Research On The Preparation And Mechanism Of The H₂TiO₃-type Lithium Exchanger And Its Application To The Extraction Of Li～+ From The Brine

There is abundant of brine with lithium in our country. Lithium, which is of very important value of exploitation, is mainly contained in the brine of plateau-salt lakes and underground brine. With the advantages of low cost of exploitation and little investment of projects, extracting lithium from liquid lithium-mine directly is thought to be an optimal and economic technical path, is adequate for making use of the dispersive and low-content resource of brine-contained lithium of our country. Because of the shortage high performance of lithium separating materials, it is different to separate and enrich lithium from large amount of alkali metals and alkaline earth metals in the brine.Much research has been done to prepared lithium separating materials recently from home to oversea. The development inorganic manganese dioxide Lithium ionic sieve, which has a high exchange capacity for Li+, has greatly propelled the research progress of extracting lithium directly from liquid lithium-mine. But it has not exploited high exchange capacity and good performance lithium separating materials globally and realized extracting lithium from liquid lithium-mine directly at present, just because it has not solved technical problems of worse stability of lithium separating materials' structure and performance basically, for the shortages of raw material choices, synthetic methods, et al.Against such a technical problem, HaTiOa-type lithium ion exchanger with performance has firstly synthesized in this work. This exchanger exhibited very good selectivity and comparatively high exchange capacity in the case of extracting lithium from brine with low content of lithium. Its exchange capacity of lithium can reach 28.76mgLi/g TiO2 and the separate factors of Ca2+ and Mg2+ are 5.95 102 and 1.19x10 , respectively. Another special property of this exchanger is good stability. After 6 cycles of exchange and elution, it can preserve 90% exchange capacity, losing 0.025%(wt%) every cycle, which is better than now prepared MnO2 ion sieve. Furthermore, this exchanger would be a new material, which can extract lithium directly from salt lakes brine, gas fields and underground brine, making the industrialized production of Li2CO3 becoming possible.From the presented reference, we find out that in our country, the most resource of lithium in salt-lakes brine is in plateau of Tibet-Qinghai and the Basin of Caidamu. The highest center of Li+ distribution lies in Zakounanmu Lake and Shiquan River belt, and the second center of Li+ distribution lies in Taijinaier-big small Caidan andbig Langtan belts. The concentration of Li+ is above 200mg/L at highest canter and more than lOOmg/L in the second center. The most resource of underground brine-contained lithium, is in the Basin of Sichuan, distributing at Northeast area of Sichuan province25# (T2j1) , Weiyuan Tectonic (Z) , Southwest area of Sichuan province (Tax, T211, Ty5) and center area of Sichuan (Tax), and there are more than 30,000,000 tons of lithium resource which could be mined for industrial purpose.Differed from present lithium separating material research thought and method, we brought forward the idea that the structure and the particle pattern of the precursor TiOa have a enormous influence on the structure and properties of the aimed exchanger Li2TiO3. Hydrolyzed techniques of the precursor were studied systematically. The results show that the TiO2, which has a particle size of 3-4um, and has a mixed crystal type(83.1% Auatase-typeTiO2+16.9% Rutile-type TiO2) is the ideal precursor, using which can increase the aimed exchanger's stability and capacity.Like Sol-Gel Method , as a new synthetic method, was firstly used to synthesis the aimed exchanger Li2TiO3. Using this method, reactants Li2CO3 and TiO2 can be maximizing mixed under the organic reagent impregnating and the original particle pattern and reactivity of the precursor TiO2 can be hold, which have greatly increase Li+ and Ti4+ diffusion velocity and shortened the diffusion space at high temperature solid-state reacti...