Study On The Effect Of Magnetization On The Flocculation Of Fine-grained Hematite

Fine-grained hematite is one of the difficult-to-select iron ore types,and it is difficult to sort due to its fine grain size.Selective flocculation is a commonly used method for processing such fine-grained iron mineral sorting process.Magnetization treatment is an effective way to improve the flocculation effect.Therefore,it is of great significance to study the magnetization treatment on the flocculation behavior of such iron ore.In this dissertation,the effects of different magnetization times and different magnetizations on the flocculation behaviors of fine-grained hematite and quartz under different magnetization patterns of magnetized pulp,magnetized chemicals and magnetized water were studied.At the same time,the combined effect of applied magnetic field and flocculant was examined.The flocculation behavior of fine-grained hematite was investigated.The changes of floc size before and after flocculation of fine-grained hematite under different magnetization methods were discussed.The main research contents and results are as follows:Pure mineral settlement test results show that starch and magnetization have no obvious effect on quartz flocculation.At the same magnetic field strength,the magnetized pulp,magnetized agent and magnetized water can increase the sedimentation rate of the fine-grained hematite compared with that of the starch only.The sizes of the enhanced strength are: magnetized water> magnetized pulp> magnetized agent.Under the same magnetization mode,the precipitation rate of fine-grained hematite increases with the increase of the magnetic field intensity of the magnetic device.Magnetic composite flocculation can significantly increase the sedimentation rate of fine-grained hematite.Compared with single polymer flocculation,magnetic composite flocculation increased the precipitation rate of fine-grained hematite by 5.7%.The results of the settlement test of the oolitic hematite show that the three magnetization methods can effectively increase the precipitation rate of the oolitic hematite.The images of the floc size under the light microscope,the statistical analysis of the density and the RBI(Relative Reflectance Index)values obtained by the PVM instrument show that the three magnetization methods can significantly promote the fine-grained hematite compared with the starch alone.The effects of the flocculation effect on the fine-grained hematite are as follows: magnetized water> magnetized pulp> magnetized agent.Zeta potential analysis,Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis show that after three magnetization methods,the Zeta potential of the fine hematite was reduced and the physical adsorption,chemical adsorption and hydrogen bonding of the starch on the hematite surface were promoted.The extended DLVO theoretical calculations show that the mechanism of magnetization on the flocculation of fine-grained hematite is that the three magnetization modes reduce the Zeta potential on the surface of the fine-grained hematite,thereby reducing the repulsive energy of the double-layered layer between the hematite particles,and promoting agglomeration of fine-grained hematite particles.