Effect of Basicity on Pelletizing Mechanism of Barium Bearing Magnetite

In this article, the effect of basicity on the compressive strength of barium bearing pellets was studied by adding a certain proportion of Ca(OH)₂ with barium bearing magnetite concentrate powder and bentonite as raw materials. The consolidation mechanism of barium bearing pellets was analyzed by means of X-ray diffrotometer, scanning electron microscope-energy spectrometer and synchronous thermal analyzer. The results show that with the increase of basicity, the compressive strength of barium-bearing pellets increases first and then decreases, and reaches the maximum value of 3 292.8 N/ pellet when the basicity is 0.8, while the porosity of pellets shows an opposite trend and the minimum porosity is 21.6%. CaO decomposed by Ca(OH)₂ reacts with Fe₂O₃ and SiO₂ respectively to form CaFe₂O₄ and CaSiO₃, and a small amount of Ca₂FeO₄ fills the pores to reduce the porosity of the pellets and increase the compressive strength. BaSO₄ is decomposed into BaO and SO₂, and BaO reacts with Fe₂O₃ to form BaFe₂O₄. SO₂ gas escapes from inside the pellet, reducing the compactness of the pellet matrix, resulting in loose and porous microstructure of the pellet.