X RAY AND INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION SPECTROSCOPY ANALYSIS OF CRISTALLOGRAPHIC STRUCTURE AND COMPOSITION OF PAVEMENT BASED CLAY MATERIALS

In order to predict technological properties of local clay based materials mixed to wood waste and to prevent human health and environment, experimental mineral structure and composition study were conducted. The influence of wood waste on the structural properties of clay samples were also investigated. Non and stabilized clay sample at 4% of cement were made at different conditions and waste wood at different content have been incorporated. Mineralogical X-ray analysis was carried out using Xray diffractometer with Geiger counter using cobalt α radiation with wavelength Å. inductively coupled plasma atomic emission spectroscopy (ICP/AES) and inductively coupled plasma optical emission spectroscopy (ICP/OES) were used respectively to determine major, Minor and trace elements. The results showed that incorporation of wood waste has a strong effect on the crystallographic structure, making partially amorphous clay structure. It is found that the waste wood content doesn’t influence the lattice constants of the components of the clay. Chemical analysis of clay sample indicates kaolinite and SiO2 as a dominant clay minerals. The results has shown some trace and heavy metal contamination.


INTRODUCTION
With the development of the wood industry, the abundance of waste wood generate an important environment pollution. A wide range of studies has been reported to recycle wood waste in clay materials in order to improve technological properties [ , , ]. Most of studies focused on mechanical properties and have shown that the addition of wood waste in clay considerably reduced the mechanical strength of the materials [ , , , , ]. Knowledge of the microscopic properties such as structure and composition of clay materials used in construction may have technological interest [ , ]. This work studies the composition of the clay and the influence of waste wood on the structure in order to improve technological properties

Apparatus and Experimental conditions
A diffractometer automated X type Siemens D5000 equipped with a cobalt anticathode was used the K  ray of cobalt with 79026 , 1   .10 -10 m wavelength. The diffracted rays following the Bragg angle were recorded by a counter type GEIGER MULLER. This counter is placed in order to receive the rays diffracted by the sample in terms .The BRAGG relationship 2 dhkl sin  =  was used to determine the inter-reticular distances.
The crystal lattice can be deduced from the expressions (6) and (7). The scanning angle varied between 4 to 84 o 2 , the scanning speed was about0.02 o 2 /second.

X ray mineral powder analysis
For carrying out the analyzes, the samples were previously dried and ground into powder particle size less than 80 m. The counting time for this test was about 5 seconds when the sample was turning from 4 to 84 o 2θ. The crystallized fraction of the samples was determined by X-ray diffractometry from their powder diffractogram. This technique is mainly qualitative and can only give a semi quantitative result. The detection limit is about 5% and can vary widely depending on the nature of the different phases.

X ray mineral analysis using oriented blade
The counting time for this test was about 2 seconds in the rotating sample from 4 to 36 o 2θ. The phylliteuse fraction of the samples was determined by diffraction from normal oriented blades glycollées for 12 hours in steam pressure and heated up to 490 o C for 4 hours. The composing proportions were estimated from peak areas

Method of identifying crystal phases
Generally the identification of a crystallized phase is made by comparison of the experimental with the theoretical diffractogram. The content of mineral components is estimated from peak areas. Match 2 software FotoMix!, XRD2DScan were used to analyze the diffraction patterns. The crystal lattice of α quartz is hexagonal. The values of www.arpnjournals.com 71 the lattice constants are obtained after indexing peaks using the expression linking to the interplanar spacing d hkl . Kaolinite crystallizes in the triclinic system. Montmorillonite crystallizes in the monoclinic system Chlorite also crystallizes in the monoclinic system.

Spectroscopy analysis
Inductively coupled plasma atomic emission spectroscopy (ICP/AES) and inductively coupled plasma optical emission spectroscopy (ICP/OES) were used respectively to determine major,minor and trace elements. The ICP-MS X7 and ICP OES Icap 6500 equipment was used with the following: RF power ~1200 W, Plasma argon gas ~ 15 l min-1), Auxiliary gas ~ 0.4 l min -1 ), Sample gas ~ 0.9 l min -1 ),Dwell time ~100 ms

RESULTS AND DISCUSSIONS
1X ray analysis of clay sample

Raw clay sample structure
The X ray pattern of analyzed clay sample before incorporating wood waste are shown in the Figure-1. The results reveal the presence of kaolinite with formulaAl 2 H 4 Si 2 O 9 and quartz  , formulaSiO 2 in raw clay sample.
Estimates of the concentrations of mineral components obtained using the method of "Peak-height ratio" is as follows:  Some traces of anatase: 8.88% and calcite: 8.31%.
By comparing the concentrations of mineral components of the crude clay and clay after incorporation of wood waste, we find that: -The concentration of SiO2 (quartz) in the crude clay (51%) is weaker than that with the clay after incorporating of mahogany wood waste (58%). Chemical reactions between clay and cement with high levels (pozzolanic reactions) form of new products that contribute to the strength of a cement stabilized earth [Akpodje 1985]; [Bell 1996].
Clay paved samples were analyzed by X-ray, after incorporating wood waste. The obtained results are shown in Figure-2.
The results showed that incorporation of wood waste has a strong effect on the crystallographic structure, making partially amorphous clay structure.

Determination of lattice constants of clay components
Experimental lattice constants before and after waste wood incorporation was measured using d hkl , the resultsare summarized in the Table-3. For the parameters a and b, the resulting values are identical to the results achieved by [13] in the case of α quartz, kaolinite and montmorillonite. There is no change on a and c lattice constant of chlorite conversely to lattice parameter a, c of quartz, kaolinite and montmorillonite. So then we can say that there has been an expansion of the crystal lattice; while in the case of chlorite this variation is observed in the parameter b, in this case we see a compression which results in a reduction of the volume of the crystal lattice.

Composition determination of clay sample
Chemical composition was determined by spectroscopy following the procedure NF P94-048. The results obtained are summarized in the Tables 1, 2 and 3.
The results indicated the presence of SiO 2 , Al 2 O 3 and Fe 2 O 3 as major oxides And some traces of MnO, MgO, CaO, Na2O, K 2 O, TiO 2 , P 2 O 5 in the form of impurities Table-  The Table-3 presents the analysis results of major and minor elements, most of them like ceramics are very useful for industry applications.

CONCLUSIONS
At the end of this study, these conclusions can be drawn: Makoua clay consists of the following minerals unevenly distributed: the quartz α, kaolinite, and interstratified chlorite/ montmorillonite which crystallize respectively in the hexagonal, triclinic and monoclinic system. In this study, we have determined the mineralogical structure of the Makoua clay and the lattice constant of the components of this clay using the mineralogical analysis by X-ray powder and oriented blades.
The results showed that incorporation of wood waste has a strong effect on the crystallographic structure, making partially amorphous clay structure. It is found that the waste wood content doesn't influence the lattice constants of the components of the clay.
Chemical analysis of clay sample indicates kaolinite and SiO 2 as predominant component.
Some trace and heavy contamination has been identified to be toxic for some industry activities.