Chrome oxide free refractories have significant economic benefits for the development of gasification technology.Spinel based and SiC based refractories are corroded by coal slag at 1500℃under reducing atmosphere.Mor...Chrome oxide free refractories have significant economic benefits for the development of gasification technology.Spinel based and SiC based refractories are corroded by coal slag at 1500℃under reducing atmosphere.Moreover,interactions between refractory materials and molten slag are also predicted by thermodynamic calculations under the same conditions.The results indicate that spinel based refractories are corroded by dissolution of molten slag,while SiC based refractories are corroded by oxidation of CO and FeO.Both of the spinel and SiC based refractories show good corrosion resistance against coal slag by the present experimental tests.Finally,preliminary developed spinel-SiC composite materials are prepared and corroded by coal slag as well,the research of which shows great potential to be used in slagging gasifiers.展开更多
The specimens were prepared using Cr2O3 micropowder, TiO2 micropowder and chromium powder as starting materials, PVA as binder, after spraying granulation and cold isostatic pressing, firing at 1 450 ℃ for 3 h in sta...The specimens were prepared using Cr2O3 micropowder, TiO2 micropowder and chromium powder as starting materials, PVA as binder, after spraying granulation and cold isostatic pressing, firing at 1 450 ℃ for 3 h in standard nitrogen and oxygen control atmosphere （ oxygen partial pressure was 1 010 Pa and 10. 1 Pa, respectively）. Effects of chromium powder （ mass percent were 0, 0. 5% , 1.0% , 1.5% and 2.0% , respectively） on sintering behaviors of Cr2O3 materials were researched. The results show that： adding 0. 5% chromium powder can obviously decrease the oxygen partial pressure in the specimens. Meanwhile, because the expansion caused by the oxidation reaction is small, Cr2O3 materials could realize the densifieation sintering under 1 010 Pa and 10. 1 Pa of oxygen partial pressure. The chromium powder addition in Cr2O3 materials shouldn＇t be excessive, otherwise, the expansion reaction occupies a dominant position, which deteriorates the properties of the materials.展开更多
Antioxidant and anti-inflammatory therapy approaches have been in the focus of attention in the treatment of different cancer diseases where oxidative stress has been implicated. Succinic acid has been previously repo...Antioxidant and anti-inflammatory therapy approaches have been in the focus of attention in the treatment of different cancer diseases where oxidative stress has been implicated. Succinic acid has been previously reported to possess radical scavenger, iron chelating and anti-inflammatory properties in the mouse fibroblast. The purpose of this study was to investigate potential therapeutic effects of succinic acid and possible signal pathway involved in the mouse fibroblast. We demonstrated highly potent antioxidant-radical scavenging activities of succinic acid.展开更多
Pure Cr2O3 refractories and high Cr2O3 bearing refractories are difficult to sinter in oxidizing atmosphere, but they can be sintered easily in carbon embedded conditions. In the latter case it is attributed to the fo...Pure Cr2O3 refractories and high Cr2O3 bearing refractories are difficult to sinter in oxidizing atmosphere, but they can be sintered easily in carbon embedded conditions. In the latter case it is attributed to the formation of liquid CrO in reducing atmosphere. The thermodynamic calculation shows that the Cr2O3 is reduced by CO at 1 550 ℃ to chromium carbides, which disproves the existence of liquid CrO. This is confirmed by further sintering experiment of the Cr2O3 refractories. Effect of atmosphere on sintering of high Cr2O3 bearing refractories and measures to accelerate the sintering process are discussed based on the experiment and thermodynamic calculation.展开更多
