QUALITATIVE DISCOVERY OF QUARTZ IN MOUAU SOILS
USING AN X-RAY DIFFRACTION METHOD
I.E.OTUOKERE*, V.E. OKO AND O.K. AMADI
Department of Chemistry, Michael Okpara University of Agriculture, Umudike
Email: tosmanbaba@yahoo.com
ABSTRACT
Qualitative determination of the mineralogical composition of Michael Okpara Universiry of
Agriculture Umudike (MOUAU) soils were performed by means of the Hanawalt method using Xray powder-diffraction. Result obtained was analyzed using Bragg-Wolf equation and
International centre for diffraction data software. Bragg’s equation was used to find the d-value
corresponding to Bragg’s angles. The d-spacing’s and relative intensities of the X-ray diffraction
patterns for the various colleges in MOUAU compare well the d-spacing in the reference stick
pattern for quartz (SiO2) 3.342 Å (100.00%), 4.257 Å (22.00%), 1.8178 Å(14.00%). Other dspacings values of the diffractogram compare well with the reference stick pattern.
X-ray
diffraction pattern of MOUAU soil suggested the presence of quartz mineral.
Keywords: Qualitative; quartz; minerals; x-ray diffraction; soil; Umudike
INTRODUCTION
Quartz, or α-quartz, is the mineral form of SiO2 stable at low temperatures and pressures.
The English word derives from the Saxon word querkluftertz (cross-vein ore)1. It occurs in
igneous, sedimentary, metamorphic, and hydrothermal mineral environments, particularly
in continental regions. It is, however, rare in oceanic rocks. As the structure is acentric, it
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occurs in both left and right-handed varieties and is both piezoelectric and pyroelectric. It
is usually nearly pure and accepts only very limited amounts of other elements in
substitution. Polymorphs include β-quartz, tridymite, cristobalite, coesite, stishovite, and
keatite. The structure of quartz consists of corner-sharing SiO4 tetrahedra so that each Si is
bonded to four oxygens, and each oxygen is bonded to two silicon atoms. The resulting
structure forms an open three-dimensional framework, so that quartz is classified as a
tektosilicate or framework silicate. Quartz is the stable form of SiO2 at atmospheric
temperature and pressure. It is denser than tridymite and cristobalite, the high temperature
forms, but less dense than the high pressure forms, coesite and stishovite 2. At 573 ºC,
trigonal low quartz transforms reversibly to hexagonal high quartz 2. Many methods of
quartz determination have been proposed, in particular chemical methods
diffraction(XRD) methods
5,6
3,4
and X-ray
which are less accurate but more rapid. The technical
evolution and automation of XRD equipment has made the XRD determination of quartz
easier and more accurate and such a method has been developed and tested on different
particle sizes7. Michael Okpara University of Agriculture, Umudike is located within 7km
east of the capital city of Abia State ‘Umuahia’ in present day Ikwuano Local Government
Area of Abia state. The presence of these institutions has undoubtedly added to a great
increase in the population of the area. Rapidly increasing population, rising standards of
living and exponential growth in industrialization and urbanization tends to add pressure
on natural resources8. In view of this; we have decided to determine mineralogical
composition of soils in Michael Okpara University of Agriculture, Umudike (MOUAU)
using an X-ray diffraction method.
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MATERIALS AND METHODS
Description of the Study Area:
Michael Okpara University of Agriculture, Umudike is located in Ikwuano Local Government Area,
Abia State. Ikwuano Local Government Area is geologically situated in the Eastern Niger Delta and
lies
within latitudes 5 20 and 5 32' N, and longitudes 7 32 and 7 40 E (Fig 1).8
0
'
0
0
'
0
'
Figure 1: Map of Ikwuano L.G.A showing, Michael Okpara University of Agriculture, Umudike
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Sample Collection:
Soil samples were collected from various colleges in Michael Okpara University of
Agriculture, Umudike (MOUAU) at a depth of 15-30 cm. The samples were packed in a
small plastic bag and labeled. The collected sample were strained to remove the fibrous
and undesired materials with the help of 2mm sieve and dried by heating to remove
humidity because humidity affects the results very badly and then grounded to make them
homogeneous before XRPD analysis. Particle size determination was made by the
Bouyoucos hydrometer method 9. Colour was compared with standards. pH was determine
using Ciba Corning pH meter.
Qualitative phase analysis:
X-ray diffraction patterns were made with a monochromatic x-ray Diffractometer system
XPERT-PRO with beta filter CuKα radiation wavelength of 1.5406Aº and automated silt.
A set of 2θ angle ranging from 10º- 90º was used; this was done at Sheda Science and
Technology Complex (SHESTCO), Abuja Nigeria. Qualitative phase analysis was used for
the study of crystal structure and unknown phases of soil.
RESULTS AND DISCUSSIONS
The textural characterization of Michael Okpara University of Agriculture, Umudike soil is
presented in Table 1. The selected d-spacings and relative intensities of the diffractogram are
presented in Table 2. The x-ray diffractogram of soil samples from MOUAU is presented in Figures
2-8. The reference pattern from International Centre for Diffraction Data using POWD-12++ have
been presented in Figure 9.
