Advan ces in Materials Physics and Che mist ry, 2012, 2, 74-77
doi:10.4236/ampc.2012.24B021 Published Online December 2012 (http://www.SciRP.org/journal/ampc)
Influence of Waste Materials Containing Tungsten
on Melting and Crystallization of Glass-ceramics
Shao min Lin, Bo Wa ng, Guishen Liu, Liqing Li, Xiaodong Hou
1Research Institute of Environmental Chemistry and Technology, Hanshan Normal University, Chaozhou, China
2National Center of Supervision and Inspection for Ceramic, Sanitary and Plumbing Fixture,
Chaozh ou Supervision Testi ng Institut e of Quality and Metrolog y, Chaozhou, China
Received 2012
ABSTRACT
Influen ces of wast e materials containing tungsten on melting and crystallization of glass-ceramics are d iscussed in this article. High
temperature melting, nucleation and crystallization of glass-ceramics were explored by means of DTA, XRD and SEM. The high
temperature melting performance of glass-ceramics ingredients can be effectively improved by mixing the right amount of waste
materials containing tungsten. But the additive amount should be properly controlled, the mixing content of waste materials contain-
ing tungsten should be a range of 0.5 ~ 2.0%. In the experiment of glass-ceramics ingredients system, the molten softening tempera-
ture of base glass powder reduced about 20℃ by adding 1% waste materials containing tungsten, and the nucleation temperature
reduced about 15℃. The nucleation and crystallization performance of glass-ceramics mineral crystals can be promoted by mixing
the right amount of waste materials containing tungsten. That is helpful to improve the quality of glass-ceramics products.
Keywords: Waste Materials C ontaining Tungsten; Glass-Ceramics; Melting Perfo r mance; N ucleation and Cr ystall ization
1. Introduction
Utilizing industrial wastes and tailings as main raw materials to
manufacture glass-cer amics is of great significance for t he sus-
tainable development of industry, not only can effectively solve
the pollution problem of industrial wastes, and can realize re-
source recycling [1,2]. But in China, the utilization rates of
industrial wastes and tailings are much less than the developed
countries. One important reason is that the industrial wastes are
various and thei r chemical co mpo sitions and mineral structures
are complex. Thus, the physical and chemical properties, com-
position and structure of industrial wastes must be researched
before utilization as resource, in order to adjust the formula
ingredients and the production process in time and avoid the
adverse effects in actual pro duction[3, 4] .
Chaozhou region is the important ceramics industry base in
China, the ceramic production is very large. Ceramic produc-
tion uses a lot of mineral resources, but also causes many in-
dustrial wastes, such as kaolin tailings, etc. The reasonable
utilization of industrial wastes is the urgent need for the sus-
tainab le develop ment of ceramic in dustry. Glass-cer amics were
prepar ed with kaoli n tailings and fly ash as p rincip al raw mate-
rials by powder sintering method, and the influences of waste
materials containing tungsten on melting and crystallization of
glass-ceramics are discu ss ed in this art icle.
2. Materials and Methods
2.1. Materials
Industrial materials: kaolin tailings, fly ash and waste
materials containing tungsten.
The samples of kaolin tailings were collected from FT
ceramics plant and sieved through 60 mesh standard
sieve. The samples of fly ash were collected from DT
power plant and sieved through 200 mesh standard sieve.
The chemical compositions ar e sho wn in Ta b le 1.
The samples of waste materials containing tungsten were
collected from XL tungsten plant, which using ion exchange
refining production process, and the tungsten content of waste
materials i s about 1.97%.
2.2. Methods
Preparation of glass-ceramics ingredients: According to the
chemical and mineral compositions of various waste materials,
the right formula system was designed, and the experimental
formula was shown in Table 2. The raw materials, such as kaolin
tailings, fl y ash, CaO, Na2CO3, BaCO3 and ZnO, were weighed
according to the proportion of ingredients, and the waste mate-
rials containing tungsten with different contents were added re-
spectively. Glass-ceramics ingredients were prepared after
mixed and grinded.
Tabl e 1. Chemical compos it ion s of kaolin taili ngs and fl y as h .
