Lightweight alumina-silica castables were prepared using closed-cell perlite(2-4 mm),open-cell perlite(4-6 mm)and coal gangue ceramsites(2-5 mm)as aggregates,floating beads(0.3-0.5 mm),sinking beads(0.6-0.8 mm),silica...Lightweight alumina-silica castables were prepared using closed-cell perlite(2-4 mm),open-cell perlite(4-6 mm)and coal gangue ceramsites(2-5 mm)as aggregates,floating beads(0.3-0.5 mm),sinking beads(0.6-0.8 mm),silica micropowder,α-Al_(2)O_(3) micropowder,zirconia and zircon micropowder as fines,and Secar 71 cement(calcium aluminate cement)as the binder.The effects of the coal gangue ceramsites addition(0,6%,12%,18%and 24%,by mass)on the properties of the as-prepared lightweight alumina-silica castables were investigated.The results show that:(1)the addition of coal gangue ceramsites can reduce the sintering shrinkage of the specimens and help to improve the strength and thermal shock resistance;(2)the samples with the addition of coal gangue ceramsites can produce pores in the matrix of the sintered samples,which provides enough space for the growth of CA6 complex solid solution and expands the irregular lamellar structure;(3)with the addition of coal gangue ceramsites increasing,the linear shrinkage of the samples heat treated at 1000 or 1200℃firstly reduces and then increases,the bulk density increases and the apparent porosity decreases;the cold compression strength and the thermal shock resistance of the specimens heat treated at 1200℃firstly increase and then decrease.Thus,the optimal addition of coal gangue ceramsites is 18%.展开更多
Alumina-silica composite coatings were prepared on the surface of graphite paper by CVD using AlCl3/SiCl4/H2/CO2 as precursor in the temperature range of 300 to 550℃. XRD and SEM were used to examine the phase comp...Alumina-silica composite coatings were prepared on the surface of graphite paper by CVD using AlCl3/SiCl4/H2/CO2 as precursor in the temperature range of 300 to 550℃. XRD and SEM were used to examine the phase composition and the microstructure of the coating, respectively. The results indicate that the dense, uniform and adherent alumina-silica composite coating can be prepared on graphite paper substrate by CVD at 550℃ using SiCl4/AlCl3/CO2/H2. The alumina-silica composite coating is composed of a number of spherical particles. Each particle is composed of a number of fine-particle. The phase of the 550℃ composite coating includes γ-alumina containing amorphous silica. The content of Cl element in composite coating decreases with the increase of the deposition temperature. The analysis results of morphology and growth mechanisms of the CVD alumina-silica indicate that the condensation within the boundary layer will be more likely to lead to the formation of gel-particles. The gel-particles size decreases with the increase of deposition temperature in the range of 300550℃. Surface reaction is the main path to generate deposition products at 550℃.展开更多
Baivumebo iron ore is special magnetite containing fluorine,kalium and sodium elements,and the main raw material for ironmaking of Baotou Iron and Steel(Group) Co.The effects of basicity and ratio of Al2O3 to SiO2(...Baivumebo iron ore is special magnetite containing fluorine,kalium and sodium elements,and the main raw material for ironmaking of Baotou Iron and Steel(Group) Co.The effects of basicity and ratio of Al2O3 to SiO2(A/S) on the formation of silico-ferrite of calcium and aluminium(SFCA) in Baivumebo low silica sinters were studied by means of mini-sintering,XPF-500 optical mineralogical microscope and CSS-88000 electronic universal testing machine.The results show that it is beneficial to the formation of complex calcium ferrite to enhance the basicity of Baivumebo low silica sinters.The acicular SFCA-I was increased with the enhancing basicity and reached the peak at basicity 2.8,then the columnar or platy SFCA formed and the bonding strength decreased.Alumina is beneficial to the formation of acicular complex calcium ferrite in Baivumebo low silica sinters.But the residual unfused Al2O3 reagent came into being when A/S was 0.35,while complex calcium ferrite still remained to be acicular.There is a common rule about mineralogy components affected by basicity and ratio of A/S,that is,SFCA is increasing accompanied with hematite and porosity reduced,but the content of glass phase is stable展开更多
