铝硅比对烧结成矿特性及冶金性能的影响

 Al₂O₃和SiO₂是复合铁酸钙的重要组分,适宜的铝硅比是获得良好烧结成矿特性和冶金性能的重要条件。基于某钢厂现场烧结原料结构,运用FactSage理论计算了烧结体系的平衡物相组成及液相组分变化规律,随着铝硅比由0.41降至0.34,烧结矿中液相、铁氧化物等优质物相含量增加,尖晶石等劣质物相含量下降,且液相中析出复合铁酸钙逐渐增多。试验揭示了不同铝硅比对烧结矿产质量、物相组成、微观结构及冶金性能的影响规律,结果表明,随着铝硅比由0.41降低到0.34,烧结矿转鼓强度、成品率、利用系数等指标显著改善,分别由58.27%、60.24%、1.585 t/(m2·h)提高至61.73%、71.87%、2.185 t/(m2·h)。矿相分析表明,随着铝硅比降低,铁酸钙含量增加并逐步向针状发展,赤铁矿、磁铁矿及孔洞含量降低,并在铝硅比为0.34时达到最佳物相组成,该结果佐证了烧结矿产质量指标变化规律。铝硅比为0.34时烧结矿冶金性能比基准烧结矿冶金性能提升,其中还原度和低温还原粉化指数RDI>3.15 mm分别由73.11%、72%提升至77.47%、80%,软化温度区间和熔滴温度区间变窄,熔滴性能总特性值S也有下降趋势,烧结矿软熔性改善明显。根据理论计算及试验结果,提出的优化配矿建议对提高烧结矿产质量、优化烧结工艺具有重要的意义。

Effect of w(Al2O3)/w(SiO2)on sintered ore mineralization characteristics and metallurgical properties

Al₂O₃ and SiO₂ are important components of composite calcium ferrite, and an appropriate ratio of alumina to silica is an important condition for obtaining good sintering ore-forming characteristics and metallurgical properties. Based on the on-site sintering raw material structure of a steel plant, the FactSage theory was used to calculate the change law of equilibrium phase composition and liquid phase composition for the sintering system. As the ratio of alumina to silica decreased from 0.41 to 0.34, the high-quality phases such as liquid phase and iron oxide in the sinter increased, the content of inferior phases such as spinel decreased, and the liquid phase precipitates and SFCA gradually increased. The experiment revealed the influence of different ratio for alumina to silica on the quality, phase composition, microstructure and metallurgical properties of sinters. The results showed that as the ratio of alumina to silica decreased from 0.41 to 0.34, the drum strength, yield and utilization factor of sinters improved significantly, from 58.27%, 60.24%, 1.585 t/(m2·h) to 61.73%, 71.87%, and 2.185 t/(m2·h), respectively. The mineral phase analysis shows that as the ratio of alumina to silica decreases, the content of calcium ferrite increases and gradually develops into acicular shape, while the content of hematite, magnetite and pores decreases, and the optimal phase composition is reached when the ratio of alumina to silica is 0.34. This result corroborates the change rule of sintered ore quality index. When the ratio of alumina to silica is 0.34, the metallurgical performance of sinter is improved compared with the benchmark sinter. The reduction degree and reduction degradation property index RDI>3.15 mm are increased from 73.11% and 72% to 77.47% and 80% respectively, the softening temperature range and the droplet temperature range are narrowed, the total characteristic value S of the droplet performance also has a downward trend, and the soft melting property of sinter is improved significantly. According to the theoretical calculation and test results, the optimization of ore blending is of great significance for improving the quality of sintered minerals and optimizing sintering process.