ChemInform Abstract: STUDY OF THE MECHANISM AND KINETICS OF THE REDUCTION OF URANYL IONS IN PHOSPHORIC ACID SOLUTIONS

1982 ◽  
Vol 13 (38) ◽  
Author(s):  
K. EL KACEMI ◽  
B. TYBURCE ◽  
S. BELCADI ◽  
J. J. RAMEAU
Keyword(s):  
Phosphoric Acid ◽  
Acid Solutions ◽  
Uranyl Ions ◽  
Mechanism And Kinetics ◽  
Kinetics Of

The Dissolution Kinetics of Tincal in Phosphoric Acid Solutions

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Yuksel Abali ◽  
Salih U Bayca ◽  
Ayse E Guler
Keyword(s):  
Particle Size ◽  
Phosphoric Acid ◽  
Dissolution Rate ◽  
Acid Concentration ◽  
Reaction Temperature ◽  
Dissolution Kinetics ◽  
Reaction Model ◽  
Acid Solutions ◽  
Liquid Ratio ◽  
Kinetics Of

In this study, the dissolution kinetics of tincal in phosphoric acid solutions was investigated. The effects of reaction temperature, acid concentration, solid to liquid ratio, particle size and stirring speed were determined in the experiments. The results showed that the dissolution rate increased with increasing acid concentration, reaction temperature, stirring speed and increased with decreasing particle size and solid to liquid ratio. The dissolution rate was found to be based on the first order pseudo homogenous reaction model. The activation energy of the tincal in phosphoric acid solution was determined as 42.28 kJ.mol-1.

Separation of uranium(VI) from tri- and tetravalent elements in phosphoric acid solutions

2006 ◽  
Vol 94 (8) ◽  
Author(s):  
V. Brandel ◽  
N. Clavier ◽  
N. Dacheux
Keyword(s):  
Phosphoric Acid ◽  
Acid Medium ◽  
New Method ◽  
Acid Solutions ◽  
Uranyl Ions ◽  
The Difference

SummaryA new method of separation of uranyl ions from di-, tri- and tetravalent cations such as thorium, zirconium, cerium(IV) and/or lanthanides(III) involving phosphoric acid medium is described in this paper. The process is based on the difference of solubility between various phosphates: M

scholarly journals Kinetics of pyrite oxidation by hydrogen peroxide in phosphoric acid solutions

1999 ◽  
Vol 64 (12) ◽  
pp. 753-764 ◽  
Author(s):  
Mile Dimitrijevic ◽  
Milan Antonijevic ◽  
Valentina Dimitrijevic
Keyword(s):  
Hydrogen Peroxide ◽  
Phosphoric Acid ◽  
Pyrite Oxidation ◽  
Negative Influence ◽  
Acid Solutions ◽  
Phosphate Ion ◽  
Shrinking Core ◽  
Kinetics Of ◽  
Rate Controlling Step ◽  
Oxidation By Hydrogen Peroxide

The kinetics of pyrite oxidation by hydrogen peroxide in phosphoric acid solutions were investigated. The effects of stirring, temperature, and particle size, as well as of the hydrogen peroxide and phosphoric acid concentrations were studied. The effect of phosphate ion addition was also examined. The oxidation kinetics was found to follow a shrinking core model, with the surface chemical reaciton as the rate-controlling step. This is in accord with an activation energy of 57 kJ/mol and a linear relationship between the rate constant and the reciprocal of the particle radius. The reaction order with respect to the hydrogen peroxide concentration was found to be equal to unity. Variation of the phosphoric acid concentration had practically no effect on the rate of pyrite oxidation. Addition of the phosphate ion in the relatively low concentration range (0.005.0.1 mol/dm 3) had a highly negative influence on the rate of pyrite oxidation, indicating that this ion has an inhibiting effect on the oxidation of pyrite by hydrogen peroxide.

Kinetics of Autocatalytic Oxidation of Mn(II) Ions by Periodate in Relation to Manganese Oscillations

1992 ◽  
Vol 57 (6) ◽  
pp. 1210-1217 ◽  
Author(s):  
Gongoryn Sodnomdordž ◽  
Milan Melicharčík ◽  
Ľudovít Treindl
Keyword(s):  
Phosphoric Acid ◽  
Acid Medium ◽  
Rate Constants ◽  
Reaction Pathway ◽  
Stirred Tank ◽  
Acid Solutions ◽  
Chemical Oscillations ◽  
Tank Reactor ◽  
Kinetics Of ◽  
Autocatalytic Oxidation

The kinetics of the autocatalytic oxidation of Mn(II) ions by periodate was investigated in unbuffered phosphoric acid solutions and in buffered solutions; the process was studied in a bath reactor in relation to the chemical oscillations in a continuously flow stirred tank reactor (CSTR), which are based on the chemistry of manganese. The rate constants k1 and k'2 corresponding to the noncatalyzed and catalyzed reaction course were determined by the Schwartz method. While MnO4- ions are the reaction product in the unbuffered phosphoric acid medium, in a CH3COOH-NaOH buffer the Mn2+ ions are only oxidized to Mn(IV). For this case, a reaction pathway is discussed where the key step encompasses dimerization of MnO(OH)+ ions followed by the formation of (MnO2)col colloids, stabilized by adsorption of H2PO4- ions on their surface. This reaction pathway is also of importance with respect to the new manganese oscillator which is based on the autocatalytic oxidation of Mn(II) ions by periodate in a CSTR.

Kinetics of polarographic reduction of uranium(VI) in phosphoric acid solutions

1972 ◽  
Vol 17 (6) ◽  
pp. 1065-1073 ◽  
Author(s):  
I.M. Issa ◽  
M. Tharwat ◽  
Y.A. Elewady
Keyword(s):  
Phosphoric Acid ◽  
Polarographic Reduction ◽  
Acid Solutions ◽  
Kinetics Of

The kinetics of aluminium(III) extraction from sulphuric acid solutions by Di-(2-ethylhexyl)-phosphoric acid

1978 ◽  
Vol 40 (8) ◽  
pp. 1571-1574 ◽  
Author(s):  
Taichi Sato ◽  
Takashi Yoshino ◽  
Takato Nakamura ◽  
Tomoya Kudo
Keyword(s):  
Phosphoric Acid ◽  
Sulphuric Acid ◽  
Acid Solutions ◽  
Kinetics Of
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