| Extracting lithium by ion sieve adsorption from brine of high Mg/Li rate is one of hot researches, and manganese oxide lithium-ion sieve with low cost, high separation factor, high adsorption capacity is becoming inorganic ion sieve adsorbent.Now solution loss of manganese and granulation process are the key technologies to be solved for lithium-ion sieve industrialization. In this thesis, the preparation process of manganese lithium-ion sieve precursor doped titanium, the acid leaching and adsorption properties of titanium composite manganese lithium sieve were mainly studied. A new kind granulation process was explored and the granular adsorbent properties were studied.MnSO4and Ti (SO4)2were used as source of manganese and titanium source, manganese lithium-ion sieve precursor doped titanium was prepared by co-precipitation-hydrothermal synthesis. After pickling lithium-ion sieve powder was obtained. Through investigating the important factors of samples synthesis, the optimum conditions of synthesizing compound lithium-ion sieve were derived. The results were the molar ratio of Ti(SO4)2and MnSO4was x(Ti/Mn)=0.03, the lithium concentration was3.2mol/L in hydrothermal synthesis reaction mother liquid, reaction temperature was230℃, reaction time was12h, calcination temperature was410℃, calcination time was6h.The acid leaching and adsorption of synthesized samples were researched. The results showed that Li in the precursor had been resolved completely after acid leaching2h, completely conversion to ion sieve adsorbent. Lithium ionic sieve adsorption rate was fast before adsorbed12h in the lithium ion solution,the lithium adsorption capacity had been19.71mg·g-1after adsorbed2h; the lithium adsorption capacity reached19.71mg·g-1adsorbed of12h, Lithium ionic sieve adsorption rate falled after adsorbed12h, the lithium adsorption capacity incressed slowly. pH value had a great influence on ionic sieve adsorption capacity, Lithium ionic sieve had better adsorption performance in alkaline conditions, Lithium ionic sieve adsorption reached the maximum34.18mg·g-1at pH=13.93,The synthetic samples used CST-200for hydrophobic modification to prepare for the subsequent granulation research. The best modified conditions were that Solution concentration of CST-200was11g·L-1, modified temperature was80℃, stirring speed was700r·min-1, modification time4h. Samples obtained under this condition had the best hydrophobic properties and the maximum contact angle0was154.55°. The modified powder particles smaller and uniform distributed after and before analyzing the modified and unmodified samlies.Apparent micro morphology analysis and acid leaching experiments of the granular lithium ion sieve adsorbent were studied. The results was that the samples were nearly round particles and has a porous structure. Lithium resolution was55%After acid leaching3h with the temperature of30℃. Adsorption capacity lithium of granular adsorbent increased with increasing temperature and simulated liquid lithium concentration.lithium adsorption capacity was12.05mg·g-1with the temperature of30℃.Respectively, using the Langmuir adsorption isotherm equation and Freundlich isotherm equation fit adsorption data in simulated fluid. The results showed that:granular adsorbent for Li+of adsorption simulation solution followed Langmuir isotherm equation and correlation coefficient R2=0.9980, monomolecular layer chemically adsorbed, lithium concentration greatly impact on the adsorption capacity. Respectively using adsorption kinetics level model,secondary model and particle diffusion model fit for granular adsorbent adsorption data in a simulated fluid. The results showed that:granular lithium-ion sieve adsorbents belong Lagergen adsorption kinetics secondary model and is a chemical adsorption process. Particle diffusion is not within the control steps of the adsorption process and adsorption process is not controlled by a single process.Adsorption of granular lithium ion sieve adsorbent in Xinjiang Lop Nor salt lake brine and separation performance and cycle performance of granular lithium ion sieve adsorbent for major ions adsorption in Salt Lake Brine were studied in this paper. The results showed that:granular lithium-ion sieve adsorption capacity balanced of6.92mg·g-1after10h.The distribution coefficient of major ion were DLi>>DNa>DK>DMg, separation factor of plasma screens for Li+and Mg2+, Na+, K+were62.65,52.51,58.54, far greater than1, so this granular has adsorbent strong adsorption selectivity and good separation performance. After10cycles parsing-adsorption process, adsorption capacity can reach5.73mg·g-1in brine, the adsorbent still keep good adsorption capacity, which illustrate granular lithium-ion sieve adsorbents has good structural stability. Figure47, Table11, Reference89in this thesis. |
PDF Full Text Request