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Preparation Of Ion Sieves By Zeolite,hausmannite And Pyrolusite And Experimental Study On Extraction Of Lithium From Brine Solution

Posted on:2017-07-12Degree:MasterType:Thesis
Country:ChinaCandidate:L WangFull Text:PDF
GTID:2321330512987304Subject:Institute of Geochemistry
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Lithium is a critical strategic material,due to its unique properties,from cutting-edge science and technology to the people's daily lives are increasingly depends on lithium and its related products.In recent years,the demand for lithium maintained a rapid growth,and with the development of new energy vehicles,which will stimulate further growth in the demand for lithium.The major sources of lithium are contained in brine lake deposits,seawater,geothermal water and solid minerals.Due to the limited amount of lithium in mineral resources and high extraction costs,it is urgent to develop extraction method from dilute liquid lithium resources.In various methods of extracting lithium from dilute liquid lithium resources including lake brine and seawater,lithium ion sieve sorbents are the most promising approach currently.It is suitable for extracting lithium from low concentration of lithium-containing brine and seawater,it also can be used for extracting lithium from high magnesium lithium ratio lake brine.The method has some advantages including simple preparation process,little environmental pollution and so on.In this paper,we used the experimental study on two kinds of preparation method of ion sieve: high temperature solid-phase sintering method and hydrothermal reaction method.We used two different reactants with high temperature solid-phase sintering method: one is the nature zeolite,the other is hausmannite?Mn3O4?,and the LiOH·H2O was selected as source of lithium reagent to react with the two kinds of reactants.Obtained precursor and ion-sieve after reactions,we examined crystalline structure,morphology and size of all products via powder X-ray diffraction?XRD?and scanning electron microscopy?SEM?.And the adsorption experiments in solution with two kinds of lithium ion-sieve were done.The results showed that the ion sieve prepared with zeolite has limited ability of adsorbing lithium from lithium-contained solution.The precursor and ion sieve prepared with hausmannite?Mn3O4?have some problems including bad crystallization,large particle size?1-5 ?m?and uneven distribution of particle size.The adsorption experiment results show that,the synthesized ion sieve has good adsorption when the solution with high initial lithium concentration;but the synthesized ion sieve has small lithium uptake capacity with low lithium concentration solution.The adsorption process is well fitted to pseudo-second-order kinetics equation,so the adsorption process is determined to be chemical adsorption.In hydrothermal reaction method,Mn?NO3?2·4H2O,Na2S2O8 and LiNO3 were used as reagent.First,pyrolusite?MnO2?was obtained,and a spinel-crystal MnO2 ion-sieve nanorods with the size of 40-80 nm in diameter and 400-800 nm in length is synthesized with pyrolusite via a hydrothermal reaction.The lithium uptake capacity of this synthesized ion sieve reached to 20 mg/g in adsorption experiments.The high capacity didn't require a control in pH of the solution.The adsorption process is well fitted to pseudo-second-order kinetics equation,so the adsorption process is determined to be chemical adsorption.The lithium selective adsorption properties were investigated by measuring the distribution coefficients?Kd?of a series of alkaline metal ions,the Kd are in the order of Na+<K+<<Mg2+<Li+,the results indicating that ion sieve has high selectivity for lithium ions,and the alkali metal ions in solution do not interfere with Li+.The recycling properties of lithium ion sieve which synthesized with hydrothermal method need to be improved.But overall,this new synthesized MnO2 nanorods ion sieve could be utilized in lithium extracting form liquid environments including lake brine,seawater and geothermal water.
Keywords/Search Tags:Lithium resource, Nano ion sieve, Lithium-containing solution, Lithium extraction experiments, Spinel-type manganese oxide
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