McMaster University DigitalCommons@McMaster Open Access Dissertations and eses Open Dissertations and eses 10-1-1976 Aack of Magnestic Refractories by Steelmaking Slags Stan-Man Kim Follow this and additional works at: hp://digitalcommons.mcmaster.ca/opendissertations Part of the Metallurgy Commons is esis is brought to you for free and open access by the Open Dissertations and eses at DigitalCommons@McMaster. It has been accepted for inclusion in Open Access Dissertations and eses by an authorized administrator of DigitalCommons@McMaster. For more information, please contact [email protected]. Recommended Citation Kim, Stan-Man, "Aack of Magnestic Refractories by Steelmaking Slags" (1976). Open Access Dissertations and eses. Paper 3121.
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McMaster UniversityDigitalCommons@McMaster
Open Access Dissertations and Theses Open Dissertations and Theses
10-1-1976
Attack of Magnestic Refractories by SteelmakingSlagsStan-Man Kim
Follow this and additional works at: http://digitalcommons.mcmaster.ca/opendissertationsPart of the Metallurgy Commons
This Thesis is brought to you for free and open access by the Open Dissertations and Theses at DigitalCommons@McMaster. It has been accepted forinclusion in Open Access Dissertations and Theses by an authorized administrator of DigitalCommons@McMaster. For more information, pleasecontact [email protected].
Recommended CitationKim, Stan-Man, "Attack of Magnestic Refractories by Steelmaking Slags" (1976). Open Access Dissertations and Theses. Paper 3121.
4.2 IMMERSION TESTS OF CARBON-FREE BRICK 664.2.1 Effect of Temperature 714.2.2 Slag Penetration and Climb 714.2.3 An Index of Hot Streng~h and the 72
Failure of Specimens4.3 MICROSCOP1C EXAMINATION OF CARBON-FREE SPECIMENS 73
4.4 ELECTRON MICROPROBE ANALYSIS OF CARBON-FREE 78SPECIMENS
vi
4.5 SUMMARY OF IMMERSION TESTS WITH CARBON-FREEBRICK SPECIMENS
4.6 CRUCIBLE TESTS OF CARBON-BEARING REFRACTORIES4.6.1 Tests with Oxidizing Slags in FlowIng
Air Atmosphere4.6.2 Tests with Iron Oxide-Free Slags in
Air Atmosphere4.6.3 Tests in Reducing Atmosphere
4.7 MICROSCOPIC OBSERVATIONS OF CARBON-BEARINGSPECIMENS4.7.1 Empty CrucIble Reacted with Flowing Air
Atmosphere4.7.2 Crucibles Reacted with Iron Oxide
Con~aining Slags4.7.3 Crucibles Reacted with Iron OXIde-Free
Slags4.7.4 Crucibles Reacted with Iron-Oxide
Cont~ining Slag in Reducing Atmosphere.4.8 ELECTRON MICROPROBE ANALYSIS OF CARBON-BEARI~G
SPECIMENS4.8.1 Empty Crucible in Flowing Air Atmosphere4.8.2 Crucibles Reacted with Iron Oxide-
Containing Slags4.8.3 Crucibles Reacted with Iron Oxide-Free
Slags4.8.4 Crucibles Reacted with Iron Oxide
Containing Slag in Reducing Atmosphereg
4.9 SUMMARY OF CRUCIBLE TESTS WITH CARBON-BEARIN~o" ~BRICK "
·CHAPTER V DISCUSSION
79
7980
82
82
84
84
85
87,
87
88
8889
90
90
\
5.1 INTRODUCTION5.1.1 A1203-MgO-Containing Slag in Steelmaking5.1.2 Carbon-Free Refractory and Slag as a
Single System5.1.3 Attack of Carbon-Free Refractories by Slag5.1.4 Capillary Penetration of Slag into
Carbon-Free Brick
929298
100102,
5.2 EFFECTS OF CO~WOSITIONAL CHANGE IN AGGRESSIVENESS 103OF SLAG5.2.15.2.25.2.3
5.2.45.2.55.2.6
Tbe Detrimental Effects of A1203 in SlagBeneficial Effects of MgO in SlagsThe Comb~ned Effects of A1203 and MgOAddi tion'S ,The Effect of Oxidation State of SlagEffects of Basicity of SlagThe Effects of Iron Oxide in the Slag
vii
103107108
109110112
4.5 SUMMARY OF IMMERSION TESTS WITH CARBON-FREEBRICK SPECIMENS
