A technique for the study of growth rates of single crystals of sparingly soluble salts

Abstract

A photomicroscopic technique has been adapted and implemented for the study of growth rates of single crystals of sparingly soluble salts. Experiments have been conducted to determine the growth of calcium oxalate monohydrate (COM) in an isothermal growth cell used in a continuous-flow system. The experimental apparatus permits the control of temperature and of supersaturation of the solution in which the crystals are grown. Growth rates of COM are found to be constant at a constant supersaturation and show little evidence of growth rate dispersion for the conditions tested. The addition of a growth modifier, L-glumatic acid, at a level of 100 ppm yields a statistically significant increase in COM growth rate. Preliminary results indicate that COM crystal growth obeys the general trend predicted by the theory of Burton, Cabrera, and Frank.