Growth Hysteresis of a Potassium Sulfate Crystal in the Presence of Chromium(III) Impurity

Abstract

The growth kinetics of a potassium sulfate crystal was investigated in the presence of traces of chromium(III) impurity (0.5 and 2 ppm) in a flow cell at different rates of change of supercooling (( 0.1 and ( 0.2 °C/min). Hysteresis in crystal growth rates with chromium(III) impurity was induced by decreasing and increasing the supercooling. The rate of supercooling change affected this hysteresis behavior. The cause of hysteresis was hypothesized to occur due to a slow adsorption of impurity at high supercooling.

Crystal Growth with Macromolecular Additives

“…Macromolecule adsorption to crystal surfaces can be slow (section 2.1), resulting in nonlinear phenomena such as growth rate hysteresis and spontaneous growth rate oscillations. Such effects on crystal growth were originally discovered for crystalline oleic acid, 388 paraffin C 36 H 74 with dioctadecylamine, 389 potassium and ammonium dihydrogen phosphates grown with Al 3+ , Fe 3+ , and Cr 3+ , 390−394 potassium sulfate with Cr 3+ , 395,396 ice, 397 and paracetamol. 398 They have been observed with MM additives to ice, 58,59,65,170 lysozyme, 66,376 calcite, 399 and COM.…”

Measurement of Crystal Face Specific Growth Kinetics

“…Here the focus is not on the method of mounting the seed crystal by adhesive since it has been reported previously in numerous studies [16][17][18]56 . Rather it is on the capability of the proposed system on measuring crystal growth kinetics.…”

“…In the first method, a solvent-proof adhesive was coated on the tip of a thin glass stick or metal wire, e.g. platinum wire or stainless steel wire, with the seed crystal sticking on it. − The seed crystal size would not be a factor to limit the application of this method. But impurity may be introduced in the system, which may influence the underlying growth mechanism and thus the growth rate of the seed crystal.…”

Growth rate hysteresis of a potassium dihydrogen phosphate (KDP) crystal in the presence of traces of impurity

“…[10]. Here briefly, growth displacements DL, of the (1 0 0) face of a potassium dihydrogen phosphate crystal was measured by optical microscopy with decreasing and increasing supercooling in a flow cell.…”

“…This behavior is called crystal growth rate hysteresis. The behavior is not known widely, and only a few cases [4][5][6][7][8][9][10] were reported. In our previous work [10], we reported the hysteresis in the growth rate of a potassium sulfate crystal induced by chromium (III).…”