The invention discloses a La < 3 + >-doped
lithium manganese oxide lithium ion sieve as well as a preparation method and application thereof, and belongs to the technical field of
salt lake lithium extraction. The preparation method comprises the following steps: by taking Mn2O3 and LiOH as raw materials, carrying out
hydrothermal reaction to generate LiMnO2, mixing the LiMnO2 with La2O3,
grinding and calcining to form a La < 3 + >-doped
spinel structure precursor La-LMO, and carrying out acid
pickling to prepare La-HMO. La < 3 + > replaces part of Mn < 3 + >, the average valence state of
manganese is improved, meanwhile, the
structural stability of the
manganese is enhanced through the high
bond energy of La-O bonds, the number of exposed manganese atoms is reduced, manganese solution loss caused by Mn < 3 + >
disproportionation reaction in the
acid treatment process is effectively inhibited, the adsorbed
oxygen content and active sites are increased, and the lithium
ion adsorption capacity is remarkably improved. The material has high-selectivity adsorption capacity on lithium ions in
salt lake brine in a strong alkaline environment, the manganese solution
loss rate is obviously lower than that of traditional HMO, the cycle life is remarkably prolonged, and the industrial application potential is remarkably improved. The preparation process of the lithium
ion sieve is simple, the
raw material cost is low, and the technical bottlenecks that an existing manganese-based lithium ion
sieve is poor in
structural stability and high in manganese solution loss are solved.