Lithium aluminum oxide has previously been identified to be a suitable compound to recover lithium (Li) from Li-ion battery recycling slags. Its formation is hampered in the presence of high concentrations of manganese (9 wt.% MnO₂). In this study, mock-up slags of the system Li₂O-CaO-SiO₂-Al₂O₃-MgO-MnO_x with up to 17 moL% MnO₂-content were prepared. The manganese (Mn)-bearing phases were characterized with inductively coupled plasma optical emission spectrometry (ICP-OES), X‑ray diffraction (XRD), electron probe microanalysis (EPMA), and X-ray absorption near edge structure analysis (XANES). The XRD results confirm the decrease of LiAlO₂ phases from Mn-poor slags (7 moL% MnO₂) to Mn‑rich slags (17 moL% MnO₂). The Mn‑rich grains are predominantly present as idiomorphic and relatively large (>50 µm) crystals. XRD, EPMA and XANES suggest that manganese is present in the form of a spinel solid solution. The absence of light elements besides Li and O allowed to estimate the Li content in the Mn‑rich grain, and to determine a generic stoichiometry of the spinel solid solution, i.e., (Li_(2x)Mn²⁺_(1−x))_1+x(Al_(2−z),Mn³⁺_z)O₄. The coefficients x and z were determined at several locations of the grain. It is shown that the aluminum concentration decreases, while the manganese concentration increases from the start (x: 0.27; z: 0.54) to the end (x: 0.34; z: 1.55) of the crystallization.

中文翻译：

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与锂离子电池锂回收相关的合成回收渣中锰的形态

先前已经确定锂铝氧化物是从锂离子电池回收渣中回收锂（Li）的合适化合物。在高浓度锰（9 wt。％MnO ₂）存在下，其形成受到阻碍。在这项研究中，制备了Li ₂ O-CaO-SiO ₂ -Al ₂ O ₃ -MgO-MnO _x系统的模拟渣，其中MnO ₂含量最高为17 moL％。含锰（Mn）相的特征在于电感耦合等离子体发射光谱（ICP-OES），X射线衍射（XRD），电子探针微分析（EPMA）和X射线吸收近边缘结构分析（XANES） 。XRD结果证实了LiAlO ₂的减少从贫锰渣（7 moL％MnO ₂）到富锰渣（17 moL％MnO ₂）的相。富含Mn的晶粒主要以同晶和较大（> 50 µm）的晶体形式存在。XRD，EPMA和XANES表明锰以尖晶石固溶体形式存在。除了Li和O以外，没有轻元素可以估算富锰晶粒中的Li含量，并确定尖晶石固溶体的一般化学计量，即（Li _{（2 x）} Mn ²⁺ _{（1- x）}）_{1+ x}（Al _{（2- z）}，Mn ³⁺ _z）O ₄。系数x和z是在晶粒的几个位置确定的。结果表明，从结晶开始（x：0.27；z：0.54）到结束（x：0.34；z：1.55），铝浓度降低，而锰浓度升高。