The microporous corundum material was prepared using alumina micro-powder as the main raw material, alumina sol and starch as binders by a wet process, achieving the bulk density of 3.05 g · cm^-3, the apparent p...The microporous corundum material was prepared using alumina micro-powder as the main raw material, alumina sol and starch as binders by a wet process, achieving the bulk density of 3.05 g · cm^-3, the apparent porosity of 9. 1%, the closed porosity of 12.3%, the median pore diameter of 0. 43 μm, and the thermal conductivity of 6. 5 W· m^-1· K^-1 at 800 ℃ which is 41.6% lower than that of common corundum. The slag resistance of the microporous corundum material was studied by immersion and compared with that of the common corundum aggregate, and the slag resistant mechanism of microporous corundum material was revealed. The results show that the slag resistance of the microporous corundum material is superior to that of the common corundum aggregate, the SEM and EDX show that on the reaction interface between microporous corundum and molten, slag, a continuous isolation layer with a large quantity of CA2 and CA6 columnar crystals is formed; while the common corundum aggregate reacts with the molten slag interface to form a discontinuous isolation layer of columnar crystals, through which a lot of molten slag corrodes or permeates into the aggregate. The mechanism is mainly that the microporous structure is more advantageous to nucleation and growth of CA2 and CA6 columnar crystals; in the reaction with the aggregate, the molten slag gets saturated and the critical solution thickness of the microporous corundum and the common corundum is 0. 16 μm and 0. 34 μm, respectively, this is caused by the smaller microporous corundum aggregate pores; and the smaller pores also increase the second phase ripening rate of microporous corundum, which is 9. 7 times of that of the common corundum.展开更多
Magnesia zirconia brick containing 11 wt% zirconia was prepared with magnesia and monoclinic zirconia as starting materials in order to replace the chrome-containing materials for Rtt furnace. The corrosion resistance...Magnesia zirconia brick containing 11 wt% zirconia was prepared with magnesia and monoclinic zirconia as starting materials in order to replace the chrome-containing materials for Rtt furnace. The corrosion resistance of magnesia zirconia brick and fused rebonded magnesia chrome brick （short for magnesia chrome brick） to high, and low basicity slag of RH fitrnace was comparatively researched by rotary slag method and their slag resistance mechanisms were analyzed. The results show that： （1） because the reaction layer containing CaZrO3 forms in magnesia zirconia brick, it has better corrosion resistance to high basicity slag than magnesia chrome brick, however, it has worse corrosion resistance to low basicity slag than magnesia chrome brick; （2） ZrO2 in the magnesia zirconia brick can absorb CaO in the slag, which decrea- ses the basicity of slag and inereases the viscosity of slag, so the degree of slag penetration in magnesia zircon.ia brick decreases ; （ 3 ） there is little zirconia in the slag layer of residual nutgnesia zirconia brick;from working face to original brick layer, the residual magnesia zirconia brick shows three layers： obviotasly deteriorative layer, slightly deteriorative layer, and original brick layer, but the residual magnesia chrome brick only shows two layers ： obviously deteriorative layer and original brick layer; the SiO2 content of residual magnesia zirconia brick is the highest in the slightly deteriorative layer, however, the SiO2 content of residual magnesia chrome brick gradually decreases front working face to original brick layer.展开更多
Low cement Al2O3 - SiO2 castables was prepared using super grade bauxite （ w（ Al2O3 ） 〉85% ） as aggregate, brown fused corundum, silicon carbide, Secar 71 CA cement, α-Al2O3 micropowder and microsilica as fine p...Low cement Al2O3 - SiO2 castables was prepared using super grade bauxite （ w（ Al2O3 ） 〉85% ） as aggregate, brown fused corundum, silicon carbide, Secar 71 CA cement, α-Al2O3 micropowder and microsilica as fine powders. The influence of SiC （0, 5 wt%, 10 wt%, and 15 wt% ）on resistance to PbO- rich slag was investigated by static crucible slag test （1 300℃ for 5 h, in air）. The slag corrosion mechanism of the castables was analyzed by means of SEM, EDS and XRD. The results show that the resistance of Al2O3 -SiO2 castables to PbO-rich slag is improved obviously by the addition of SiC. The corrosion mechanism of the PbO-rich slag can be discribed as that PbO in the slag reacts with SiO2 and CaO in Al2O3 - SiO2 castables, forming low-melting compounds （such as PbO · SiO2 and 2PbO · SiO2 ）.展开更多
