表面活性剂耦合絮凝剂对萃余酸的净化除杂研究OA

After solvent extraction in the production of wet-process phosphoric acid,a significant amount of raffinate is generated,which contains up to approximately 45%P2O5.However,due to its high impurity content and high viscosity,the raffinate acid is difficult to be utilized at high value.In this paper,the purification of extractive acid was studied by using the flocculation sedimentation method and coupling flocculants with surfactants.The results show that under the optimal conditions of 2%flocculant,3%surfactant,stirring at 400 r/min for 40 min and a reaction temperature of 60℃,the sedimentation rate and filtration rate of the raffinate reach 3.09 cm/h and 136.32 L/(m2·h),which increase by 13.71 times and 4.19 times respectively compared with that of the untreated raffinate.The removal efficiencies for Fe,Mg,and Al reach 69.6%,28.4%,and 45.2%,respectively.In repeated scale-up trials at an industrial level,the sedimentation and filtration rates increase by 14.09 times and 4.25 times,respectively,with metal removal rates of 67.4%for Fe,27.9%for Mg,and 45.2%for Al,while the phosphorus content remains stable.Through the synergistic action of surfactants and flocculants,metal ions form insoluble compounds with phosphate and silicate ions,which aggregate,settle,and are effectively removed via filtration.The combination of surfactant and flocculant significantly enhances the solid-liquid separation performance of the raffinate and achieves high removal rates of metal ion impurities.This confirms that flocculation sedimentation is effective in treating high-viscosity,high-impurity,and high-solid-content systems,offering an industrially viable solution for raffinate purification.