A large amount of mine water will be discharged during the production process of the coal mine. It will be directly discharged without treatment, which will not only cause pollution of the surrounding environment of the mining area, but also waste a lot of valuable water resources. The utilization of mine water resources is based on solving the problems of serious shortage of water and mine water pollution in the coal producing areas, which are bothering the development of the coal industry. The treatment process of mine water depends on its utilization route. The treatment of mine water is mainly to remove suspended solids, various ions and other impurities in the water. To achieve the requirements of drinking water or industrial water, the basic process is coagulation-precipitation-filtration-disinfection. Among them, coagulation (flocculation) treatment is one of the most important processes in the whole process of mine water treatment process. The choice of coagulant and coagulation test are important conditions to ensure the treatment effect of mine water.
Effect of Different Coagulant Concentrations on Coagulation Effect of Mine Water
The removal rate of turbidity of mine water increases with increasing concentration within a certain concentration range.
Effect of Different Coagulant Dosage on Turbidity Removal Rate of Mine Water
The removal rate of turbidity in the water sample of the mine increases with the increase of the dosage of the coagulant. When the maximum value is reached, there is a process of decline. This is because when the dosage of the coagulant is insufficient, the coagulant cannot be sufficiently contacted with the suspended matter in the water, and some suspended matter still exists in the water sample, and when the coagulant is used excessively, the colloidal particles are recharged. The electrostatic repulsion between the colloidal particles is increased, and the suspended matter is again in a stable state. As a result, the remaining turbidity of the supernatant increased. The removal rate is reduced; in addition, the excess coagulant also "wrapps" the surface of the particles, and this "wrapping" effect weakens the cohesive capacity between the particles. When the concentration of suspended solids in the mine water is very low, the charge of the colloid is less, and the colloidal neutralization and destabilization can be achieved when the coagulant is added in a small amount. As the concentration of suspended solids in the mine water increases, the colloid is carried. As the amount of charge increases, the amount of coagulation required will increase accordingly in order for the colloid to reach the adsorption neutralization and destabilization.
Effect of pH on turbidity removal rate
The removal rate of turbidity in mine water samples increases first and then decreases with the increase of pH value. This is due to the pH value of the zeta potential on the surface of colloid or microparticles in water, the hydrolysis of coagulant and the existence of hydrolysate. The effect directly affects the effect of coagulation and sedimentation.
Effect of coagulant and coagulant on turbidity removal rate of mine water
The removal rate of mine water turbidity increases with the increase of PAC and PAM concentration within a certain dosage range. The combination of polyaluminum chloride and polyacrylamide has a better effect on the removal of turbidity than the two when used alone, and the dosage is also significantly reduced. This is because polyaluminum chloride is an inorganic polymer electrolyte. The main function in the flocculation process is to reduce the surface potential of the suspended particles, thereby weakening the same-sex repulsive force of the particles and promoting the aggregation of the particles during the collision. Although polyaluminum chloride directly provides high-priced polymeric ions in the post-hydrolysis, the agglomeration and bridging effects are relatively weak. Polyacrylamide is an organic polymer flocculant. This linear polymer flocculant has a bridge chain function and can agglomerate the particulate agglomerates into flocs sufficient for sedimentation.
