Papers by Keyword: Lithium

Abstract: Nowadays, in industrial production, lithium consumption is strongly increasing and it can be assumed that waste material with an increased content of this metal could also appear. One of the most important sectors where different types of waste can be utilized is the cement industry. Therefore, it is desirable to monitor the influence of lithium on formation and properties of the clinker. In the presented work, this effect was monitored in laboratory conditions up to 5 wt.% Li₂O. X-ray diffraction, DTA and optical microscopy were employed as research methods. Among other things, it has been found that Li₂O causes the decomposition of the alite, the major clinker phase, to a microcrystalline mixture of belite and free lime, depending on its content and clinker cooling rate.

Abstract: This study investigated the crystallization of soda-lime silicate (NCS) system by re-melting soda-lime silicate glass cullet with Al₂O₃ CaCO₃ and Li₂O. The Li₂O was added as a nucleating agent. The effect of the nucleating agent on crystallization was investigated in order to study the possibility for use as a parent glass for glass-ceramics. Soda-lime silicate cullet was the main raw material and its chemical composition by weight was 68% SiO2 2% Al2O3 9% Na₂O 9% K₂O 3.5% CaO 2.5% MgO 1.2% TiO₂ 3% SrO and 2% ZnO. Glass batches with composition (%wt) of (65-x) Cullet:13Al₂O₃:22CaCO₃:x(Li₂O) (x = 0, 1, 2, 4, 6 and 8) were melted at 1500°C for 3 hours and annealed at 600°C. All glasses added with Li₂O were clear except x = 8. The crystallization was investigated by Differential Scanning Colorimetry technique (DSC). The results exhibited the exothermic peak of crystallization (T_p^I and T_p^II). The glasses with added Li₂O exhibited decreasing crystallization temperature with increasing Li content. The glasses were heated at temperatures around the crystallization temperature (700, 750 and 800°C). After heat treatment, the crystalline phase in the glasses was determined by X-ray diffraction technique (XRD). The microstructure was investigated by optical microscope and Scanning Electron Microscope (SEM). The phases of Nepheline (Na,K)AlSiO₄ and Wollastonite (CaSiO₃) were found. The crystallization depended on the heat treatment temperature. The thermal expansion of the glasses was determined by the dilatometric method to indicate the characteristics of the glass-ceramics. In conclusion, Li₂O had a strong effect on the crystallization in soda-lime silicate system. The result could be applied for the production of glass-ceramics from soda-lime cullet.

Abstract: The FAME (Flexible and Mobile Economic Processing Technologies) project targets the development of flexible and economic processing technologies for small and low-grade European ore deposits with complex mineralogy, targeting greisen, skarn and pegmatite ores. Amongst the valuable elements to be recovered are W, Sn, Li and minor constituents like In, Ge, Ga, Nb or Ta. To improve the processing of by-product sulfides to recover critical elements like In or Ga and to develop innovative processing strategies for raw materials, biohydrometallurgical technologies are investigated. There are different approaches in FAME for the biohydrometallurgical recovery of valuable metals from low grade ores: 1) the extraction of Li from zinnwaldite and lepidolite, 2) the heap leaching of low grade sulfide ore unsuitable for conventional processing to recover Zn and In, and 3) the bioleaching of sulfide concentrates in a two-stage tank process for recovery of Zn and Cu. So far the most promising results were achieved for heap-leaching of low-grade Zn-In ores achieving 7.4 ppm In in the leaching solution and for Li extraction (28%) from zinnwaldite.

Abstract: The sorption properties of the outer surface of carbon nanotubes with respect to lithium are studied in connection with the search for new materials for lithium battery electrodes. The regularities of the atom ensemble structure with the increased adsorbate concentration have been investigated using ab initio method of computer modeling. Carbon nanotubes (7.7) fragment containing 112 carbon and up to 50 lithium atoms was studied. It is shown that the process of the sequential filling of the nanotube surface by adsorbate consists of two stages. The first of them (the concentration of Li is less than 8 – 9 at. %): distribution of adsorbate atoms on the surface of the tube is determined by the Coulomb repulsion of lithium ions. Chemical interaction between lithium atoms becomes significant at concentration 9 at. %. It leads to the formation of structures such as trimers and tetramers of lithium.

