ABSTRACT

The huge reserves of red mud have a significant potential source of scandium. The scandium can be recovered from red mud by direct acid leaching but the extraction yields are generally low, and the leaching efficiency of iron and silicon is higher. Therefore, the highly selective process steps (a combined sulfation-roasting-water leaching process) were studied to extract scandium from red mud, and in order to minimize costs and waste generated. This study focuses on the phase transformation mechanism and leaching behavior of Sc, Na, Al, Fe, Ti, Ca, and Si in the red mud sulfation-roasting-water leaching process. The results show that the maximum Sc leaching efficiency of 91.98% was obtained at optimum conditions: the roasted at 1023 K for 60 min, the ratio of sulfuric acid to red mud of 0.9 mL/g, the leaching temperature is 323 K, the liquid-to-solid ratio of 5 mL/g, and stirred constantly at 200 rpm leach for 2 h. While the leaching efficiencies of Ca, Na, Fe, Al, Si, and Ti are 21.05%, 93.26%, 1.21%, 9.51%, 1.42%, and 0, respectively. The sulfation-roasting-water leaching process proves to be a promising technique and commercially viable process that allows selective extraction of scandium from red mud, which may contribute to provide options for the treatment of red mud produced continuously by the aluminum industry.

摘要

赤泥储量巨大，是钪的重要潜在来源。直接酸浸可从赤泥中回收钪，但提取率普遍较低，铁、硅的浸出效率较高。因此，研究了从赤泥中提取钪的高选择性工艺步骤（硫酸化-焙烧-水浸出组合工艺），以最大限度地降低成本和产生的废物。本研究重点研究了Sc、Na、Al、Fe、Ti、Ca和Si在赤泥硫酸化-焙烧-水浸出过程中的相变机理和浸出行为。结果表明,在最佳条件下获得最高Sc浸出效率91.98%:1023 K焙烧60 min,硫酸赤泥配比0.9 mL/g,浸出温度323 K, 液固比为5mL/g，200rpm不断搅拌浸出2h。Ca、Na、Fe、Al、Si、Ti的浸出效率分别为21.05%、93.26%、1.21%、9.51%、1.42%、0。硫酸化-焙烧-水浸出工艺被证明是一种有前途的技术和商业上可行的工艺，可以从赤泥中选择性提取钪，这可能有助于为铝工业连续产生的赤泥的处理提供选择。