Steady-state kinetics and equilibrium between ground water and granitic rock

Other

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

14

Scientific paper

A hypothesis is presented that the dissolution of albite includes the exchange of sodium for hydrogen ion in a surface layer of the mineral and the structural collapse of the residual anionic lattice of the layer. The ion exchange is described by the first law of diffusion ( D 25° C = 3 × 10 -22 and 1.5 × 10 -20 cm 2 sec -1 at P CO 2 = 0 and 26.2 atm, respectively). The surface residual layer reaches a steady-state thickness ranging from n × 10 -8 to n × 10 -5 cm according to the temperature and P CO 2 . The increase in aqueous sodium with time in a continuous ground-water system is described by a simple exponential equation. The equation is used to estimate the percolation time of ground water from the data on the chemical composition of a water sample. The probable times range from 14 to 3840 days for various ground-water systems and are compared to the times of percolation calculated from the geothermal and hydraulic data. Both estimates are found to be in general agreement. The concentrations of Al and Si in cold water from granitic rocks are shown to be controlled by the chemical equilibrium with respect to an aged aluminosilicate. The aluminosilicate precipitates from ground water as an amorphous isoelectric solid. Its chemical composition is represented by a simplified stoichiometric formula [ Al ( OH ) 3 ]( 1- x )[ SiO 2 ] x and varies linearly with pH of the solution. The atoms of Al, O and H tend to occupy a fixed position in the solid given by the gibbsite structure upon aging in the field. The solubility product of the solid is estimated from the published data on experimental and field research into the dissolution of feldspars: log K = (1 - x ) × log [ Al 3+ ] + x log [ H 4 SiO 4 ] - (3 - 3 x ) log [ H + ] = 8.56 - 11.26 x , where x is the molar fraction of silica in the aluminosilicate.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Steady-state kinetics and equilibrium between ground water and granitic rock does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Steady-state kinetics and equilibrium between ground water and granitic rock, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Steady-state kinetics and equilibrium between ground water and granitic rock will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-1312379

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.