Fundamental Research On The Activation Of Vanadium Titanomagnetite By High Pressure Roller Mill And Strengthening The Preparation Of Pellet

Iron ore pellets have significant advantages in improving blast furnace burden structure and energy conservation.Improving pellet output and quality is an important development direction for iron and steel enterprises to realize low-carbon production.At present,it is of great significance to use complex iron ore resources to prepare high-quality pellets in China.There are many smelting problems in vanadium titanium magnetite pellets.In this paper,the basic research on the preparation of vanadium titanium magnetite pellets strengthened by high pressure roller grinding was carried out with vanadium titanium magnetite as raw material.The main conclusions are as follows:It is found that the specific surface area of vanadium titanomagnetite increases after high-pressure roll grinding,and the particle size distribution obviously shifts to the fine-grained distribution.When the pressure of high-pressure roll grinding increases from 6 MPa to 14 MPa,the average particle size decreased from 60.26μm without roller grinding to 52.48μm and34.67μm respectively.With the continuous refinement of particle size,the number of small particles attached to large particles gradually increases,the shape of particles changes from block to strip and flake,and the increase of internal cracks of particles makes new fracture surfaces appear.The unsaturated bonds and charged structural units attached to the new surface are conducive to improving the adsorption capacity of materials and the spheroidization of vanadium titanium magnetite.The influence of high pressure roller mill on the mineral distribution characteristics and crystal structure of vanadium titanium magnetite is revealed.After high-pressure roller grinding,the dispersion degree and degree of freedom of ilmenite and magnetite increase,and the degree of association with other minerals decreases gradually.Taking Fe₃O₄ as the main phase in vanadium titanomagnetite as the research object,the height of XRD diffraction peak of Fe₃O₄ decreases,the half peak widens,the grain size decreases,the crystal distortion occurs and the crystal distortion rate increases.Under the action of high-pressure roller grinding mechanical force,the lattice is distorted and dislocated to form unstable metastable phase.The degree of amorphous increases gradually with the increase of high-pressure roller grinding pressure.The activation of vanadium titanomagnetite shows that the gibbs surface excess free energy,grain boundary energy,dislocation energy and amorphous activation energy show an increasing trend,and the total energy storage gradually increases from 13.35 k J/mol to 25.01 k J/mol.The mechanism of strengthening the quality of vanadium titanomagnetite pellets by high pressure roller grinding was found out.The high-pressure roller mill improves the particle size inside the pellet.The particle size refinement is conducive to improve the degree of particle recrystallization.At the same time,the cracks caused by crushing are conducive to the dispersion of binder phase,so as to strengthen the pellet.The pressure of high-pressure roller mill is 12 MPa,the feed moisture is kept at about 7.5%,and the compressive strength of pellets is increased from 2168 N/piece of roller mill to 3422 N/piece.44 Figures,14 Tables,95 References.