The effect of machine parameters and the composition of additives in the pelletization process on the physical and mechanical properties of pellets in Se Chahoon Pelletization, Bafgh

Pelletization is a technique in which fine particles of iron ore concentrate are gradually mixed with lime and an adhesive (bentonite or fondue cement). These products are called raw pellets. These pellets must have standard metallurgical properties. Also, to prevent crushing during transportation, it must have sufficient physical and mechanical properties. In this research, the parameters affecting the pelletizing process, including the speed and rotation angle of the balling disc, the moisture content, the type and combination of the adhesive used, and the optimal conditions for the production of pellets with the desired dimensional characteristics and mechanical properties were determined. Bentonite and a combination of bentonite and Cement Fondu were used as an adhesive. The falling number and fracture strength tests were carried out on raw and dried pellets. Based on the results of the conducted experiments, the best pelletizing efficiency was recorded for a rotation angle of ۴۰ degrees relative to the horizon, a rotation speed of ۳۰ rpm, and a pelletizing duration of ۶۰ minutes in the balling disc. The optimal moisture level in the moisture testing was around ۹%. The increased bentonite content in the pellet showed an increasing/decreasing trend for the strength and falling number, and the highest strength was recorded for ۳-۴% bentonite content. The maximum compressive strength of dry pellets increased about six times compared to wet pellets with ۹% moisture content. Using a mixture of Cement Fondu and bentonite in the pellets increases the strength. Still, after baking at high temperatures, lower strength was obtained compared to that of the pellet containing bentonite. Also, according to the results, the positive effect of increased fracture strength at high temperatures for the pellets made with a combination of ۲% bentonite and ۲% Cement Fondu is far less than pellets made with ۳% bentonite and ۱% Cement Fondu, while the same pellet showed an opposite result at ambient temperature.