4.6 CRUCIBLE TESTS OF CARBON-BEARING REFRACTORIES4.6.1 Tests with Oxidizing Slags in Flowing
Air Atmosphere4.6.2 Tests with Iron Oxide-Free Slags 1n
Air Atmosphere4.6.3 Tests in Reducing Atmosphere
4.7 MICROSCOPIC OBSERVATIONS OF CARBON-BEARINGSPECIMENS4.7.1 Empty CrucIble Reacted with Flowing Air
Atmosphere4.7.2 Crucibles Reacted with Iron Oxide
Con~aining Slags4.7.3 Crucibles Reacted with Iron OXide-Free
Slags4.7.4 Crucibles Reacted with Iron-Oxide
Cont~ining Slag in Reducing Atmosphere
4.8 ELECTRON MICROPROBE ANALYSIS OF CARBON-BEARI~G
SPECIMENS4.8.1 Empty Crucible in Flowing Air Atmosphere4.8.2 Crucibles Reacted with Iron Oxide-
Containing Slags4.8.3 Crucibles Reacted with Iron Oxide-Free
Slags4.8.4 Crucibles Reacted with Iron Oxide
Containing Slag in Reducing Atmosphere'" Q
4.9 SUMMARY OF CRUCIBLE TESTS WITH CARBON-BEARIN~o ~BRICK 0
•
'CHAPTER V DISCUSSION
79
7980
82
82
84
84
85
87.
87
88
8889
90
90
929298
100102,
, 5.1 INTRODUCTION5.1.1 A1203-MgO-Containing Slag in Steelmaking5.1.2 Carbon-Free Refractory and Slag as a
Single System5.1.3 Attack of Carbon-Free Refractories by Slag5.1.4 capillary Penetration of Slag into
Carbon-Free Brick
5.2 EFFECTS OF CO~WOSITIONAL CHANGE IN AGGRESSIVENESS 103OF SLAG5.2.15.2.25.2.3
5.2.45.2.55.2.6
The Detrimental Effects of A1203 in SlagBeneficial Effects of MgO in SlagsThe Comb~ned Effects of Al 20 3 and MgOAddi t ion7:> .The Effect of Oxidation State of SlagEffects of Basicity of SlagThe Effects of Iron Oxide in the Slag
vii
103107108
109110112
/
TABLE
I
2
3
5
6
7
8
LIST 01" TABLES
TITI:.E
MagnesIum and calclum silicates in bInaryequillbrium wIth MgO
Influence of CaO/S102 ratio on the phasedIstrlbutlon of E'lements·
Influence of composItion and microstructureon bondIng
ChemIcal analYSIS and physIcal data ofrefractory brIcks
Composltlon of slags
Specimen elongatIon, slag clImb andpenetratIon
Calculated partial pressures Qf Mg(g) andCO in contact with carbon
-Fractions 'of decarburization by MgO and CO2
PAGE
17
21
21
....56
58
68
117
146
--
LIST OF FIGURES•
FIGURE
1
TITLE
Schemat1c representation of progress ofrefining In a BOF. ('1)
PAGE
6
2 Typical changes in iron-oxide content and 8temperature wIth blowing tfme.(3)
3 Typical changes In slag co~osltion ~ith 8blowing time.(3)
4 The specifIc aggressiveness as function of 10'tlme.(8)
5 Phase dIagram for the system CaO-MgO-Si02 .(12) 18
6 Photomicrographs illustrating the structure of 23three periclase grains. In each case, thelarge gray crystals are MgO and the sil~cate
locat"ion 1S indicated. A 95 percent MgO grainis shown contairling appreciable silicate aroundthe MgO crystals. A 98 percent MgO grain conta1ns less silicate, but the silicate is stilllocated around the crystals. The 97 percent MgOgrain wIth a higjer CaOjSi02 ratio containsSIlicate as concentrated areas and not as a film
. around MgO crystals. Reflected light, X52.(3)
7 ComparIson of chemical compositions of peri- 23clase brick used wit~ and without pitch.(3)
8 Schematic of wear of indicated brick typ~s.(3) 25
9 Illustration of wetting of pores of brick 25with and ~ithout carbon.(3)
. ,10 Relative slag erosion versus density of peri- 28
clase brIck made wIth indicated pitches.(3)
11 Effect of heat treatment of pitch on crystal- 28linity of carbon residue.(3)
12
13
14
Typical wear pattern of BOF lining.(38)
Relation of residual carbon content and relative slag erosion for indicated temperedpericlase and magnesite brick.(3)
Typical zonal lining of BOF.(38)
28
36
36
"
~r
) 0-
,FIGURE -
TITLE PAGE"
