Constant-composition study of the kinetics of the dissolution of strontium fluoride in aqueous solution

Abstract

A highly reproducible constant-composition technique has been used to study the rates of dissolution of strontium fluoride crystals over a range of undersaturation. At 25 °C and at higher driving forces (relative undersaturation 0.06–0.25) the process appears to follow normal diffusion-controlled dissolution, while at very low undersaturation (0.008–0.015) a surface-controlled reaction predominates. The two regions of undersaturation show markedly different dependences upon the addition of organic phosphonate inhibitors, the action of which can be interpreted in terms of a Langmuir-type adsorption equation.