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Structural Order of Clays from Gounioube’s Deposit (Ivory Coast): Study by Electron Paramagnetic Resonance Spectroscopy

Jean-Pierre S. Sagou , Séka Simplice Kouassi, Lébé Prisca M.-S. Kouakou, Léon Koffi Konan, Y. J. Andji-Yapi, Thierry Allard
American Journal of Materials Science and Engineering. 2017, 5(1), 37-42. DOI: 10.12691/ajmse-5-1-5
Published online: September 29, 2017

Abstract

Cristallinity in kaolin samples from Gounioube’s deposit is studied. For this purpose, the behavior of iron and electronic defects related to irradiation damage in these clays is examined by using Electron Paramagnetic Resonance spectroscopy measurements, which point out the presence of structural defects in these materials. A deep inspection carried out by comparison of raw and bleached samples also confirms poorly cristallized samples kaolinite.

1. Introduction

Clay materials are part of many non-metallic mineral resources in Ivory coast. Among the sites containing these materials, there is Gounioube’s deposit. Clays mined from this deposit were previously characterized to determine their potential technological applications since it is well established that clay materials may be used in several domains as ceramic floor tiles 1, 2, bricks 3, 4, roof tiles 5, 6, dinner wares 7, sanitary wares 8, and glasses 9. At this end, the investigations were carried out through standard methods as Differential Thermal Analysis, X-Ray Diffraction, Mössbauer, UV-visible and InfraRed spectroscopies, which allowed to determine mineralogical and physico-chemical properties of these clays. It is in such context that cristallinity studies were performed. It should be noted that cristallinity is a feature that is very sensitive to the subtle environmental changes 10. A same mineral clay may show different degrees of crystallinity in vertical and lateral profiles 11. During alteration, the crystallinity of particular mineral phases develops. It begins with the nucleation and crystalline growth as controlled by many internal (structural) and external (environmental) conditions. Crystallinity changes may also result from recrystallization, which can be either spontaneous or induced. Cristallinity studies carried out on Gounioube’s kaolin samples seem indicate that clays from this site present structural defects at long-distance 12. The validity of this hypothesis is elucidated through the present work, which will also allow to extend the analysis to short-distance level. For this purpose, the Electron Paramagnetic Resonance (EPR) spectroscopy measurements are used to study the behavior of iron and electronic defects related to irradiation damage in these clays. This path will consist to deepen the investigation of the effects of iron statutes on the structural order of Gounioube’s deposit clays.

2. Materials and Methods

2.1. Materials

The present work is concerned fourteen kaolin samples. These clays have been collected in different pits (Figure 1), at different depth on the Gounioube’s deposit (City of Anyama) located at 30 km from Abidjan in the south of Ivory Coast 13, 14 and referenced from G1 to G14. The field is mainly out of a detrital sandy-clay plateau from the terminal continental level (Miocene-pliocene), resulting from a ferrallitic alteration of the basal rocks under humid tropical climate 13, 15, 16.

2.2. Experimental Method

The kaolin samples were analyzed by EPR spectroscopy in an ESP300E spectrometer, using X band (9.422 GHz) at room temperature, with a gain of 8.103 for overall samples and 2.104 for defaults. Magnetic field calibration was performed with the DPPH standard (g = 2.0037 ± 0.0002). Calibrated silica tubes (suprasil grade) were filled to a depth of 15 mm with a known amount of dry powdered sample (about 40 mg) prior to analysis. There is currently no standard to measure the concentrations of the various paramagnetic species found in natural kaolinites. The comparisons between samples are therefore made by determining either the surface area or the intensity of the experimental signals, which gives a relative estimation of the concentrations of the corresponding paramagnetic species. Thus, the EPR spectra were recorded in the form of a signal derived from the absorbance whose intensity varies as a function of the applied magnetic field and calibrated with respect to a standard (DPPH) which allow to determine the accurate position, in energy of the bands. The effect of reducing/chelating treatment on the kaolin samples was analysed through CBD method 17, 18, 19, 20. The chemical and mineralogical compositions obtained by Inductively Coupled Plasma (ICP) and X-Ray Diffraction (XRD) techniques respectively indicated that the major minerals of theses clays are kaolinite, quartz and mica 21. Mössbauer spectroscopy allowed to observe the iron role during thermal transformations and showed that iron is found in various forms such as Fe3+, Fe2+ in octahedral substitution into the kaolinite network according to types of iron oxyhydroxides (hematite and / or goethite) and ferric gels 12. It appears that Fe3+ is one of the most common impurities in the kaolinite structure and a low cation exchange capability is generally attributed to this mineral 22.

