In order to make corundum castables satisfy more severe service conditions in high temperature industries,colloidal alumina due to the same main component with corundum castables was introduced for a pure binding syst...In order to make corundum castables satisfy more severe service conditions in high temperature industries,colloidal alumina due to the same main component with corundum castables was introduced for a pure binding system.The influence of three dispersants(citric acid,FS10 and urea)on the flow ability of colloidal alumina bonded corundum castables was researched to choose a suitable dispersant for solving the shaping problem.In order to further understand the influence of dispersants on the flow ability and the mechanism,the rheological property and Zeta potential value of the colloidal aluminadispersant system and the matrix-colloidal alumina-urea-water system were tested.The results show the castables added with the urea have the best flow ability,and the appropriate addition of the urea is 0.5%.展开更多
In order to improve the flow ability and early-stage strength of colloidal alumina bonded corundum castables,the colloidal alumina with 20%of solid content was used as the binder,and tabular corundum aggregates and fi...In order to improve the flow ability and early-stage strength of colloidal alumina bonded corundum castables,the colloidal alumina with 20%of solid content was used as the binder,and tabular corundum aggregates and fines,and active alumina micropowder CL370 as the main starting materials.Influences of setting accelerating agents(magnesia fines and sodium meta-aluminate)on the linear change rate,the modulus of rupture and the microstructure of corundum castables after different heat-treatments were researched.The results show(1)cement bonded corundum castables have the highest modulus of rupture after 24 h of demolding,and colloidal alumina bonded corundum castables have the lowest one;both magnesia fines and sodium meta-aluminate can improve the strength after 24 h of demolding;(2)after firing at 1000℃for 3 h,the modulus of rupture of all specimens decreases,even lower than that after 24 h of demolding;(3)after firing at 1600℃for 3 h,the castable specimen added with 0.1 mass%magnesia fines has the highest modulus of rupture;the tabular phases appear interwovenly in the specimen;(4)taking the comprehensive properties into account,0.1 mass%of magnesia fines is appropriate,and the addition of sodium meta-aluminate shall be lower than 0.3%.展开更多
Self-propagating high-temperature synthesis (SHS) with reduction process was used to fabricate TiB2 powder from TiO2-B2O3-Mg system. The colloidal alumina-bonded TiB2 paste was prepared and coated on the cathode carbo...Self-propagating high-temperature synthesis (SHS) with reduction process was used to fabricate TiB2 powder from TiO2-B2O3-Mg system. The colloidal alumina-bonded TiB2 paste was prepared and coated on the cathode carbon blocks. Various properties of the baked paste such as the corrosive resistance, thermal expansion and wettability were tested. Experimental results showed that the colloidal alumina-bonded TiB2 coating could be well wetted by liquid aluminum; and the thermal expansion coefficient of the coated material was 5.8x10(-6) degreesC(-1) at 20-1000 degreesC, which was close to that of the traditional anthracite block cathode (4x10(-6) degreesC(-1)); the electrical resistivity was 8 mu Omega (.)m at 900 degreesC when the content of alumina in the coated material was about 9% in mass fraction. In addition, some other good results such as sodium resistance were also reported.展开更多
文摘In order to make corundum castables satisfy more severe service conditions in high temperature industries,colloidal alumina due to the same main component with corundum castables was introduced for a pure binding system.The influence of three dispersants(citric acid,FS10 and urea)on the flow ability of colloidal alumina bonded corundum castables was researched to choose a suitable dispersant for solving the shaping problem.In order to further understand the influence of dispersants on the flow ability and the mechanism,the rheological property and Zeta potential value of the colloidal aluminadispersant system and the matrix-colloidal alumina-urea-water system were tested.The results show the castables added with the urea have the best flow ability,and the appropriate addition of the urea is 0.5%.
文摘In order to improve the flow ability and early-stage strength of colloidal alumina bonded corundum castables,the colloidal alumina with 20%of solid content was used as the binder,and tabular corundum aggregates and fines,and active alumina micropowder CL370 as the main starting materials.Influences of setting accelerating agents(magnesia fines and sodium meta-aluminate)on the linear change rate,the modulus of rupture and the microstructure of corundum castables after different heat-treatments were researched.The results show(1)cement bonded corundum castables have the highest modulus of rupture after 24 h of demolding,and colloidal alumina bonded corundum castables have the lowest one;both magnesia fines and sodium meta-aluminate can improve the strength after 24 h of demolding;(2)after firing at 1000℃for 3 h,the modulus of rupture of all specimens decreases,even lower than that after 24 h of demolding;(3)after firing at 1600℃for 3 h,the castable specimen added with 0.1 mass%magnesia fines has the highest modulus of rupture;the tabular phases appear interwovenly in the specimen;(4)taking the comprehensive properties into account,0.1 mass%of magnesia fines is appropriate,and the addition of sodium meta-aluminate shall be lower than 0.3%.
文摘Self-propagating high-temperature synthesis (SHS) with reduction process was used to fabricate TiB2 powder from TiO2-B2O3-Mg system. The colloidal alumina-bonded TiB2 paste was prepared and coated on the cathode carbon blocks. Various properties of the baked paste such as the corrosive resistance, thermal expansion and wettability were tested. Experimental results showed that the colloidal alumina-bonded TiB2 coating could be well wetted by liquid aluminum; and the thermal expansion coefficient of the coated material was 5.8x10(-6) degreesC(-1) at 20-1000 degreesC, which was close to that of the traditional anthracite block cathode (4x10(-6) degreesC(-1)); the electrical resistivity was 8 mu Omega (.)m at 900 degreesC when the content of alumina in the coated material was about 9% in mass fraction. In addition, some other good results such as sodium resistance were also reported.
