Slag Interaction with linings.
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Transcript of Slag Interaction with linings.
Study of Tundish Refractory and Slag Interaction
Presented by:Jitendra Salecha
Under the guidance of:Mr. R.K Adepu
Refractory Technology Group
Study of Tundish Refractory and Slag Interaction
Tundish Linings
Working lining
Back-up lining
Study of Tundish Refractory and Slag Interaction
Average sequence length in LD #1 =14 No. of Heats/Hrs in a month = 600 No. of tundishes used in a month =42 Changeover time for a tundish =1-1.5 hrsIf average sequence length is increased by 2 then: No. of tundishes required in a month =37 BENEFITS: Production will be increased by reducing
changeover time for tundish Cost of refractory will also be reduced
OBJECTIVES
To increase the sequence length of the tundish
To reduce the cost of the refractory per ton of steel
To suggest the best suitable refractory to be used as working lining in tundish in LD #1
Study of interaction between working lining and slag
Cup test By Contact angle measurement with different
working linings and different grade slags Study of wear mechanism
By XRD and SEM analysis of reacted working lining
Evaluation of DVM working lining By XRD and SEM
Addition in the refractory to improve the life Carbon fiber, paper fiber, alumina fiber,
mineral wool fiber etc
PLAN
CUP TEST
Refractory:Magnavibe TCO, TCH
Slag:HC, MC, LC (steel grade)
Furnace1350oC, for 8 hrs
XRD & SEM of reacted portion
XRD & SEM of Unreacted portion
Samples after firingMC Slag HC SlagLC Slag HC Slag
Magnavibe
TC
OM
agnavibe T
CH
•Physically, there is no substantial difference in penetration of different grade of steel slag as seen from above figures.
• But MC steel grade slag having higher % of MnO(viz. 13.35%) also has same penetration
CUP TEST
Refractory:Magnavibe TCO, TCH
Slag:HC, MC, LC (steel grade)
Furnace1350oC, for 8 hrs
XRD & SEM of reacted portion
XRD & SEM of Unreacted portion
XRD of pure vibro mass
Position [°2Theta]30 40 50 60 70 80
Counts
0
500
1000
1500
36 M1 UnreactedMagnesium Silicate 62,0 %Iron Diiron(III) Oxide 6,2 %Magnesium Oxide (1/1) 31,8 %
Selected Pattern: Magnetite 98-007-8202
Residue + Peak List
Accepted Patterns
As expected ….
The major phase found in pure vibro mass is Forsterite and Periclase. However, a small amount of magnetite is also present.
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Composition:
Magnesium silicate (Mg2SiO4) : 62.0 %
Periclase(MgO): 31.8%
Magnetite(Fe3O4) :6.2%
XRD of reacted vibro mass
Position [°2Theta]30 40 50 60 70 80
Counts
0
500
1000
36 H1 ReactedMagnesium Iron Silicate (1.86/0.14/1) 100,0 %
Selected Pattern: Magnetite 98-007-8202
Residue + Peak List
Accepted Patterns
36H1 Reacted
Position [°2Theta]30 40 50 60 70 80
Counts
0
1000
2000
3000
36 M1 ReactedMagnesium Iron Silicate (1.8/.2/1) 100,0 %
Selected Pattern: Magnetite low 98-001-7288
Residue + Peak List
Accepted Patterns
36L1 Reacted
Composition:
Magnesium Iron silicate(36H1) (Fe0.14Mg1.86SiO4): 100 %
Magnesium Iron silicate(36L1)
(Fe0.2Mg1.80SiO4): 100 %
Comment:
There was only one major phase found in reacted portion of the brick. From these XRD analysis it can be said that the slag is in glassy phase which presence cannot be seen in XRD
back
CUP TEST
Refractory:Magnavibe TCO, TCH
Slag:HC, MC, LC (steel grade)
Furnace1350oC, for 8 hrs
XRD & SEM of reacted portion
XRD & SEM of Unreacted portion
SEM of pure vibro mass(2736)
MgO rich area
Forsterite rich area
Forsterite rich area
MgO rich areaCao,MgO,SiO2
rich area
Silica rich area
1 2back
SEM of Deskulled Sample(T-18)
CaO and FeO rich Area
Ca silicate rich area
MgO rich area
Iron rich area
Ca , Mg silicate rich area
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SEM of deskulled sample(T-10)
Al2O3 rich area
Ca,Mg silicate rich area
Iron rich area
MgO rich area Ca,Mg silicate rich area
Chromite rich area1 2 back
OBSERVATIONS
From XRD, it can be seen that there was only one major phase present in reacted portion that magnesium iron silicate.
From SEM, the infiltration of slag into refractory material was clearly visible.