15 Lining number versus lining life.(3) 42
16 Frequency curves of turndown 'temperature on 42. BOF campaigns;(23)~.
17 Effect of S.i. and Ti contents of toni on 42lining 1if(>.(3)
\
18 Schematic diagram of furnace. 51.'~ 4
19 Temperature profile' of furnace at 1600°C 54
20 Specimen temperature and heating and cooling 61. <
schedule.
Figures 21 to 60 inclusive are located at the end of the thesis.
21"
22
Carbon-ftec magne'si te brick sPecimens I from left: I
after immersion in ma:;ter slag (46% CaO, 30% Si02,17/0 FeD) aDd '7% MnO) fnr 20) 40, 60, 80 and 100minutes in t~at order. '
Carbon-fr('~~ magnesIte bli ~k specimens, from leftfresh specimen, and th0se 01 5 minute immersionIn slags, A, 0, C, L, c;.n, H, J, K, L, N, P, Q andR in that order (Table·5, page 58, for slag compo-sition). '
23
24
Partially sectioned carbon-free magnesite brickspecimens, from left~ fresh specimen, and those ofSO second lmmersion in slags A, B, C, D, E, F, G,H, J, K, L, N, P, Q and R in that orqer (Table 5,pag~ 58, for slag composition)...
•Partially sectioned carbon~free magnesite brickspecimens, from left, fresh specimen, and those~f
5 minute immersion in slags'A, B; C, D, E, F, a, H,J, K, L, N. P, Q and R in that order (Table 5, page58, for slag composition).
"
25
'. I
26
27
Carbon-free magnes~te brick speci~ens reacted at1550°C, from left, after 5 minute immersion in slagsA, C and F; partially sectioned specimens after 30seconds in slags A, C and F; and partially sectioned
.sp€cimens after S'rninutes in slags A, C and F: slag A(master slag),~~~ag C (10% A120S), ahd slag F (15%'A1 20S-8% MgO): -
Speci~~n e~ongation an4 slag climb vs. s!ag composition.~
Slag p~netration vs. slag composition.
FIGURE~
28
29
30
•31
TItLE
Magnesite brick fragments which remained in slag D(15% A1203) for ano~her'30 minutes at 1600°C after5 minute immersion test; dark areas are slag phasesand'MgO grains have suffered slag penetration alongthe subgrain boundarie~ (13X).
Photomicrographs (33X) of as-received burned magnesitebrick; (a) in plain light and (b) under crossed nicols:P, periclase; 8, silicate; V, pore.
Thin sectlon photograph (4.2X) of carbon-free specimenafter 5 minute immersion in slag A (master slag);brown regions are slag-penetrated matrix and lightareas are void spaoes .
Thin section photograph (4.2X) of carbon-free specimenafter 5 minute, immersion in slag K (8% MgO); brownregions are slag-penetrated matrix and light areasare void spaces. w
32 Thin section photograph (4.12X) of carbon-free specimenafter 30 seconds immersion in slag C {lO% A1203);brown regions are slag-penetrated matrix and lightareas are void spaces.
33 Ca-Al-si1icate compound (dendrites) developed in thematrix of carbon-free brick specimen after 5 minuteimmersion in slag C (84X).
34 ' Thin section photograph (4.2X) of carbon-free specimenafter 5 minute immersion in slag F (15% A1203-8% ·MgO);brown regions are slag-penetrated matrix and lightareas are void spaces. The thin section has been madefrom the portion remaining in the specimen holder.
35- Thin section photograph (4.2X) of carbon-free specimenafter 5 minute, immersidn in slag G (10% A1203-13% MgO);brown regions are slag-penetrated matr~x and lightareas are void spaces:
36 Ca-Al-silicate compound (dendrites) developed in thematrix of carbon-free brick specimen after 5 minuteimmersion in slag G (84X).
37 Thin section photograph (4.2X) of carbon-free specimenafter 5 minute immersion in Fe203-containing slag P(46% CaO, 30% 8i02, 17% Fe203, 7% MnO): brown'regionsare slag-penetrated 'matrix and light areas are voidspaces.
