Abstract In the present work, a feasible approach was developed for the recovery of cerium and lanthanum from rare earth polishing powder wastes to synthesize shape-controlled CeO2 and perovskite-type La0.6Ca0.4CoO3 powders. The process proposed here includes six steps: (i) Pre-roasting treatment, (ii) H2SO4 digestion and water leaching, (iii) double salt (NaRE(SO4)2·xH2O) precipitation, (iv) conversion of NaRE(SO4)2·xH2O into RE‑carbonate, (v) oxidation and separation of cerium and lanthanum, and (vi) oxalic salt precipitation conversion and calcinations to synthesize CeO2 and glycine-nitrate combustion process to get La0.6Ca0.4CoO3.The recovery yield for the total process was 91.73% for cerium and 90.45% for lanthanum. In the preparation process of CeO2 and La0.6Ca0.4CoO3, CeO2 powders with controlled shapes were obtained by modifying the final pH value in the precipitate transformation from Ce(OH)4 to cerium oxalate and subsequent calcinations. On the other hand, based on the polarization curves, the prepared La0.6Ca0.4CoO3 exhibited a good catalytic activity for oxygen reduction reaction, showing potential applications in zinc-air batteries.

中文翻译：

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稀土抛光粉废料中铈和镧转化为CeO2和La0.6Ca0.4CoO3

摘要 在目前的工作中，开发了一种从稀土抛光粉废料中回收铈和镧以合成形状可控的 CeO2 和钙钛矿型 La0.6Ca0.4CoO3 粉末的可行方法。这里提出的工艺包括六个步骤：(i) 预焙处理，(ii) H2SO4 消化和水浸，(iii) 复盐 (NaRE(SO4)2·xH2O) 沉淀，(iv) NaRE(SO4) 的转化2·xH2O 转化为稀土碳酸盐，(v) 铈和镧的氧化和分离，以及 (vi) 草酸盐沉淀转化和煅烧合成 CeO2 和甘氨酸-硝酸盐燃烧过程得到 La0.6Ca0.4CoO3。铈的总过程为 91.73%，镧的为 90.45%。在CeO2和La0.6Ca0.4CoO3的制备过程中，通过改变从 Ce(OH)4 到草酸铈的沉淀转化和随后的煅烧过程中的最终 pH 值，获得了形状可控的 CeO2 粉末。另一方面，根据极化曲线，制备的 La0.6Ca0.4CoO3 对氧还原反应表现出良好的催化活性，显示出在锌空气电池中的潜在应用。