Effect of Thiourea Compounds on Dissolution Rate of Iron and Mild Steel - Adsorption and Inhibition, Steady State and Potential

1955 ◽  
Vol 47 (9) ◽  
pp. 1773-1781 ◽  
Author(s):  
A. C. Makrides ◽  
Norman Hackerman
Keyword(s):  
Steady State ◽  
Mild Steel ◽  
Dissolution Rate

Dissolution behaviour of soil kaolinites in acidic solutions

Clay Minerals ◽  
2013 ◽  
Vol 48 (3) ◽  
pp. 447-461 ◽  
Author(s):  
K. Khawmee ◽  
A. Suddhiprakarn ◽  
I. Kheoruenromne ◽  
I. Bibi ◽  
B. Singh
Keyword(s):  
Steady State ◽  
Dissolution Rate ◽  
Initial Period ◽  
Reference Sample ◽  
Stoichiometric Ratio ◽  
Solution Ph ◽  
Weathered Soils ◽  
Dissolution Behaviour ◽  
Georgia Kaolinite ◽  
Highly Weathered Soils

AbstractHighly weathered soils of the tropics and subtropics commonly have kaolinitedominated clay fractions. Under acidic conditions prevailing in these soils kaolinite dissolution occurs, contributing to the high levels of soluble Al in these soils. This study evaluates the dissolution behaviour of kaolinites from subsurface horizons of highly weathered soils from Thailand, along with a soil kaolinite from Western Australia (WA kaolinite) and Georgia kaolinite (KGa-2). Kaolinite-dominated clay fractions were isolated from soils by sedimentation and chemically treated to remove iron oxides. The dissolution rate of kaolinites was measured in 0.01 M NaCl as a function of pH (1–4; HCl) at 25±1°C using non-stirred flow-through reactors. Kaolinite dissolution rates were calculated from the release of Al and Si at the steady state. In most of the experiments and at all pH values, the release of both Si and Al underwent a distinct transition from an initial period of rapid release to significantly slower release at the steady state. Aluminium and Si concentrations at the steady state were higher for soil kaolinites than the reference sample (KGa-2). At the steady state the dissolution of all kaolinites was stoichiometric except for the soil kaolinites from Thailand at pH 4, where the Al/Si ratio was well below the stoichiometric ratio. Log dissolution rate (RSi) of soil kaolinites ranged from –13.75 to –12.51, with the dissolution rate increasing significantly with decreasing solution pH. However, the dissolution rate was similar or pH independent between pH 2 and 3, which is the pH range of the point of zero net charge (PZNC) for both soil and reference kaolinites. The dissolution rate of soil kaolinite was significantly higher than the KGa-2 sample at pH < 3. The results obtained on kaolinite samples from highly weathered soils show that in highly acidic systems kaolinite is a source of soluble Al. Soil kaolinites with poorly ordered small crystals dissolve faster than better crystalline reference kaolinite (KGa-2) with larger crystals.

scholarly journals The Role Of Chemical Reaction In Waste-Form Performance

1987 ◽  
Vol 112 ◽  
Author(s):  
P. L. Chambré ◽  
C. H. Kang ◽  
W. W.-L. Lee ◽  
T. H. Pigford
Keyword(s):  
Mass Transfer ◽  
Steady State ◽  
Dissolution Rate ◽  
Chemical Reaction ◽  
Borosilicate Glass ◽  
Reaction Rate ◽  
Waste Form ◽  
Spent Fuel ◽  
Wide Range ◽  
Chemical Reaction Rate

AbstractThe dissolution rate of waste solids in a geologic repository is a complex function of waste form geometry, chemical reaction rate, exterior flow field, and chemical environment. We present here an analysis to determine the steady-state mass transfer rate, over the entire range of flow conditions relevant to geologic disposal of nuclear waste. The equations for steady-state mass transfer with a chemical-reaction-rate boundary condition are solved by three different mathematical techniques which supplement each other. This theory is illustrated with laboratory leach data for borosilicate-glass and a spherical spent-fuel waste form under typical repository conditions. For borosilicate glass waste in the temperature range of 57°C to 250°C, dissolution rate in a repository is determined for a wide range of chemical reaction rates and for Peclet numbers from zero to well over 100, far beyond any Peclet values expected in a repository. Spent-fuel dissolution in a repository is also investigated, based on the limited leach data now available.

