPOSE: To stably produce hardly water-soluble salt which is adequate for fillers, cosmetics, etc., and has a uniform grain size by supplying the crystal of the hardly water-soluble salt as a seed crystal, uniformizing nucleus generation and crystal growth, measuring the liquid turbidity in a reactor, observing the crystallization state and calculating the particle size of the discharge crystals.
CONSTITUTION: A raw material soln. is prepd. in raw material vessels 11, 12. The seed crystal is dispersed in a solvent and is prepd. as a slurry in a seed crystal vessel 19. The raw material soln. and the seed crystal slurry after the prepn. are sent to a tubular reactor 6 where the raw material soln. reacts to form the crystal of the hardly water-soluble salt. The crystals are stored in a junction vessel 17. Further, the crystals are classified by a classifier 18 and the products are received in a liquid receiving vessel 15. the mother liquor contg. the fine crystals is discharged as waste liquid. The turbidity is measured by a luminance meter mounted at the tubular reactor 6 and is subjected to data processing by a personal computer, etc., by which the particle size of the product is calculated. Further, the supply rate is automatically controlled by a control valve of a seed crystal supplying line and the desired average particle size is obtd.
TSUKAHARA ITSURO
KOIKE TOSHIMITSU
TAGUCHI KAZUO
MAKAWA MITSUSHI
MIYAI TETSUHIKO
