Preparation And Lithium Extraction Performance Of Modified Manganese Lithium Ion Sieve

Under the vigorous implementation of the dual carbon development strategy,the rapid development of electric vehicles powered by lithium batteries has greatly exacerbated the consumption of lithium resources.Manganese based lithium ion sieves are expected to be applied in salt lake lithium extraction due to their high lithium adsorption selectivity and capacity.However,due to the significant dissolution loss and poor granulation effect of manganese during acid desorption,they are difficult to be commercially applied.In order to reduce the dissolution loss of manganese lithium ion sieve in the acid leaching process,three methods are adopted to reduce the dissolution loss of manganese:Cr doping,molecular sieve loading,and hydrogel granulation.Firstly,manganese based lithium ion sieves with Li:Mn=0.5,0.7,and 0.9 were synthesized by calcination using manganese carbonate as the manganese source and lithium hydroxide monohydrate as the lithium source.Cr doped manganese based lithium ion sieves with Cr:Li:Mn=1:7:10,2:7:10,and 3:7:10 were synthesized by calcination using chromium trioxide as the chromium source,manganese oxide as the manganese source,and lithium hydroxide monohydrate as the lithium source.The successful preparation of Li Mn₂O₄=and Li Cr_0.25Mn_1.75O₄ was confirmed through XRD and FT-IR characterization,and the microstructure of the products was analyzed through SEM.The effects of adsorption temperature,p H value,and solid-liquid ratio on adsorption capacity were determined through single factor experiments.The adsorption and acid leaching desorption experiments showed that the Li:Mn=0.7manganese based lithium ion sieve prepared by high-temperature solid-phase method had the maximum lithium adsorption capacity of 28.60 mg·g^-1,and the dissolution loss rate of manganese was 21.01%.The maximum adsorption capacity of the Cr doped manganese based lithium ion sieve with Cr:Li:Mn=2:7:10 was 23.57 mg·g^-1,and the dissolution loss rate of manganese was 5.90%,The adsorption process fits the pseudo second-order adsorption kinetic model.Drawing inspiration from the synthesis method of molecular sieves,silicon based molecular sieves loaded with manganese based lithium ion sieves were prepared using anhydrous lithium nitrate as the lithium source,manganese nitrate tetrahydrate as the manganese source,and fumed silica as the carrier using citric acid complexation method;Using anhydrous lithium nitrate as lithium source,manganese nitrate tetrahydrate as manganese source and silicon dioxide as carrier,silicon-based molecular sieves loaded with manganese lithium ion sieves were prepared by urea coprecipitation method.The synthesis of Li₄Mn₅O₁₂ was confirmed through XRD and FT-IR characterization,and the microstructure of the product was analyzed through SEM.The influence of adsorption temperature,p H value and solid-liquid ratio on the adsorption capacity was determined through single factor experiments.The adsorption and acid leaching desorption experiments showed that the manganese lithium ion sieve with Li:Mn:Si=7:10:24 prepared by citric acid complexation method had the maximum lithium adsorption capacity of 15.74 mg·g^-1,and the manganese dissolution rate was 8.21%.The manganese lithium ion sieve with Li:Mn:Si=5:10:21 prepared by urea coprecipitation method had the maximum adsorption capacity of 22.20 mg·g^-1,and the manganese dissolution rate was 5.23%,The adsorption process fits the pseudo second-order adsorption kinetic model.Taking manganese carbonate as manganese source and lithium hydroxide monohydrate as lithium source,the powdered manganese lithium ion sieve was prepared by high temperature solid phase method.The successful synthesis of Li Mn₂O₄and gel materials was proved by XRD and FT-IR characterization,and the micro morphology of the products was analyzed by SEM.The influence of adsorption temperature,p H value and solid-liquid ratio on the adsorption capacity was determined through single factor experiments.The adsorption and acid leaching desorption experiments showed that the maximum lithium adsorption capacity of the manganese based lithium ion sieve with Li:Mn=0.7 after hydrogel granulation was 23.59 mg·g^-1,and the manganese dissolution rate was 2.79%.The adsorption process was consistent with the pseudo second-order adsorption kinetic model.