Impact of Silicon Migration Through Buffer Material on the Lifetime of Vitrified Waste

2009 ◽  
Vol 1193 ◽  
Author(s):  
Seiichiro Mitsui ◽  
Hitoshi Makino ◽  
Manabu Inagaki ◽  
Takanori Ebina
Keyword(s):  
Steady State ◽  
Dissolution Rate ◽  
Glass Matrix ◽  
Dissolution Behavior ◽  
Preliminary Calculation ◽  
Disturbed Zone ◽  
Buffer Material ◽  
Excavation Disturbed Zone ◽  
Radionuclide Release ◽  
The Impact

AbstractA sensitivity analysis was conducted to evaluate the impact of silicon migration through buffer material on the lifetime of vitrified waste. The results indicate that the lifetime depends on a combination of the dissolved glass fraction in the non-steady-state phase controlled by the silicon pore diffusion coefficient (Dp) and the silicon distribution coefficient (Kd) in the buffer material and the steady-state dissolution rate defined by Dp and the groundwater flow rate (Q) in the excavation disturbed zone. In the case where the glass dissolution rate reaches the steady-state dissolution rate, the sensitivity of the lifetime to Dp and Q varies according to the magnitude relationship between Dp and Q. We also discuss the impact on the lifetime of glass hydration, which proceeds simultaneously with glass matrix dissolution. The results show that glass hydration is less important for the lifetime than glass matrix dissolution in an open system and it can be concluded that silicon migration through the buffer material will be an important process for estimating the lifetime of the vitrified waste. A preliminary calculation of the long-term waste behavior with realistic assumptions indicates the importance of the silicon migration parameters Kd and Dp, which control the dissolution behavior of the vitrified waste in the non-steady-state phase, for evaluating radionuclide release.

Forsterite dissolution in superheated basaltic, andesitic and rhyolitic melts

1990 ◽  
Vol 54 (374) ◽  
pp. 67-74 ◽  
Author(s):  
C. H. Donaldson
Keyword(s):  
Steady State ◽  
Natural Convection ◽  
Dissolution Rate ◽  
Atmospheric Pressure ◽  
Initial Value ◽  
Steady State Condition ◽  
Rate Of Dissolution ◽  
Constant Rate ◽  
The Difference ◽  
Initial Dissolution Rate

AbstractDissolution rates of small forsterite spheres in superheated melts of basalt, andesite and rhyolite composition have been measured at 1300°C, atmospheric pressure. The rate is constant (83 µm hr−1) in the basalt, regardless of run duration. In the andesite the initial dissolution rate is 200µm hr−1, followed by a decrease to a constant value of 16µmhr−1 in 2–3 hours. Dissolution rate in the rhyolite decreases from an initial value of 1.7 to <0.1 µmhr−1 over 280 hours and never reaches a constant rate. Once the rate of dissolution has become constant, the film of contaminated melt that forms in melt about a crystal does not thicken with time, indicating attainment of a steady-state condition. Steady state is attributed to natural convection arising from the difference in density between the film of contaminated melt surrounding a crystal and that beyond. The density difference is approximately 2% of the density of the rock melt.

Steady state hydrogen evolution enhanced during the abrasive wear from mild steel

Wear ◽  
1988 ◽  
Vol 124 (3) ◽  
pp. 331-336 ◽  
Author(s):  
Pyun Su-Il ◽  
Kim Jong-Sang ◽  
Bertram Frisch ◽  
Christopher Messerschmidt
Keyword(s):  
Steady State ◽  
Mild Steel ◽  
Abrasive Wear ◽  
Hydrogen Evolution

Free External Tube Inversion Simulation Using FEM

1996 ◽  
Author(s):  
Ali Çolakoğlu ◽  
R. O. Yıldırım ◽  
B. Kaftanoğlu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Steady State ◽  
Mild Steel ◽  
Experimental Result ◽  
The Finite Element Method ◽  
Steel Tubes ◽  
Static Tests ◽  
External Tube ◽  
Outside Diameter

Abstract In this work the finite element method is employed to investigate the free external tube inversion. At the same time, quasi-static tests on cold drawn seamless mild steel tubes (BS 3602-CFS 360) with 50.8 mm (2 in) outside diameter, 1.6 mm (0.064 in) wall thickness and 203.2 mm (8 in) length are performed. The energy absorption capacities and steady-state inversion loads are observed. The finite element predictions are compared with a typical experimental result.

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