Recovery and concentration of strong mineral acids from dilute solutions through LLX. II. reversible extraction with branched-chain amines

Tri(2-ethylhexyl) amine (TEHA) was found to be a considerably weaker extractant for mineral acids than straight chain aliphatic amines. It is still, however, markedly stronger than solvating extractants such as alcohols and esters. Its medium strength provides for a relatively wide range of efficient and reversible extraction. TEHA and similarly branched chain tertiary amines are therefore suitable for recovery of strong mineral acids from effluents containing them in low concentrations. Effects of diluents and modifiers and of amine concentration were found to provide a strong tool for adjusting the range of efficient and reversible extraction to characteristics of treated solutions.