Extraction of aluminum and iron from bauxite: A unique closed‐loop ore refining process utilizing oxalate chemistry

Abstract

The Bayer process holds an exclusive status for alumina extraction, but a massive amount of caustic "red mud" waste is generated. In this work, three oxalate reagents:and oxalic acid (H 2 C 2 O 4 ) were investigated for the Al and Fe extraction process from NIST SRM 600 Australian-Darling range bauxite ore. More than 90% of Al and Fe was extracted into the aqueous phase in less than 2 h with 0.50 M C 2 O 2À 4 for all three reagents. The Fe and Al can be selectively precipitated by hydrolyzing the aqueous phase. By acidifying the Al and Fe free filtrate, 80% of the C 2 O 2À 4 can be precipitated as KHC 2 O 4 ÁH 2 C 2 O 4 . Greater than 90% of the aqueous acid can also be recycled using a cation-exchange resin. The proposed closed-loop process is an energy-efficient, cost-effective, environmentally-friendly route for extracting Al and Fe from bauxite ore.

Lithium and Cobalt Recovery from LiCoO2 Using Oxalate Chemistry: Scale-Up and Techno-Economic Analysis

“…Similar to the processes demonstrated in this work, Li has to be precipitated before the addition of the NMC oxalate. If any Fe 3+ and Al 3+ impurities are present, they can be selectively precipitated in the form of the respective metal hydroxides, as demonstrated in our previous work for bauxite ore . The higher solubility of Li­(OH) 2 compared to Fe and Al hydroxides will retain Li in the aqueous phase for Li 2 CO 3 precipitation.…”

A Review of Sodium Oxalate Solubility in Water

“…The solubility of disodium oxalate is not only of interest to industries that use it but is also an input to alternative analyses for reagent selection. For instance, recent hydrometallurgical process development teams chose to use dipotassium oxalate as a reagent instead of disodium oxalate because of the higher solubility of dipotassium oxalate. , …”

“…For instance, recent hydrometallurgical process development teams chose to use dipotassium oxalate as a reagent instead of disodium oxalate because of the higher solubility of dipotassium oxalate. 14,15 The impetus for the present study is to better understand oxalate behavior in alkaline nuclear waste at sites such as Hanford and Savannah River in the United States. The Hanford Site maintains an inventory of nuclear waste constituents in a database called the Tank Waste Inventory Network System.…”