scholarly journals Kinetics of carbonate mineral dissolution in CO2-acidified brines at storage reservoir conditions

2016 ◽  
Vol 192 ◽  
pp. 545-560 ◽  
Author(s):  
Cheng Peng ◽  
Benaiah U. Anabaraonye ◽  
John P. Crawshaw ◽  
Geoffrey C. Maitland ◽  
J. P. Martin Trusler
Keyword(s):  
Kinetic Model ◽  
Carbonic Acid ◽  
Dissolution Kinetics ◽  
Carbonate Reservoir ◽  
Mineral Dissolution ◽  
Direct Reaction ◽  
Carbonate Mineral ◽  
Dissolution Rates ◽  
Saturated Water ◽  
Kinetics Of

We report experimental measurements of the dissolution rate of several carbonate minerals in CO2-saturated water or brine at temperatures between 323 K and 373 K and at pressures up to 15 MPa. The dissolution kinetics of pure calcite were studied in CO2-saturated NaCl brines with molalities of up to 5 mol kg−1. The results of these experiments were found to depend only weakly on the brine molality and to conform reasonably well with a kinetic model involving two parallel first-order reactions: one involving reactions with protons and the other involving reaction with carbonic acid. The dissolution rates of dolomite and magnesite were studied in both aqueous HCl solution and in CO2-saturated water. For these minerals, the dissolution rates could be explained by a simpler kinetic model involving only direct reaction between protons and the mineral surface. Finally, the rates of dissolution of two carbonate-reservoir analogue minerals (Ketton limestone and North-Sea chalk) in CO2-saturated water were found to follow the same kinetics as found for pure calcite. Vertical scanning interferometry was used to study the surface morphology of unreacted and reacted samples. The results of the present study may find application in reactive-flow simulations of CO2-injection into carbonate-mineral saline aquifers.

scholarly journals The initial dissolution rates of simulated UK Magnox–ThORP blend nuclear waste glass as a function of pH, temperature and waste loading

2015 ◽  
Vol 79 (6) ◽  
pp. 1529-1542 ◽  
Author(s):  
N. Cassingham ◽  
C.L. Corkhill ◽  
D.J. Backhouse ◽  
R.J. Hand ◽  
J.V. Ryan ◽  
...  
Keyword(s):  
Dissolution Kinetics ◽  
Intrinsic Rate ◽  
Waste Glass ◽  
High Level Waste ◽  
Dissolution Mechanism ◽  
Dissolution Rates ◽  
Forward Rates ◽  
Glass Dissolution ◽  
High Level ◽  
Kinetics Of

AbstractThe first comprehensive assessment of the dissolution kinetics of simulant Magnox–ThORP blended UK high-level waste glass, obtained by performing a range of single-pass flow-through experiments, is reported here. Inherent forward rates of glass dissolution were determined over a temperature range of 23 to 70°C and an alkaline pH range of 8.0 to 12.0. Linear regression techniques were applied to the TST kinetic rate law to obtain fundamental parameters necessary to model the dissolution kinetics of UK high-level waste glass (the activation energy (Ea), pH power law coefficient (η) and the intrinsic rate constant (k0)), which is of importance to the post-closure safety case for the geological disposal of vitreous products. The activation energies based on B release ranged from 55 ± 3 to 83 ± 9 kJ mol–1, indicating that Magnox–THORP blend glass dissolution has a surface-controlled mechanism, similar to that of other high-level waste simulant glass compositions such as the French SON68 and LAW in the US. Forward dissolution rates, based on Si, B and Na release, suggested that the dissolution mechanism under dilute conditions, and pH and temperature ranges of this study, was not sensitive to composition as defined by HLW-incorporation rate.

Dissolution kinetics of colemanite in SO2 saturated water

1988 ◽  
Vol 19 (3) ◽  
pp. 385-392 ◽  
Author(s):  
M.Muhtar Kocakerim ◽  
Mahir Alkan
Keyword(s):  
Dissolution Kinetics ◽  
Saturated Water ◽  
Kinetics Of

Experimental Determination of Chlorite Dissolution Rates

1994 ◽  
Vol 353 ◽  
Author(s):  
Christopher A. Rochelle ◽  
Keith Bateman ◽  
Robert MacGregor ◽  
Jonathan M. Pearce ◽  
David Savage ◽  
...  
Keyword(s):  
Dissolution Kinetics ◽  
Research Programme ◽  
Mineral Dissolution ◽  
Dissolution Rates ◽  
Disturbed Zone ◽  
Ph Conditions ◽  
Engineered Barriers ◽  
The Uk ◽  
Mineral Dissolution Kinetics

