Barite growth rates as a function of crystallographic orientation, temperature, and solution saturation state

VITAL, MÉLANIE; MARTINEZ, DANIEL E.; MORVAN, GILLES; DAVAL, DAMIEN; HEAP, MICHAEL J.

CRYSTAL GROWTH & DESIGN

AMER CHEMICAL SOC

Lugar: Washington; Año: 2020 vol. 20 p. 3663 - 3672

1528-7483

As the spontaneous formation of barite scale represents a major concern for various industrial, environmental, and geological sectors, the present study reports on a detailed investigation of barite growth kinetics as a function of crystallographic orientation for temperatures ranging between 10 °C and 70 °C, and initial saturation indices (SI) of 1.1 and 2.1. The growth rates were estimated for (001), (210), and (101) faces using vertical scanning interferometry. Generally, our dataset confirm that barite growth is a fast process, where the (001) face exhibits the slowest growth rates, whereas (210) represents the fastest growing face. The measured rates spanned over nearly 3 orders of magnitude, between 0.6 nm.h-1 (T = 10 °C, SI = 1.1, (001) face) to approximately 330 nm.h-1 (T = 70 °C, SI = 2.1, (210) face). Overall, face-specific barite growth rates (r^((hkl))) can be successfully fit using the following rate law:r^((hkl))=A^((hkl)).exp⁡〖((〖-E〗_a^((hkl)))⁄RT).(〖10〗^SI-1)〗where A^((hkl))and〖 E〗_a^((hkl)) represent the face-specific Arrhenius pre-exponential factor and activation energy, respectively, R is the gas constant, and T refers to the absolute temperature. In addition, because of the modest growth anisotropy of the various investigated faces, the following isotropic rate law can be used to satisfactorily account for the measured rate data:r^((hkl))=A.exp⁡〖((-E_a)⁄RT).(〖10〗^SI-1)〗with average values of A = exp(13.05) nm.h-1 and Ea = 33.7± 1.1kJ.mol-1. Taken together, our results suggest that over the range of conditions investigated in the present study, barite growth kinetics is surface-controlled, with the same rate-limiting step for all faces, while possibly verifying the principle of detailed balancing and micro-reversibility. These results imply that previous modeling exercises of steady-state barite growth based on isotropic rate laws may remain valid, at least over the range of conditions investigated in the present study.