Dry Weak Magnetic Field Airflow Suspended Magnetic Separator Developed

Magnetic separation is one of mineral processing methods,which uses magnetic difference between different minerals in homogeneous to separate.Magnetic separation is easy to run,economical and effective,so was widely used in ferrous metal ore separation,non-ferrous and rare metal ore separation,medium recovery in heavy medium separation,remove iron impurities from non-metallic mineral to protect crusher and other equipment,scrap steel recovery from steel slag and remove pollutants form sewage of production and livelihood.Magnetic separator can be divided into dry and wet magnetic separator according to election media.The latter is the most extensive application of magnetic separator.Domestic ores are "poor,small,complex",many mines located in drought or cold areas,water resources shortage and more attention to environmental protection. In these conditions,develop a new type dry magnetic separator which in line with actual situation,can separate fine ore,minimize pollution damage to he water has economic and social significance.Dry weak magnetic field air suspension magnetic separator selected minerals for fine.In the way of feed ore in lower part and particles enter sorting room under the air, fine be separated because of force and move trails in dispersed state.The equipment composed by feeding,wind,plumb,separation,power and mining systems.This paper studied the force and motion state of fine suspended in air,analyzed the movement of fine in vertical and curved pipe,studied the force of magnetic and non-magnetic(or weakly magnetic)particles in magnetic field and got their trajectory. This paper developed the dry weak magnetic field air suspension magnetic separator, and used the device made mineral test.Test showed that the efficiency was good. According to the results,dry weak magnetic field air suspension magnetic separator as a new dry separator can be widely used in mineral separation.1.In the magnetic processing,the role mineral subjected was magnetic and mechanical,different magnetic particles along different paths due to different magnetic role.The movement trails of magnetic and non-magnetic(or weakly magnetic)particles was determined by the ratio of magnetic and all mechanical role on particles.2.NdFeB permanent magnetic materials was widely used because of high magnetic properties,good mechanical properties,lower prices,no strategic metal such as cobalt,nickel.This study made a reasonable distribution of NdFeB and ferrite, achieved a magnetic line which improved the magnetic properties significantly and meet sorting requires.3.The force of fine mineral suspended in the air suffered including dray resistance of air on the particles,gravity,buoyancy,pressure gradient force,Magnus effect lift,Saffman lift,quality of the false,Basset force,point of contact,and particles in the pipeline also suffered the centrifugal force.4.This paper studied the force state of particles in the separation.First stage was particles vertical moved in the air,second stage was particles entered in magnetic field initially,third stage was particles separated in magnetic field.5.Particles in suspended state made different movement trails because of their different size,quality,shape,density,volume,mutual friction role of mineral particles and changes of velocity gradient,so as to provide the conditions of separation.6.In this paper,the numerical analysis of particles movement in the equipment was made.This paper derived the trajectory equation of mineral group suspended in the air at vertical pipe in the absence of external magnetic field.Analyzed the force state of single particle move in the elbow,got the relationship of time and distance from the bottom-up to the stability.Studied the relationship of speed changes with the time and distance of the particles in the suspended state of from the level to vertical rise pipe,got the relationship equation.Studied the particles speed relation with the time and distance of non-magnetic ore tablets in the state of from level to vertical pipe. Established trajectory equation in the Lagrangian coordinates of particles in the processing using Newton's second law. 7.This paper developed the suspension magnetic separator according to the principles,and analyzed the magnetic material selection,the magnetic properties of magnetic field,the selection of grinding equipment,the design of plumb and separation interval,the selection of equipment of rotor speed control and the design of mine system,and finally identified the components of the equipment and system structure parameters.8.In this paper,made the mineral separation experiments used the dry magnetic separator.Through studied the relationship of air pressure of air system,feed volume of mineral,magnetic separation regional structure and separation effect,determined the best conditions for the election,and in these conditions made a mineral separation test.9.This paper compared the mineral test results of suspension dry magnetic separator and wet drum separator,and made a conclusion.In the same conditions such as particles size range,the feed volume of ore and magnetic field strength,the suspension dry magnetic separate compared to wet magnetic separate,concentrate grade is lower 1.91%and concentrate recovery is higher 0.61%.It had two reasons for the test differences of suspended dry magnetic separate and wet magnetic separate. Firstly,water is wet magnetic separation medium,in the wet processing,the particles made a magnetic roller sports under the changed magnetic field of water and magnetic lines of magnetic turn,these made part of gangue minerals was cleared out,so enhanced the concentrate product quality.In suspended dry magnetic,the particles also made a magnetic roller sports under the magnetic lines of magnetic turn,but airstream's "elimination" is below to the water's "elimination".Secondly,in the wet magnetic separation,non-magnetic(or weakly magnetic)minerals under the influence of water and their own gravity into the bottom of the groove,and then drained,so less risk of being entrained again.In the suspension dry magnetic processing,the non-magnetic(or weakly magnetic)minerals was upward in the airflow,downward direction of its gravity,the more risk of being entrained again in effect of turbulence, so the concentrate indicators declined.