Operating condition and service results of several tested bricks in slagline area of the VOD vessel are described. It has been shown that the fully co-clinkered magnesite chrome brick is superior, followed by two-stag...Operating condition and service results of several tested bricks in slagline area of the VOD vessel are described. It has been shown that the fully co-clinkered magnesite chrome brick is superior, followed by two-stage calcined magnesite-dolomite brick , prereacted magnesite-chrome brick and one-stage calcined magnesite-dolomite brick. Chemical and petrological examination were carried out by conventional analysis and optical microscope respectively. The reason of damage of the tested bricks are discussed and described as follows : (1) MgO in brick is erased and dissolved by slag to destroy structure of the direct bond ; (2) slag penetrating into the brick and then reacting with it to form various belts leading to spatting ; (3 ) reducing action of reducing agents ; (4) vaporization of some composition in the brick at high temperature under vacuum causes reducing weight and increasing porosity and (5 ) serious ma-chanic abrasion. Therefore, some opinions on increasing lining life of VOD vessels are suggested.展开更多
Dissolution kinetics of magnesitic-dolomite and magnesite-chrome refractories in secondary steelmaking slags was studied by means of the rotating cylinder method under forced convection. Materials investigated include...Dissolution kinetics of magnesitic-dolomite and magnesite-chrome refractories in secondary steelmaking slags was studied by means of the rotating cylinder method under forced convection. Materials investigated include four magnesitic-dolomite samples（MgO content 40% to 93%）and two magnesite-chrome samples （co-clinkered and semi-rebonded）.Synthetic slags simulative of VOD and AOD slags with varying basicity （0.6-2.68） are used.The experiments are carried out in Ar atmosphere at different temperatures （1 600 ℃-1 750 ℃） and revolution speeds （200 r·min^-1 to 500 r·min^-1）.The microstructure of specimens （before and after slag tests） are studied by optical microscopy, SEM and EPMA. Based on our experimental results the mechanism and kinetics of the dissolution process are discussed.展开更多
The corrosion resistance of four kinds magnesitechrome bricks against converter salg was investigated by static crucible slag tests. The microstructures of the asdelivered and tested refractories were analyzed by mean...The corrosion resistance of four kinds magnesitechrome bricks against converter salg was investigated by static crucible slag tests. The microstructures of the asdelivered and tested refractories were analyzed by means of SEM and EDS. The results showed that： Different magnesite-chrome bricks have different slag resistances. Generally, the slag resiantance sequence is as follows： rebounded fused magnesite-chrome brick 〉 semi-reboun- ded magnesite-chrome brick 〉 direct-bonded magnesitechrome brick 〉 silicate bonded magnesite-chrome brick. Slag reacts with the periclase of magnesite-chrome refractories, which results in the dissoving of periclase in fayalite slag. However, the complex spinels have superior slag resistance.展开更多
JC 497-92 (96)1 Contents and Applied ScopeThis standard specifies the classification, shapes and dimensions, technical requirements, test methods, inspection rules, marking, packing, transportation, storage and qualit...JC 497-92 (96)1 Contents and Applied ScopeThis standard specifies the classification, shapes and dimensions, technical requirements, test methods, inspection rules, marking, packing, transportation, storage and quality certificate of direct-bonded magnesite-chrome bricks for building materials industry. This standard is applicable to the direct-bonded magnesite-chrome bricks for cement kiln, glass melting tank and other industrial furnaces.2 Normative ReferencesGB 2997: Test method for the apparent porosity, water absorption, bulk density and true porosity of dense shaped refractory productsGB 5070: Chemical analysis method for magnesite-Chrome refractoriesGB 5072: Test method for cold crushing strength of dense shaped refractory productsGB 5989: Test method for refractoriness under load of dense shaped refractory products (Differential, with rising temperature)GB 7320: Test method for thermal expansion of refractory productsGB 7321: Sample preparation for testing of dense shaped refractory productsGB 10324: Type definition of refractory productsGB 10325: Piling, sampling, acceptance, storage and transportation of refractory products展开更多
文摘Operating condition and service results of several tested bricks in slagline area of the VOD vessel are described. It has been shown that the fully co-clinkered magnesite chrome brick is superior, followed by two-stage calcined magnesite-dolomite brick , prereacted magnesite-chrome brick and one-stage calcined magnesite-dolomite brick. Chemical and petrological examination were carried out by conventional analysis and optical microscope respectively. The reason of damage of the tested bricks are discussed and described as follows : (1) MgO in brick is erased and dissolved by slag to destroy structure of the direct bond ; (2) slag penetrating into the brick and then reacting with it to form various belts leading to spatting ; (3 ) reducing action of reducing agents ; (4) vaporization of some composition in the brick at high temperature under vacuum causes reducing weight and increasing porosity and (5 ) serious ma-chanic abrasion. Therefore, some opinions on increasing lining life of VOD vessels are suggested.
文摘Dissolution kinetics of magnesitic-dolomite and magnesite-chrome refractories in secondary steelmaking slags was studied by means of the rotating cylinder method under forced convection. Materials investigated include four magnesitic-dolomite samples（MgO content 40% to 93%）and two magnesite-chrome samples （co-clinkered and semi-rebonded）.Synthetic slags simulative of VOD and AOD slags with varying basicity （0.6-2.68） are used.The experiments are carried out in Ar atmosphere at different temperatures （1 600 ℃-1 750 ℃） and revolution speeds （200 r·min^-1 to 500 r·min^-1）.The microstructure of specimens （before and after slag tests） are studied by optical microscopy, SEM and EPMA. Based on our experimental results the mechanism and kinetics of the dissolution process are discussed.
文摘The corrosion resistance of four kinds magnesitechrome bricks against converter salg was investigated by static crucible slag tests. The microstructures of the asdelivered and tested refractories were analyzed by means of SEM and EDS. The results showed that： Different magnesite-chrome bricks have different slag resistances. Generally, the slag resiantance sequence is as follows： rebounded fused magnesite-chrome brick 〉 semi-reboun- ded magnesite-chrome brick 〉 direct-bonded magnesitechrome brick 〉 silicate bonded magnesite-chrome brick. Slag reacts with the periclase of magnesite-chrome refractories, which results in the dissoving of periclase in fayalite slag. However, the complex spinels have superior slag resistance.
文摘JC 497-92 (96)1 Contents and Applied ScopeThis standard specifies the classification, shapes and dimensions, technical requirements, test methods, inspection rules, marking, packing, transportation, storage and quality certificate of direct-bonded magnesite-chrome bricks for building materials industry. This standard is applicable to the direct-bonded magnesite-chrome bricks for cement kiln, glass melting tank and other industrial furnaces.2 Normative ReferencesGB 2997: Test method for the apparent porosity, water absorption, bulk density and true porosity of dense shaped refractory productsGB 5070: Chemical analysis method for magnesite-Chrome refractoriesGB 5072: Test method for cold crushing strength of dense shaped refractory productsGB 5989: Test method for refractoriness under load of dense shaped refractory products (Differential, with rising temperature)GB 7320: Test method for thermal expansion of refractory productsGB 7321: Sample preparation for testing of dense shaped refractory productsGB 10324: Type definition of refractory productsGB 10325: Piling, sampling, acceptance, storage and transportation of refractory products
