Study On The New Technology For Extrating Lithium From Seawater Using The Ion-Sieve

The technology of extraction lithium from seawater using ion-sieve was researched on the basis of the predecessor research, including the main disturbance cations on the enrichment of Li+ in seawater, various kinds of factors in the process of adsorption and the separation of lithium carbonate from the enriched lithium solution, so as to produce a new process to realize industrialization of extracting lithium carbonate from the seawater.The adsorptive capacity of the precursor which was synthesized in optimum conditions was 30.27mg per gram ion-sieve. The technology for extracting lithium from seawater using granular adsorbent was studied. The results showed that the main cations in seawater such as Mg2+,Ca2+,K+,Na+ all have the effect of disturbances on the absorption of Li+. The order is Mg2+>Ca2+>K+>Na+. In the phase of absorption, the velocity of seawater has little effect on the absorption within the range of low velocity. However, higher flux of seawater is disadvantage to the effect of the absorption of Li+ when it is over 30mL/min. Higher temperature is good for the absorption of lithium in seawater. After comparison, we chose HCl as eluent. In the phase of elution, the effect of eluting was improved but not obviously as the concentration of elution increasing, so the appropriate concentration of HCl 1mol/L. The results of experiment also indicated that a lower flux of eluent is advantage to the effect of elution and high temperature has little improvement. The betters are the 5mL/min flux and the 40℃-60℃. In optimum conditions, the largest concentration of Li+ in elution solution can reach to 1.88g/L and the mean concentration of solution is 0.92g/L.To separate lithium carbonate from the enriched lithium solution, the process and technology parameters were determined. The lithium carbonate with a purity up to 99% was obtained in the end and the recovery of lithium was 39.24%.