Wettability Characteristics by Contact Angle Measurement
Experimental Set-Up
The sessile drop unit, schematic sketch
Picture
PROCEDURE
200
1100 1100
1250
0
200
400
600
800
1000
1200
1400
0 50 100 150 200 250 300
Time (min)
Te
mp
era
ture
(C
)
1100 C
1250 C
10 C/min
1 C/min
Substrate & Slag Heating schedule Live pictures
Substrate: Magnavibe TCO & TCHSlag: : LC, HC
Comparison of contact angle
0
20
40
60
80
100
120
140
160
180
200
1100 1120 1140 1160 1180 1200 1220 1240
37LC
37HC
36LC
36HC
36H3-HC
Con
tact
an
gle
Temperature
Contact Angle v/s Temperature
Observation of CA experiments The salient observations during CA Experiment:
There was no change in the shape of slag nobule till 1130C
After 1130C slag started softening and changed into a spherical shape and developed a specific contact angle with refractory substrate
This contact angle was constant over a range of temperature from 1130C to 1180C, during which complete softening took place
After 1180C the slag became more fluid and started absorbed into the substrate, by 1250 slag has been completely absorbed.
CONCLUSIONS From CUP Test, it can be concluded that there is no
substantial difference in penetration of slag into refractory material
From XRD and SEM, it can be observed that slag penetrated into refractory material. This shows interaction between working lining and slag.
From Contact Angle measurement, slag started melting from 1130oC.This gives indication of low melting phases present in Slag.
Owing to low melting temperature of slag, some additives (MgO and CaO) should be added to increase its melting point to enhance the life of tundish working lining
THANK YOU THANK YOU ! !
Back up slides
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COMPOSITION of HC and LC
%Fe %CaO %SiO2 %MgO %MnO %Al2O3 %TiO2 %Cr2O3
HC 2.38 14.1 51.25 10.99 7.06 11.69 0.78 0.47
LC 1 14.48 59.47 8.0 8.08 7.92 0.28 0.14
MC
1 15.81 54.37 8.18 13.35 8.20 0.30 0.16
Compositon of TCO and TCH
%Fe %MgO %SiO2 %CaO %Al2O3
TCO 4.34 64.14 28.56 0.55 0.14
TCH 4.28 63.36 29.22 0.52 0.12
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%Weight of pure vibro mass-1
O-K Mg-K Si-K Ca-K Fe-K
2736(3)_pt1 39.98 59.84 0.18
2736(3)_pt2 40.89 24.44 18.37 15.97 0.33
2736(3)_pt3 44.90 32.93 21.55 0.62
2736(3)_pt4 40.51 59.34 0.15
2736(3)_pt5 38.21 23.44 19.71 18.64
2736(3)_pt6 45.04 31.95 21.17 1.85
2736(3)_pt7 42.24 18.39 19.88 19.49
1
%Weight of pure vibro mass-2 O-K Na-K Mg-K Al-K Si-K S-K Ca-K Ti-K Fe-K
2736(2)_pt1
40.20 7.40 18.81 33.59
2736(2)_pt2
35.05 7.84 19.96 37.15
2736(2)_pt3
40.99 57.64 0.61 0.35 0.41
2736(2)_pt4
40.53 58.83 0.15 0.08 0.40
2736(2)_pt5
43.89 28.59 20.73 6.80
2736(2)_pt6
48.10 5.71 1.98 0.69 37.03 0.20 5.65 0.63
2736(2)_pt7
45.49 28.05 19.93 6.54
2736(2)_pt8
44.01 28.77 20.88 6.33
2736(2)_pt9
39.94 59.33 0.14 0.59
2736(2)_pt10-
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%Molecular weight in T-18
Mgo Al2O3 SiO2 CaO TiO2 MnO FeO
Pt_1 5.38 2.20 2.81 29.30 4.48 3.84 52.00
Pt_2 16.32 - 38.48 20.96 - 16.11 8.12
Pt_3 - 3.54 47.41 34.06 7.68 5.59 1.71
Pt_4 100
Pt_5 100
Pt_6 27.24 - 37.36 28.60 0.77 6.04 -
%Molecular weight in T-10-1
MgO Al2O3 CaO FeO SiO2 MnO K2O Fe
Pt_1 14.41 76.92
- 2.80 - 5.86 - -
Pt_2 18.39 - 38.55
3.95 31.04
7.28 0.79 -
Pt_3 - - - - - - - 100
1
%Molecular weight in T-10-2
MgO Al2O3 CaO FeO SiO2 MnO TiO2 Cr2O3
Pt_1 87.10 7.15 5.75
Pt_2 25.47 34.34 1.70 34.12 4.37
Pt_3 24.66 10.73 2.98 0.98 60.64
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