Abstract: This paper contains the continuation of basic research from 2012 - the molar ratio influence to water glass coatings basic properties (adhesion, diffusion properties, surface quality) was expanded with basic resistance (combination of sun, UV light and rain). Most silicate coatings for concrete protection are currently based on potassium water glass. Water glass matrix itself is, however, insufficient for coatings matrix and often is modified by polymer substances for the coating purpose. Combinations of water glass basic matrix (Sodium, Potassium, Lithium, Sodium - Lithium and Potassium - Lithium) with the appropriate polymer modifiers is also content of the presented paper. Polymer dispersions modification effect to basic properties and resistance to developed silicate coating binder is also part of paper.

Abstract: The adsorption of lithium atoms on carbon nanotubes with double vacancy structural defects (2V-defect) is being studied with first-principle modeling. The structure of defective tubes in ground state is considered, the role of effects related to finite sizes of a model is evaluated. It is demonstrated that the location of a carbon 8-ring formed by 2V-defect above the center is the most preferable for a lithium atom.

Abstract: The impact of Li⁺ dopant-ions in fluorine-containing electrolytes on electrodeposited manganese (IV) oxide material was under investigation in this paper. The dependence of phase composition of this material at Li⁺-concentration range in the electrolyte below the stoichiometric content of lithium in hollandite A₂Mn₈O₁₆ (Mn:Li ≈ 4:1) was established. The hollandite phase stabilization as a template effect caused by Li⁺-ions is gradually reduced with the Li⁺ concentration growth from 0.025 to 0.15mol∙L^-1 LiOH concentration range. The hollandite content sharply drops at close to the stoichiometric Mn:Li ratio for the hollandite phase. In contrary, the concentration of cation-deficient ε-MnO₂ becomes significant. Thus, the template effect of Li⁺ cations at electrolytic doping from fluorine-containing electrolytes consists of stabilization of the hollandite tunnels at longer distance with the size of coherent scattering regions of this phase more than of about 20—50 Å comparing with undoped materials. It is supposed that Li⁺-ions presence makes tunnel space unavailable unlike water molecules or ammonium cations. Therefore, to realise molecular sieves based on manganese (IV) oxides the availability of tunnels should be taken into account.

Abstract: The layered LiNi_1/3Mn_1/3Co_1/3O_{2 ­­} that formed with the α-NaFeO₂ structure were synthesised by conventional solid state method. Rietveld refinement results indicated that the amount of cation disorder (or known as interlayer mixing) affected by temperature. The samples that prepared at 950°C in oxygen possessed slightly lower amount of interlayer mixing and excellent cycling performance compared to samples that prepared at 900°C. The initial charge-discharge capacity delivered was ~204 mAh/g and ~140 mAh/g, respectively. Furthermore, the structural and electrochemical properties were quite comparable to reported in literatures.

Abstract: The layered rock salt LiNi_0.7Mn_0.3O₂ was prepared by conventional solid-state synthesis route. The prepared samples were analysed using X-ray diffraction (XRD) to determine purity of samples. Then, structural analysis and crystallographic properties of samples were analysed using Rietveld refinement. Rietveld refinement results indicated that the amount of cation disorder in the layered rock salt structure highly influenced by temperature and synthesis conditions. The most optimum temperature to obtain the highest degree of cation ordering is between 850^oC and 900^oC in air.

Abstract: AZ31 magnesium alloy and its alloy with 5% lithium were extruded to 1mm in thickness sheets at 380 ^oC with extrusion ratio of 101. Microstructure evolution and mechanical behavior of the extruded Mg alloy sheets were examined. The microstructure and texture evolution were investigate by electronic backscattered diffraction (EBSD) and X-ray diffraction (XRD). Mechanical performance was carried out by tensile tests at room temperature. In addition, the evolution of neutral layer and microstructure was also examined by V-bending. It was found that Li addition resulted in the strong divergence of the grain orientation. (0002) basal texture of AZ31 alloy sheets with 5% lithium has been weakened. The room temperature ductility of these textural sheets was enhanced owing to the tilted weak basal texture. Moreover, it exhibits superior ductility during V-bending process at room temperature.