Sample SiO2 Al2O3 Fe2O3 CaO MgO K2O Na2O Loss
Kaolin tailings (％) 73.74 15.10 0.35 0.24 1 .1 6 5.65 1 .2 6 3.28
Fly ash (％) 44.40 36.15 4.92 6.88 1.96 1.0 0 0.60 3.26
Tabl e 2. Proportions of formula com positions.
Kaolin tailings
(
％
) Fly ash (
％
) CaO (
％
) Na2CO3 (
％
) BaCO3 (
％
) ZnO (
％
)
70.00 5.81 14.00 4.65 4.65 2.33

S. M. LIN ET AL.
75
2) Preparation of base glass powder: The glass-ceramics in-
gredients were filled in corundum crucibles and melted in high
temperature furnace. After heating up to 1420℃ with heating
rate of 5~10℃/min, the samples were melted at 1420℃ for
180 minutes, then were taken out for water-quenching heat
treatment in high temperature melting state. The base glass
powder of glass-ceramics was prep ar ed after grinded and sieved
through 20 mesh standard sieve.
4) Differential Thermal Analysis: The samples of base glass
powder were analyzed by DTA (DTA, Model TA-50H), after
grinded and sieved through 200 mesh standard sieve.
5) Preparation of glass-cerami cs sam pl es : The base gla ss pow der
was filled in corundum moulds and sintered in high temperature
furnace. The glass-ceramics samples were prepared after the
nucleation and crystallization in the appropriate thermal system.
The nucleation temperature is in the range from 920℃ to
980℃, the crystallization temperature is in the range from
1130℃ to 11 90℃.
6) Samples analysis: The surface microstructure of
glass-ceramics samples was analyzed by SEM (SEM, Model
JSM- 6360LA), after soaked in 4% HF solution for 60 seconds
and dried. The mineral crystal compositions of glass-ceramics
samples were an al yzed by XRD ( XR D, Model D8 ADVANCE),
after grinded and sieved through 200 mesh standard sieve.
3. Results and Discussion
3.1. Influence of Waste Materials Containi ng
Tungsten on High Temperat ure M e lting
Performance
In order to resear ch the influence of waste material s containing
tungsten on high temperature melting performance of glass-
ceramics i ngredients, the raw materials were weighed according
to the basic formula compositions. The waste materials con-
taining tungsten were added respectively with 0%, 0.5%, 1%,
2.5% and 5 %, and th e samples of A0, A1, A2, A3 and A4 were
prepar ed. A series samples were filled in the divided corundum
moulds and melted in high temperature furnace at 1380℃.
Then the molten state of A series samples was observed after
furnace cooling. The result is shown in Figure 1.
Figure 1 shows that A series samples are melted and vitri-
fied. There are a number of bubbles in molten mass of sample
A0, and the bubbles reduce gradually fro m A0 to A2. Although
the bubbles in samples A3 and A4 also is less, but the molten
mass color turned into dark brown gradually. That is because
Figure 1. Comparison of the molten state of A series samples.
the impurities in waste materials have adverse effect, when the
additive amount is too high. The high temperature melting per-
formance of glass-ceramics ingredients can be effectively im-
proved by mixing the right amount of waste materials contain-
ing tungsten. But the additive amount should be properly con-
trolled, in order to avoid the adverse effect of the impurities in
waste materials. When the mixing content of waste materials
containing tungsten is 1%, the melting performance of ingre-
dients system can be impr oved effectively.
3.2. Influence o f Waste M at erials Contai ning
Tungsten on Molten Softening Tempera ture
and Nuclea tion Temperature
In order to resear ch the influence of waste material s containing
tungsten on the molten crystallization process of base glass
powder, the raw materi als were weigh ed accord ing to t he basic
formula compositions. Samples B0 and B1 were prepared, and
sample B1 was added 1% waste materials containing tungsten.
The samples of base glass powder of B series samples were
analyzed by DTA, after melted, water-quenched, grinded and
sieved through 200 mesh standard sieve. The results are shown
in Figure 2.
