| Preparation excellent structure and properties of titanium and zirconium compound oxides by template method as used to extract lithium from brine. Firstly, preparation the particle size at about 100 nm PMMA microspheres use MMA as it’s mo nomer and by control the five influence factor(The dosage of emulsifier, The dosage of Initiator, reaction time, temperature, stir speed) and emulsion polymerization technology. Then, get the compact arranged PMMA microspheres from emulsion by high speed centrifugal method, and use as template after drying and grinding. Using lithium acetate, zirconyl nitrate and tetrabutyl titanate as metal source,citric acid as chelating agent,F-127 as soft template, anhydrous ethanol as solvent to preparation precursor. To fill the hard template by the precursor, after vacuum filtration, constant temperature drying, program type roasting to obtain the With precursor solution to fill the hard template PMMA, again by vacuum filtration, drying temperature, program type roasting obtained with good structure of titanium and zirconium compound adsorption material precursor Li4Ti5-xZrxO12 with good structure. Explored the roasting temperature and determined it of 850℃, heating rate of 2℃/min. calcination program determined of 2℃/min from room temperature warming up to 300℃, maintain 1h, again 2 DEG C / min warming up to 800℃,maintain 2h. Explored the unknown molecular of titanium zirconium composite material and determined the unknown X is 0.06, then the molecular formula is Li4Ti4.94Zr0.06O12. Characterized the synthetic products of it’s structure and ion ion exchange properties by using X ray diffraction, scanning electron microscopy, saturated adsorption capacity and PH titration etc. The best concentration of acid in the dehydrogenation of 0.2mol/L has the highest removal rate of hydrogen ion. The best concentration of Li+ is 0.05mol/L and the saturated exchange capacity is 50.61 mg Li+/g adsorbent.Determined the ion exchange isotherm plots of ion sieve adsorption to lithium on 15℃,30℃,45℃ and the mean activity coefficient of the ion sieve H+-Li+ exchange system by Frank-Thampson dispersion lattice theory. At the same time, get the system Killand diagram and calculated a series of thermodynamic constants, such as Thermodynamic equilibrium constant, Gibbs free enthalpy ?, standard enthalpy change ? and standard entropy change ? etc. thermodynamic equilibrium constant. The adsorption exchange performance of ion sieve(LiTiZr-H)to Li+ is better than to H+ in the same solution. The system of the titanium zirconium composite ion sieve adsorption exchange reaction is an exothermic process as the result of enthalpy change.Determine the kinetic curve of the exchange reaction of ion sieve LiTiZr-H on different concentrations of Li+(0.01, 0.03, 0.05mol/L) at the room temperature by the relationship of the adsorption exchange quantity and the time.Describe the reaction control process according to the Nernst-Plank dynamics theory. liquid film diffusion control of linear driving force, reacted layer diffusion control of shell-progressive mechanism and liquid film diffusion control of shell-progressive mechanism all these three control process kinetic curves does not conform to the requirements formula according to the experimental results, so it’s not these three control process. The intraparticle diffusion kinetic curve control reflects the linear relationship, and has high similarity, so the intraparticle diffusion control can be identified as the control process of the reaction. |
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