基金Financial supports from the National Natural Science Foundation of China(Nos.51474165 and 51204126)
文摘The microporous corundum material was prepared using alumina micro-powder as the main raw material, alumina sol and starch as binders by a wet process, achieving the bulk density of 3.05 g · cm^-3, the apparent porosity of 9. 1%, the closed porosity of 12.3%, the median pore diameter of 0. 43 μm, and the thermal conductivity of 6. 5 W· m^-1· K^-1 at 800 ℃ which is 41.6% lower than that of common corundum. The slag resistance of the microporous corundum material was studied by immersion and compared with that of the common corundum aggregate, and the slag resistant mechanism of microporous corundum material was revealed. The results show that the slag resistance of the microporous corundum material is superior to that of the common corundum aggregate, the SEM and EDX show that on the reaction interface between microporous corundum and molten, slag, a continuous isolation layer with a large quantity of CA2 and CA6 columnar crystals is formed; while the common corundum aggregate reacts with the molten slag interface to form a discontinuous isolation layer of columnar crystals, through which a lot of molten slag corrodes or permeates into the aggregate. The mechanism is mainly that the microporous structure is more advantageous to nucleation and growth of CA2 and CA6 columnar crystals; in the reaction with the aggregate, the molten slag gets saturated and the critical solution thickness of the microporous corundum and the common corundum is 0. 16 μm and 0. 34 μm, respectively, this is caused by the smaller microporous corundum aggregate pores; and the smaller pores also increase the second phase ripening rate of microporous corundum, which is 9. 7 times of that of the common corundum.
文摘Magnesia zirconia brick containing 11 wt% zirconia was prepared with magnesia and monoclinic zirconia as starting materials in order to replace the chrome-containing materials for Rtt furnace. The corrosion resistance of magnesia zirconia brick and fused rebonded magnesia chrome brick （short for magnesia chrome brick） to high, and low basicity slag of RH fitrnace was comparatively researched by rotary slag method and their slag resistance mechanisms were analyzed. The results show that： （1） because the reaction layer containing CaZrO3 forms in magnesia zirconia brick, it has better corrosion resistance to high basicity slag than magnesia chrome brick, however, it has worse corrosion resistance to low basicity slag than magnesia chrome brick; （2） ZrO2 in the magnesia zirconia brick can absorb CaO in the slag, which decrea- ses the basicity of slag and inereases the viscosity of slag, so the degree of slag penetration in magnesia zircon.ia brick decreases ; （ 3 ） there is little zirconia in the slag layer of residual nutgnesia zirconia brick;from working face to original brick layer, the residual magnesia zirconia brick shows three layers： obviotasly deteriorative layer, slightly deteriorative layer, and original brick layer, but the residual magnesia chrome brick only shows two layers ： obviously deteriorative layer and original brick layer; the SiO2 content of residual magnesia zirconia brick is the highest in the slightly deteriorative layer, however, the SiO2 content of residual magnesia chrome brick gradually decreases front working face to original brick layer.
文摘Low cement Al2O3 - SiO2 castables was prepared using super grade bauxite （ w（ Al2O3 ） 〉85% ） as aggregate, brown fused corundum, silicon carbide, Secar 71 CA cement, α-Al2O3 micropowder and microsilica as fine powders. The influence of SiC （0, 5 wt%, 10 wt%, and 15 wt% ）on resistance to PbO- rich slag was investigated by static crucible slag test （1 300℃ for 5 h, in air）. The slag corrosion mechanism of the castables was analyzed by means of SEM, EDS and XRD. The results show that the resistance of Al2O3 -SiO2 castables to PbO-rich slag is improved obviously by the addition of SiC. The corrosion mechanism of the PbO-rich slag can be discribed as that PbO in the slag reacts with SiO2 and CaO in Al2O3 - SiO2 castables, forming low-melting compounds （such as PbO · SiO2 and 2PbO · SiO2 ）.
