Experiment Of Pre-concentration By Permanent Magnetic Separation For Exteemely Poor Hematite In Anshan

Magnetic separation is a highly efficient method of sorting minerals which plays an extremely important role in the iron ore beneficiation.Since the advent of Nd-Fe-B permanent magnet materials,permanent magnet magnetic separation equipment has been rapidly developed.In order to improve the utilization efficiency of hematite resources,reduce the ore beneficiation cost,save energy and reduce consumption.It is of great economic and environmental significance to study the technology of permanent magnetic preconcentration about extremely poor hematite.Aiming at the large amount of extremely poor hematite resources which is currently unavailable in Anshan,this paper uses the permanent magnet strong magnetic pre-selection equipment and the high-pressure roller mill ultra-fine crushing equipment to carry out the stage pre-selection tailing test.The magnetic system of the permanent magnet strong magnetic pre-selection equipment was optimized by Ansys magnetic field simulation software.The simulation is carried out in the case where the width ratio b:a of the main magnetic pole and the magnetic guide plate are 3:1,4:1and 5:1,respectively.And the results show that as the b:a value increases,the magnetic induction intensity of the roller table changes great.It is finally determined that the b:a of the roughing roller of the dry double-roll permanent magnet pre-selective magnetic separator is 3:1,and the b:a of the sweeping roller is 4:1.The proportion of the permanent magnet roller b:a of the wet downstream permanent magnet roller type high gradient magnetic separator is 4:1.The magnetic field test is performed on the actually processed permanent magnet roller.When b:a is 3:1?magnetic pole 15mm,magnetic guide plate is 5mm?,the magnetic induction intensity of the roller table is 1.0T.What's more,the magnetic field gradient is up to5.808×10⁷A/m².If b:a is 4:1?magnetic pole 20mm,magnetic guide plate is 5mm?,the magnetic induction intensity of the roller table will be 1.25T.In addition,the magnetic field gradient is up to 5.12×10⁷ A/m².The test ore sample is the extremely poor hematite in Qidashan Iron Mine.The TFe grade is 18.25%.The main metal minerals are mainly hematite,and the gangue minerals are mainly quartz.The-15 mm ore is pre-divided into two grades of-15+3mm and-3 mm.GY-2-150×450 dry double-roller permanent magnet strong magnetic pre-selection magnetic separator?maximum magnetic induction intensity of rough roller table is 1.0T,sweeping roller table maximum magnetic induction is1.25T?.Dry tail throwing test was carried out for-15+3mm.Under the condition of1.25m/s magnetic roller speed,the grade of pre-selected concentrate iron was 23.85%,the recovery rate was 65.28%,the grade of pre-selected tailings iron was 10.49%,and the yield of tail throwing was 16.97%.The dry pre-selected concentrate was subjected to ultrafine crushing test using a?400×100 laboratory high-pressure roll mill with a roll surface pressure of 4000 kN/m²,a roll speed of 0.25 m/s,and a P₈₀ of 1.62 mm.The pulverization process uses a grading full closed pulverization process with a screen opening of 3 mm.Wet pre-selection and tailing test using SCG-150downstream wet type permanent magnet roller type high gradient magnetic separator for-3mm grain size?including-3mm product after high-pressure roll mill ultrafine crushing and-3mm pre-classified in raw ore?.Under the condition of the magnetic roller rotation speed of 0.9m/s,the concentrate grade can reach 31.44%,the recovery rate of raw ore is 75.60%,the wet preselected tailings grade is 7.20%,the comprehensive tailing grade is 8.19%,and the tailing yield is 56.12%.This paper analyzes the stress of mineral particles in permanent magnet strong magnetic preselection equipment.It is calculated that the specific magnetic forces of hematite particles in the magnetic field of rough roller and the magnetic field of sweeper roller of dry-type double-roll permanent magnet magnetic preconcentration magnetic separator are 74.15N/kg and 81.71N/kg respectively.With the above feeding method,the maximum specific magnetic force required for dry magnetic separation is 47.55N/kg.The helicite particles are subjected to a specific magnetic force of about 81.71N/kg in a wet cocurrent type permanent magnet roller type high gradient magnetic separator.The device uses the following feeding method,and the maximum specific magnetic force required for wet magnetic separation is 24.16N/kg.The specific magnetic force of the particles in both devices is greater than the specific magnetic force required for magnetic separation,so the magnetic particles can be recovered.At the same time,the mechanism of the ratio of the main magnetic pole width b to the pole gap width a on the magnetic field characteristics is explored,and the factors affecting the separation of magnetic separation equipment for PMF preselection are analyzed.This paper provides a certain research basis for the resource utilization of the extremely poor hematite in Anshan.