Figure 2 shows the DTA curves of base glass powder of
samples B0 and B1. The molten softening temperature of sam-
ple B1 is about 825℃, and that of sample B0 is about 845℃.
The nucleation temperature of sample B1 is about 885℃, and
that of sample B0 is about 899℃. After adding 1% waste mate-
rials containing tungsten, the molten softening temperature of
base glass powder reduces about 20℃ and the nucleation tem-
perature redu ces about 15℃.
(a)
(b)
Figure 2. DTA curves of base glass powder of B series samples. (a)
DTA curve of sample B0; (b) DTA curve of sample B1.

S. M. LIN ET AL.
76
3.3. Influence of Waste Materials Containi ng
Tungsten on Nucleation and Cr y st allization
Behavior
In order to resear ch the influence of waste material s containing
tungsten on the molten crystallization process of base glass
powder, the glass-ceramics samples C0 and C1 were prepared
after the nucleation crystallization processing, and sample C1
was added 1% waste materials containing tungsten. The surface
microstructure of glass-ceramics samples C0 and C1 was ana-
lyzed by SEM. The results are shown in Fig ure 3.
(a)
(b)
(c)
(d)
Figure 3. SEM photographs of glass-ceramics samples. (a) SEM
photograph of sample C0 (×500); (b) SEM photograph of sample
C0 (×2000); (c) SEM photograph of sample C1 (×500); (d) SEM
photograph of sample C1 (×2000).
Figure 3 shows the SEM photographs of glass-ceramics
samples C0 and C1. Compared to the image o f sampl e C1, th ere
are many undeveloped crystal nucleus existing in the image of
sample C0. The crystal size of sample C1 is larger than that of
sample C0 , and the crystal stru cture is more co mpact . It is seen
that the nucleation and crystallization behavior of
glass-ceramics mineral crystals can be promoted by mixing the
right amount of waste materials containing tungsten. That is
helpful to improve the quality of glass-ceramics products.
The mineral crystal compositions of glass-ceramics samples
C0 and C1 were analyzed by XRD, after grinded and sieved
through 200 mesh standard sieve. The results are shown in
Figure 4.
Figure 4 shows the XRD patterns of glass-ceramics sa mpl es
C0 and C1. All the peaks were compared with JCPDS files. The
XRD results show that the main crystalline phase of
glass-ceramics samples C0 and C1 is β-wollastonite. Compared
to the XRD pattern of sample C0, the characteristic peaks of
glass- ceramics sample C1 have higher intensities at 23.2°,
25.4°, 26.9° and 30.0°. This once again shows that the nuclea-
tion and crystallization behavior of glass-ceramics mineral
crystals can be promoted by mixing the right amount of waste
materials containing tungsten.
4. Conclusions
Based on these results, three conclusions can be derived.
● The high temperature melting performance of
glass-cera mics ingred ients can be effectively i mproved b y
mixing the right amount of waste materials containing
tungsten. But the additive amount should be properly
controlled, in order to avoid the adverse effect of the
impurities in waste materials. The mixing content of
waste material s containing tungsten should be a range of
0.5 ~ 2.0%.
● In the experiment of glass-ceramics ingredients system,
the molten softening temperature of base glass powder
reduced about 20℃ by adding 1% waste materials con-
taining tungsten, and the nucleation temperature reduced
about 15℃. That is of great significance for saving

S. M. LIN ET AL.
77
energy and reducing consumption in the actual produc-
tion.
(a)
(b)
Figure 4. XRD patterns of glass-cer ami cs s amp les. (a) XRD pattern
of sample C0; (b) XRD pattern of sample C1.
● The nucleation and crystallization performance of glass-
ceramics mineral crystals can be promoted by mixing the
right amount of waste materials containing tungsten.
That is helpful to improve the quality of glass-ceramics
products.
5. Acknowledgements
This work was supported by the National Natural Science
Foundation of China (No. 21207027), the Science and Tech-
nology Project of General Administration of Quality Supervi-
sion (No. 2008QK277), the Natural Science Foundation of
Guangdong Province (No. 8452104101001541), the Science
and Technology Project of Chaozhou (No. 2008S21).
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