DISSOLUTION OF CALCIUM FLUORIDE IN AQUEOUS SOLUTION RTIFICIAL SEA WATER).

DISSOLUTION OF CALCIUM FLUORIDE IN AQUEOUS SOLUTION
RTIFICIAL SEA WATER).
• . M. HAMZA , ···A. I;BELTAGY AND·· S. HAMDONA
• Chemistry Department, Faculty of Sc1ence. Henoffa University, Sh1bin
El-Kom. Egyot.
**1 1 • nst tute o. OceanographY and Fisheries, Alexandr1a. Egypt.
The kfnetics of dissolut10n of calcium fluoo’1de has
been studfed over a range of undersaturatfon for will
characterfzed seed at 25°C and 0.5 H fonfc strength using
a constant-compositfon method fn whfch the undersaturation
and fonfc strength were mafntafned constant by addftfon
of sodfum chlorfde as dfluent. Mechanfsm and rate of
dfssolutfon has been fnvestigated as a function of degree
of undersaturat.ton , hydrodynamfcs, solid / solution ratios.
temperature and the presence of addftives. At hfgher relatfve
undersaturatfon (0.24 – 0.40) the process appears to follow
normal diffusion – controlled dfssolutfon. whfle at low
undersaturatfon (0.075 – 0.20) a surface-controlled reactfon
predominates. The two regions of undersaturation show
markedly different dependences upon the addition of metal
ion fnhibitors.