Bida Clay: A Source of Raw Material For Engineering Applications
Bida Clay: A Source of Raw Material For Engineering Applications
Bida Clay: A Source of Raw Material For Engineering Applications
ISSN No:-2456-2165
Abstract:- Clay from Bida was investigated and Kaolin clay from Ejigbo (Lagos) was studied by [18],
characterized using XRF, XRD, SEM and physico- who found that it has high crystallinity and orderly-arranged
mechanical methods. The XRF analysis shows high value structures that can serve as a basis for supporting
of 69.58% SiO2, 23.15% Al2O3, and 2.93% Fe2O3, with nanoparticles with hydroxyl groups that act as anchoring
low amount of other oxides like CaO, K2O and Na2O. active regions catalytic substrates. The clay was also found
The clay deposit from the XRD results was found to be to have a large surface area, excellent form, and strong
kaolinitic with refractoriness of 12500C and a good 12 thermal stability. In addition, [1] investigated the
cycles of thermal shock resistance were observed. The characterisation and micro-structural aspects of the ceramics
physico-mechanical characteristics of the clay studied use of Mgbom clay around Afikpo (Ebonyi State). The clay
were found to improve as the firing temperature was found to have the three primary minerals quartz,
increased. This was attributed to decrease in porosities kaolinite and haematite; however, the clay's burned behavior
and increase in compaction of the samples. The revealed that it was unsuitable for uses such as electrical
mechanical properties values of cold crushing strength insulation, thermal insulation, refractory and porcelain.
(CCS) of 202.41kgF/cm2 was attained and meet the
requirements for production of tiles, refractory lining of Numerous experts have looked into a few of the clays
heat treatment furnaces and kilns. The chemical that can be found in Nigeria. In order to assess the viability
properties from XRF results were found to be within the of various clay samples from various deposits, [21], [1],
standard requirements for application in ceramic and [11], [4] and [9] determined the chemical and mineralogical
refractory applications. nature and characteristics of the samples, such as bulk
density, thermal stability, cold crushing strength and
Keywords:- Bida; clay; kaolin; physico-mechanical; XRD; porosity. They discovered favorable characteristics that can
XRF. compete with worldwide standards and satisfy the criteria
for use as refractory material or ceramic raw materials.
I. INTRODUCTION
The estimated two billion metric tons of kaolin
Clays are used for a wide variety of engineering reserves in Nigeria have drawn interest from both domestic
applications. The main reason for the utilization of a certain and international companies due to their wide range of uses
clay mineral in one area of application is because of their and their distinctive characteristics [18]. Yet there is
chemical and physical properties that are dependent on their continuous imports of various items used in daily life to
structure and composition [6]. This explains their usage in drilling fluids; porcelain; vehicles; ceramic industry, to
sanitary-wares, electrical porcelain, high quality tableware, produce household wares like plates, cups, flower vases,
glazes or tiles. electrical sockets (insulators), toilet seats, bath tubs,
refractory bricks; but has enough raw materials for the
In general, clay minerals are important industrial production of these tools widely available across the country
minerals that are used in for producing many ceramics all of which is most urgently needed. The clay deposits in
products and with each product requiring clay with these places should be thoroughly characterized,
appropriate and specific properties. Millions of tonnes are beneficiated, and processed in order to determine the overall
used annually in several applications [3]. These uses include ore grade and to exploit and determine the markets for the
uses as refractory materials for ovens, furnaces and lining items in the nation.
kilns in the process industries, construction, agriculture and
geology [2; 18; 22]. The Nigerian government is concentrating its attention
to development of solid mineral sector as a result of
Clay deposits (from Ndia - akum, Taraba State) were lingering oil crises around the world. Large deposits of these
characterized for industrial application by [15] using clays are present within Niger state and are yet to be
physicochemical, XRF and TGA methods. The TGA results exploited. Therefore, the aim of this study is to characterize
indicated loss of some weight on heating and high and study the physico-mechanical properties of clay from
temperature thermal stability of the clay with improved Bida with a view to predict the engineering characteristics
physical properties such as shrinkage, bulk density and and evaluate its potentials economically, for the nation’s
plasticity. technological and industrial development.
The clay materials used in this research was sourced A. Chemical Analysis
from Patishin, 3 to 4 km along Bida-Minna road, Bida - The chemical analysis results of the clay samples from
Niger State (Nigeria). The raw samples were randomly the study location indicates high value of SiO2 of 69.58%,
collected from different points at a depth of 2m to cover a 23.15% Al2O3 and Fe2O3 of 2.93 %. Low value of CaO,
good depth of the entire site. The clay was placed in a dry Na2O, K2O and lost on Ignition (LOI) was also observed in
clean polythene. For five days, the raw samples were sun- the studied clay (Table 2).
dried and pulverized and sieved to 0.15 microns, to ensure
the elimination of debris and coarse materials. The abundance of K-feldspar (orthoclase and
microcline) is indicated by the substantially greater alkalis
The clay was characterized to determine its chemical K2O/Na2O ratio (3.13) in the sample. The felsic nature of
properties to ascertain its properties for ceramics and this clay is shown in the lower concentrations of P2O5, CaO
industrial applications using XRF, XRD and scanning and MnO. This composition is comparable to Mgbom [1]
electron microscope (SEM). A 2kg weight of the clay was and Kutigi deposits [5]. This deposit contains high silica
mixed with water to achieve moldability for production of composition of approximately 70% with little to moderate
test specimen. The samples for mechanical properties alumina component which is comparable to results of [18]
(modulus of rupture, cold crushing strength) and physical from Ejigbo in Lagos state, and hence suitable for use in
properties (porosity, linear shrinkage, water absorption) zeolite and ceramics application.
