Advanced Materials Research Vol. 770 (2013) pp 201-204
© (2013) Trans Tech Publications, Switzerland
doi:10.4028/www.scientific.net/AMR.770.201
Online: 2013-09-04
Development of Barium Borosilicate Glass using Rice Husk Ash:
Effect of BaO
Suparat Tuscharoen1,a,*, Suwimon Ruengsri2,b and Jakrapong Kaewkhao1,3,c
1
Center of Excellence in Glass Technology and Materials Science (CEGM), Nakhon Pathom
Rajabhat University, Nakhon Pathom, 73000, Thailand
2
Chemistry Program, Nakhon Pathom Rajabhat University, Nakhon Pathom, 73000, Thailand
3
Thailand center of Excellence in physics, CHE, Ministry of education, Bangkok, 10400,Thailand
a
[email protected], [email protected], [email protected]
Keywords: Borosilicate glasses, Density, Refractive Index, Rice Husk Ash
Abstract. This paper is report on the physical and optical properties of development
barium-borate-rice husk ash (BaBRHA) glass system. The glasses containing BaO in
xBaO:(80-x)B2O3:20RHA where x = 30, 35, 40 and 45 wt% have been prepared by melt quenching
technique. The physical properties of this glass are shown from density data. The optical properties
were investigated from refractive index and transmission by using Abbe-refractometer and
UV-visible spectrometer respectively.
Introduction
Rice husk ash (RHA) contains an active form of silica (SiO2) and is available in large quantities in
Thailand. It has been estimated by the Thai Rice Exporter Association (TREA) that the production
of paddy will be about 20 million tones by the year 2012 [1]. Paddy consists of 72% of rice, 5-8%
of bran and 20-22% husk on average. Thus, 20 million tones of paddy will give us about 4 million
tones of husk. Presently about 4 million tones of rice husk is produced in Thailand per annum.
About 4 million tons of rice husk ash is produced in Thailand, which is mostly thrown away as
waste. Rice husk contains ash from 13 to 29% by weight depending on the variety, climate and
geographic location [2]. The ash is largely composed of silica (87-97%) with small amount of
alkalies and other trace elements. Therefore, it is necessary to search for a new option for the
treatment of the RHA. One possibility is to use a glass production because of the high silica content
and low transition oxide contamination. Previous our work [3], we developed BaO:B2O3: RHA
glass system with high addition of BaO concentration (45-70 wt %), and investigate on physical,
optical and radiation shielding properties at 662 keV. The optical properties were investigated and
radiation shielding properties is better than commercial window and ordinary concrete. However,
from transmission spectra, broad peak around 1100 nm from Fe2+ ions (contamination from RHA)
was obtained and optical transmission degradation may be occurred. So, in this work, low
concentration of BaO addition in BaO:B2O3: RHA glasses have been prepared and investigate their
optical properties. In addition, the physical and structural properties were also studied.
Experimental
The oxides of barium and boron used in this work were of analytical reagent grade, and the oxide of
silica was of rice husk ash produced from Nakhon Pathom Province, Thailand. The processes to
obtain RHA and analyze their compositions were explained in [3]. The xBaO:(80-x)B2O3:20RHA
(where x = 30, 35, 40 and 45 wt.%) were prepared by the melt quenching technique. All chemicals
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Applied Physics and Material Applications
used in the present work, BaCO3, H3BO3 and RHA. Appropriate amounts of the raw materials were
thoroughly mixed and ground in a pestle and mortar for half an hour. The prepared mixture was
then heated in a high purity alumina crucible at 1200°C by an electric furnace for about 3 h to
ensure complete melting of all components. The melt was then quickly poured into a preheated
stainless steel mold and annealed at 450°C for 1 h and let it cooled down slowly to room
temperature. The amount of the glass batch is about 30 g/melts. The obtained glass was cut and
finely polished into a size of 5 mm × 10 mm × 3 mm. The chemical compositions of the glasses,
prepared in the present work, are summarized in Table 1. By applying Archimedes principle, the
densities of glasses were measure using 4-digit sensitive microbalance (AND, HR-200). The
refractive index (n) of the glass samples was measured using an Abbe′ refractometer (ATAGO) with
mono-bromonaphthalene as a contact layer between the sample and prism of the refractometer. A
sodium vapor lamp, λ = 589.3 nm (D line), was used as the light source. The transmission spectra
of glasses were performed using a UV-visible spectrophotometer (Varian, Cary 50) in the
wavelength range 300-1100 nm, using air as the reference.
