Two types of low carbon MgO - C refractories with 6% graphite were prepared using microporous magnesiarich spinel （5 - 3 and 3 - 1 mm ） and fused magnesia （5 - 3 and 3 - 1 mm ） as coarse aggregates, respectively, ...Two types of low carbon MgO - C refractories with 6% graphite were prepared using microporous magnesiarich spinel （5 - 3 and 3 - 1 mm ） and fused magnesia （5 - 3 and 3 - 1 mm ） as coarse aggregates, respectively, fused magnesia （ ≤1 mm） as fine aggregate, magnesia powder （≤ 0. 088 mm ） , flake graphite powder （ ≤0. 088 mm）, metal Al powder （ 〈0. 074 mm） as matrix, and phenol resin as binder. After curing at 220 ℃ and coke-embedded firing at 1 500 ℃ , the apparent porosity, cold crushing strength, cold modulus of rupture, permanent linear change on heating, thermal shock resistance and slag resistance of the specimens were studied comparatively. The results indicate that： （ 1 ） after curing at 220 ℃ and coke-embedded firing at 1 500 ℃, the specimen with microporous magnesia-rich spinel replacing fused magnesia has lower bulk density and higher apparent porosity than the common low car- bon MgO - C specimen. After curing at 220 ℃, the specimen with microporous aggregate has lower strength than common low carbon MgO - C specimen, but after coke-embedded firing at 1 500℃, it has higher strength and lower permanent linear change on heating; （2） low carbon MgO - C specimen using microporous magnesia-rich spinel to replace fused magnesia aggregate has better thermal shock resistance but worse slag resistance.展开更多
This work intends to provide a comprehensive review on the development of Al_(2)O_(3)-C refractories with low/ultra-low carbon content.It covers three parts:carbon materials,microstructure optimization of the refracto...This work intends to provide a comprehensive review on the development of Al_(2)O_(3)-C refractories with low/ultra-low carbon content.It covers three parts:carbon materials,microstructure optimization of the refractory matrix by ceramic phases,and application of metal Al as raw material.Carbon black,expanded graphite,and ultrafine microcrystalline graphite,as price-competitive carbon materials,can be chosen to prepare the low-carbon Al_(2)O_(3)-C refractories after some special treatment.Ni/Co/Fe-catalyzed phenolic resin contributes to improving the properties of the low-carbon Al_(2)O_(3)-C refractories.The performance deterioration of the low-carbon Al_(2)O_(3)-C refractories can also be improved by in-situ formed or pre-synthesized ceramic phases.Metal Al,characterized by plasticity forming,acceleration of sintering,oxidation resistance,and high reactivity,can be used as raw materials to completely replace graphite,and the prepared resin bonded Al-Al_(2)O_(3)based refractories are one novel development direction of the ultra-low carbon Al_(2)O_(3)-C refractories.展开更多
The low cost and high efficient clean steels metallur- gy has been focused much attention in China. Among the factors affecting the cleanliness and consequent quali- ty of steel products, refractories are one of the k...The low cost and high efficient clean steels metallur- gy has been focused much attention in China. Among the factors affecting the cleanliness and consequent quali- ty of steel products, refractories are one of the key fac- tors. Meanwhile the restriction of resource, energy and environment is getting stronger, thus the improvement of refractories becontes much more important. In this paper, refractories selection principle Jbr clean steel production according to their thermodynamic features was ex- plained; refractories for tundLsh and flow control in con- tinuous casting, which play important roles in prohibi- ring secondary contamination of molten steel, were intro- duced. Moreover, new development of low-carbon and carbon-free refractory materials was also described.展开更多
文摘Two types of low carbon MgO - C refractories with 6% graphite were prepared using microporous magnesiarich spinel （5 - 3 and 3 - 1 mm ） and fused magnesia （5 - 3 and 3 - 1 mm ） as coarse aggregates, respectively, fused magnesia （ ≤1 mm） as fine aggregate, magnesia powder （≤ 0. 088 mm ） , flake graphite powder （ ≤0. 088 mm）, metal Al powder （ 〈0. 074 mm） as matrix, and phenol resin as binder. After curing at 220 ℃ and coke-embedded firing at 1 500 ℃ , the apparent porosity, cold crushing strength, cold modulus of rupture, permanent linear change on heating, thermal shock resistance and slag resistance of the specimens were studied comparatively. The results indicate that： （ 1 ） after curing at 220 ℃ and coke-embedded firing at 1 500 ℃, the specimen with microporous magnesia-rich spinel replacing fused magnesia has lower bulk density and higher apparent porosity than the common low car- bon MgO - C specimen. After curing at 220 ℃, the specimen with microporous aggregate has lower strength than common low carbon MgO - C specimen, but after coke-embedded firing at 1 500℃, it has higher strength and lower permanent linear change on heating; （2） low carbon MgO - C specimen using microporous magnesia-rich spinel to replace fused magnesia aggregate has better thermal shock resistance but worse slag resistance.
文摘This work intends to provide a comprehensive review on the development of Al_(2)O_(3)-C refractories with low/ultra-low carbon content.It covers three parts:carbon materials,microstructure optimization of the refractory matrix by ceramic phases,and application of metal Al as raw material.Carbon black,expanded graphite,and ultrafine microcrystalline graphite,as price-competitive carbon materials,can be chosen to prepare the low-carbon Al_(2)O_(3)-C refractories after some special treatment.Ni/Co/Fe-catalyzed phenolic resin contributes to improving the properties of the low-carbon Al_(2)O_(3)-C refractories.The performance deterioration of the low-carbon Al_(2)O_(3)-C refractories can also be improved by in-situ formed or pre-synthesized ceramic phases.Metal Al,characterized by plasticity forming,acceleration of sintering,oxidation resistance,and high reactivity,can be used as raw materials to completely replace graphite,and the prepared resin bonded Al-Al_(2)O_(3)based refractories are one novel development direction of the ultra-low carbon Al_(2)O_(3)-C refractories.
文摘The low cost and high efficient clean steels metallur- gy has been focused much attention in China. Among the factors affecting the cleanliness and consequent quali- ty of steel products, refractories are one of the key fac- tors. Meanwhile the restriction of resource, energy and environment is getting stronger, thus the improvement of refractories becontes much more important. In this paper, refractories selection principle Jbr clean steel production according to their thermodynamic features was ex- plained; refractories for tundLsh and flow control in con- tinuous casting, which play important roles in prohibi- ring secondary contamination of molten steel, were intro- duced. Moreover, new development of low-carbon and carbon-free refractory materials was also described.
