Design of amides and long-chain alkyl alcohols for high selectivity recovery of titanium and iron from ilmenite

Currently, first removal of iron and then extraction of titanium from the ilmenite leachate using solvent extraction was a popular research topic for recovery of strategic materials titanium and iron. However, the reported studies showed poor extraction efficiency and selectivity for titanium and iron in the later stage due to the randomness of initial screening of extractants, which had resulted in a lengthy process for removing impurity metal ions and increased costs. This paper designed the functional extractants for high selectivity recovery of titanium and iron from ilmenite HCl leachate based on the extraction mechanism, respectively. The extraction mechanisms were first demonstrated in detail. Then, the designed extractant, amides and long-chain alkyl alcohols, showed desired advantages and high performance for extraction of iron (99.95%) and titanium (99.23%) through actual extraction of metal ions from ilmenite HCl leachate, respectively. Meanwhile, the separation coefficients of iron and titanium to other metal ions were much greater than 1. Subsequently, the distribution and transfer laws of impurity metal ions, V, Cr, Mn, Mg, Ca and Al, in aqueous and organic phases were specifically revealed during all processes, and majority of impurity metal ions coextracted were removed. Finally, 99.82 wt% of iron solution and 99.87 wt% of titanium solution were obtained, respectively. This study may contribute to the design of functional extractants and its application in efficient recovery of valuable metals.