FIGURE TITLE
38 Thin section photograph (4.2X) of carbon-free specimen~a>-j;.ter 5 rllinute immersion in Fe203 sla.g Q (10% A1202):brown regions are slag-penetrated matrix and lightareas Are void spac0s. The thin section has been madefrom the portion remaining in the holder.
39 Thin section microphotograph (84X) showing dendriticcrystallization in the matrix of cylindrical carbonfree brick specimen after 5 minute immersion in Fe203slag Q (10% A1203).
40 Thin section photograph (4.2X) of cylindrical carbonfree specimen after 30 second immersion in Fe203 slagR (15% AI203-8% MgO): brown regions are slag-penetratedmatrix and light areas are void spaces.
41 Thin section photograph (4.2X) of carbon-free specimenafter 30 second immersion in slag N (CaO/Si02 ~ 1);brown regions are slag-penetrated matrix and lightareas are void spaces.
42 Monticellite (CMS) d~veloped in t~e matrix of carbonfree brick specimen after 5 minute immersion in slag N(CaOjSi02 =1); 84X ..
43 Thin section photographs (4.2X) of cylindrical carbonfree brick specimen which has been withdrawn by standardprocedure after 30 second immersion in slag H; (a) inplain light and (b) under crossed nicols .. Brown regionsare Fe- and Mn-rich slag-penetrated outer layer. Brightareas are the matrix penetrated mainly by silicate ofslag.
44 Thin section photographs (4.2X) of cylindrical carbonfree brick specimens which have been withdra\m immediately after (a) 30 second and (b) 5 minute immersionsin slag G (10% A1203-l3% MgO).
45 Composite strip charts~of electron microprobe analysisover cross-sections of cylindrical carbon-free brickspecimens; ea) as-received and (b) after 30 secondimmersion in slag H (distance from the surface of thespecimen) .
46 Cross-sections of carbon-bearing brick cruciblestested in air atmosphere for 2 hours, from left, withoutslag, with slags C, F and N at 1600°C and with slag Vat 1650°C in that order.
47 Cross-sections of carbon-bearing brick cruciblestested at 1600°C in air atmosphe~e for 2 hours, fromleft, without slag and with siags T and U in that order.
xiii
--
..
II< •
. ,.
FIGURE
48
TITLE
Cross-sections of carbon-bJaring brick cruciblestested at 1600°C for 30 minutes in graphite container,from left. without slag and with slags A, D and H inthat order.
50
-
49 Thin section photograph (4.2X) of pitch~impregnatcd
magnesite brick coked in a graphite container at 1600°Cfor 30 minutes.
Thin section photograph (4.2X) of crucible wall madeof carbon-bearing magnesite brick maintained in airatmosphere at l600°C for 2 hours; carbon-bearingceqtral region is ~urrounded by light decarburizedzones an~ thin white layers are noticed at the'boundaries between these two regions.
51 Carbon-bearing magnesite brick crucibles reacted inair atmosphere for 2 hours with slag N (a) andslag C (b) at 1600°C and.slag V (c) at l650°C.
52 Thin section photomicrographs (33X) of carbon-bearingbrick crucibles reacted in air atmosphere for 2 hourswith (a) slag N (CaO/S102 = 1) (.b) slag C (CaO/Si02 = 1.5)at 1600°C and (c) slag V (CcaO/SiOZ = 2) at 1650°C.
53 Thin section photographs (4.2X) of sectioned cruciblewall made of carbon-bearing brick reacted with (a)irap oxide-free slag T (10% AlZ03) and (b) U.(15% AlZ038% MgO) in air atmosphere at l600°C for 2 hours.
54 Thin section photographs (4.2X) of sectioned cruciblewall made of carbon-bearing brick reacted with slag D(15% Al z0 3 ) in graphite container at 1600°C for 30minutes; (a) in plain light and (b) under crossed nicols.
55 Composite strip charts of microprobe analysis over apitch-impregnated magnesite brick sample coked at 1600~C
for 30 minutes in a graphite container (distance fromthe surface of the specimen).
56 Composite strip charts of microprobe analysis over acarbon-bearing magnesite brick sample tested in airatmosphere at 1600°C for Z hours (distance is fromthe surface o~ the specimen).
57 Composite strip charts of microprobe analysis alongthe line GHI of Figure 51(b) over a well-defined denseMgO layer formed in a carbon-bearing magnesite brick /crucible reacted with slag C in air atmosphere at1600°C for 2 hours; slag, right and refractory, left.