The experimental cristallinity indexes of the fourteen kaolin samples are also previously 23 determined and are listed in Table 1. In these data, R1 and R2 indexes evaluated according to Liétard 24 definition and DC(001) corresponding to the angular width at half intensity of the (001) line of kaolinite are deduced from X-Ray Diffraction measurements whereas P1 and P2 indexes deternined according to Liétard 24 and Cases and al. 25 definition are recorded from Infra Red spectroscopy technic.

  • Table 1. Cristallinity indexes of kaolin samples from Gounioube’s deposit where R1 and R2 indexes are deduced according Liétard [24] definition, DC(001) is angular width at half intensity of the (001) line of kaolinite, P1 and P2 indexes are evaluated according to Liétard [24] and Cases and al. [25] definition

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3. Results and Discussion

Figure 2(a-d) show the EPR spectra of the fourteen kaolin samples. These results are distributed according different pits of Gounioube’s deposit. All spectra exhibit similar shape and their appearance is characteristic of natural kaolinites 23, 26. Such curves result from the superimposition of various signals described in the literature 27, 28, 29, 30, which can be distinguished into two kinds of Fe3+ ion domains.

The first one located at low magnetic field ranged between 1200 and 2000 Gauss, is diluted domain, showing a complex signal due to ferric iron as an impurity in kaolinite. This is attributed to isolated Fe3+ ions occupying Al3+ sites of the kaolinite structure. It can be due to both of distinct sites referenced Fe(I) and Fe(II) 22, 27 localized in diluted domain and showing different distortions 31. The other domain governed by non-homogeneously broadened lines and by magnetic dipole-dipole interaction among Fe3+ ion centers is referred to concentrated domain. In this area, the large signal based on 2500 G is due to oxyhydroxides of iron associated to the kaolinite whereas the strait intense signal centered on 3300 G is assigned to electronic defects located into the kaolinite network. This former can be explained either to spin-spin interactions among irons in the oxy-hydroxides adsorbed to the mineral indicated or to ferric gels 32, 33. Its relative large amplitude in Gounioube’s kaolin samples indicates sufficiently high concentration of Fe(I) probably due to the existence of strait structural connections taking place between oxyhydroxides of iron and the kaolinite. Furthermore, the contribution of electronic defects to this signal can also involve the surface properties of kaolinite and govern the behavior of its processing. By comparison of these spectra to those of well cristallised kaolinites in literature as Georgia clays 34, these signals are characteristic of crystalline defects at high-distance. This behevior is in good agreement with the cristallinity indexes that are deduced from Infra Red and X-Ray diffraction spectra 23 and summarized in Table 1. Indeed, these indexes correspond to values of P1 negative and P2 less than 1, a signature of poor cristallinity. On the X-ray diffraction spectra recorded in the same context, the diffractograms showed that the different peaks are weakly resolved 23. In addition, the apparent coherent domain of these kaolin samples appears significantly different from what is expected for well crystallized kaolinites. All of these experimental methods emphasize a poor cristallinity in kaolinites, meanning a structural desorder in Gounioube’s clays. Moreover, in the framwork of a previous work 12, the study of Fe-role during thermal transformations and all phases containing iron through Mossbauer spectroscopy technic showed low mechanical strengths for the kaolinite samples from Gounioube’s deposit. Such situation was due to the fact that a part of Fe-content is located outside the clay structure and does not contribute to the clay densification process, so that the mechanical strengths of the clays were found low 12.

CBD treatment that consists to clays bleaching is carried out to remove the iron oxyhydroxides locacted in clays. Figure 3 shows the comparison of Fe-content between the samples before and after this treatment. As showed on the histograms, the plots show a decrease of Fe-content after CBD process for all studied samples. It appears clearly that the bleaching is widely efficient for G13 for which the magnitude of Fe2O3 varies from 18.27% to 1.87%, a value that is almost common for the other samples investigated. This content still remains relatively high meaning that a certain Fe-content could not be eliminated by the CBD treatment. This certainly corresponds to Fe incorporated in the crystal structure of the native clay. CBD treatment shows that most of the Fe contained in Gounioube’s kaolin samples is included in iron minerals, intimately associated with kaolinite what is a usual occurrence. In order to distinguish the iron under occlusion status from that one located inside the clay structure, the data recorded after CBD treatment are compared to that one evaluated in RPE spectra.

The results are displayed in Figure 4, which shows the evolution of residual amount of iron after CBD treatment as a function of magnetic field. As can be seen on the plot, there is a low dispersion of the distribution of the ferric ion but no correlation with magnetic field in particular at low field since correlation coefficient is found relatively low. By comparison of these data to RPE Spectra in Figure 2, Figure 4 shows the disappearance of signals at low magnetic field ranged between 1200 and 2000 G and also the strait intense signal centered on 3300 G. This indicates that the ferric Fe referenced as Fe(I) and Fe(II) is under a non-occluded status between the kaolinite leaflets. Thus, the plot in Figure 4 is only due to nanoscopic iron oxyhydroxides intercalated between the layers of the kaolinite as observed also by others authors 35, 36.