The microstructure and properties of phosphate bonded Cr2O3 - -Al2O3 - ZrO2 specimens fired in air or coke bed were investigated firstly. Then property change of the Cr2 O3 - Al2 O3 - ZrO2 bricks after secondary treat...The microstructure and properties of phosphate bonded Cr2O3 - -Al2O3 - ZrO2 specimens fired in air or coke bed were investigated firstly. Then property change of the Cr2 O3 - Al2 O3 - ZrO2 bricks after secondary treat- ment in simulation environment was studied. Finally, corrosion resistances of the Cr2 O3 - Al2 O3 - ZrO2 bricks in air and simulation environment were compared; and microstructure of on-site used Cr2O3 - Al2O3 - ZrO2 bricks in slagging gasifiers was analyzed. The results show that the atmosphere has significant effect on the mi- crostructure and properties of the phosphate bonded Cr2O3 -Al2O3 -ZrO2 bricks. As the specimens are fired in air, the phosphate forms a composite solid solution with Cr2 O3 and Al2 O3, therefore, strength of the speci- mens is enhanced. For specimens fired in coke bed, a certain amount of gases are generated owing to the re- duction of phosphate and part of Cr2 O3, which results in the increasing number and size of the pores, bad interfa- cial bonding between Cr2O3 aggregates and matrix as well as low strength of the specimens. During service process in reducing atmosphere, the phosphate binder and part of Cr2O3 in edge of the specimens are also re- duced, leading to significant increase of number and size of the pores in the edge of the specimens; as a result, inreducing atmosphere, the specimens show much worse corrosion resistance than in air.展开更多
Six kinds of Cr2O3 - Al2 O3 fused grains （the mass percent of Cr203 was 15%, 40%, 50%, 60%, 85% and 99%, respectively ） were prepared using chrome green and Al203 powder as starting materials by electro-fnsion, n...Six kinds of Cr2O3 - Al2 O3 fused grains （the mass percent of Cr203 was 15%, 40%, 50%, 60%, 85% and 99%, respectively ） were prepared using chrome green and Al203 powder as starting materials by electro-fnsion, named as CR15, CR40, CR50, CR60, CR85, and CR99, respectively. The corrosion resistance of the six kinds of Cr2O3- Al2O3.fused grains （4-1 ram） was studied using rotary slag corrosion method. The results show that： （ 1 ） the corrosion resistance of the fused grains increases with the Cr203 content and the grain size increasing; （2）the grains of CR99 and CR85 with higher Cr2O3 content are corroded at the slag surJace layer, because FeO and Al2O3. in the slag corrode the grains ; FeO reacts with Cr2O3 in the aggregates.forming （Fe, Cr ）3O4 ,spinel firstly, and the spinel reacts with other phases forming composite spinel; when FeO is fidly consumed, Al2 O3 penetrated into the grains reacts with Cr2O3 Jorming Al2O3 - Cr2O3 solid solution on the grains surface; （3） for CR60, the corrosion exists both in the slag surface layer and in the penetration layer; in the penetration layer, CaO and SiO2 react with Al2O3 in Al2O3 - Cr2O3 solid solution forming anorthite , gehlenite ,and glass phase; the grains of CR50, CR40 and CRI5 have the same corrosion mechanism with CR60 in the penetration layer.展开更多
基金This work was supported by the National Natural Science Foundation of China(U1604252).
文摘Chrome oxide free refractories have significant economic benefits for the development of gasification technology.Spinel based and SiC based refractories are corroded by coal slag at 1500℃under reducing atmosphere.Moreover,interactions between refractory materials and molten slag are also predicted by thermodynamic calculations under the same conditions.The results indicate that spinel based refractories are corroded by dissolution of molten slag,while SiC based refractories are corroded by oxidation of CO and FeO.Both of the spinel and SiC based refractories show good corrosion resistance against coal slag by the present experimental tests.Finally,preliminary developed spinel-SiC composite materials are prepared and corroded by coal slag as well,the research of which shows great potential to be used in slagging gasifiers.
文摘The specimens were prepared using Cr2O3 micropowder, TiO2 micropowder and chromium powder as starting materials, PVA as binder, after spraying granulation and cold isostatic pressing, firing at 1 450 ℃ for 3 h in standard nitrogen and oxygen control atmosphere （ oxygen partial pressure was 1 010 Pa and 10. 1 Pa, respectively）. Effects of chromium powder （ mass percent were 0, 0. 5% , 1.0% , 1.5% and 2.0% , respectively） on sintering behaviors of Cr2O3 materials were researched. The results show that： adding 0. 5% chromium powder can obviously decrease the oxygen partial pressure in the specimens. Meanwhile, because the expansion caused by the oxidation reaction is small, Cr2O3 materials could realize the densifieation sintering under 1 010 Pa and 10. 1 Pa of oxygen partial pressure. The chromium powder addition in Cr2O3 materials shouldn＇t be excessive, otherwise, the expansion reaction occupies a dominant position, which deteriorates the properties of the materials.
