Research On Rheological Properties Of Al₂O₃-SiC Castable Matrix And Physical Properties Of Al₂O₃-SiC Castable

Al₂O₃-SiC castable is widely used in making iron and garbage incinerator system, but the high addition of SiC in castable influences the rheological properties of castable. So it is particularly important to select the appropriate dispersant . Based on this, our experiment study the influence of dispersing agent such as AC10NP, AC10P, AC103AP, FS20, Derven7S and Compac500 on the rheological properties of SiC castable matrix. And then we work over the physical properties of three different types of SiC castable---- the 90 # SiC, 95 # SiC, 98 # SiC .This research is divided into five areas: (1) Measure the relationship between the matrix viscosity and the shear rate with the viscometer, study the effects of different dispersants on the rheological properties of Al₂O₃-SiC castable matrix. (2) Select the appropriate dispersion agent, study the effects of 90 # SiC, 95 # SiC and 98 # SiC on the rheological properties of Al₂O₃-SiC castable matrix . (3) Select the appropriate dispersant, measure the relationship between Zeta potential and the PH value byζpotential measurements, study the effects of dispersants on the PH value of 90 # SiC, 95 # SiC and 98 # SiC castable matrix. (4) Select the appropriate dispersant, study the physical properties of Al₂O₃-SiC castable, such as bulk density, apparent porosity, flexural strength, compressive strength at room temperature, alkali resistance and anti-spalling performance, etc. (5) Select the appropriate dispersant, research the effects of the addition of new type aluminate cement, CA50 alumina cement, Secar71 cement and blended cement (aluminate cement new and Secar71 cement) on the conventional physical properties, alkali resistance and slag resistance of Al₂O₃-SiC castable.The results show that:(1) Different types of dispersing agent in Al₂O₃-SiC castable have their own corresponding addition, the castable`s rheological properties changes as the dispersant type and addition changed. For 90 # SiC castable substrate, the most suitable dispersant are Derven7S and sodium tripolyphosphate, adding amount is 2wt%; for 95 # SiC castable substrate, the most suitable dispersants are FS20, Derven7S and Compac500,and the most appropriate addition of the dispersants are 0.2wt%, 0.3wt% and 0.2wt% respectively; and for 98 # SiC castable substrate, the appropriate dispersing agent is FS20, the best addition is 0.2wt%.(2) For a specified dispersant (such as FS20), the 98 # SiC substrate shows the best rheological properties , while the 90 # SiC matrix showed the worst. When the addition of SiC is 28.57wt%, the matrix show the minimum viscosity and the best rheological properties; when the SiC addition amount is 57.14wt%, the matrix show the maximum viscosity and the worst rheological properties.(3) The SiC castable matrix shows a strong alkaline, but the absolute value of Zeta potential is small . Zeta potential values gradually increased as the PH value reduced, and the three types of SiC substrates reached the maximum Zeta potential value at PH≈3.8.(4) Castable with high SiC content possess good physical properties. Samples has good anti-oxidation, anti-alkali and thermal shock resistance at 1100℃. At 800℃ 1500℃, the specimen(processed with different temperature) XRD diffraction analysis shows that, in addition to corundum and SiC, there is a small amount of mullite produced,and no formation of low communion Al-Si phase material.(5) Different types of cement combined by Al₂O₃-SiC castable usually have excellent general physical properties, good anti-alkali erosion and anti-slag corrosion performance.