The indexes of cristallinity listed on Table 1 established that kaolin samples from Gounioube’s deposit are characterized by a structural disorder. An inspection of this feature is carried out to provide a better understanding of its behavior. At this end, few clays for which the order-disorder properties are well established and available in litterature 37, 38, are considered as references in order to make comparison with our data. Figure 5 exhibits all of these data in which the references are exhibited in yellow zone whereas our experimental values are indicated in blue domain. The kaolin samples that are not displayed in this Figure have a value of zero R2 (see Table 1). In comparison to our data, the distribution of reference clays is characterized by a large dispersion for which various degrees of order and disorder can be distinguished. These may be described by three kinds of regime. Clays nominated as DCV, GB1, GB3 and KGa1 are governed by an order at long-distance and a disorder at short-distance while it occurs for references FU710 and FBT2 a disorder at short-distance. Gounioube’s clays behave as PDP3, CHA2, KGa2 and GOY, the third group of references. Their location on the plot indicates a structural disorder at both of short and long distances. Our data are so in good agreement with the indexes retrieved from X-Ray Diffraction and InfraRed spectroscopy meaurements, which predicted a poorly cristallized structure in kaolin samples from Gounioube’s deposit.

4. Conclusion

The present study allowed to investigate the structural order of kaolin samples from Gounioube’s deposit. The iron status in raw materials before and after bleaching by CBD treatment underlines the structural defects in which it appears an desorder at high and short distances. This result confirms thus the hypothesis concerning a lack of cristallinity in Gounioube’s clays.

References

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In article      View Article
 
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In article      View Article
 
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In article      View Article
 
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In article      View Article
 
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In article      View Article
 
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In article      View Article
 
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In article      View Article
 
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Published with license by Science and Education Publishing, Copyright © 2017 Jean-Pierre S. Sagou, Séka Simplice Kouassi, Lébé Prisca M.-S. Kouakou, Léon Koffi Konan, Y. J. Andji-Yapi and Thierry Allard

Creative CommonsThis work is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

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Normal Style
Jean-Pierre S. Sagou, Séka Simplice Kouassi, Lébé Prisca M.-S. Kouakou, Léon Koffi Konan, Y. J. Andji-Yapi, Thierry Allard. Structural Order of Clays from Gounioube’s Deposit (Ivory Coast): Study by Electron Paramagnetic Resonance Spectroscopy. American Journal of Materials Science and Engineering. Vol. 5, No. 1, 2017, pp 37-42. http://pubs.sciepub.com/ajmse/5/1/5
MLA Style
Sagou, Jean-Pierre S., et al. "Structural Order of Clays from Gounioube’s Deposit (Ivory Coast): Study by Electron Paramagnetic Resonance Spectroscopy." American Journal of Materials Science and Engineering 5.1 (2017): 37-42.
APA Style
Sagou, J. S. , Kouassi, S. S. , Kouakou, L. P. M. , Konan, L. K. , Andji-Yapi, Y. J. , & Allard, T. (2017). Structural Order of Clays from Gounioube’s Deposit (Ivory Coast): Study by Electron Paramagnetic Resonance Spectroscopy. American Journal of Materials Science and Engineering, 5(1), 37-42.
Chicago Style
Sagou, Jean-Pierre S., Séka Simplice Kouassi, Lébé Prisca M.-S. Kouakou, Léon Koffi Konan, Y. J. Andji-Yapi, and Thierry Allard. "Structural Order of Clays from Gounioube’s Deposit (Ivory Coast): Study by Electron Paramagnetic Resonance Spectroscopy." American Journal of Materials Science and Engineering 5, no. 1 (2017): 37-42.
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  • Figure 5. Comparison of order-desorder between kaolin samples from Gounioube’s deposit and reference clays retrived from literature [37,38]. Red circles =kaolinites from Gonioube’s deposit. Green traingles = reference clays
  • Table 1. Cristallinity indexes of kaolin samples from Gounioube’s deposit where R1 and R2 indexes are deduced according Liétard [24] definition, DC(001) is angular width at half intensity of the (001) line of kaolinite, P1 and P2 indexes are evaluated according to Liétard [24] and Cases and al. [25] definition
[1]  Boussen S., Sghaier, D., Chaabani, F., Jamoussi, B., Bennour A., “Characteristics and industrial application of the Lower Cretaceous clay deposits (Bouhedma Formation). Southeast Tunisia: Potential use for the manufacturing of ceramic tiles and bricks”, Applied Clay Science, 123. 210-221. Avril 2016.
In article      View Article
 
[2]  Dondi M., Raimondo M., Zanelli C., “Clays and bodies for ceramic tiles: Reappraisal and technological classification”. Applied Clay Science, 96, 91-109, July 1994.
In article      View Article
 
