| Aiming at the present situation of Al2O3-SiC-C vibration castables for BF trough in China, the environment-friendly self-flow castable for BF trough with excellent performance,which is combined by sialon,has been successfully developed by adding sialon pioneer body material Si3N4 instead of C.The effects of additions of micropowder, cement, various dispersant and, Si3N4 and B4C on the performance of castables have been investigated. The emphasis is put on the effects of addition of Si3N4 on physical properties of the specimens.The mechanisms of Sialon-boned self flowing castables with excellent physical properties and slag resistance have been analyzed by XRD and SEM. On the above basis, the effects of B4C addition on the performance of BF trough castables has been studied. The results show that : the flow value of self-flowing castable is about 185mm with additions of 13% alumina powder, 4% silica powder, 3% cement, 6 %Si3N4, 0.4%B4C,and suitable sodium hexametaphosphate as dispersant; With addition of Si3N4,the bulk density and strength at the room temperature first increases and then decreases, subsequently the apparent porosity first decreases and then increases. The optimum amounts is 3% to 6%; The mechanism of slag resistance of the castables is due to poor wettability of Si3N4 to iron melt. Sialon produced is difficult to oxidize and acts as new bonding phase contributing to direct bonding between solid phases. So the slag resistance of the materials is improved. With addition of B4C , B4C within specimens will be oxidized to produce B2O3 during the rising of temperature and melts into liquidous states at medium temperature promoting sintering of the specimen. So the strength of the materials is enhanced. Moreover, the boron-containing glass phase production during reaction will form a layer of dense oxidation film on the surface of materials inhibiting further oxidizing. The optimum addition of B4C is suggested to be 0.4% under the experimental conditions. |
PDF Full Text Request