Control of dust from tailings pond using conventional halides and polymer materials

Mine tailings, the byproducts of mineral processing, are special solid wastes generally classified as loose sandy silts or silty sands that are vulnerable to wind erosion, especially in arid and semiarid regions. Mine tailings also contain potentially toxic elements such as Cd, Cr, Mn, Ni, Zn, Pb, and As. Thus, fugitive dust from mine tailings is associated with a number of environmental and safety concerns. In recent years, dust control has become a hot topic in the environmental management of tailings storage facilities. Using the response variables of wind erosion resistance and penetration resistance, the experimental variables of the solution concentration, spray amount, and external air speed, laboratory tests were conducted to investigate the effects of conventional halides and polymer materials on dust control. The results indicate that the wind erosion resistance and penetration resistance of the crust can be improved with increase in the concentration of the dust-depressor and the amount of spray used. In the halide solution, CaCl₂ exhibited the best dust control effect. When the wind speed is 7.5 m·s⁻¹ and the spraying amount of CaCl₂ is 4.5 L·m⁻² at a concentration of 50 g·L⁻¹, the loss quantity of tailings is 0.75 g·m⁻²·min⁻¹ and the penetration resistance is 466 kPa. Among the polymer materials, polyacrylamide exhibits the best dust control effect. The loss quantity of tailings is 0.30 g·m⁻²·min⁻¹ and the penetration resistance is 248 kPa when the wind speed is 7.5 m·s⁻¹ and the spraying amount of polyacrylamide is 4.5 L·m⁻² at a concentration of 0.5 g·L⁻¹. This paper emphasizes that the selection of dust-depressor can be determined based on the local annual mean wind speed, whereby polyacrylamide should be selected as the dust suppressant for a tailings pond when the annual mean wind speed is high. Otherwise, CaCl₂ should be selected as the dust-depressor for a tailings pond.