Vanadium–titanium magnetite ore blend optimization for sinter strength based on iron ore basic sintering characteristics

• The method for improving V–Ti sinter strength based on the basic sintering characteristics (BSCs) was proposed.
• The application of the method on V–Ti sinter was verified useful.
• The key factor influencing the V–Ti sinter strength was revealed.
• The principle of choosing matching ore for V–Ti sinter strength was proposed.
• The mechanism of the key factors influencing the sinter strength was analyzed.

Vanadium titanium magnetite (V–Ti) ore is one kind of important polymetallic minerals in China and the mainstream route of comprehensive utilization process is blast furnace (BF) → basic oxygen furnace (BOF). V–Ti sinter is one of the main burdens employed for BF and poor tumbler strength (TI) limits its efficiency. In order to optimize the V–Ti blends for sinter TI, the basic sintering characteristics (BSCs) of 5 kinds of V–Ti ores, 2 ordinary ores and 3 groups of optimization V–Ti blends were studied. In addition, the sinter pot tests were conducted to obtain the TI of the produced sinter. The influencing factors on assimilation temperature (AT), the relations between the 4 characteristics of BSCs, and the factors influencing the V–Ti sinter TI were analyzed. The results showed that the BSCs of 5 kinds of V–Ti ores DB, HW, YT, JL and FH were good except liquid phase fluidity characteristic index (LF). The key reason why V–Ti sinter had a poor TI was the low LF, which caused the sinter with a large-pore structure. Therefore, the matching ores for optimization V–Ti blends should have a high LF. In addition, self-strength of the bonding phase (BS) and crystal intensity (CI) had an important impact on TI when the melt formed was sufficient and meanwhile the melt had a high LF. Moreover, the proper AT was the prior factor for the melt generation. In addition, the optimization V–Ti blends had good BSCs. The sinter TI with 7% NF ore addition could meet the production requirements for its TI was higher than 65%. Totally, the method of V–Ti magnetite ore blend optimization for sinter strength based on iron ore basic sintering characteristics was useful.