Introduction of Kinetic Effects into the Thermodynamic Modelling of CaCO3 Scale Precipitation

2018 ◽  
Author(s):  
Duarte J. Silva ◽  
K. S. Sorbie ◽  
Eric J. Mackay
Keyword(s):  
Thermodynamic Modelling ◽  
Kinetic Effects

scholarly journals Experimental Study of Pyrite Oxidation at 100 °C: Implications for Deep Geological Radwaste Repository in Claystone

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 427 ◽  
Author(s):  
Héloïse Verron ◽  
Jérôme Sterpenich ◽  
Julien Bonnet ◽  
Franck Bourdelle ◽  
Régine Mosser-Ruck ◽  
...  
Keyword(s):  
Oxidation Rate ◽  
Carbonic Acid ◽  
Near Field ◽  
Pyrite Oxidation ◽  
Thermodynamic Modelling ◽  
Stable Phase ◽  
Native Sulfur ◽  
Kinetic Effects ◽  
Pco2 Monitoring ◽  
Set Up

The oxidation of pyrite is one of the near field processes of the chemical evolution of clay rock planned to host a deep geological radioactive waste repository during operation. Indeed, this process can lead to transitory acidic conditions in the medium (i.e., production of sulphuric acid, carbonic acid) which may influence the corrosion kinetics of the carbon steel components of some disposal cells. In order to improve the geochemical modelling of the long-term disposal, the oxidation of pyrite in contact with clays and carbonates at 100 °C must be evaluated. In this study, special attention was paid to the pyrite oxidation rate thanks to an original experimental set-up, involving several pyrite/mineral mixtures and a reactor coupled to a micro gas chromatograph (PO2 and PCO2 monitoring). Although thermodynamic modelling expects that hematite is the most stable phase in a pure pyrite heated system (low pH), experiments show the formation of native sulfur as an intermediate product of the reaction. In the presence of calcite, the pH is neutralized and drives the lower reactivity of pyrite in the absence of native sulfur. The addition of clay phases or other detrital silicates from the claystone had no impact on pyrite oxidation rate. The discrepancies between experiments and thermodynamic modelling are explained by kinetic effects. Two laws were deduced at 100 °C. The first concerns a pure pyrite system, with the following law: r P y =   10 − 4.8 · P O 2 0.5 · t − 0.5 . The second concerns a pyrite/carbonates system: r P y + C a =   10 − 5.1 · P O 2 0.5 · t − 0.5 where PO2 corresponds to the partial pressure of O2 (in bar) and t is time in seconds. Different mechanisms are proposed to explain the evolution with time of the O2 consumption during pyrite oxidation: (i) decrease of the specific or reactive surface area after oxidation of fine grains of pyrite, (ii) decrease of O2 pressure, (iii) growing up of secondary minerals (Fe-oxides or anhydrite in the presence of calcium in the system) on the surface of pyrite limiting the access of O2 to the fresh surface of pyrite, and (iv) change in the pH of the solution.

Intrinsic kinetic effects during martensitic transformations

2003 ◽  
Vol 112 ◽  
pp. 133-137 ◽  
Author(s):  
A. Fraile-Rodriguez ◽  
P. P. Rodriguez ◽  
R. B. Pérez-Saez ◽  
A. Lopez-Echarri ◽  
J. San Juan
Keyword(s):  
Martensitic Transformations ◽  
Kinetic Effects ◽  
Intrinsic Kinetic

The Kinetic Effects, Caused by Thickness Fluctuations of Quantum Semiconductor Wire

2017 ◽  
Vol 9 (2) ◽  
pp. 02024-1-02024-4
Author(s):  
M. A. Ruvinskii ◽  
◽  
B. M. Ruvinskii ◽  
O. B. Kostyuk ◽  
◽  
...  
Keyword(s):  
Quantum Semiconductor ◽  
Kinetic Effects

THERMODYNAMIC MODELLING OF CRUST-MAGMA HEAT INTERACTIONS IN THE TVZ

2018 ◽  
Author(s):  
Laura Anne Blackstone ◽  
◽  
Darren Gravley ◽  
Guilherme A.R. Gualda ◽  
David Dempsey ◽  
...  
Keyword(s):  
Thermodynamic Modelling

THERMODYNAMIC MODELLING OF MAFIC GRANULITES: DISCREPANCIES BETWEEN OBSERVED AND PREDICTED PHASE EQUILIBRIA

2018 ◽  
Author(s):  
Jacob B. Forshaw ◽  
◽  
David J. Waters ◽  
David R.M. Pattison ◽  
Richard M. Palin ◽  
...  
Keyword(s):  
Phase Equilibria ◽  
Thermodynamic Modelling

scholarly journals Ionic conductivity of Li 2 O‐P 2 O 5 glasses from thermodynamic modelling of their chemical structure

2021 ◽  
Author(s):  
Alberto López‐Grande ◽  
Rajesh Dagupati ◽  
Pedro Galán del Sastre ◽  
Francisco Muñoz
Keyword(s):  
Ionic Conductivity ◽  
Chemical Structure ◽  
Thermodynamic Modelling

Unraveling Kinetic Effects during Photoelectrochemical Mineralization of Phenols. Rutile:Anatase TiO2 Nanotube Photoanodes under Thin-Layer Conditions

2020 ◽  
Author(s):  
Dalia Leon ◽  
Alberto Maimone ◽  
David Carvajal ◽  
Lorean Madriz ◽  
Benjamín R. Scharifker ◽  
...  
Keyword(s):  
Thin Layer ◽  
Tio2 Nanotube ◽  
Kinetic Effects
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