Strength variation of green pellets and pelletizing mechanism in the pelletization process of vanadium–titanium iron concentrate using organic binders

To enable low-carbon smelting of vanadium‑titanium iron ore in hydrogen-based shaft furnaces, enhancing green pellet performance via organic binders is critical, which improves the iron content and strength of the charged pellets. This work aims to study the effect of pectin, a new organic binder, on the pelletizing properties of vanadium‑titanium iron concentrates (VTIC) compared with traditional binder bentonite and carboxymethyl cellulose (CMC). Optimal binder ratios were determined as 0.2 wt% for pectin and 0.4 wt% for CMC, with corresponding pelletizing times of 11 min and 14 min, respectively. Pectin exhibited superior pelletizing performance. Herein, we analyzed the adsorption and binding mechanism of organic binders during the formation of VTIC green pellets by using the zeta potential, Fourier transform infrared spectroscopy and molecular dynamics. It was found out that pectin exhibited more suitable water absorption properties between VTIC, which contributed to higher strengths of green pellets than those obtained from the CMC. In pelletizing process, both pectin and CMC were adsorbed onto the VTIC primarily by hydrogen bonding involved in the different functional groups. Specifically, carboxyl groups for pectin and hydroxyl groups for CMC. Molecular dynamics simulation results further elucidated these adsorption processes on crystal surface. The negative effect of excessive organic binder concentration on this adsorption process is explained from the perspective of the hydrogen bond energy generated between different interfaces. • Optimized hydrophilicity enables low-ratio pectin to strengthen VTIC green pellets. • MD reveals pectin's higher adsorption energy than CMC on different minerals. • Combined MD-FTIR/Zeta to reveal aqueous-phase binder-VTIC interaction mechanism. • Excessive binder concentrations weaken adsorption, CMC shows higher H-bond sensitivity.