tests were processed and subjected to heating (sintering) at
temperatures of 12500C, 11500C, 10500C and 9500C under There is the availability of oxides in the clay, which
an hour soaking time [16, 22 and 17]. The required tests play important role in the industrial applications of clays
were all completed in accordance with ASTM standards [8]. especially kaolin and it also helps to stepdown the melting
temperature of quartz and control glass viscosity. High
SiO2and Al2O3 indicate that it could be useful in the
production of ceramics and refractories [14]. Its high silica
concentration also makes it a useful raw material for the
production of zeolite, amorphous silica alumina, tiles, and
bricks. The Fe2O3 content makes it unsuitable for use in
tiles, pottery and sanitary-wares. The opacity and lightness
of the clay makes it useful for paints and coating in plastic
[1]. The content of the studied clay compared with industrial
engineering specifications makes the clay deposit an
important mineral (raw material) for the production of
ceramics and refractory bricks.
The x-ray diffraction (XRD) result is shown in Figure 1. The mineralogy of the raw clay is composed of kaolinite
{Al2Si2O2(OH)4} and quartz. This confirms the studied clay to be kaolinitic in nature.
(a)
(b)
(c)
Fig. 2: XRD Spectrum of Sintered Clay at (a) 9500C (b) 11500C and (c) 12500C
Table 3: Physico-Mechanical Properties of the Clay compared with ISO standards [3; 7; 12; 13; 20]
Property 9500C 10500C 11500C 12500C Ceramics Refractory Fireclay
3
Bulk Density (g/cm ) 1.62 1.63 1.58 1.59 ≥1.85 ≥1.80 ≥1.85
Apparent Density (g/cm3) 2.22 2.23 2.42 2.47 ≤2.2 - ≤2.2
Water Absorption (%) 21.29 20.08 18.23 18.06 - - -
Apparent Porosity (%) 34.46 32.73 28.83 28.67 10 – 30 10 – 30 20 - 30
Linear Shrinkage (%) 1.12 1.28 1.30 1.65 ≤10 ≤7 ≤8
2
CCS (KgF/cm ) 89.12 131.85 175.70 202.41 15.30 14.68 15.30
M.O.R (KgF/cm2) 5.41 8.46 10.30 14.48 - - -
Elastic Modulus (KgF/cm2) 438.07 676.07 492.01 139.60 - - -
(a)
(b)
(c)
Fig. 4: SEM Photomicrograph of Sintered Samples at: (a) 9500C, (b) 11500C and (c) 12500C
When fired, the clay was observed to undergo phase Apparent density = (5)
transformation from the original phases of the virgin raw
kaolin. As the temperature is increased towards 12500C, there
Cold crushing strength (C.C.S) = (6)
is change in phase transformation to quartz- sillimanite phase
up to 10500C and from quartz-sillimanite phase to quartz-
mullite phases at 11500C and 12500C respectively, as can be Modulus of Rupture (M.O.R) = (7)
seen from the XRD patterns of various samples. Figure 2
shows the XRD results of sintered clay at different Elastic Modulus = (8)
temperatures. The SEM photomicrograph of Figures 4
showed flakes of mullite observed in quartz-glassy phase, as
Where, W = Saturated weight, D= dry weight, S =
observed in a similar manner by [6].
suspended weight, Ld= Dry length, Lf = Fired length, p =
B. Refractoriness and Thermal Shock Resistance Density of water = 1g/cm3, F= yielding/breaking load, L=
In case of refractoriness, it shows that the experimented distance between supports or gauge length, d= height/depth,
clay has moderate refractoriness and can withstand b= breadth, D= deflection and C.C.S= Cold Crushing
temperatures of 12500C which makes it useful for Strength.
applications in low temperature areas. Examples are low
The water absorption rate of sintered clay samples
temperature ovens, microwave and kilns, compared to others
reduces with sintering temperature increase from 21.29% to
that have useful application in heat treatment furnace for
18.06% at 9500C and 12500C respectively. Also, the porosity
annealing and ladles [13]. The clay investigated did not meet
of sintered clay indicates that there is a general reduction in
the standard requirement for refractory materials in terms of
the porosities of clay as the temperature increases. These
thermal shock resistance and refractoriness. However, it has
conditions could be associated with the reduction in pore
12 cycles of thermal shock resistance as seen in Table 1,
spaces and increase in densification within the ceramic body
which are below the required cycles for standard refractories
within the investigated temperature range as reported by [19].
[12].
The porosity values of 34.46% at 9500C and 28.67% at
C. Physico-mechanical Properties 0
1250 C were comparable to ISO standards of 10 to 30% for
The mechanical and physical properties of the deposit
ceramics and refractory applications as seen in Table 3 and
under investigation were determined using the equations
Figure 4 respectively. The linear shrinkage values peaked at
below:
1.65% compared to ≤7 and ≤10 for refractory and ceramics
respectively, just as the bulk density increased as the
Linear shrinkage = (1) temperature increased to a peak value of 1.59g/cm3 as
compared to ISO standard value of ≤1.8.
Water absorption = (2)
In terms of mechanical properties, the cold crushing
strength of the clay tested was observed to improve with the
Apparent porosity = (3)
sintering temperature increment, this leads to an increase in
densification and reduction in porosities, making the samples
Bulk density = (4) more rigid. A cold crushing strength of 89 KgF/cm 2 and
202kgF/cm2 were obtained at 9500C and 12500C respectively.