Technical Note Liquid–liquid extraction (LLE) of iron and titanium by bis-(2-ethyl-hexyl) phosphoric acid (D2EHPA) Glauco Corre ˆa da Silva a , Jose ´ Waldemar Silva Dias da Cunha a , Jo Dweck b , Julio Carlos Afonso c, * a Nuclear Institute of Engineering, Caixa Postal 68456, 21941-909 Rio de Janeiro, Brazil b School of Chemistry, Federal University of Rio de Janeiro, Caixa Postal 68561, 21949-900 Rio de Janeiro, Brazil c Institute of Chemistry, Federal University of Rio de Janeiro, Caixa Postal 68563, 21949-900 Rio de Janeiro, Brazil Received 20 April 2007; accepted 22 October 2007 Available online 3 December 2007 Abstract This work presents the results of the Fe(III) and Ti(IV) separation using D2EHPA (1.5 mol L 1 in n-dodecane), after ilmenite leach- ing with H 2 SO 4 . It was possible to recover over 99 wt% Ti in a two-stage process. The co-extracted Fe was stripped (>99.5 wt%) with 4.5 mol L 1 H 2 SO 4 . Fe can be extracted from this solution by D2EHPA (1.5 mol L 1 in n-dodecane) in 61.2 mol L 1 H 2 SO 4 . Both met- als can be stripped from the organic phase by aqueous F  (pH 4.5). The stripping and the residual acid solutions can be recycled. The LLE process is a feasible alternative for producing high purity TiO 2 . Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Hydrometallurgy; Leaching; Solvent extraction 1. Introduction Ilmenite is a Fe(II) titanate (FeTiO 3 ) containing other elements such as Al, Cr, Mg, Mn, Nb, P, Si and V. The Brazilian monazite sands are mainly found in coastal regions and contain about 20 wt% ilmenite. They are pro- cessed by the Brazilian Nuclear Industries (INB), the mon- azite being recovered as a raw material for lanthanides, Th and U. Ilmenite is a by-product, as are rutile and zirconite (ZrSiO 4 ), and is sold as a low commercial value Ti ore. The development of technological applications for Ti and its corresponding alloys/oxide justifies large-scale pro- duction of such compounds. The known reserves of Ti oxi- des (rutile/anatase) are decreasing, so other Ti minerals must be used, ilmenite being the immediate choice due to its abundance (Sarker et al., 2006). Ilmenite processing requires drastic leaching conditions, basically with hot concentrated mineral acids (El-Hazek et al., 2007; Liang et al., 2005; Sarker et al., 2006; Li et al., 2006). The main industrial route is the sulphate pro- cess (thermal hydrolysis). The production of 1 ton of syn- thetic TiO 2 by this route generates about 3.5 ton of wastes (Liu et al., 2006). 2. Liquid–liquid extraction (LLE) The separation of Ti from Fe is critical in obtaining high purity grade TiO 2 . LLE of Ti is a good strategy for this purpose and an alternative in reducing wastes generated in conventional processes. Bis-(2-ethyl-hexyl) phosphoric acid (D2EHPA) is resistant to hydrolysis in acid medium during Ti extraction, which is extracted in preference to Fe (Biswas et al., 2002; Phalke et al., 1997). Aqueous H 2 SO 4 is the most used medium. Most literature studies have reported standard diluted solutions of the elements and quite different free acidities from those produced after leaching Ti minerals by industrial routes. The present work aims at developing a separation and purification process for Fe(III) and Ti(IV) from H 2 SO 4 0892-6875/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.mineng.2007.10.013 * Corresponding author. Tel.: +55 21 2562 7555; fax: +55 21 2562 7262. E-mail address: julio@iq.ufrj.br (J.C. Afonso). This article is also available online at: www.elsevier.com/locate/mineng Available online at www.sciencedirect.com Minerals Engineering 21 (2008) 416–419