Journal of Minerals & Materials Characterization & Engineering, Vol. 9, No.2, pp.123-131, 2010 Printed in the USA. All rights reserved
Potential of Tin Tailings an Industrial Waste for Refractory Materials
V.S. Aigbodion1*, A. AbdulRasheed1, S.O. Olajide1, J.O. Agunsoye2, I.Y. Sulaiman3
1Department of Metallurgical and Materials Engineering, Ahmadu Bello University, Zaria,
2Department of Metallurgical and Materials Engineering, University of Lagos, Nigeria
3National Research institute for chemical technology, Zaria. Nigeria
Corresponding Author:, +2348028433576
The potential of using Tin tailings industrial waste, from the mineral processing industry for the
production of refractory bricks for furnaces lining was studied. The waste was obtained at Tin
Ore beneficiation plant, screen and sieve. The sieve Tin tailing was then used in the production
of refractory bricks. The properties namely: chemical analysis firing shrinkage, porosity, cold
crushing strength, refractoriness and thermal shock resistance were determined. The result
obtained show that cold crushing strength and thermal shock increased as the sieve size
decreases, which means that high strength bricks can be made from this waste. Also the brick
made with 0.9mm sieve size has the highest value of firing shrinkage, lowest value of porosity
and with acceptable value of thermal shock resistance. This industrial waste has refractory
properties that can be compared with Indian fire clay refractory. Hence, this waste can be
employed in refractory brick s production for furnace lining.
Keywords: Tin tailings, Re fr ac to r y, C ol d cr u sh ing strength, Porosit y, Shock resistance
The Tin Ore obtained from the mine site is beneficiated into Tin concentrate, middling and Tin
tailings. After the beneficiation of Tin Ore to obtained Tin concentrate, Tin tailings are collected
as a waste from the process; this waste consists of about 25% of the total weight of Ore
beneficiated [1].
124 V.S. Aigbodion, A. AbdulRasheed, S.O. Olajide, J.O. Agunsoye, I.Y. Sulaiman Vol.9, No.2
The Tin tailings which are collected separately are disposed off in a secluded area and become
wasted along river banks and farm lands or in mined out holes or they are poured on the top of
slopes [1-2]. Based on economics as well as environmental related issues, enormous efforts
have been directed worldwide towards tin tailings management issues i.e. of utilization,
storage and disposal. Different avenues of tin tailings utilization are more or less known but
none of them have so far proved to be economically viable or commercially feasible. Until
now, there are no researches on the economic value of this waste for industrials application.
Hence this research is looking into the possibility of using these industrial wastes from the
mineral processing industry for the production of refractory materials, since it has been
confirmed from the early work of [3], that Tin tailings contains inorganic materials, mainly of
mixtures of oxides that can withstand high temperature condition.
2.1 Materials
The Tin tailings used in this work were obtained from the Jos Tin mining field in Nigeria, others
materials used are: Arabic gum, Water and cotton wool
2.2 Equipment
Equipment used in the course of the research are: Meter balance, Crucible tong, Thermometer,
Drying oven, Density bottles, Hydraulic press, Mixer, Hood type furnace, Steel mold and set of
2.3 Methods
2.3.1 Chemical analysis of the sample
The chemical composition of the tailings was determined using the XRF analysis method at the
scientific laboratory of National metallurgical development centre, (NMDC), Jos.
2.3.2 Production of the test samples
The undesirable particles (gangues) are removed from the Tin tailings by gravity/magnetic
separation method, which was then crushed and grounded. It is thoroughly mixed together
manually to obtain a uniform mixture. It was screened into 3-size fractions classified into coarse,
medium and fine fractions [3]. The coarse particles are retained in 0.355mm and 0.25mm sieve
size; the medium particles are retained in the 0.18mm and 0.125mm sieve size, while the fine
particles are retained in 0.09mm sieve size. The five particles sieve size were each thoroughly
Vol.9, No.2 Potential of Tin Tailings 125
mixed together with Arabic Gum, Water was finally sprinkled on the mixture to make it viscous
and mouldable.
The mixed blends were each packed into a mould box and pressed using hydraulic jack. A
pressure of about 9kg/cm2 was applied to enhance excellent mouldability, homogeneity and
surface smoothness of the samples [3-5].
The mould bricks were dried in an open air for 24 hrs at 110°C to expel any moisture and to
avoid crack during firing. The dried brick were then fired in an automatic digital electric furnace
(Hood-type furnace) at a preset heating rate of 7°C/min (see Plate 1) at different temperatures
shown below; 200 for 6 hours, 650 for 4 hours, 950 for 3 hours, 1100 for 8 hours and 1600 for 8
hours. After firing, the bricks were allowed to cool in the furnace at a cooling rate of 1°C/min
Plate 1. The Samples placed inside the furnace for firing
2.4 Test Procedure
2.4.1 Apparent porosity and bulk density
The test specimen was dried in an oven at 110°C to a constant weight (D) with an accuracy of
0.1gram; the dried specimen was suspended in distilled water such that the specimen does not
touch the bottom or sides of the beaker.
