Abstract Gamma-phase of the lithium aluminate (LiAlO2) is a ceramic powder used in molten carbonate fuel cells (MCFCs) and in other nuclear and ceramic applications. Upon exposure to water vapor and carbon dioxide at 25 °C, we have observed, that gamma-LiAlO2 converts to lithium aluminum carbonate hydroxide hydrate, Li2Al4(CO3)(OH)12·3H2O (LACHH) and Li2CO3. The conversion was detected by X-ray diffraction (XRD) and carbonate analysis. An equation for the conversion is given, and the morphology is determined by scanning electron microscopy. A high-temperature XRD study and thermogravimetric/differential thermal analysis (TGA/DTA) showed that LACHH decomposes at 250 °C. The decomposition products of LACHH and Li2CO3 react to form of alpha-LiAlO2 at first and then to gamma-LiAlO2 at temperatures of 650 and 1000 °C, respectively. This paper represents research of obtaining lithium aluminum carbonate hydroxide hydrate, Li2Al4(CO3)(OH)12·3H2O (LACHH) suitable for aluminothermic recovery of lithium. Thermodynamic calculations were carried out and the characteristics of the LACHH and compounds based on it were determined. Optimal conditions of the process (temperature, concentration of aluminum solution, duration of deposition) were investigated: running the process at 90 °C for 4 h with slow stirring at 60–90 rpm using an aluminum solution of 120 g/l Al2O3 (caustic module 3.8), the consumption of reagents for the preparation of aluminum solution is less by 25–40 %. The maximum yield of LACHH is 94,25%. XRD analysis confirms the deposition of LACHH. Also the possibility of its implementation as a raw material in a combined process of the aluminothermic production of lithium “Synthesis–Reduction” was confirmed. These materials interlayered with free-electron compound, in addition to traditional methods of use, are highly perspective materials in various technologies: in the production of lithium, potential for use as a matrix of red phosphor, carbonate fuel cells are perspective in use in high-temperature power generating devices.

中文翻译：

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铝酸盐溶液湿法制备氢氧化铝碳酸锂、Li2Al4(CO3)(OH)12·3H2O

摘要 铝酸锂 (LiAlO2) 的伽马相是一种陶瓷粉末，用于熔融碳酸盐燃料电池 (MCFC) 以及其他核和陶瓷应用。在 25 °C 下暴露于水蒸气和二氧化碳时，我们观察到，γ-LiAlO2 转化为碳酸锂铝氢氧化物水合物、Li2Al4(CO3)(OH)12·3H2O (LACHH) 和 Li2CO3。通过X射线衍射(XRD)和碳酸盐分析检测转化。给出了转化方程，并通过扫描电子显微镜确定了形态。高温 XRD 研究和热重/差热分析 (TGA/DTA) 表明 LACHH 在 250 °C 下分解。LACHH 和 Li2CO3 的分解产物首先反应形成 α-LiAlO2，然后分别在 650 和 1000 °C 的温度下反应形成 γ-LiAlO2。本文代表了获得适合铝热回收锂的锂铝氢氧化物水合物Li2Al4(CO3)(OH)12·3H2O(LACHH)的研究。进行了热力学计算，并确定了 LACHH 和基于它的化合物的特性。研究了该工艺的最佳条件（温度、铝溶液浓度、沉积持续时间）：使用 120 g/l Al2O3（苛性碱模块 3.8)，用于制备铝溶液的试剂消耗量减少 25-40%。LACHH 的最大产率为 94.25%。XRD 分析证实了 LACHH 的沉积。也证实了其在铝热生产锂“合成-还原”的联合过程中作为原材料实施的可能性。这些夹层有自由电子化合物的材料，除了传统的使用方法外，在各种技术中都是非常有前景的材料：在锂的生产中，用作红色磷光体基质的潜力，碳酸盐燃料电池在高-温度发电装置。