In this work, a novel approach of leaching valuable metals, such as niobium, yttrium and cerium, from a niobium-bearing ore of low grade by roasting KHSO4–H2SO4 system was experimentally studied. Through the work, the effects of roasting temperature, roasting time, mass ratio of agents to ore and the types of leaching agents on the extraction of Nb, Y and Ce were investigated, and the roasting KHSO4–H2SO4–ore system was thought as an effective method to extract these valuable metals. It was found that the recovery of Nb, Y and Ce can, respectively, reach 90.20%, 97.22% and 98.41% in condition of roasting temperature of 300 °C, roasting time of 2 h, mass ratio of KHSO4-to-H2SO4 to ore of 0.5:1:1, particle size of − 74 μm (~ 95%), leaching solution of oxalic acid (30 g·L−1), leaching temperature of 90 °C and leaching liquid-to-solid ratio of 5:1. The leaching kinetics of the calcined Nb-bearing ore in oxalic acid solution was successfully modeled by chemical reaction model, and the apparent activity energy was obtained to be 14.16 kJ·mol−1. The results generated from this work will provide the fundamentals for extracting Nb, Y and Ce from a niobium-bearing ore of low grade and have potential applications value in future.

中文翻译：

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KHSO4-H2SO4焙烧体系从低品位铌矿中提取Nb、Y、Ce新方法

在这项工作中，实验研究了一种通过焙烧 KHSO4-H2SO4 系统从低品位含铌矿石中浸出铌、钇和铈等有价值金属的新方法。通过这项工作，研究了焙烧温度、焙烧时间、药剂与矿石的质量比以及浸出剂的类型对 Nb、Y 和 Ce 提取的影响，认为焙烧 KHSO4-H2SO4-矿石体系是一种提取这些有价金属的有效方法。结果表明，在焙烧温度为 300 ℃、焙烧时间为 2 h、KHSO4 与 H2SO4 的质量比为 90.20%、97.22% 和 98.41% 的条件下，Nb、Y、Ce 的回收率分别达到矿石0.5:1:1，粒度−74 μm（~95%），草酸浸出液（30 g·L−1），浸出温度90℃，浸出液固比5 :1。用化学反应模型成功模拟了煅烧含铌矿石在草酸溶液中的浸出动力学，得到表观活性能为14.16 kJ·mol-1。这项工作的结果将为从低品位含铌矿石中提取 Nb、Y 和 Ce 提供基础，并在未来具有潜在的应用价值。