Influence of Specific Surface Area on the Strength of Iron Oxidized Pellets

Blaine specific surface area (SSA) is an essential physical property of iron concentrate and is availably improved by a high-pressure grinding roller (HPGR) to enhance the pelletability and the qualities of oxidized pellets. In this study, the four concentrates with various SSA were obtained by HPGR treatment to produce the oxidized pellets. The results show that the high degree of lattice deformation corresponds to high SSA which is beneficial for improving the quality of green, preheated, and fired pellets. The compressive strength increases from 600 to 1870 N·pellet−1 for preheated pellets and increases from 2530 to 4270 N·pellet−1 for fired pellets when SSA increased from 849 cm2/g to 1601 cm2/g, under the optimal condition of preheating at 1050 °C for 12 min and firing at 1250 °C for 15 min. The oxidation of magnetite is accelerated. Low porosity and microphotographs with integrated hematite joined crystallization support the strength enhancement by high SSA.