Granulation Process Of Lithium Ion-sieve

MnO2ion sieve was a promising Li+adsorbent as its high selectivity to Li+, huge adsorption capacity and stability. Meanwhile, the powder ion sieve couldnot be directly used to industry application. Thus granulation to lithium ion sieve had been the key problem constraints the industrialization process of lithium ion sieve. Aiming at these problems, different granulation methods were taken to granulate the powder, their effects on the adsorption properties of the lithium ion sieve were also studied.Agar bond molding and amides polymeric molding methods were taken to prepare two kinds of granulated lithium ion sieve. IR, SEM and BET were used to characterize the properties of the ion sieve. Adsorption kinetics, adsorption isotherm, selectivity analysis were used to evaluate granulated ion-sieves’ adsorption performance. The recycle stability and adsorption kinetics of polymeric molding lithium ion-sieve.By using agar as the granulation reagent and orifice coagulation bath as the preparation method, the spherical ion sieve with diameter range from2.0to3.5mm were obtained with crosslinking modification. The equilibrium adsorption capacity reached4.25mmol·g-1. However, the hydrolysis of agar in acid solution would lead to a dramatically decrease of mechanical strength. The swelling quality of the polyamides lithium ion sieve was improved. The results indicating increase the powder content and crosslinking degree would reduce the swelling of the material in different solution. The adsorption performance studies showed that the equilibrium adsorption capacity of polyamides ion sieve reached3.15mmol·g-1, and pseudo-second-order kinetic model showed good fitting results in adsorption process. But the adsorption rate was0.1times slower than the powder. The adsorption rate was mainly controlled by the size of the granulated ion sieve. Fixed bed recycle study showed that the adsorption capacity of the polyamides ion sieve was around0.5mmol·g-1in30adsorption/desorption cycles. A model was build to calculate the membrane diffusion coefficient and intraparticle diffusion coefficient. Membrane diffusion coefficient was5.2×10-5m·s-1, intraparticle diffusion coefficient was4×10-10m2·s-1, indicating the rate determining step was intraparticle diffusion.