Study On Particle Migration Of Pingguo Aluminum Ore Mud Under Negative Pressure And Its Influence On Permeability

With the development and utilization of mineral resources and the improvement of mineral processing technology,the amount of tailings slurry generated in the beneficiation process has increased year by year.The safety issues involved in this have aroused great concern from the state and relevant organizations,and the main way to deal with tailings slurry is wet discharge,but this method has caused a large amount of tailings accumulation.Due to the characteristics of small particle size,many clay particles and high moisture content,tailings mud cannot be drained and consolidated for several years or even more than ten years under natural conditions.The large amount of tailings sludge storage brings a huge burden to the surrounding ecological environment,and at the same time poses a threat to the safety of the lives and property of surrounding residents,so it is of great significance to study the method of accelerating the drainage of mineral sludge in tailings reservoirs to reduce the risk of tailings pond leakage.In this paper,the experimental slime was taken from the third-stage ore washing workshop of Pingguo Aluminum Industry.Settlement tests were carried out on the slime under different initial water content.The permeability and particle migration experiments were carried out under different negative pressure sizes,different geotextile types,different filter layer mud thickness and different layer collocation.The experimental results can provide theoretical basis for the design of negative pressure drainage system and comprehensive utilization of tailings mud in mines.The main results are as follows:（1）All forces and mechanisms should be considered when the particle size is in the range of 0.10-50.00um during migration.At 0.10-1.00um,the effect of Brownian diffusivity should be mainly considered.The effects of hydrodynamic force,gravity and inertia should be mainly considered at 10.00-50.00um.The particle size of 0.10～10.00μm is the transition range from colloids to suspended particles.（2）The initial moisture content has a great influence on the settling and delamination effect of mineral mud.With the increase of the initial moisture content of mineral mud,the delamination law of mineral mud gradually becomes obvious.When the initial moisture content of mineral mud is 240%,obvious three-delamination phenomenon appears after the settlement of mineral mud is stable,so the initial moisture content of mineral mud settling and delamination limit W₀=240%;When the initial water content W₀≥300%,the particle size of the slime is stratified into four layers,and the particles with a particle size above 0.7um have obvious stratification characteristics.（3）There are four different stages in the process of ore mud infiltration and migration under the action of negative pressure,which are:mud compaction stage,seepage channel formation stage,seepage channel gradually plugging stage,and the stage where seepage flow rate and permeability coefficient tend to be stable.（4）Through the time of the peak occurrence of seepage and the increase rate of each factor on the seepage flow,the influence of each factor on the water output and permeability coefficient of the sludge is the type of geotextile,the size of negative pressure,the thickness of the filter layer,and the interlayer matching.（5）During the experiment,the fine sludge particles formed flocs due to adsorption,so the particle size of the upper sludge loss particles was mainly concentrated in the range of 0.75-2um,and the sludge particles of the remaining particle groups also had a small amount of migration.The increase of negative pressure in the experimental system can increase the maximum particle lost by the upper sludge.The difference in particle size between the upper and lower layers of sludge can be reduced,which can reduce the maximum particle size lost.Thickening of the geotextile reduces the maximum particle size lost.