Ostwald ripening of crystalline precipitates in aqueous solutions at constant temperature and periodic temperature changes

Abstract The Ostwald ripening of crystalline precipitates in aqueous solutions is measured, the systems being H 2 O‐NaNO 3 and H 2 O‐Tetraethyl‐ammoniumiodide (TEAI). By comparison of the results at constant temperature with the theory, it is found that the growth kinetics of both substances seems to be determined by a second order reaction. For the application of Ostwald ripening in preparative chemistry and chemical engineering, it is suggested to age the precipitate at periodically changing temperature. This leads to an increase of the aging rate by more than one order of magnitude. The dependence of this increase on frequency and amplitude of the temperature changes is measured.