Research On The Formation Mechanism And Control Methods Of Using Electricity To Control Suspension Density

Coal is the major basic energy source in China,so it is particularly important to realize the efficient and clean use of coal.As one of the important programs for the efficient and clean use of coal,dry coal preparation technology is more suitable for China and has significant research value,due to its unique advantages of no water consumption.The traditional dry sorting needs to compress air,so it is easy to pollute the environment.In addition,there are deficiencies such as low sorting efficiency,poor sorting accuracy,interference of the selected materials with the fluidized bed,and easy blocking of the gas distribution.This study proposes a new ideal of dry sorting technology.The magnetic force is firstly used to replace the drag force between the gas and particles.So that the magnetic particles are formed into a suspension with a certain density under the interaction of a magnetic force and a gravitational field.Thus materials of different densities can be separated.The main work of this article is as follows:(1)For the first time,the magnetic particles form a suspension with certain density under the interaction of magnetic force and gravity.And an exploratory test device is designed and manufactured.The effect law of magnetic field on magnetic particles was studied.Our experimental results show that magnetic particles can form a suspension with certain density under the interaction of magnetic force and gravity.Under this test platform,the suspension density changes with current intensity and frequency.(2)The formation mechanism of the suspension was preliminary explored.The analysis results show that when the magnetic force in the solenoid reaches a certain strength,its axial magnetic force is greater than the gravity.And the magnetic particles are suspended.Changing the magnetic field will affect the motion range of the particles and this volume,thereby affecting the density of the suspension.(3)The discrete element method was used to simulate analysis the motion of the particles in the suspension.A single-factor simulation test was conducted on the threefactors of magnetic field strength,frequency,and particle size.And we know the influence law of three factors on the density characteristics,fluidity,and particle motion of the suspension.(4)Taking the density uniformity and fluidity of the suspension as indicators.The orthogonal tests were conducted on magnetic field strength,frequency and particle size to seek the optimal combination.The results show that the suspension has better density characteristics,when the current density is 0.25 A,the frequency is 25 Hz,and the particle diameter is 0.3mm.This combination parameters are used to conduct a sorting test will obtained a good sorting result.It shows that the suspension has a sorting function.