文摘Antioxidant and anti-inflammatory therapy approaches have been in the focus of attention in the treatment of different cancer diseases where oxidative stress has been implicated. Succinic acid has been previously reported to possess radical scavenger, iron chelating and anti-inflammatory properties in the mouse fibroblast. The purpose of this study was to investigate potential therapeutic effects of succinic acid and possible signal pathway involved in the mouse fibroblast. We demonstrated highly potent antioxidant-radical scavenging activities of succinic acid.
文摘Pure Cr2O3 refractories and high Cr2O3 bearing refractories are difficult to sinter in oxidizing atmosphere, but they can be sintered easily in carbon embedded conditions. In the latter case it is attributed to the formation of liquid CrO in reducing atmosphere. The thermodynamic calculation shows that the Cr2O3 is reduced by CO at 1 550 ℃ to chromium carbides, which disproves the existence of liquid CrO. This is confirmed by further sintering experiment of the Cr2O3 refractories. Effect of atmosphere on sintering of high Cr2O3 bearing refractories and measures to accelerate the sintering process are discussed based on the experiment and thermodynamic calculation.
文摘The microstructure and properties of phosphate bonded Cr2O3 - -Al2O3 - ZrO2 specimens fired in air or coke bed were investigated firstly. Then property change of the Cr2 O3 - Al2 O3 - ZrO2 bricks after secondary treat- ment in simulation environment was studied. Finally, corrosion resistances of the Cr2 O3 - Al2 O3 - ZrO2 bricks in air and simulation environment were compared; and microstructure of on-site used Cr2O3 - Al2O3 - ZrO2 bricks in slagging gasifiers was analyzed. The results show that the atmosphere has significant effect on the mi- crostructure and properties of the phosphate bonded Cr2O3 -Al2O3 -ZrO2 bricks. As the specimens are fired in air, the phosphate forms a composite solid solution with Cr2 O3 and Al2 O3, therefore, strength of the speci- mens is enhanced. For specimens fired in coke bed, a certain amount of gases are generated owing to the re- duction of phosphate and part of Cr2 O3, which results in the increasing number and size of the pores, bad interfa- cial bonding between Cr2O3 aggregates and matrix as well as low strength of the specimens. During service process in reducing atmosphere, the phosphate binder and part of Cr2O3 in edge of the specimens are also re- duced, leading to significant increase of number and size of the pores in the edge of the specimens; as a result, inreducing atmosphere, the specimens show much worse corrosion resistance than in air.
文摘Six kinds of Cr2O3 - Al2 O3 fused grains （the mass percent of Cr203 was 15%, 40%, 50%, 60%, 85% and 99%, respectively ） were prepared using chrome green and Al203 powder as starting materials by electro-fnsion, named as CR15, CR40, CR50, CR60, CR85, and CR99, respectively. The corrosion resistance of the six kinds of Cr2O3- Al2O3.fused grains （4-1 ram） was studied using rotary slag corrosion method. The results show that： （ 1 ） the corrosion resistance of the fused grains increases with the Cr203 content and the grain size increasing; （2）the grains of CR99 and CR85 with higher Cr2O3 content are corroded at the slag surJace layer, because FeO and Al2O3. in the slag corrode the grains ; FeO reacts with Cr2O3 in the aggregates.forming （Fe, Cr ）3O4 ,spinel firstly, and the spinel reacts with other phases forming composite spinel; when FeO is fidly consumed, Al2 O3 penetrated into the grains reacts with Cr2O3 Jorming Al2O3 - Cr2O3 solid solution on the grains surface; （3） for CR60, the corrosion exists both in the slag surface layer and in the penetration layer; in the penetration layer, CaO and SiO2 react with Al2O3 in Al2O3 - Cr2O3 solid solution forming anorthite , gehlenite ,and glass phase; the grains of CR50, CR40 and CRI5 have the same corrosion mechanism with CR60 in the penetration layer.
