Study On Curing And Water Permeability Of Iron Ore Tailings

Iron ore is a kind of discharge of waste after selecting the "useful components" andgrinding process from iron ore plant in certain economic and technological conditions.Currently, treatment methods of tailings generally can be divided into filling and stockpiling.With the amount of tailings increasing, stockpiling is becoming prevailing. Tailings have ashape of discharging sludge at the beginning and It is easy to form the natural disasters ofdebris flow. In addition, As the tailings contain more process agent and once they can be seepinto the ground, they will cause great pollution to the environment and groundwater.Therefore, It is the most important problem urgently how to secure storage of tailings andeffectively utilize waste.This paper mainly include three phases: The first stage is the curing process in order toimprove the strength and reduce mobility of the tailings with aiming at solving thestockpiling of tailings dam and the intensity of the filling. To solidify the ore powder wecarried a series of tests by adding32.5cement and admixture32.5cement and coal gangue,by contrast the flexural and compressive strength to determine the best curing recipe; Thesecond stage is to study iron tailings foaming process. In order to make the iron tailings towater-permeable, make stockpiled tailings to have a drainage capacity and avoid collapseproblems caused by excessive hydraulic pressure. We adoped physical method and chemicalmethod to foam, chemical method is directly added H2O2. To determine the optimal dosage ofPVA、Na2SO4、H2O2,the experimental results centers around bubble uniformity, pore size hole,specimen flexural and compressive strength after the foaming; The third stage is to study thepermeability coefficient of specimen after the foaming. the permeability coefficientmeasurement for different formulations of specimen, considering the strength and density, wedetermined the optimum formula finally.Tailings curing test shows, in the single cement curing experiment,flexural andcompressive strength increases with amount of cement, then20%cement dosage can meetthe strength requirements. Combined with cement and coal gangue, the best ratio is2:1.Tailings foaming tests showed that optimum amount of foam stabilizer PVA is0.5%, Bubble is large and uniform on the dosage. When addition of early strength agent Na2SO4is1%,compressive strength of7days increased by115.8%compared without early strengthagent. When the optimal dosage of foaming agent H2O2is10%, bubble size of the specimenbecame moderate and distributed uniform after foaming.Permeability coefficient tests showed that chemical method is more suitable than thephysical method for tailings. The larger the strength is, the smaller the permeabilitycoefficient. The optimum ratio is the best formula foaming test, the aperture is large and thepore distributed uniform, permeability coefficient reaches3.72×10-2cm/s.