The dynamic nature of crystal growth in pores.
The kinetics of crystal growth in porous media controls a variety of natural processes such as ore genesis and crystallization induced fracturing that can trigger earthquakes and weathering, as well as, sequestration of CO2 and toxic metals into geological formations. Progress on understanding those processes has been limited by experimental difficulties of dynamically studying the reactive surface area and permeability during pore occlusion. Here, we show that these variables cause a time-dependency of barite growth rates in microporous silica. The rate is approximately constant and similar to that observed on free surfaces if fast flow velocities predominate and if the time-dependent reactive surface area is accounted for. As the narrower flow paths clog, local flow velocities decrease, which causes the progressive slowing of growth rates. We conclude that mineral growth in a microporous media can be estimated based on free surface studies when a) the growth rate is normalized to the time-dependent surface area of the growing crystals, and b) the local flow velocities are above the limit at which growth is transport-limited. Accounting for the dynamic relation between microstructure, flow velocity and growth rate is shown to be crucial towards understanding and predicting precipitation in porous rocks.
School of Materials, The University of Manchester, M13 9PL, Manchester, UK.|Research Complex at Harwell, Rutherford Appleton Laboratory, OX11 0FA, Harwell, UK.|Chemical Sciences Division, Oak Ridge National Laboratory, PO Box 2008, MS-6110, Oak Ridge, TN 37831 USA.
Jose R A
JR
Godinho
The University of Melbourne, Department of Infrastructure Engineering, Parkville, VIC, 3010, Australia.|CSIRO Land and Water, Glen Osmond, PB2, SA 5064, Australia.|Institute of Physics of the Earth of Russian Academy of Sciences, Bolshaya Gruzinskaya 10, Moscow, 107031, Russia.
Kirill M
KM
Gerke
Chemical Sciences Division, Oak Ridge National Laboratory, PO Box 2008, MS-6110, Oak Ridge, TN 37831 USA.
Andrew G
AG
Stack
School of Materials, The University of Manchester, M13 9PL, Manchester, UK.|Research Complex at Harwell, Rutherford Appleton Laboratory, OX11 0FA, Harwell, UK.
Peter D
PD
Lee