(249m) Simultaneous Oxidation and 2-Octanol Extraction of Iron from Simulated Ilmenite Hydrochloric Acid Leachate

Abstract

Separation of ferrous iron from titanium (IV) in a simulated ilmenite hydrochloric acid leachate by simultaneous oxidation and 2-Octanol extraction was investigated. The effects of extraction time, oxygen flow rate, O/A phase ratio, temperature, and hydrochloric acid concentration were studied. The results showed that with pure oxygen as oxidant and 100% (v/v) 2-Octanol as extractant, the oxidation of ferrous and extraction of iron were up to 99% and 86%, respectively while no titanium was co-extracted under O/A 1:3, hydrochloric acid concentration 9.35 mol/L, oxygen flow rate 1000 ml/min, reaction temperature 35 ºC and reaction time 30 min. With two stages of cross-current operation, the total iron extraction amounted over 99.5% and still no titanium was co-extracted. The composition of extraction complex was HFeCl₄·5(2-Octonol). 100% of iron stripping was obtained using distilled water as a stripping liquor at an O/A ratio of 1:1 through a single contact. Thus, an almost complete separation of iron (II) and titanium (IV) from the simulated leachate by simultaneous oxidation and 2-Octanol extraction was feasible. The process could by-produce Fe₂O₃ with high purity. The kinetics of both the extraction and stripping of iron (III) were very fast while the oxidation of iron (II) was comparatively slow. The oxidation could be accelerated significantly by increasing hydrochloric acid concentration and reaction temperature. Enhancement of the oxidation through improving the structure of gas-liquid-liquid multiphase reactor was also expected. An improved hydrochloric acid process for pigment production was proposed.

Keywords: solvent extraction; iron; 2-Octanol; oxidation; hydrochloric acid process

[1] R. K. Biswas, M. A. Habib, N. C. Dafedar, 1992,  A study on the recovery of titanium from hydrofluoric acid leach solution of ilmenite sand Hydrornetallurgy, 28 (1), 119-126.

[2] Wang, X. M., Liang, B., Lü,L., Wu, P., Li, C., Ma, J. Simultaneous oxidation and extraction of iron from simulated ilmenite hydrochloric acid leachate [J]. Hydrometallurgy. 129-130 (2012) 105–110.

[3]Saji, J.K., Rao, T.P., Iyer, C.S.P., Reddy, M.L.P., 1998. Extraction of iron(III) from acidic chloride solutions by Cyanex 923. Hydrometallurgy 49, 289–296.

[4] Saji, J.K., Saji, J., Reddy, M.L.P., Ramamohan, T.R., Rao, T.P., 1999b. Solvent extraction of titanium(IV) from acidic chloride solutions by Cyanex 923. Hydrometallurgy 51(1), 9–18；

[5] Thomas, J., Surender, G.D., Reddy, M.L.P., 2002. Liquid–liquid extraction of tetravalent titanium from acidic chloride solutions by trialkylphosphine oxide. Proceedings of International Symposium on Solvent Extraction (ISSE), September, 2002, Bhubaneswar, India, pp. 159–168.

[6]Sato, T., 2003. Liquid–liquid extraction of titanium(IV) from hydrochloric acid solutions by di-(2-ethylhexyl) phosphoric acid. Sigen-to-Suzai 119, 175–181.

[7] Liang, B., Li, C., Zhang, C.G., Zhang, Y.K., 2005. Leaching kinetics of Panzhihua ilmenite in sulfuric acid. Hydrometallurgy 76 (3-4), 173-179.

[8] Li, C., Liang, B., Guo, L.H., 2007. Dissolution of mechanically activated Panzhihua ilmenites in dilute solutions of sulfuric acid. Hydrometallurgy 89 (1-2), 1-10.

[9] Li, C., Liang, B., Wang, H.Y., 2008. Preparation of synthetic rutile by hydrochloric acid leaching of mechanically activated Panzhihua ilmenite. Hydrometallurgy 91 (1-4), 121-129.