Ion Exchange - Lime Neutralization Benxi Uranium Tailing Wastewater Treatment Research

In this study, the adsorption properties and mechanism of D263B touranium were studied. The tailings impoundment water of753mine wastreated by technique of D263B resin adsorpting-calcareousnessneutralizing.As a strong-base anion exchange resin, the D263B resin wasselected a suitable adsorptive material based on study of ion exchangecapacities, adsorption ratio.The results of adsorption in batch method indicate that theadsorption process of D263B reach equilibrium after150minutes and theuptake capacities for uranium reached35.23mg·g^-1. Adsorptioncapacities increase with the increase of temparature and the initialconcentration of metal ions. Adsorption capacities is not effected stronglyby pH. NaCl solutions were applied to desorption of metal ions onD263B，and the results indicate that elution and regeneration propertiesare very good. The results of adsorption in the column experimentindicate that with increasing the flow rate and uranium initialconcentration, the breakthrough point reached ahead, and the efficiencyof the resin function groups decreased. The dynamic desorptionexperiment indicate that desorption rate increase with the increase ofNaCl concentration and the decrease of flow rate, at determinate NaClsolutions volume.Adsorption kinetics, isotherm and thermodynamics were researched,and the adsorption mechanism of D263B to uranium was discussed. Theadsorption process was controlled by liquid film diffusion, particlediffusion and chemical reaction simultaneously. The adsorption reactionapproximately equal to first order reaction. Isotherm adsorption processcan be well described by Langmuir models, which indicats that theadsorption is a monolayer one; In the process, ΔH is plus and ΔG isnegative, indicated that the adsorption of D263B for uranium isspontaneous and endothermic.A project was carried out to recovering uranium from tailingsimpoundment water by D263B and then neutralizing adsorpted tailwater by calcareousness to precipitate the reduced heavy metal. The effect ofgranularity and dosage of calcareousness on removal efficiency bod ofMn²⁺ and uranium was studied. The result indicate that the treated waterreach emission standard on conditons that the mixing time exceed10minand pH exceed11.