The specimen was boiled for 2hrs, while still in suspension it was cooled to room temperature
and its weight(S) noted. The specimen was removed and the water wiped off from the surface by
126 V.S. Aigbodion, A. AbdulRasheed, S.O. Olajide, J.O. Agunsoye, I.Y. Sulaiman Vol.9, No.2
lightly blotting with a wet towel and the soaked specimen was weighed in air (W). The apparent
porosity is then calcula te d as [ 5]
Where, W – D = actual volume of open pores of the specimen.
W – S = External volume of d specimen.
Bulk density was also calculated from the relationship as [3]
Bulk density=D/W-S (g/cm3)
2.4.2 Firing shrinkage
The green weight of the brick was taking after moulding; air dried and fired in the furnace for
1600°C. The diagonal line across the brick in the green state and fired state were measured using
the vernier caliper. The firing shrinkage was then calculated as a percentage of the original wet
length as shown below [6];
Where, LB = Dimension of green brick, LD = Dimension of fired brick.
2.4.3 Cold crushing strength
In the determination of the cold crushing strength of the bricks, an asbestos board of about 5mm
thickness was placed between the platens of the press and bearing faces of the test pieces which
was placed centrally on the platen. Load was applied at a rate of 20KN/minute using the
hydraulic strength testing machine. The crushing strength was calculated using the relationship
2.4.4 Refractoriness
The Pyrometric Cone Equivalent (PCE) as recommended by ASTM Test C-24 was used in the
determination of the refractoriness of the sample [5-6].
2.4.5 Thermal shock resistance
Test samples were put in the furnace that was maintained at 1100°C and then soaked at that
temperature for 30mins and the piece was removed from the furnace with a crucible tongs and
cooled for 10mins [4]. The test sample were examined to note the presence of cracks and the
Vol.9, No.2 Potential of Tin Tailings 127
specimen is returned back to the furnace, heated for 10mins and cooled again for 10mins [7].
This cycle of heating and cooling was repeated for a number of times until fracture occurred.
This number of complete cycles to produce failure on each sample was noted and taken as the
measure of the thermal shock resistance.
3.1 Results
The results of the chemical composition of the Tin tailings are shown in Table 1, Table 2, show
the physical appearance of the bricks after firing. The results of the porosity, bulk density, firing
shrinkage, cold crushi n g strength and thermal shock resistance are shown in Figures 1-5.
3.2 Discussion
3.2.1 Mineral characterization and chemical composition
The Tin tailings contain both magnetic mineral (iron ore, columbite) and non-magnetic minerals
(cassiterite, monozite, zircon sand in large quantity, silica etc.). The result of the chemical
analysis of the Tin tailings confirmed that the tailings are made of inorganic oxides. ZrO2 have
the higher percentage of (68.7%), then SiO2 (11%) and the least is EuO3 (0.001%) (See Table 1).
This was in line with earlier observation of [3].
Table 1. Chemical Composition of Jos Tin Tailings.
Compound Si
SiO2 Ca
CaO Ti
TiO2 V
V2o5 Cr
Cr2O3 Mn
MnO Fe
Fe2O3 Ni
NiO As
As2O3 Y
Y2O3 Zr
Unit (%) 11 0.25 1.2 0.07 0.23 0.29 4.75 0.03 0.015 0.790 68.7
Compound Nb
Nb2O5 Ag
Ag2O Sn
SnO2 Ba
BaO Eu
EuO3 Yb
Yb2O3 Hf
Ta2O5 Au
Au Pb
PbO Th
ThO2 U
Unit (%) 0.57 1.4 0.64 0.53 0.001 0.45 0.84 0.31 0.10 0.13 0.78 0.45
3.2.2 Visual observation
The physical appearance of the bricks after firing revealed that as the sieve sizes decreasing,
there was a colour change from deep-brown to ash e.g. 0.355mm sieve has deep-brown colour,
while sieve size of 0.090mm have ash colour (see Table 2). Also there was no crack in all the
bricks after firing (see P late 2).
128 V.S. Aigbodion, A. AbdulRasheed, S.O. Olajide, J.O. Agunsoye, I.Y. Sulaiman Vol.9, No.2
Plate 2. Photo of the produced bricks after firing.
Table 2. The physical appearance and colour of the bricks after firing.
Sieve size(mm) Appearance after
firing above 16000C Colour after firing
above 16000C
0.355 No crack Deep-brown
0.250 No crack Deep-brown
0.180 No crack Deep-brown
0.125 No crack Deep-brown
0.090 No crack Ash
3.2.3 Apparent porosity
The apparent porosity of the Tin tailings decreases as the sieve size decreases. The apparent
porosity value of 32.66% for sieve size 0.090mm is greater than that of the recommended value
of 22-25 for medium heat duty, 23-26 for high heat duty fire clay refractory (see Figure 1)[4].
