Enrichment Of Rare Earth Ions In Leaching Tailings By Nanofiltration

As a result of a large amount of rare earth mining,resulting in a large number of leaching tailings,the treatment of these tailings consume a lot of manpower and resources,and rare earth ions on the treatment of ineffective.In order to solve the problem of recovery of rare earth ions in the tail water,a new separation technology,nanofiltration membrane technology was used to enrich the rare earth ions in the tailings,and the adsorption performance of the rare earth ions was considered.In this study,the leaching tailings were taken from an ion-type rare-earth mine in Jiangxi Province.The three kinds of nanofiltration membranes used were commercial NF1 and NF2,NF3,respectively,and the materials were all polyamides.The main research and results are described as follows:(1)The performance of three kinds of nanofiltration membranes was analyzed.The results show that the fluxes of three kinds of membranes increase with the pressure increasing,and the interception rate of monovalent ions decreases with the increase of pressure;The existence of divalent ions increased first and then decreased the process,there is the best between 0.6 ~ 0.8MPa.After comparing the membrane pore size,contact angle,roughness and Zeta potential of the three membranes,the performance of the membrane NF2 was optimal.(2)The effects of three kinds of nanofiltration membranes on the enrichment process of rare earth ions(La,Y,Ce,Nd,Pr)were studied.The results showed that the feed flow,pressure,the effect of pH,temperature and pressure on the retention of nanofiltration membrane was significant.The optimum conditions for the enrichment of the rare earth ions were from 4.5 L/min to 5.5 L/min,the pressure was from 0.6 MPa to 0.8 MPa,the pH value was from 3.5 to 4.5 and the temperature was from 25 ? to 30?.Under the optimum conditions,the enrichment times of the five ions were more than 3.8 after 20 hours running.(3)The adsorption behavior of three kinds of membranes on five kinds of rare earth ions were studied by the adsorption kinetic model and adsorption isotherm model.The results showed that the adsorption of La,Y,Ce and Nd by NF1,And the adsorption capacity of Pr increased with the increase of the initial concentration of rare earth ions.The adsorption capacities of the ions on the three kinds of membranes increased with the increasing of the radius and roughness of the films.The five ions showed the same The adsorption capacity increases with the increase of ionic radius.The results showed that NF3 could promote the enrichment of rare earth ions in the tailings of low concentration leachate.The NF2 used in the study was more suitable for concentrating such leaching tailings,20 hours rich Set the effect of 3.8 times or more.