Papers by Keyword: Lithium

Abstract:

In the Kroll and Hunter processes to produce titanium from TiCl₄, magnesium and sodium are used respectively as reducing agents. These processes are slow and very energy intensive and consequently much work was done over the years to improve the economics of producing these metals. In this regard, more success has been achieved with improving the economics of magnesium electrowinning than with alkali metal electrowinning. Magnesium electrowinning cells generally have electrodes with a planar shape and alkali metal electrolysis cells have electrodes with a cylindrical shape. Furthermore, recent advances in magnesium electrolysis allowed the introduction of bipolar electrodes, whereas such electrodes have not been introduced in alkali metal electrowinning cells. It is conceptually possible to replicate the advances in the construction of magnesium electrowinning cells to improve sodium or other alkali metal electrowinning cells. However, there are underlying fundamental reasons why it would be difficult to do so.In this paper the technologies for magnesium and alkali metal electrowinning cells are briefly reviewed. The reasons why it would be difficult to copy the improvements made in magnesium electrowinning technology to alkali metal electrowinning technology are then explained in terms of the implications of the underlying chemical and physical properties of the chemicals involved in the processes.

Abstract: The crystalline structure of lepidolite is introduced in this paper, its application in lithium ion battery is paid attention. Because of the extraction difficulties from brines in China, it is necessary to take advantage of lepidolite resources, driven by the huge economic benefit and social benefit requirements. The components and particle size distributions of lipodilites in Yichun and Yifeng are experimentally analyzed.

Abstract: Because of the extraction difficulties from brines in China, it is necessary to take advantage of the lepidolite resources, driven by the huge economic benefit and social benefit requirements. Several factories use refined lepidolite to produce lithium carbonate in Yichun city because of the rare metals and high price of battery-grade lithium carbonate. The primary separation of lepidolite from complex silicate minerals is froth flotation. In this paper, the froth flotation process for production of refined lepidolite from Ta & Nb waste minerals in Yichun city and in Yifeng town is discussed.

Abstract: It is well known that the phase diagram plays an important role in exploitation and utilization of salt lake resources. To effectively employ the systems containing lithium and carbonate, the study on phase equilibrium is essential to the comprehensive utilization of the salt lake resources. In this paper, progresses on phase equilibria of salt-water systems containing lithium and carbonate were presented.

Abstract: Salt lake brine resource is one of the strategic resources in the western of China. Phase equilibria and phase diagrams are the theoretic foundation for the exploitation of salt lake brine resources. Hence, studies for the stable and metastable phase equilibria of lithium-containing salt-water systems are of the great importance for the development of salt lake brine resources. In this paper, the stable and metastable phase equilibria of lithium-containing salt-water systems were summarized, and the problems existed at present and the new trends in the future are also discussed.

Abstract: The three-dimensionally ordered nanopores 3DON lithium ionic sieve precursors Li₄Ti₅O₁₂ were synthesized by homemade polymethyl methacrylate (PMMA) colloidal crystal templates filled with lithium acetate, tetrabutyl titanate, oxalic acid and critric acid mixed solution after melt crystallization. The corresponding LiTi-H as a new lithium ion-sieve was obtained after the dilute hydrochloric acid treatment. The morphology and structure of the material were analyzed with SEM and X-ray diffraction (XRD), and saturated exchange capacity, adsorptive selectivity and reusability characterized the ion exchange properties. It turns out that PMMA colloidal crystal templates and 3DON precursors Li₄Ti₅O₁₂ arranged orderly and macro pore diameter was approximately 80nm. What’s more, Li₄Ti₅O₁₂ were spinel phase and lithium ionic sieve LiTi-H had a high selectivity for Li⁺, saturated exchange capacity for Li, 56.81mg (Li⁺).g^-1 and good acid stability.

