Dispersion And Coagulation Mechanism Of Silica Coupling Agent On Colloidal Silica Bonded Alumina Castables

In order to overcome the drawback of low green mechanical strength of colloidal silica bonded castables,the effect of KH-570 on the coagulation and dispersion mechanism of colloidal silica bonded alumina castables was studied based on the investigation of its hydrolysis mechanism,at the same time,the properties of the colloidal silica bonded alumina castables with KH-570 addition were also investigated and the results indicate that:?1?Compared with KH-550 and KH-560,KH-570 is more suitable as a coagulant for colloidal silica bonded alumina castables to ensure the necessary installation performance and improved green mechanical strength at the early stage.?2?There is a relatively larger hydrolysis degree of KH-570 and the lower condensation degree of hydrolysis products in a mix medium of water and ethanol with the mass ratio of 5:1.When KH-570 is hydrolyzed in colloidal silica,its hydrolyzed product can undergo polycondensation reaction with colloidal silica particles,and in turn accelerate the hydrolysis of KH-570.At the same time,the hydrolysis of KH-570 can also have a significant effect on the gelation process of colloidal silica.?3?Colloidal silica bonded alumina castables show better flow ability when the addition amount of KH-570 was 0.6wt%¹.2wt%of colloidal silica,and its flow ability can reach 215mm with 0.9wt%of KH-570.Cold moduls of rupture and cold curshing strength of samples after treated at 50°C and 110°C are significantly increased to 6Mpa,8.5Mpa and 45Mpa,75Mpa,respectively.The structure of the castables is optimized and the apparent porosity and D₅₀?median diameter?have been significantly reduced,which caused a good slag resistance.In additon,KH-570 plays a significant role in promoting the sintering of colloidal silica bonded alumina castables.The colloidal silica bonded castables performs higher sintering strength when adding more KH-570.