研究了无有机胺醇水体系低硅铝比ZSM-5沸石的绿色合成方法。在无有机胺模板剂和不加晶种的醇水体系中,一步合成了形貌均一的小晶粒聚集体低硅铝比ZSM-5沸石,考察了合成体系中各配料的含量以及晶化温度对合成低硅铝比ZSM-5沸石的影响。利...研究了无有机胺醇水体系低硅铝比ZSM-5沸石的绿色合成方法。在无有机胺模板剂和不加晶种的醇水体系中,一步合成了形貌均一的小晶粒聚集体低硅铝比ZSM-5沸石,考察了合成体系中各配料的含量以及晶化温度对合成低硅铝比ZSM-5沸石的影响。利用XRD、FTIR、SEM、N_(2)吸附-脱附、^(27)Al MAS NMR和^(29)Si MAS NMR等方法对合成的ZSM-5沸石进行表征。实验结果表明,当n(Si)∶n(Al)=20,n(Na_(2)O)∶n(SiO_(2))=0.071,n(C_(2)H_(5)OH)∶n(SiO_(2))=1.77,晶化温度为160℃时,可合成具有高结晶度的纯相ZSM-5沸石。^(27)Al MAS NMR表征结果显示,合成的ZSM-5沸石主要含有骨架四配位铝,无非骨架铝。合成的ZSM-5沸石的比表面积和微孔孔体积分别为384 m^(2)/g和0.14 cm^(3)/g,总酸量达到789μmol/g,骨架n(Si)∶n(Al)=14.4。展开更多
文摘Lightweight alumina-silica castables were prepared using closed-cell perlite(2-4 mm),open-cell perlite(4-6 mm)and coal gangue ceramsites(2-5 mm)as aggregates,floating beads(0.3-0.5 mm),sinking beads(0.6-0.8 mm),silica micropowder,α-Al_(2)O_(3) micropowder,zirconia and zircon micropowder as fines,and Secar 71 cement(calcium aluminate cement)as the binder.The effects of the coal gangue ceramsites addition(0,6%,12%,18%and 24%,by mass)on the properties of the as-prepared lightweight alumina-silica castables were investigated.The results show that:(1)the addition of coal gangue ceramsites can reduce the sintering shrinkage of the specimens and help to improve the strength and thermal shock resistance;(2)the samples with the addition of coal gangue ceramsites can produce pores in the matrix of the sintered samples,which provides enough space for the growth of CA6 complex solid solution and expands the irregular lamellar structure;(3)with the addition of coal gangue ceramsites increasing,the linear shrinkage of the samples heat treated at 1000 or 1200℃firstly reduces and then increases,the bulk density increases and the apparent porosity decreases;the cold compression strength and the thermal shock resistance of the specimens heat treated at 1200℃firstly increase and then decrease.Thus,the optimal addition of coal gangue ceramsites is 18%.
文摘Alumina-silica composite coatings were prepared on the surface of graphite paper by CVD using AlCl3/SiCl4/H2/CO2 as precursor in the temperature range of 300 to 550℃. XRD and SEM were used to examine the phase composition and the microstructure of the coating, respectively. The results indicate that the dense, uniform and adherent alumina-silica composite coating can be prepared on graphite paper substrate by CVD at 550℃ using SiCl4/AlCl3/CO2/H2. The alumina-silica composite coating is composed of a number of spherical particles. Each particle is composed of a number of fine-particle. The phase of the 550℃ composite coating includes γ-alumina containing amorphous silica. The content of Cl element in composite coating decreases with the increase of the deposition temperature. The analysis results of morphology and growth mechanisms of the CVD alumina-silica indicate that the condensation within the boundary layer will be more likely to lead to the formation of gel-particles. The gel-particles size decreases with the increase of deposition temperature in the range of 300550℃. Surface reaction is the main path to generate deposition products at 550℃.
基金Sponsored by Inner Mongolia Science Foundation of China(2009MS0702)
文摘Baivumebo iron ore is special magnetite containing fluorine,kalium and sodium elements,and the main raw material for ironmaking of Baotou Iron and Steel(Group) Co.The effects of basicity and ratio of Al2O3 to SiO2(A/S) on the formation of silico-ferrite of calcium and aluminium(SFCA) in Baivumebo low silica sinters were studied by means of mini-sintering,XPF-500 optical mineralogical microscope and CSS-88000 electronic universal testing machine.The results show that it is beneficial to the formation of complex calcium ferrite to enhance the basicity of Baivumebo low silica sinters.The acicular SFCA-I was increased with the enhancing basicity and reached the peak at basicity 2.8,then the columnar or platy SFCA formed and the bonding strength decreased.Alumina is beneficial to the formation of acicular complex calcium ferrite in Baivumebo low silica sinters.But the residual unfused Al2O3 reagent came into being when A/S was 0.35,while complex calcium ferrite still remained to be acicular.There is a common rule about mineralogy components affected by basicity and ratio of A/S,that is,SFCA is increasing accompanied with hematite and porosity reduced,but the content of glass phase is stable
文摘研究了无有机胺醇水体系低硅铝比ZSM-5沸石的绿色合成方法。在无有机胺模板剂和不加晶种的醇水体系中,一步合成了形貌均一的小晶粒聚集体低硅铝比ZSM-5沸石,考察了合成体系中各配料的含量以及晶化温度对合成低硅铝比ZSM-5沸石的影响。利用XRD、FTIR、SEM、N_(2)吸附-脱附、^(27)Al MAS NMR和^(29)Si MAS NMR等方法对合成的ZSM-5沸石进行表征。实验结果表明,当n(Si)∶n(Al)=20,n(Na_(2)O)∶n(SiO_(2))=0.071,n(C_(2)H_(5)OH)∶n(SiO_(2))=1.77,晶化温度为160℃时,可合成具有高结晶度的纯相ZSM-5沸石。^(27)Al MAS NMR表征结果显示,合成的ZSM-5沸石主要含有骨架四配位铝,无非骨架铝。合成的ZSM-5沸石的比表面积和微孔孔体积分别为384 m^(2)/g和0.14 cm^(3)/g,总酸量达到789μmol/g,骨架n(Si)∶n(Al)=14.4。