0.09 0.19 0.29 0.39
Sieve Size(mm)
% Porosit
Figure 1. Variation of Porosity with Sieve Size.
Vol.9, No.2 Potential of Tin Tailings 129
3.2.4 Bulk density
Bulk density of the refractory bricks increases with decreasing sieve size. The bulk density of
1.90-2.30g/cm3 for fireclay is less than that obtain for the Tin tailing bricks (see Figure 2) [4].
0.09 0.19 0.29 0.39
Sieve Size(mm)
Bulk Density( g/cm
Figure 2. Variation of Bulk Density with Sieve Size.
3.2.5 Firing shrinkage
The firing shrinkage value increases with decreasing sieve size. The firing shrinkage value of 3%
and 3.6% obtained in the Tin tailings is not up to the maximum value of 7% and above for
fireclay. This value is adequate for refractory product io n ( s ee Figure 3) [3-5].
0. 5
1. 5
2. 5
3. 5
0.09 0.190.29 0.39
Sieve Size(mm)
% of Linear Shrink age
Figure 3. Variation of Linear Shrinkage with Sieve Size.
3.2.6 Cold Crushing Strength
The cold crushing strength increases with decreasing sieve size. The cold crushing strength value
for all the sieve size corresponds to the standard values of Indian fireclay refractory of 250-300
130 V.S. Aigbodion, A. AbdulRasheed, S.O. Olajide, J.O. Agunsoye, I.Y. Sulaiman Vol.9, No.2
kg/cm2 for super heat duty 1 and 400-600 for super heat duty 2 (see Figure 4) [4]. The values
obtained for all the sieve sizes are high enough for a refractory material and is accounted for
good bonding and vitrification during firing [3].
0.09 0.19 0.29 0.39
Sieve Size(mm)
C old Crushing Strength(kg/cm
Figure 4. Variation of Cold Crushing Strength with Sieve Size.
3.2.7 Thermal shock resistance
The thermal shock resistance of the Tin tailings increases as the sieve size decreases. The
thermal shock resistance is poor as the sieve size decreases from 0.355-0.125mm. The thermal
shock resistance of the bricks increases to 16 cycles at 0.09mm sieve size and this blend falls
within the accepted range of 15+ cycles (see Figure 5) [5].
Sieve Size(mm)
Thermal shock
resistance(cycl es)
Figure 5. Variation of Thermal Shock Resistance with Sieve Size.
3.2.8 Refractoriness
The sample was observed to have Seger Cone No 23, with equivalent temperature of 16000C.
This result show that Tin tailings from Jos, Nigeria has a refractoriness of 16000C which
corresponds with the standard value for medium heat duty and high heat duty of the Indian
fireclay refractory [4, 8].
Vol.9, No.2 Potential of Tin Tailings 131
From the results of the research carried out on Tin tailing an industrial waste from the mineral
processing industry for refractory bricks production, based on the outcomes the following
conclusions can be made:
1) The increase in cold crushing strength as the sieve size decreases shows that high strength
bricks can be made from this waste.
2) The refractory brick made with 0.9mm sieve size has the highest value of firing
shrinkage, lowest value of porosity and with acceptable value of thermal shock
resistance. This implies that good refractory brick can be produced with this sieve size
3) This industrial waste (tin tailings) has refractory properties which can be compared with
Indian fire clay refractory.
4) This waste can be employed in refractory brick production for furnace lining.
The Authors acknowledge with thanks the management of the National Metallurgical
Development Cen tre, Jos, Nigeria for allowing us used their equipment.
[1] “Production of Tin in Jos” 2005, 1-34.
[2] “Jos Tin smelting company” , 2006, 23-32.
[3] AbdulRasheed. A, Characteristics studies of Jos Tin Tailings, Unpublished B. Eng thesis
Department of Metallurgical engineering, Ahmadu Bello University Zaria, 2009, 12-45
[4] Chesti, A.R, .Refractories manufacture, properties and Application. Prentice Hall of private
limited, London, 1986, 1-140.
[5] Aigbodion V.S and Asuke,F; Effect of kankara clay on some Refractory properties of
Igbokoda silica sand “Int er -R es ea rc h j ou rn al on Engr. Sci and Tech. vol.4 No.2, 2007, 34-40
[6] Hassan, S.B; Refractory properties of Bauchi and onibode clay of Nigeria for furnace lining,
“African journal of sciences and technology.vol.1 No.1, 2000, 45-52.
[7] Aigbodion,V.S, AbdulRahaman, A.S, Madugu, I.A, ; “characterization study of the effect of
zircon sand on some refractory properties of Alkaleri clay”., inter- Research journal in Engr.
Sci and Tech. Vol.4, No. 2, 2007, 23-30.
[8] Reinhard Schuman jr, Metallurgy Engineering vol.1, Addison Wesley pub. Co. Inc,
1982, 89-96.