Dissolution kinetics and mechanisms of reaction of Udi clay in nitric acid solution

Ajemba, Regina O.; Onukwuli, Okechukwu Dominic

doi:10.5251/ajsir.2012.3.3.115.121

Cited by 14 publications

(10 citation statements)

References 10 publications

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“…A nucleation model was applied and concluded that the reaction with respect to aluminum was of the first order and had an activation energy of 108.68 kJ/mol. Ajemba and Onukwuli [12] investigated the dissolution kinetics and mechanisms of reaction of Udi clay in a nitric acid solution (excess above 90%). The clay was calcinated at 700 ºC and showed extractable alumina concentrations of 26.5% with a high concentration of Fe 2 O 3 (18.45%) and the presence of interferents such as K 2 O, SO 3 , MgO and others.…”

Section: Resultsmentioning

confidence: 99%

“…Kaolin is a possible alternative to bauxite because it contains high alumina concentrations and is abundant in the Amazon region. The aluminum production process using kaolin can also produce silica with high specific area [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…Hulbert and Huff [10] carried out a kinetic study of calcinated kaolin dissolution with three different acids: sulfuric, hydrochloric and nitric. Ajemba and Onukwuli [12] studied the dissolution kinetics and reaction mechanisms of Udi clay with an excess of nitric acid above 50% of the required stoichiometry. Phillips and Wills [19], Olsen et al [20], and others studied the aluminum dissolution process of kaolinitic clays.…”

Section: Introductionmentioning

confidence: 99%

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Dissolution kinetics of Amazonian metakaolin in nitric acid

2018

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The kinetic study of Amazon metakaolin dissolution was performed with the application of the shrinking core model for spherical and 'flat plate' particles with constant size. The Amazon kaolin was calcinated at 700 ºC in order to produce metakaolin. This metakaolin was leached with 5% excess nitric acid at 70, 80 and 95±3 ºC for 3 h. Samples were collected every 15 min and subjected to aluminum analysis. The acid leaching was a chemically controlled process. The spherical morphology showed better fit than the flat plate particles when taking into account the regression coefficients. 91.58 kJ/mol of activation energy was found as well as an aluminum leaching reaction of the first order. The results found in this work using 5% excess acid and Amazon kaolin were consistent with previous research results using excess acid above 50% and standard kaolin.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dissolution kinetics of Amazonian metakaolin in nitric acid

2018

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“…1.0 (-1.000) 1.5 (0.000) 2.0 (+1.000) In order to establish the kinetic parameters and rate-controlling step for the leaching of lead from 'Enugu Coal' in nitric acid solution, the experimental data were fitted to the kinetic models. Such plots are quite extensively used in kinetic studies [9]. The kinetic relationships are expressed in terms of the fraction of reacted particle X, with time.…”

Section: Kinetics Of Leaching Processmentioning

confidence: 99%

Optimization and Kinetic Modeling of the Removal of Lead from Enugu Coal by Acid Leaching

Ezenwa

Oluchukwu

Agaba³

2019

JENRR

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Removal of lead from Enugu coal with different acids as the leachant under different conditions such as leaching time, particle size, acid concentration, and leachant volume was investigated in this studies. The filtrate from each treatment was analyzed with Atomic Absorption X-ray Spectrometer (AAS) to determine the amount of lead leached. Nitric acid was found to be the best acid for the leaching of lead from Enugu coal. Kinetic studies carried out showed that the dissolution rate increased with: decreasing particle size, increase in stirring speed, acid concentration and leaching temperature. The experimental results revealed that the dissolution rate is a chemical reaction controlled via hydrogen ion concentration [H+], with reaction order of 0.9 and the reaction kinetics can be expressed as 1-(1-X)1/3 =2.566x10-4(CHNO3)0.86 (dp).992 (L/S).44 (SS).049 exp(53.49/RT). A quadratic model was predicted and optimized using second order orthogonal design (Box-Benken) which resulted in Particle size of 40µm, reaction time of 8.5 hours, and HNO3 concentration of 2mol/dm3. The optimum conditions were validated at model desirability of 1. Experimental value of 96.39% with error of 0.530% was removed.

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“…Some researchers used acid and alkali treatment for surface properties modifi cation of the selected minerals as reported earlier 10, 11 . However, to evaluate which methods of activation show excellent results, an ellaborative characterization of these porous materials regarding their pore size, surface area, porosity and pore size distribution, morphology and thermal properties are required to select and optimize the performance of porous and hierarchically structured & ordered materials for both direct and indirect use in many industrial applications 16- 19 . In this work we will study and evaluate the effectiveness of the intercalation procedure for original as well as variously intercalated pre-baked clay samples in turn of their morphological characteristic.…”

Section: -9mentioning

confidence: 99%

Morphological Evaluation of Variously Intercalated Pre-baked Clay

Ullah

Ahmad

2014

Polish Journal of Chemical Technology

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The use of porous materials is enjoying tremendous popularity and attention of the advance scientifi c communities due to their excellent adsorptive and catalytic activities. Clays are one of the most important candidates in the porous community which shows the above mentioned activities after modifi ng with a different intercalating agent. The paper is focused on the infl uence of some inorganic intercalating agents (NaOH) on the morphology of the variously intercalated clay samples. The alkali metal was used as the inorganic intercalating agent. The effect of intercalation temperature, intercalation agent concentration and intercalation time on the pre-baked clay morphology were also part of the study. Scanning electron microscopy (SEM) study was performed to evaluate the morphological changes of the resultant intercalates. Different morphological properties were improved signifi cantly in the case of the inorganically modifi ed clay samples. Thus, such intercalations are suggested to be effective if the clays under study are to be used for different industrial process at elevated conditions.

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Dissolution kinetics and mechanisms of reaction of Udi clay in nitric acid solution

Cited by 14 publications

References 10 publications

Dissolution kinetics of Amazonian metakaolin in nitric acid

Dissolution kinetics of Amazonian metakaolin in nitric acid

Optimization and Kinetic Modeling of the Removal of Lead from Enugu Coal by Acid Leaching

Morphological Evaluation of Variously Intercalated Pre-baked Clay

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