The dissolution kinetics of a granite and its minerals—Implications for comparison between laboratory and field dissolution rates

2005 ◽  
Vol 69 (3) ◽  
pp. 607-621 ◽  
Author(s):  
Jiwchar Ganor ◽  
Emmanuelle Roueff ◽  
Yigal Erel ◽  
Joel D. Blum
Keyword(s):  
Dissolution Kinetics ◽  
Dissolution Rates ◽  
Kinetics Of

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.

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.

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.

scholarly journals Dissolution kinetics of hydrated calcium aluminates (AFm-Cl) as a function of pH and at room temperature

2017 ◽  
Vol 81 (5) ◽  
pp. 1245-1259 ◽  
Author(s):  
Nicolas C. M. Marty ◽  
Sylvain Grangeon ◽  
Catherine Lerouge ◽  
Fabienne Warmont ◽  
Olivier Rozenbaum ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Room Temperature ◽  
Dissolution Kinetics ◽  
Dissolution Rates ◽  
Ph Values ◽  
Surface Areas ◽  
Calcium Aluminates ◽  
Waste Repositories ◽  
Kinetics Of ◽  
Hydrated Calcium

AbstractThe determination of reliable weathering/dissolution rates for cement phases is of fundamental importance for the modelling of the temporal evolution of both radioactive waste repositories and CO2 geological storage sites (e.g. waste matrix, plug in boreholes). Here, the dissolution kinetics of AFm-Cl (hydrated calcium aluminates containing interlayer Cl) has been studied using flow-through experiments conducted at pH values ranging from 9.2 to 13. Mineralogical (XRD) and chemical (EPMA, TEM) analyses have been performed to determine the evolution of the phases during the dissolution experiments. For pH values between 10 and 13, the dissolution of AFm-Cl is congruent (i.e. Ca/Al ratios close to 2 both for solids and outlet concentrations). In contrast, the precipitation of amorphous Al-phases and possibly amorphous mixed Al/Ca phases is observed at pH 9.2, leading to Ca/Al ratios in the outlet solutions higher than those of the initial solid. Therefore, at pH 9.2, even if Cl–/OH– exchange occurs, estimation of dissolution rate from released Cl appears to be the best proxy. Dissolution rates were normalized to the final specific surface areas (ranging from 6.1 to 35.4 m2 g−1). Dissolution rate appears to be pH-independent and therefore the far-from-equilibrium dissolution rate at room temperature is expressed as: logR(mol m–2 s–1) = –9.23 ± 0.18

Kinetics of pyrite, pyrrhotite, and chalcopyrite dissolution byAcidithiobacillus ferrooxidans

2016 ◽  
Vol 62 (8) ◽  
pp. 629-642 ◽  
Author(s):  
Ayse Tuba Kocaman ◽  
Mustafa Cemek ◽  
Katrina Jane Edwards
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Dissolution Kinetics ◽  
The Other ◽  
Mineral Surfaces ◽  
Dissolution Rates ◽  
Ion Concentrations ◽  
Ph Changes ◽  
Kinetics Of Dissolution ◽  
Kinetics Of ◽  
Number Of Cells

The main objective of this study was to investigate the dissolution kinetics of pyrite, pyrrhotite, and chalcopyrite. Crushed minerals were reacted with Acidithiobacillus ferrooxidans (25 °C). The kinetics of dissolution was investigated by monitoring pH and Fe2+and Fe3+ion concentrations in the leaching solutions. Pyrite, pyrrhotite, and chalcopyrite dissolution by A. ferrooxidans was found to be a chemically controlled process. With bacteria, the dissolution rates of the minerals increased in the order of pyrrhotite, pyrite, and chalcopyrite. The number of cells attached to mineral surfaces increased in the same order. Acidithiobacillus ferrooxidans was found to enhance the dissolution rates of the minerals. The acid-insoluble trait of pyrite and acid-soluble trait of the other 2 minerals affected the pH changes in the leaching solutions.

Aqueous dissolution kinetics of pyrochlore, zirconolite and brannerite at 25, 50, and 75 °C

2000 ◽  
Vol 88 (9-11) ◽  
Author(s):  
S. K. Roberts ◽  
W.L. Bourcier ◽  
H.F. Shaw
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Dissolution Rate ◽  
Dissolution Kinetics ◽  
Kcal Mole ◽  
Dissolution Rates ◽  
Flow Through ◽  
Kinetics Of ◽  
Total Dissolution ◽  
Calculated Average

We measured the rates of dissolution of pyrochlore, zirconolite, and brannerite in pH-buffered solutions of pH 2, 4, 6, 8, 10, and 12 at temperatures of 25, 50, and 75 °C in flow-through reactors. The dissolution rates for all phases show a minimum near pH 8. Zirconolite dissolves the slowest of the three phases, with a slightly higher rate for pyrochlore and a much higher dissolution rate for brannerite. Brannerite dissolves as much has 30 times faster than zirconolite. The rates increase with temperature, but the magnitude of the increase varies with pH. The calculated average apparent activation energy for dissolution is 6±3 kcal/mole. Dissolution is non-stoichiometric at all pHs. Ti and Hf are released most slowly, and are often below detection limits (1 ppb for Ti, 0.2 ppb for Hf). Releases of Ca, U, Gd, and Ce appear to be stoichiometric below pH 8. At pH 8 and above only U is measurable in solution. Dissolution rates are slow under all conditions, and commonly in the range of 1-100 nm total dissolution/year (between 10

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