This work explored the way to improve hot modulus q/' rupture (HMOR) and refractoriness under load (RUL) by adding mild-calcined coal gangue (MCG) in Al2O3 -SiO2 ultra low cement (ULC) castables, making use o...This work explored the way to improve hot modulus q/' rupture (HMOR) and refractoriness under load (RUL) by adding mild-calcined coal gangue (MCG) in Al2O3 -SiO2 ultra low cement (ULC) castables, making use of the in-situ effect of the MCG during heating-up. The influence of respective additions of 5%, 10% and 1.5% of the MCG powders calcined at 700℃ was investigated on HMOR at 1400 ℃ and RUL of the castables. With increased addition of the MCG, HMOR and RUL become significantly enhanced. At 10% of the MCG addition, HMOR reaches 3 MPa, as compared to 0. 3 MPa in the case of no MCG addition. RUL of the specimens dried at 110 ℃for 24 h can be increased by some 270 ℃ with 10% of the MCG addition. RUL 0.11 the specimens preheated at 1 500℃ for 3 h maintains the growth trend with the MCG addition increasing. The microstructure of the heated castable samples was investigated by means of SEM. The in-situ formed needle-like and interlaced mullite in the matrix is contributive to the tmprovement.展开更多
B4C was added into the low-carbon MgO-C materials in order to improve the oxidation resistance. The results show adding 0. 3wt% B4C can get the best oxidation resistance and adding 0. 2 wt% B4C can get the highest hot...B4C was added into the low-carbon MgO-C materials in order to improve the oxidation resistance. The results show adding 0. 3wt% B4C can get the best oxidation resistance and adding 0. 2 wt% B4C can get the highest hot modulus of rupture. Altogether, adding 0. 2wt% B,C into the low-carbon MgO-C materials can get better oxidation resistance and hot strength.展开更多
In order to improve the properties of alumina-carbon refractories,specimens were prepared using white fused corundum,zirconia-mullite and flake graphite as the raw materials,phenolic resin as the binder,adding differe...In order to improve the properties of alumina-carbon refractories,specimens were prepared using white fused corundum,zirconia-mullite and flake graphite as the raw materials,phenolic resin as the binder,adding different mass fractions(1.5%,2.0%,and 2.5%,respectively)of glass dust,cold isostatic pressing by 120 MPa,drying and firing at 900℃for 3 h.Effects of the glass dust addition on the apparent porosity,bulk density,cold modulus of rupture,hot modulus of rupture and thermal shock resistance were studied.The results show that the cold modulus of rupture of the specimens is improved significantly as the results of glass dust accelerating sintering.However,the hot modulus of rupture decreases.As the glass phase buffers the strain produced by thermal shock,the thermal shock resistance of alumina-carbon specimens is improved,especially for low carbon alumina-carbon materials.展开更多
Ferrotitanium slag(FS)is a waste slag produced during the smelting of ferrotitanium alloys by thermite reduction.Its alumina content is high and can be used as alumina raw material.Iron runner castables containing dif...Ferrotitanium slag(FS)is a waste slag produced during the smelting of ferrotitanium alloys by thermite reduction.Its alumina content is high and can be used as alumina raw material.Iron runner castables containing different amounts of FS were prepared and characterized.The results show that the introduction of FS is beneficial to the sintering of the castables sample.When the FS concentration is 11.2 wt.%,the aggregate and matrix of the castables sample have a good combination,and the mechanical strength of the Al_(2)O_(3)–SiC–C castable reaches a maximum at room temperature.However,excessive introduction of FS generates a large amount of anorthite phase,which reduces the mechanical strength of the Al_(2)O_(3)–SiC–C castable at room temperature.In addition,the high-melting phase CaTiO_(3)is formed in FS,which has good mechanical properties.Meanwhile,the cracks of FS are reduced,and the combination between phases is closer,thus significantly improving the hot modulus of rupture of the castable.When the FS concentration is not above 33.6 wt.%,the castables show good slag resistance.The TiO_(2)in FS is transformed into TiC by carbothermal reaction,which is enriched at the boundary and prevents further reaction of the slag.展开更多
文摘This work explored the way to improve hot modulus q/' rupture (HMOR) and refractoriness under load (RUL) by adding mild-calcined coal gangue (MCG) in Al2O3 -SiO2 ultra low cement (ULC) castables, making use of the in-situ effect of the MCG during heating-up. The influence of respective additions of 5%, 10% and 1.5% of the MCG powders calcined at 700℃ was investigated on HMOR at 1400 ℃ and RUL of the castables. With increased addition of the MCG, HMOR and RUL become significantly enhanced. At 10% of the MCG addition, HMOR reaches 3 MPa, as compared to 0. 3 MPa in the case of no MCG addition. RUL of the specimens dried at 110 ℃for 24 h can be increased by some 270 ℃ with 10% of the MCG addition. RUL 0.11 the specimens preheated at 1 500℃ for 3 h maintains the growth trend with the MCG addition increasing. The microstructure of the heated castable samples was investigated by means of SEM. The in-situ formed needle-like and interlaced mullite in the matrix is contributive to the tmprovement.
文摘B4C was added into the low-carbon MgO-C materials in order to improve the oxidation resistance. The results show adding 0. 3wt% B4C can get the best oxidation resistance and adding 0. 2 wt% B4C can get the highest hot modulus of rupture. Altogether, adding 0. 2wt% B,C into the low-carbon MgO-C materials can get better oxidation resistance and hot strength.
基金National Natural Science Foundation of China (51772277)the National Key R&D Program of China (2017YFB0304000)
文摘In order to improve the properties of alumina-carbon refractories,specimens were prepared using white fused corundum,zirconia-mullite and flake graphite as the raw materials,phenolic resin as the binder,adding different mass fractions(1.5%,2.0%,and 2.5%,respectively)of glass dust,cold isostatic pressing by 120 MPa,drying and firing at 900℃for 3 h.Effects of the glass dust addition on the apparent porosity,bulk density,cold modulus of rupture,hot modulus of rupture and thermal shock resistance were studied.The results show that the cold modulus of rupture of the specimens is improved significantly as the results of glass dust accelerating sintering.However,the hot modulus of rupture decreases.As the glass phase buffers the strain produced by thermal shock,the thermal shock resistance of alumina-carbon specimens is improved,especially for low carbon alumina-carbon materials.
基金supported by the National Natural Science Foundation of China(52002295 and 52172023).
文摘Ferrotitanium slag(FS)is a waste slag produced during the smelting of ferrotitanium alloys by thermite reduction.Its alumina content is high and can be used as alumina raw material.Iron runner castables containing different amounts of FS were prepared and characterized.The results show that the introduction of FS is beneficial to the sintering of the castables sample.When the FS concentration is 11.2 wt.%,the aggregate and matrix of the castables sample have a good combination,and the mechanical strength of the Al_(2)O_(3)–SiC–C castable reaches a maximum at room temperature.However,excessive introduction of FS generates a large amount of anorthite phase,which reduces the mechanical strength of the Al_(2)O_(3)–SiC–C castable at room temperature.In addition,the high-melting phase CaTiO_(3)is formed in FS,which has good mechanical properties.Meanwhile,the cracks of FS are reduced,and the combination between phases is closer,thus significantly improving the hot modulus of rupture of the castable.When the FS concentration is not above 33.6 wt.%,the castables show good slag resistance.The TiO_(2)in FS is transformed into TiC by carbothermal reaction,which is enriched at the boundary and prevents further reaction of the slag.