[3]  Wahyuni A. S., Gunawan A., “Performance of Clay Brick of Bengkulu”. Procedia Engineering, 95. 504-509. 2014.
In article      View Article
 
[4]  Gencel, O., “Characteristics of fired clay bricks with pumice additive”. Energy and Buildings, 102. 217-224. 2015.
In article      View Article
 
[5]  De Silva G.S., Surangi M.L.C., “Effect of waste rice husk ash on structural, thermal and run-off properties of clay roof tiles”. Construction and Building Materials, 154. 251-257. 2017.
In article      View Article
 
[6]  Sultana M. S., Ahmed A. N., Zaman M. N. Rahman M. A., Nandy P. K., “Utilization of hard rock dust with red clay to produce roof tiles”. Journal of Asian Ceramic Societies, 3(1). 22-26. March 2015.
In article      View Article
 
[7]  Ngun B. K., Mohamad H., SulaimanS K, Okada K, Ahmad Z. A., “Some ceramic properties of clays from central Cambodia”. Applied Clay Science, 53(1). 33-41. July 2011.
In article      View Article
 
[8]  De Miranda S., Patruno L., Ricci V., Saponelli R., Ubertini F., “Ceramic sanitary wares: Prediction of the deformed shape after the production process”. Journal of Materials Processing Technology, 215. 309-319. 2015.
In article      View Article
 
[9]  Jollivet P., Gin S., Schumacher S., “Forward dissolution rate of silicate glasses of nuclear interest in clay-equilibrated groundwater”. Chemical Geology, 330-331. 207-217. November 2012.
In article      View Article
 
[10]  Sx Y. “A comparative study on the illite crystallinity and the clay mineral reflectance spectral index for subdividing the very low-grade metamorphic belt along the Lizhou-Hekou geological section in the Youjiang sedimentary basin, Guangxi, China”. Science in China, Series D-Earth Sciences, 47(9). 834-845. 2004.
In article      View Article
 
[11]  Kühnel R. A., Roorda H. J., Steensma J. J., “The Crystallinity of Minerals-A New Variable in Pedogenetic Processes: A Study of Goethite and Associated Silicates in Laterites”. Clays and Clay Minerals, 23. 349-354. 1975.
In article      View Article
 
[12]  Andji Y.Y. J., Toure A., Kra G., Juma J.C., Yvon J., Blanchart P., “Iron role on mechanical properties of ceramics with clays from Ivory Coast”. Ceramics International, 35. 571-577. March 2009.
In article      View Article
 
[13]  Andji J. Y. Y., Kouakou L. P. M.-S., Touré A. A., Kra G. “Morphométrie Quantitative des Echantillons du Gisement de Gounioubé”. European Journal of Scientific Research, 124(3). 367-376. Sepetmber 2014.
In article      
 
[14]  Andji, Y.Y. J., “Contribution to the mineralogical and physicochemical characterization of clays from Gounioubé”. Thèse 3èm cycle, Université de Cocody Abidjan, Côte d’Ivoire. 154 pages. 1998.
In article      
 
[15]  Kouakou L. P. M.-S., Andji-Yapi Y. J., Coulibaly Y., “Mineralogy, geochemistry of clay raw material from Ivory Coast (West Africa) used as pharmaceutical products”. J. Soc. Ouest-Afr. Chim., 034. 38- 44. 2012.
In article      View Article
 
[16]  Dorthe J. P. (1964): “Etude des gisements d’argiles dans la région de Gounioubé”. Rapport SODEMI, 84. 1964.
In article      
 
[17]  Batista A.H., Melo V.F., Gilkes R., “Scanning and transmission analytical electron microscopy (STEM-EDX) identifies minor minerals and the location of minor elements in the clay fraction of soil”. Applied Clay Science, 135. 447-456. January 2017.
In article      View Article
 
[18]  Fan S.-S., Chang F.-H., Hsueh H.-T., Ko T.-H., “Measurement of Total Free Iron in Soils by H2S Chemisorption and Comparison with the Citrate Bicarbonate Dithionite Method”. Journal of Analytical Methods in Chemistry, Article ID 7213542. 7 pages. December 2016.
In article      View Article
 
[19]  Dethier D. P., Birkeland P. W., McCarthy J. A., “Using the accumulation of CBD-extractable iron and clay content to estimate soil age on stable sur-faces and nearby slopes, Front Range, Colorado”. Geomorphology, 173-174. 17-29. November 2012.
In article      View Article
 
[20]  Mehra O.P., Jackson M.L., “Iron oxide removal from soils and clays by a dithionite–citrate system buffered with sodium bicarbonate” in Seventh National conference on Clays and Clay Minerals, 7. 317-327. 1960.
In article      PubMed
 
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