Fig. 1 Shown the cut and polished glasses sample
Table 1. The chemical composition in oxide form of RHA at different temperature
Sintering
% by weight
condition
SiO2
Sintered
at 600 oC
Sintered
at 800 oC
Sintered
at1,000 oC
P 2 O5
SO3
K2 O
CaO
TiO2
MnO
Fe2O3
CuO
ZnO
BaO
94.321 1.704 0.795 2.065 0.694 0.010 0.231
0.143
0.005 0.024 0.008
95.305 1.412 0.596 1.650 0.632 0.007 0.224
0.135
0.005 0.025 0.010
95.377 1.752 0.295 1.387 0.734 0.014 0.202
0.194
0.009 0.026 0.010
Table 2. Chemical composition (wt%), density, molar volume and refractive index of
barium-borate-rice husk ash (BaBRHA) glasses
Samples
wt%
Vm
Refractive
ρ
3
3
(g/cm )
(cm /mol)
index
BaBRHA-1
BaBRHA-2
BaBRHA-3
BaBRHA-4
(x)BaO
(80- x)B2O3
RHA
30
35
40
45
50
45
40
35
20
20
20
20
3.2467±0.0075
3.3431±0.0010
3.4602±0.0030
3.5861±0.0029
26.94
27.33
27.64
27.98
1.5917±0.0008
1.5973±0.0001
1.6072±0.0010
1.6172±0.0000
Advanced Materials Research Vol. 770
(a)
203
(b)
(c)
Fig. 2 The properties of BaBRHA glasses as function of BaO concentration (a) density
(b) refractive index (c) transmittance
Results and Discussion
The chemical compositions in oxide form of rice husk ash (RHA) after thermal treatment at 600,
800 and 1,000 oC are reported in Table 1. The major composition of RHA is SiO2 and low transition
oxide contamination (MnO and Fe2O3). The P2O5 is a glass former, while CaO is intermediate. For
K2O is flux in a glass melting. However, P2O5, CaO and K2O are not produce color in glass. For
glass sample characterizations, the chemical composition, density, molar volume and refractive
index of prepared BaBRHA-glass samples are listed in Table 2. The replacement of all B2O3 and
RHA with BaO leads to an increase in density, due to higher molecular weight of BaO compare
with B2O3. The molar volumes of these glasses were increased with increasing of BaO content;
indicate that the loose packing were increases due to BaO acts as modifier. In this case, the
non-bridging oxygens (NBOs) are increased in number in the borate network so molar volumes
were increased [4]. The plot of density and refractive index as a function of BaO concentration are
shown in Fig.2 (a) and (b) respectively. The refractive index of BaBRHA glasses are from
1.5917-1.6712. The refractive index of the glasses increases with increasing of BaO content due to
the increase of density, molar refractivity and the molar electronic polarizability of oxide ions [5].
In order to investigate the optical properties of these glasses at various concentrations, the
transmittance was measured as a function of wavelength in the range of 300-1,100 nm as shown in
Fig. 2(c). All the glasses showed that the transmittance higher than 50% in the visible region. For
the near infrared region (> 700 nm), the new glasses in this work with addition BaO concentration
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Applied Physics and Material Applications
at 40 and 45 wt% showed that the transmittance higher than the previous work at 50 wt% of BaO
[3]. This result can explain in term of Fe2+ ions form decreased when low addition of BaO than 50
wt% and better optical transmission spectra was obtained.
Conclusions
This paper is report on the physical and optical properties of development barium-borate-rice husk
ash (BaBRHA) glass system. The RHA from Nakhon Pathom Province, Thailand were produced by
heat treatment technique. The major composition of RHA is SiO2 and low transition oxide
contamination (MnO and Fe2O3). The P2O5 is a glass former, while CaO is intermediate. For K2O is
flux in a glass melting. However, P2O5, CaO and K2O are not produce color in glass. The density of
prepared glasses increases with increasing BaO content. This is the effect of a higher molecular
weight of BaO than B2O3 as well as an increase of the loose packing of the glass system according
to the modifier of BaO. The refractive index of the glasses increases with increasing of BaO content
due to the increase of density, molar refractivity and the molar electronic polarizability of oxide
ions. From transmission spectra, the new glasses in this work with addition BaO concentration at 40
and 45 wt% showed that the transmittance higher than the previous work at 50 wt% of BaO [3].
This result can explain in term of Fe2+ ions form decreased when low addition of BaO than 50 wt%
and better optical transmission spectra was obtained.
Acknowledgements
The authors would like to thanks National Research Council of Thailand (NRCT) for financial
support.
References
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Applied Physics and Material Applications
10.4028/www.scientific.net/AMR.770
Development of Barium Borosilicate Glass Using Rice Husk Ash: Effect of BaO
10.4028/www.scientific.net/AMR.770.201
DOI References
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http://dx.doi.org/10.1016/S0921-4526(96)01032-0
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