AbstractCurrent concepts of the geological disposal of low- and intermediate-level radioactive wastes in the UK envisage the construction of a mined facility (incorporating cementitious engineered barriers) in chlorite-bearing rocks. To model accurately the fluid-rock reactions within the ‘disturbed zone’ surrounding a repository requires functions that describe mineral dissolution kinetics under pH conditions that vary from near neutral to highly alkaline.Therefore, an experimental study to determine the dissolution rates of Fe-rich chlorite has been undertaken as part of the Nirex Safety Assessment Research Programme. Four experiments have been carried out at 25 °C and four at 70 °C, both sets using a range of NaCl/NaOH solutions of differing pH (of nominal pH 9.0,10.3, 11.6 and 13.0 [at 25 °C]).Dissolution rates have been calculated and were found to increase with increasing pH and temperature. However, increased pH resulted in non-stoichiometric dissolution possibly due to preferential dissolution of part of the chlorite structure relative to another, or reprecipitation of some elements as thin hydroxide or oxyhydroxide surface coatings on the chlorite.These results also show that chlorite dissolution is appreciably slower than that of albite and quartz at both 25 and 70 °C, but slightly faster than that of muscovite at 70 °C.

The effect of orthophosphate on carbonate mineral dissolution rates in seawater

1986 ◽  
Vol 56 (3-4) ◽  
pp. 313-323 ◽  
Author(s):  
Lynn M. Walter ◽  
Elizabeth A. Burton
Keyword(s):  
Mineral Dissolution ◽  
Carbonate Mineral ◽  
Dissolution Rates

Dissolution Kinetics of Phosphate Ore in SO2-Saturated Water

1994 ◽  
Vol 33 (9) ◽  
pp. 2220-2225 ◽  
Author(s):  
Ahmet Yartasi ◽  
M. Muhtar Kocakerim ◽  
Sinan Yapici ◽  
Cengiz Ozmetin
Keyword(s):  
Dissolution Kinetics ◽  
Phosphate Ore ◽  
Saturated Water ◽  
Kinetics Of

Dissolution Kinetics of Ulexite in CO2-Saturated Water

1993 ◽  
Vol 32 (4) ◽  
pp. 393-396 ◽  
Author(s):  
M. Muhtar Kocakerim ◽  
Sabri Çolak ◽  
Tom Davies ◽  
Mahir Alkan
Keyword(s):  
Dissolution Kinetics ◽  
Saturated Water ◽  
Kinetics Of

Initial dissolution kinetics of ionic oxides

1981 ◽  
Vol 374 (1756) ◽  
pp. 141-153 ◽  
Keyword(s):  
Linear Relation ◽  
Stable Solution ◽  
Dissolution Kinetics ◽  
Theoretical Models ◽  
Initial Increase ◽  
Unit Surface Area ◽  
Solution Ph ◽  
Dissolution Rates ◽  
Kinetics Of ◽  
Total Dissolution

It is shown th at factors previously recognized, but not regarded as critical, can dominate dissolution kinetics of ionic oxides. The use of the nearly perfect {100} MgO surfaces of smoke cubes to obtain very precise values of dissolution rates per unit surface area, in dilute HC1, HC1O 4 and HNO 3 , has shown th at rates extrapolated to zero dissolution are almost independent of pH in the range 2.0- 3.5. Dissolution rates were measured by monitoring solution pH as a function of time. This revealed increasing rates with increasing pH up to about 5 % total dissolution, followed ultimately by a return to the linear relation between Ig(rate) and pH (slope ca. — 0.5) normally expected. The initial increase in rate is due to increasing [Mg 2+ ] in solution and is observed with [Mg 2+ ] as low as 1 % of the [H + ]. A linear relation between lg(rate) and [Mg 2+ ] is found during the early stages of dissolution. Other cations (Al 3 +, Na + ) also increase the initial rate, to a similar extent. Electron-microscope observations of the cubes show alteration of the surfaces to a castellated structure (of {100}-based projections and intrusions) on wetting before dissolution, and the development of facets having an average (110}-natureduring dissolution. The results are in conflict with current theoretical models, and a qualitative account of the mechanism of the establishment of a ‘ stable ’ solution double layer is given.

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