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Statistical Studies of the Physicochemical Analytic Results of a Series of Synthetic Calcium Hydroxyapatite Containing Carbonate and Sodium 被引量:1
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作者 Faouzia Rockh B. Hadj Yahia Ismail Khattech 《American Journal of Analytical Chemistry》 2014年第5期343-357,共15页
The objective of this study is to present a simple method of statistical calculation that allowed us to determine the relationship between the different data obtained from the characterization of the synthetic carbona... The objective of this study is to present a simple method of statistical calculation that allowed us to determine the relationship between the different data obtained from the characterization of the synthetic carbonated apatites containing sodium, in order to find the fundamental substitution mechanism(s) for incorporation of Na+ and?CO32- and to establish the general formula. For that, a series of hydroxyapatites containing carbonate and sodium (Na-CO3HAps) has been obtained by the precipitation method. All the compounds were characterized by infrared spectra (IR), powder X-ray diffraction (PXRD) and elemental analysis. The statistical treatment of the experiment result allows us to determine the relationship between one variable and the change in the other and to found the fundamental substitution mechanism(s) for incorporation of Na+ and?CO32- . Analysis of variance (ANOVA) allows us to test the models proposed. 展开更多
关键词 Carbonated Calcium Hydroxyapatite CONTAINING SODIUM Na-CO3HAps STATISTICAL STUDIES Multiple Linear Regression Analysis of Variance (ANOVA)
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Attack of Tunisian Phosphate Ore by a Mixture of Sulfuric and Phosphoric Acid: Thermochemical Study by Means of Differential Reaction Calorimetry 被引量:1
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作者 Olfa Lachkar-Zamouri Khemaies Brahim +1 位作者 Feten Bennour-Mrad Ismail Khattech 《Advances in Materials Physics and Chemistry》 2018年第10期411-427,共17页
A calorimetric, Differential Reaction Calorimetry (DRC), study of the thermochemical of the attack of a phosphate ore from Gafsa region (Tunisia) by a mixture of sulfuric and phosphoric acid is undertaken at different... A calorimetric, Differential Reaction Calorimetry (DRC), study of the thermochemical of the attack of a phosphate ore from Gafsa region (Tunisia) by a mixture of sulfuric and phosphoric acid is undertaken at different solid-liquid ratio and different temperature. The plot of the quantity of heat measured by integrating the raw signal as a function of the dissolved mass in the same volume solution at 25℃ presents three straight segments attributed at the formation of the hemihydrate (CaSO4·1/2H2O:HH), the dihydrate (CaSO4·2H2O:DH) or a mixture of these two products checked by X-ray diffraction, infrared spectroscopy and thermal analysis (Differential Scanning Calorimeter: DSC). The attack by the acid mixture was performed at higher temperature and showed in addition the formation of another form of calcium sulfate:anhydrous (CaSO4:AH). Moreover, the variation of mass enthalpy versus temperature presents a break at the T = 45℃. According to our results, it seems that the effect of the temperature on the sulfo-phosphoric attack reaction on the natural phosphate (NP) generates a change of mechanism at around 45℃. 展开更多
关键词 Dissolution THERMOCHEMISTRY DIFFERENTIAL Reaction CALORIMETER PHOSPHATE ORE Liquid/Solid Temperature
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Effect of Different Kinetic Factors on the Thermochemistry of Sulfophosphoric Attack Reaction of Natural Phosphate Tunisian by DRC
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作者 Olfa Lachkar-Zamouri Khemaies Brahim +1 位作者 Faten Bennour Ismail Khattech 《Advances in Materials Physics and Chemistry》 2018年第11期429-440,共12页
Mixture of phosphoric and sulfuric acid solutions has been used to investigate the dissolution of natural phosphates (PN) by DRC. The effect of concentration, particle size and stirring speed reaction is examined. The... Mixture of phosphoric and sulfuric acid solutions has been used to investigate the dissolution of natural phosphates (PN) by DRC. The effect of concentration, particle size and stirring speed reaction is examined. Thermochimique properties of each kinetic parameters reaction are determined. It was found that these parameters have a considerable effect on the thermochemical aspect of the attack reaction. It is known that the process of PN sulphophosphoric acid attack leads to the formation of dihydrate (CaSO4.2H2O: DH). The present work shows the precipitation of other residues their formula depends on factors studied. The increase in concentration leads to the formation of hemihydrate (CaSO4v1/2H2O:HH) beside DH for the low values of% H2SO4 due to the solubility of dihydrate on the etching solution and the precipitation of (Ca (H2PO4)2.2H2O) next of DH for low agitation values because of the lack of turbulence between the liquid phase and the solid phase which favors the precipitation of this latter compound. 展开更多
关键词 Thermochimique PHOSPHATE Ore Differential REACTION CALORIMETRY Concentration STRING Speed Particle Size
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Preparation, Characterization and Statistical Studies of the Physicochemical Results of Series of “B” Carbonated Calcium Hydroxyapatites Containing Mg<sup>2+</sup>and CO<sup>2-</sup><sub style="margin-left:-10px;">3</sub>
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作者 S. Ben Abdelkader F. Bel Hadj Yahia I. Khattech 《American Journal of Analytical Chemistry》 2014年第14期995-1009,共15页
In this study, series of hydroxyapatites containing Mg2+ and?CO2-3 are prepared by the precipitation method with independently varying concentrations of?CO2-3 and Mg2+. All the compounds are characterized by infrared ... In this study, series of hydroxyapatites containing Mg2+ and?CO2-3 are prepared by the precipitation method with independently varying concentrations of?CO2-3 and Mg2+. All the compounds are characterized by infrared spectra (IR);powder X-ray diffraction (PXRD) and elemental analysis. The physical analysis results show that the prepared compounds are pure B-type carbonate apatite. The presence of Mg2+ and?CO2-3 in the apatite cause the following effects on its physical properties: a decrease in a-dimension but no changes in c-dimension and a decrease in crystallinity as shown in XDR patterns and IR spectra. The results of the chemical analysis allow us to predict the predominant substitution mechanisms for the CO2-3 and the Mg2+ incorporations in the calcium hydroxyapatites and to calculate their relative contributions x, y and z. (II);?? 2. (IV);?? (V). Statistical studies of the results “multiple linear regression, analysis of variance (ANOVA) and t-test of the regression coefficients” allow us to determine and to test the mathematical model proposed. Finally, the present study makes it possible to write the general formula for these com-pounds. 展开更多
关键词 B-Type Carbonated Calcium Hydroxyapatite CONTAINING Magnesium “B” CO3Mg-HAps Substitution Mechanism(s) Multiple Linear Regression F-TEST (ANOVA) T-TEST of the Coefficients
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