Aiming at the bottleneck of the difficult scrubbing and separation of scandium and titanium in the solvent extraction process for scandium recovery, a novel strategy for scandium–titanium separation via citrate complex scrubbing is proposed based on the difference in complexation properties between scandium/titanium and hydroxycarboxylic acids. The mixed Na₃Cit + H₂O₂ system was screened as the optimal scrubbing agent. The effects of key parameters including dosages of Na₃Cit and H₂O₂ and phase ratio (O/A) on scrubbing performance were systematically investigated. The optimal process conditions were determined as follows: temperature of 25 °C, molar ratio n(Na₃Cit)/n(Ti) = 30:1, molar ratio n(H₂O₂)/n(Ti) = 3:1, phase ratio (O/A) of 1:1, shaking speed of 200 r/min, and scrubbing time of 30 min. Under the optimal conditions, the titanium scrubbing efficiency reaches 97.37% with zero co-scrubbing efficiency of scandium. The separation efficiency is 14.47 times higher than that of the conventional H₂SO₄ + H₂O₂ scrubbing system, which significantly enhances the scandium–titanium separation performance. This work provides a feasible technical route for the deep separation and purification of scandium and titanium from titanium white waste acid.

This study addresses the challenge of achieving efficient separation of vanadium and chromium from vanadium–chromium slag (VCS) while simultaneously tackling issues related to artificial granite waste residue (AGWR), such as its substantial stockpiling and associated air pollution. AGWR was used as a substitute calcination additive for calcium carbonate to achieve efficient separation through a calcination-leaching process. Orthogonal experiments were conducted to investigate the effects of AGWR addition amount, calcination temperature, and calcination time on the leaching behavior of vanadium and chromium. During calcination, vanadium reacts with CaO (a decomposition product of AGWR) to form acid-soluble calcium vanadate. Concurrently, chromium hydroxide decomposes into chromium oxide, which is poorly soluble in dilute acid. Subsequent leaching of the calcination product with dilute sulfuric acid leaches vanadium (V) into the solution, while chromium (Cr) remains in the residue, thus achieving separation. The experimental results showed that under the conditions of 30% AGWR addition; calcination at 850 °C for 1 h; leaching at 90 °C for 2 h with a liquid-to-solid ratio of 10:1 and a sulfuric acid concentration of 50 g·L⁻¹; the leaching rate of vanadium reached 85.68%, whereas that of chromium was only 2.34%. These results demonstrate highly efficient separation of vanadium and chromium, offering valuable insights for resource recovery from both VCS and AGWR.