Red mud is a polymetallic waste generated during Bayer's process of alumina production. High alkalinity (pH > 11), multiple elements, and micron-sized particles make red mud recycling energy-intensive and challenging. The following work presents a hydrometallurgical flowsheet for separation of different red mud elements and recovery of high purity Fe (II) product using cost-effective reagents, energy-efficient processes, and minimal waste generation. Red mud preprocessing was carried out by mild hydrochloric acid wash (1 M, 13 pct pulp density, 40 °C 15 minutes), followed by leaching of hematite from neutralized red mud in oxalic acid (2 M, 10 pct pulp density, 95 °C, 2.5 hours). UV light-assisted photochemical reduction of oxalic leach solution of red mud separated more than 98 pct Fe in the form of ferrous oxalate (purity more than 99 pct) within 5 hours. The process's material balance shows a overall recovery of more than 85 pct Fe value as solid ferrous oxalate of high purity and concentrating titanium oxide in the residue and aluminum in the leaching solution.

赤泥是拜耳氧化铝生产过程中产生的多金属废料。高碱度（pH > 11）、多种元素和微米级颗粒使赤泥回收耗能巨大且具有挑战性。以下工作介绍了使用经济高效的试剂、节能工艺和最少废物产生的湿法冶金流程，用于分离不同的赤泥元素和回收高纯度 Fe (II) 产品。赤泥预处理是通过温和的盐酸洗涤（1 M，13 pct 纸浆密度，40 °C 15 分钟）进行的，然后从草酸中中和的赤泥中浸出赤铁矿（2 M，10 pct 纸浆密度，95 ° C，2.5 小时）。赤泥草酸浸出液的紫外光辅助光化学还原在 5 小时内分离出超过 98% 的草酸亚铁形式的铁（纯度超过 99%）。该工艺的物料平衡表明，作为高纯度固体草酸亚铁和浓缩残留物中的氧化钛和浸出液中的铝，总体回收了超过 85% 的铁值。