2012 Volume 52 Issue 3 Pages 378-384
The aim of this present paper was to systematically optimize and determine the mass ratio of two organic active fractions (fulvic acid and humic acid) in a type of novel organic binder (named Modified Humic Acid (MHA)) developed in China for iron ore pelletizing. The experimental data demonstrated that the mass ratio of Na-HA to Na-FA had an obvious influence on the performance of MHA binders. The drop number of green pellets grew to reach a plateau of 11.7 times when the mass ratio of Na-HA to Na-FA was increased to 7:3. Obviously, the crushing strength of dried and fired pellets was increased with the increase of mass ratio of Na-HA to Na-FA. Especially, dried or preheated pellets remarkably increased their crushing strength after the mass ratio of 6:4. From these results, the optimum mass ratio Na-HA to Na-FA in MHA binders for iron ore palletizing was concluded to be 7:3. The pelletizing performance of MHA binders could be undoubtedly improved by optimizing the mass ratio of Na-HA to Na-FA. The explanation for improving the pelletizing performance of MHA binders by optimizing the mass ratio of two fractions lies in that the influencing factors (acidic groups and viscosity) for deciding the pelletizing performance of MHA binders can be optimized and balanced by changing mass ratio of Na-HA to Na-FA. The reason for that mechanical strength of fired pellets was influenced by mass ratio of active fractions in MHA binders, was considered to be attributed to the thermal stability difference of active fractions.
