Preparation Of Sialon-TiNC By Using Pyrophyllite And Rutile And Its Application In Iron Runner Castable

In this work, aiming to meet the requirement for high-performance, low cost and the long-life refractory of blast furnace iron runner, Sialon-TiNC and Al2O3-SiC-TiNC composite powder were synthesized by using pyrophyllite, rutile and coke as raw materials during the carbothermal reduction and the carbothermal reduction and nitridation process. The influence of relevant technological conditions on phase was studied by thermodynamic analysis, XRD, SEM and EDS; the property of erosion resistance of Sialon-TiNC and Al2O3-SiC-TiNC composite materials was investigated and the high performance Al2O3-SiC-C iron runner castable adding Sialon-TiNC was prepared.The influence of different atmosphere (buried carbon conditions and flowing nitrogen atmosphere), different carbon content (the theoretical carbon content, exceeding 10%, exceeding 50% and exceeding 100%), different temperature range (1300～1600℃and 1400～1550℃) and the proportions of rutile on the phase composition and microstructure of the products was investigated. The results show that during the buried carbon condition the main phases in product with 10% rutile addition are corundum,β-SiC and TiN0.3C0.7 under 1600℃for 4 hours, whereas in flowing nitrogen atmosphere the main phases in product with 10% rutile addition areβ-Sialon and TiNi.7C0.3. The increasing in temperature and carbon content is beneficial for the forming ofβ-SiC andβ-Sialon. Besides, the existence of TiNC (TiN0.3C0.7 and TiN0.7C0.3) is contribute to improve the erosion resistance property of samples.The property of slag resistance of Al2O3-SiC-TiNC and Sialon-TiNC composite materials was studied. The results show that samples with different Ti content possessed high resistance to slag erosion due to the TiNC (TiN0.3C0.7 and TiN0.7C0.3) can enhance the resistance to slag erosion in samples. Particularly, samples with 10% rutile addition have the optimum performance of slag erosion resistance and oxidation resistance. The influence of Sialon-TiNC addition (0,3%,6%,9%,12%) on the physical properties at room temperature, oxidation resistance and resistance to slag erosion of Al2O3-SiC-C iron runner castable was investigated. The result shows that, the oxidation resistance and resistance to slag erosion of Al2O3-SiC-C iron runner castable containing different Sialon-TiNC addition are improved to some degrees. More specifically, the specimen with 6% Sialon-TiNC addition having optimum oxidation resistance, the thickness of oxide layer in samples treated under 1450℃is 2.77mm, while the thickness of oxide layer in sample without adding Sialon-TiNC is 5.16mm. Besides, Sialon-TiNC could prevent slag erosion and penetration to the iron runner castable. And the specimen with 6% Sialon-TiNC addition have optimum low temperature (110℃×24h) and high temperature modulous of rupture which are 7.75MPa and 7.35MPa, and cold crushing strength which are 29.53MPa and 31.83MPa, respectively. The permanent linear change of specimen treated under 1450℃is just 0.01%, and the apparent porosity is 13.86%, bulk density is 2.84g/cm3. Under the condition of experiment, Al2O3-SiC-C castable with 6% Sialon-TiNC addition possesses optimum comprehensive performance.Industrial application of Al2O3-SiC-C castable added Sialon-TiNC with optimize amount was evaluated. The result shows that Sialon-TiNC composite powder materials, obtained from easily available pyrophyllite, rutile and coke, can substitute 30wt% micropowder of the high-cost corundum, SiC and alumina in traditional Al2O3-SiC-C castable, which achieving good application effect. Because the high energy consumption corundum and SiC can be replaced by the modified cheap mineral materials, the cost for producing castable could be reduced, which means this work can provide scientific basis and a technical route for the research and development of high performance iron runner castable, and play a pivotal role in relief the bauxite resources shortage and energy conservation.