608
D. Fonseca et al.
Table 2 Refractory grades used in the rotary drum furnace slag tests
Abbreviation Description
Main oxides
A
Alumina-chromia product type ACr80/10 ISO
10081-4
91% Al 2 O 3 , 9% Cr 2 O 3
DB
Magnesia-chromite product type MCr60 ISO
10081-2, direct bonded (sintered grains)
67% MgO, 18% Cr 2 O 3
DBP
Magnesia-chromite product type MCr60 ISO
10081-2, direct bonded, premium
65% MgO, 20% Cr 2 O 3
DBL
Magnesia-chromite product type MCr60 ISO
10081-2, direct bonded, low permeability
68% MgO, 17% Cr 2 O 3
DB7
Magnesia-chromite product type MCr70 ISO
10081-2, direct bonded
72% MgO, 14% Cr 2 O 3
R
Magnesia-chromite product type MCr60 ISO
10081-2, rebonded (pre-reacted grains)
61% MgO, 22% Cr 2 O 3
The slag tests were performed at approximately 1710 °C for 3 h, with slag renewal
every 30 min. The test temperature was significantly above the operating temperature
of lead furnaces (generally up to 1300 °C maximum) in order to accelerate the corrosion of the refractory specimens. The corrosion resistance of the refractory grades
was compared by measuring the difference in the thickness of each specimen before
and after the tests (wear %). Refractory grades A and DB (one magnesia-chromite and
one alumina-chromia grade) were chosen to be analyzed through optical microscopy
after the slag tests 4 and 6. In addition, the polished sections corresponding to refractory A used in test 4 and DB used in test 6 were analyzed through scanning electron
microscopy (SEM).
Results and Discussion
The results from each corrosion test are shown in Table 3 and illustrated in the
diagram in Fig. 2. Figure 3 shows the visual aspect of the specimens (cross section)
after test 4. Due to the high number of refractory grades (6) and slags (6) tested in
Table 3 Results of the slag corrosion tests performed in the rotary drum furnace (wear %)
Test #
A
DB
DBP
DBL
DB7
R
1
2.66
4.87
4.58
5.69
4.63
2.65
2
2.84
1.82
2.91
4.16
3.80
1.35
3
4.52
2.73
3.48
2.82
2.87
2.12
4
4.63
3.75
2.95
2.67
2.86
3.11
5
2.15
3.90
2.96
3.36
3.81
2.07
6
2.85
2.63
2.37
1.72
2.53
0.97
D. Fonseca et al.
Table 2 Refractory grades used in the rotary drum furnace slag tests
Abbreviation Description
Main oxides
A
Alumina-chromia product type ACr80/10 ISO
10081-4
91% Al 2 O 3 , 9% Cr 2 O 3
DB
Magnesia-chromite product type MCr60 ISO
10081-2, direct bonded (sintered grains)
67% MgO, 18% Cr 2 O 3
DBP
Magnesia-chromite product type MCr60 ISO
10081-2, direct bonded, premium
65% MgO, 20% Cr 2 O 3
DBL
Magnesia-chromite product type MCr60 ISO
10081-2, direct bonded, low permeability
68% MgO, 17% Cr 2 O 3
DB7
Magnesia-chromite product type MCr70 ISO
10081-2, direct bonded
72% MgO, 14% Cr 2 O 3
R
Magnesia-chromite product type MCr60 ISO
10081-2, rebonded (pre-reacted grains)
61% MgO, 22% Cr 2 O 3
The slag tests were performed at approximately 1710 °C for 3 h, with slag renewal
every 30 min. The test temperature was significantly above the operating temperature
of lead furnaces (generally up to 1300 °C maximum) in order to accelerate the corrosion of the refractory specimens. The corrosion resistance of the refractory grades
was compared by measuring the difference in the thickness of each specimen before
and after the tests (wear %). Refractory grades A and DB (one magnesia-chromite and
one alumina-chromia grade) were chosen to be analyzed through optical microscopy
after the slag tests 4 and 6. In addition, the polished sections corresponding to refractory A used in test 4 and DB used in test 6 were analyzed through scanning electron
microscopy (SEM).
Results and Discussion
The results from each corrosion test are shown in Table 3 and illustrated in the
diagram in Fig. 2. Figure 3 shows the visual aspect of the specimens (cross section)
after test 4. Due to the high number of refractory grades (6) and slags (6) tested in
Table 3 Results of the slag corrosion tests performed in the rotary drum furnace (wear %)
Test #
A
DB
DBP
DBL
DB7
R
1
2.66
4.87
4.58
5.69
4.63
2.65
2
2.84
1.82
2.91
4.16
3.80
1.35
3
4.52
2.73
3.48
2.82
2.87
2.12
4
4.63
3.75
2.95
2.67
2.86
3.11
5
2.15
3.90
2.96
3.36
3.81
2.07
6
2.85
2.63
2.37
1.72
2.53
0.97