Study On The Preparation Of Lithium Ion-sieve Based On Manganese And Its Lithium Extraction

In recent years,the demand of lithium and its compounds was ever-increasing.China is a liquid lithium resource-rich country.In order to extract lithium from salt lake brine and concentrated seawater economically and efficiently,it is necessary to prepare of lithium ionic sieve adsorbent.Doing some researches with ionic sieve could provide some references for lithium extraction from salt lake brine and concentrated seawater using ionic sieve.The granular lithium ionic sieve precursor was prepared with granulous mixture baked for 5 h at 800?,in which the content of MnCO₃ and Li₂CO₃ was 41.60%,the attapulgite clay was 12.17%,and the content of sodium silicate was 46.23%.And the granular lithium ionic sieve adsorbent was finally obtained after elution of the above precursor.And then the process of elution and adsorption,and the effect of different temperature,flow rate,contacting time and concentration of eluent or solution containing lithium on the properties of ionic sieve were studied.The result of granular adsorbent in the process of static state elution showed that the ratio of lithium extraction was up to 90.53%with HCl solution as the eluent,and the uptake of lithium was up to 16.49 mg/g which was only 50%of the capacity of the powdery one;the ratio of lithium extraction was about 92.53%with Na₂S₂O₈ solution as the eluent,and the adsorptive capacity for lithium could reach 20.17 mg/g which was less than 34.56 mg/g for the corresponding powdery one.The process of adsorption and elution of the granular adsorbent in column indicated that the difference of adsorption and elution time,concentration,flow rate and temperature affected the adsorption and elution process.The ratio of the extraction of lthium and the dissolution of Mn and the Li-uptake of ionic sieve were increased with the extension of time,whose speed changed from fast to slow with a same regular roughly;with the concentration of Na₂S₂O₈ solution ranging from 12%to 38%,the ratio of lithium extraction increased by 28.87%.During the circulation of elution-adsorption,the extraction ratio of Li and the dissolution raio of Mn in the fifth time only occupied 9.58%and 10.03%of those in the first time,respectively,and the Li-uptake was only 59%of that in the first time;when the flow velocity of elution decreased from 10 ml/min to 2 ml/min,the extraction ratio of Li was enhanced by 77.75%;and when the flow velocity of adsorption decreased from 10ml/min to 2 ml/min,the adsorption capacity increased by 24.00%.With the eluent at 65?,the extraction ratio of Li amounted to 50.55%,which hit the highest point;in the adsorption process,when the temperature went up from 25?to 75?,the adsorption capacity increased by 40.16%;during the circulation of elution-adsorption,the fifth adsorption capacity declined by 40.96%comparing with the first time;it is the best time to collect the solution enriched lithium at the beginning of each elution process with the effluent ranging from 80 to 120 ml,because the concentration of lithium in above effluent reached the top.In the process of dynamic elution and adsorption,the eluent with 38%Na₂S₂O₈ at65?was suggested to use at 2 ml/min,and then the Mn dissolution was only 2.07%;with the increase of adsorption temperature,the adsorption capacity of granular lithium ionic sieve was improved continuously,and the optimal Li-uptake was 11.97 mg/g at 75?during the circulation of elution-adsorption.