Abstract: Polystyrene microspheres with 120nm diameter were synthesized by emulsion polymerization and three-dimensionally ordered colloidal crystal templates were obtained by centrifugal sedimentation.Three dimensionally ordered nanopore (3DON) manganese oxide lithium ion-sieve was prepared after filtration, two heated roasting and acid modified by using precursor solution filling the colloidal crystal templates, which was prepared by Lithium salt, manganese salt and citric acid. SEM, XRD, and saturated exchange capacity test were used to characterize the roasting condition, appearance, structure, and ion exchange performance of the oxide. The results showed that, the optimum roasting condition of preparing lithium ion-sieve precursors were found as follows: heating rate at 2°C/min, 300 °C roasting 4h and 800 °C roasting 8h, The 3DON Li₄Mn₅O₁₂ lithium ion sieve precursor has the shape of three-dimensional cross-linked connected into the network structure. Li₄Mn₅O₁₂ was regularly arranged and the hole wall was integrity,average pore size of approximately 90nm.3DON Li4Mn5O12 showed good stability for acid and the retrofit of lithium ion-sieve showed a high selectivity for Li⁺. The saturated exchange capacity of Li⁺ is 51.98mgLi⁺/g.

Abstract: This paper discusses two Al-Cu alloys for aerospace applications, one of which has an addition of between 1.6 and 2.0 wt.% of Li. The alloys are AA2024-T3 (Al-Cu) and AA2099-T8E77 (Al-Cu-Li). Microstructural analysis via Field Emission Gun Transmission Electron Microscope (FEGTEM) and Field Emission Gun Scanning Electron Microscope (FEGSEM) utilising Energy Dispersive Spectroscopy (EDS) and Electron Backscatter Detector (EBSD) techniques have been used to characterise the two microstructures and phases contained within them. Anodic polarisation and immersion testing in a 3.5 wt.% NaCl solution have been carried out and a comparison of the corrosion mechanisms has been made. AA2024-T3 had a fine, equiaxed grain structure, whereas AA2099-T8E77 had a substantial amount of recrystallized grains. Finer grains were also observed on AA2099-T8E77, however, the vast majority were larger than the maximum detection limit of the EBSD technique. Intergranular and pitting corrosion were observed on both alloys following immersion testing, however, the intergranular corrosion (IGC) was more prominent on AA2099-T8E77. Anodic polarisation indicated that AA2024-T3 was more noble, highlighting that the Li-containing AA2099-T8E77 alloy was more susceptible to corrosion. The T₁ (Al₂CuLi) phase within AA2099-T8E77 was seen to be highly active following immersion and anodic polarisation tests. The corrosion pits on AA2099-T8E77 were seen to propagate to a depth of ~ 80 to 100 μm, with a maximum of 126 μm recorded. For AA2024-T3 the maximum depth recorded was 77 μm and the average depth was between 60 and 70 μm.

Abstract: In this paper, the mechanism that lithium-modified rectorite (Rec-Li) and raw rectorite adsorbed methylene blue dye in wastewater was investigated, and the adsorption properties of the two adsorbents were also compared. The results showed that the static saturated adsorption capacity of raw rectorite was 77.75mg/g, however, the capacity of lithium-modified rectorite was up to 189.62mg/g, the adsorption efficiency was increased by 144%. Therefore, the adsorption capacity of Rec-Li to methylene blue was much higher than raw rectorite. The Rec-Li and raw rectorite were characterized respectively by means of fourier transform infrared spectrophotometer (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) and colloid index measurement. The analysis indicated that, after modification by lithium, the colloid index was changed from 12mL/3g to 198mL/3g and the interlayer spacing was changed from 0.01~0.1μm to 1~1.5μm. With the increasing of the colloid index, the dispersion effect of adsorbent in wastewater and the contact area between adsorbent and pollutants were improved. And the increase of interlayer spacing was conducive to pollutants entering the hole and so that the adsorption capacity of Rec-Li was increased significantly.

Abstract: Diffusion of lithium, sodium and potassium in SiC has been studied by secondary ion mass spectrometry. The alkali metal diffusion sources have been introduced by ion implantation. Subsequent anneals have been carried out in vacuum or in Ar atmosphere in the temperature range 700 °C - 1500 °C for 5 min to 16 h. The bombardment-induced defects in the vicinity of the ion implanted profile are readily decorated by the implanted . In the bulk, the diffusing alkali metals are most likely trapped and detrapped at boron and/or other defects during diffusion. The diffusivity of the studied alkali metals decreases as the mass increases, Li⁺<Na⁺<K⁺, but the sodium mobility in SiC is substantial already at 1100 °C.