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Table 1: pH and soil texture of MOUAU Soil
College
CAERSE
CAFST
CASAP
CASE
CMBB
CNREM
COLPAS
Sand (%)
95.21
97.21
99.21
95.21
94.21
92.21
96.21
Silt (%)
4.20
2.20
0.30
4.20
5.00
7.20
3.00
Clay (%)
0.59
0.59
0.49
0.59
0.79
0.59
0.79
pH
4.31
7.47
8.51
5.22
4.30
5.43
7.00
Table 2: Selected d-spacing (Å) and relative intensity (%) of the X-ray diffractogram for
the Colleges in MOUAU are presented in Table 2.
d1 Å(%)
3.33517 (100.00%)
3.33960 (100.00%)
3.33223(100.00%)
3.33898 (100.00%)
3.33536 (100.00%)
3.33734 (100.00%)
3.32038 (100.00)
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d2 Å(%)
4.23748 (68.70%)
4.24678(54.40%)
4.24132(19.05%)
4.24962(10.16 %)
4.24252 (20.87)
4.24724 (29.09%)
4.21452(21.62%)
d3 Å(%)
1.81512 (15.24%)
1.81538(26.78%)
1.81497(8.05%)
1.81657(7.42%)
1.81559 (10.90)
1.81640 (11.22%)
1.81129(17.83%)
College
CAERSE
CAFST
CASAP
CASE
CMBB
CNREM
COLPAS
Figure 2: X-ray diffractogram of soil from CAERSE, MOUAU
Figure 3: X-ray diffractogram of soil from CAFST, MOUAU
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F igure 4: X-ray diffractogram of soil from CASAP, MOUAU
Figure 5: X-ray diffractogram of soil from CASE, MOUAU
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Figure 6: X-ray diffractogram of soil from CMBB, MOUAU
Figure 7: X-ray diffractogram of soil from CNREM, MOUAU
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Figure 8: X-ray diffractogram of soil from COLPAS, MOUAU
Figure 9: The reference stick pattern from ICDDusing POWD-12++
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The pH analysis (Table 1) of the soil showed that CAERSE, CASE, CMBB and CNREM
soils are acidic; CAFST and COLPAS are neutral while CASAP is mildly alkaline. Acidic
loving crops would flourish in the acidic soils. Some of the acidic loving crops are sweet
potatoes, peppers, potatoes, beans, cabbage, carrots, cucumbers, onions, sweet corn,
tomatoes and grapes11. The soil texture (Table 1) showed that MOUAU soil is a sandy soil.
The d-spacings and relative intensities of the X-ray diffraction pattern (Table 2) for the
various colleges compare well the d-spacing in the reference stick pattern for quartz SiO2
3.342 Å (100.00%), 4.257 Å (22.00%), 1.8178 Å(14.00%). Other d-spacing values of the
diffractogram compare well with the reference stick pattern. The identification of quartz
with hexagonal Crystal system, space group P3221, a (Å): 4.9141, b (Å): 4.9141, c (Å):
5.4060, alpha(°):90.0000, beta (°): 90.0000 ,gamma (°):120.0000, volume of cell (10^6
pm^3):113.10 , Z: 3.00 and RIR: 3.06
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have been suggested. The occurrences of quartz
have been reviewed recently1. Quartz is an abundant mineral in igneous, metamorphic,
hydrothermal, and sedimentary environments. In plutonic igneous rocks, it is abundant in
silicic rocks ranging in composition from quartz diorite to granite but absent in more mafic
compositions. In volcanic rocks, it is common in quartz latites to rhyolites, but uncommon
in vitric silicic tuffs. It is common to abundant in welded silicic tuffs. In metamorphic
rocks, it is abundant in schists and gneisses of pelitic to granitic compositions. In
hydrothermal rocks, it is an abundant as the principal gangue mineral; in low to high
temperature vein deposits. Because of its resistance to chemical weathering, it is the
principal mineral phase in sandstones and abundant in other non-marine sedimentary
rocks. It is also abundant as cryptocrystalline chert in marine limestones and dolomites.
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Numerous varieties have been described, and defined mainly on color. Quartz is most
commonly colorless and transparent. Rose quartz is pink and contains minor Mn
impurities, recently identified as dumortrierite 2. Citrine is yellow, and amethyst is purple.
CONCLUSION
The pH of soils in MOUAU is acidic. This will favor acid loving crops. The soil texture is
sandy. X-ray diffraction pattern of MOUAU soil sediments showed that it contains quartz
mineral. The discovery of quartz in MOUAU is of enormous economic importance.
Extraction of Quartz in MOUAU is hereby recommended.
REFERENCES
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10. URL:http://www.webmineral.com/data/Quartz.shtml-17th October 2009
11. URL:http//www.gardeningknowhow.com/22nd -July 2014
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