Treatment Of Wastewater Containing NH₃-N And Cu²⁺ In Nonferrous Metallurgy Industry Using Liquid Membrane Technology

The wastewater in.hydrometallurgical system always contains ions including Cu²⁺,Zn²⁺,Ni²⁺,and NH₄⁺,and ammonium hydroxide is usually used as a ligand to extract them in the process.Treatment of wastewater containing NH₃-N and Cu²⁺has been studied here by using liquid membrane technique.NH₃-N in wastewater was extracted by using different types of surfactants to make emulsion.The results show that ME emulsion has very good stability,small swelling,high efficiency for treatment and easy demulsification.ME is suitable for wastewater treatment as a surfactant. The compositions of emulsion and extraction conditions were also explored.The emulsion for extraction of NH₃-N was prepared by mixing 50%of 10%sulfuric acid,and 50%oil mixture containing 3%ME,96% kerosene,and 1%liquid paraffin in 10-15 minutes with stirring at the speed of 6000rpm.The extraction conditions of NH₃-N were studied for the industry.Rew is 1:8 at above pH 11 for outside water phase under ambient temperature.This condition was applied to extraction of wastewater containing NH₃-N from an industrial company.Extraction rate of NH₃-N is above 99.5%in lab scale and the emulsion can be recycled after treatment.Based on the lab scale experiments,The scale-up experiments at the same company was studied.The results show that the wastewater containing 0.62—2.2 g·L^-1.NH₃-N can be treated by two-stage countercurrent extraction and NH₃-N level in the treated water is below the national standard for discharge(＜15ppm).The cost is below 10yuan/ton.ME as a surfactant with the carries of P204 and N902 was also studied.The results show that P902 is better than N204 for the treatment of wastewater containing Cu²⁺.The effect of inside acidity,the amount of carrier and surfactant,Roi,Rew,pH of wastewater,and extraction time for Cu²⁺was explored.The optimum extraction conditions of wastewater treatment for a company are 3%of the support,5%of surfactant,Roi 1:1,2 M inside acidity,initial pH 4 of wastewater,and Rew 1:5.The results show that Extraction rate of Cu²⁺is above 95%,and accumulation of Cu²⁺can be enriched at 14800 mg·L^-1.The study also shows that the emulsion has very good stability,small swelling,fast phase separation and easy demulsification.Through innovation of the demulsification equipment,the emulsion can be demulsified in 5-10 minutes.No fire is initialized in the process of treatment compared to the previous process.The interface of the emulsion is very clear.The water and oil phases can be easily separated.The composition of the emulsion is not changed.