The Mechanism of the Effect of Al2O3 Content on the Liquid Phase Fluidity of Iron Ore Fines

Abstract

The sintering process is significantly important for the ironmaking in China because of the large amount of sinter consumed. Al2O3 is an important element determining the quality and quantity of sinter. However, different conclusions have been made regarding the effects of Al2O3 on the amount and fluidity of the liquid phase formed in the sinter phase. Therefore, it is necessary to examine the effects of Al2O3 content on the amount and fluidity of the liquid phase. The present work investigated the effects of different Al2O3 contents of iron ore fines on the liquid phase formation, mineral composition, and consolidation strength. The results showed that a small amount of Al2O3 increased the amount of calcium ferrite, making the liquid phase formation easier. As the Al2O3 content in iron ore fines increased, the liquidity index decreased continuously, while the fluidity and the consolidation strength of the sintered body were directly related to the content squared. The quality of the sinter is optimal when the Al2O3 content of the iron ore fines is about 2 wt % (the SiO2 content is 4 wt %).

Improving High-Alumina Iron Ores Processing via the Investigation of the Influence of Alumina Concentration and Type on High-Temperature Characteristics

“…The similar SiO 2 and Al 2 O 3 contents of the sintered tablets of iron ores B and H lead to a similar SFCA amount of about 60%. Moreover, compared to the formation amount of SFCA of the sintered tablet of iron ore E with that of iron ore F, it is found that the exorbitant Al 2 O 3 content is adverse to SFCA formation on the condition of low SiO 2 content, in accordance with the results of previous investigations [9,44]. Meanwhile, the Al 2 O 3 content also affects the morphology of SFCA.…”

Effective Utilization of Limonitic Nickel Laterite via Pressurized Densification Process and Its Relevant Mechanism

“…Comparing Figure 6b with Figure 6a, it is observed that the sinter macrostructure of the pressurized densification sintering process is much denser overall while that of the traditional sintering process remains rather looser especially for the lower part. This proves that heat accumulation behavior of limonitic laterite sintering from top to bottom is extremely poorer due to the high crystal water, MgO, and Al2O3 contents, resulting in the massive loss of heat [22][23][24][25]46]. As it turned out, the poor sintering performance of the product sinter of the traditional sintering process is obtained corresponding to the results of Figure 3.…”

“…However, although many experimental tests of limonitic laterite sintering have been carried out successfully and the relevant industrial production has already been achieved in Chinese research institutions and stainless-steel enterprises, the poor sintering performance of limonitic laterite remains a bottleneck to smooth production [17][18][19]. This is principally because the high crystal water (>30%) and LOI (>10%) contents of limonitic laterite contribute to the formation of highly porous loose sinter [20][21][22][23], and the massive existence of high-melting-point minerals, such as Al 2 O 3 , MgO, and Cr 2 O 3 is deleterious to liquid-phase flowing, leading to the substantial increase of solid fuel consumption [24][25][26][27]. Meanwhile, compared with ordinary iron ores, limonitic laterite possesses rather lower total iron content (40-50%), indicating the limited amount of liquid bonding phases [28][29][30][31]; all of which eventually lead to a poor tumble index (<50%), low productivity (<1.0 t•m −2 •h −1 ), and high solid fuel rate (>140 kg/t) of a product sinter of limonitic laterite.…”