Extraction of beryllium from Indian beryl by ammonium hydrofluoride D.D. Thorat ⁎, B.M. Tripathi, D. Sathiyamoorthy Powder Metallurgy Division, Bhabha Atomic Research Centre, Vashi Complex, Turbhe, Navi Mumbai 400705, India abstract article info Article history: Received 22 November 2010 Received in revised form 2 May 2011 Accepted 3 May 2011 Available online 10 May 2011 Keywords: Beryl ore Fluorinating agents Ammonium hydrofluoride Beryllium oxide A new technique of decomposing beryl ore at low temperature with ammonium hydrofluoride (NH 4 HF 2 ) is proposed. Removing the fluorides of silicon and aluminium from the reaction product as volatile and insoluble compounds, respectively, have been investigated experimentally and the feasibility of the process has been established to extract beryllium fluoride (BeF 2 ) as a soluble compound. The sequence of reaction of beryl ore with the strong fluorinating agent NH 4 HF 2 has been studied by TG/DSC, intermediates and final products were identified by XRD. The product yield was found to be up to 93%. A process flow sheet to produce beryllia (BeO) and BeF 2 for subsequent magnesiothermic reduction to produce beryllium metal is proposed based on the experiments conducted at bench scale. Methods of recycling NH 4 HF 2 have been suggested, thereby making the proposed route superior to the conventional methods in terms of recovery, low temperature of operation, fluoride recycling, and significant reduction in effluent as well as improved safety in handling of beryllium. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Beryllium is rare in the earth's crust (6 × 10 -4 % per weight) and its presence is rather limited (Zaki et al., 2005). It does not occur as free metal in nature. There are about 30 minerals containing beryllium, the most significant of them being beryl (3BeO·Al 2 O 3 ·6SiO 2 ), phenacite (2BeO·SiO 2 ), chrysoberyl (BeO·Al 2 O 3 ) and bertrandite (4BeO·2SiO 2 ·H 2 O) (Zaki et al., 2005). The main interest in beryllium is its unique combination of mechanical, thermal and nuclear properties. Properties of such as high melting point (1285±5 °C) (Zaki et al., 2005), low neutron absorption and high scattering cross sections make beryllium attractive for use in nuclear reactors as neutron reflector and moderator. Beryllium, because of its neutron multiplication properties by (n, 2n) reaction for high energy neutrons, coupled with low neutron damage in displacements per atom (dpa) (Argentina et al., 2000), is considered as neutron multiplier material in the solid breeder blanket of the International Thermonuclear Experimental Reactor (ITER). Beryllium is also consid- ered as plasma facing material (PFM) (Argentina et al., 2000) in ITER. Because of its high thermal conductivity combined with electrical resistivity, BeO is an ideal material for heat sinks in electronic circuits and packages. The high melting point (2570 °C), coupled with negligible vapour pressure right up to the temperature of melting, make BeO a suitable crucible material for many melting and sintering operations (SAHA, 1994a). One of the priority applications of beryllium in fusion reactors is in the form of molten salt mixture of LiF and BeF 2 commonly referred to as Flibe. This salt system has been considered for application as a renewable plasma-facing surface in advanced concepts of fusion reactors and also as a coolant (Argentina et al., 2000). Beryllium intermetallics, particularly Be 12 Ti are an advanced material under consideration as neutron multiplier for fusion demon- stration blanket (Kawamura et al., 2002). Aluminium matrix-beryllium composites can find special applications in avionics, space related optical systems, structural components for satellites, propellants etc. These composites combine the high modulus and low density of beryllium with the favourable fracture toughness, ductility and fabrication characteristics of aluminium. Because of an ever increasing number of applications for beryllium and its compounds in various domains of science and technology, it is important to develop an efficient method for extracting beryllium from its ore and it has been a thrust area of research and development in beryllium technology till date. In the present study, an attempt has been made to develop an economically viable, efficient, and waste free process for extracting beryllium from Indian beryl using ammonium hydrofluoride. 2. Background In India, beryllium is extracted from beryl ore. There are fairly large deposits of this ore available in India at locations in Andhra Pradesh, Rajasthan and Bihar. In its pure form, beryl ore is a beryllium-aluminium silicate (3BeO·Al 2 O 3 ·6SiO 2 ). A typical composition of Indian Beryl is about 11–12% BeO, 19% Al 2 O 3 , 64% SiO 2 ,1–2% alkali metal oxides, and minor amounts of other oxides (SAHA, 1994b). Hydrometallurgy 109 (2011) 18–22 ⁎ Corresponding author. Tel.: + 91 22 2788 7178; fax: + 91 22 27840032. E-mail addresses: thoratdd@yahoo.com (D.D. Thorat), biranchi.barc@gmail.com (B.M. Tripathi), dsathiyamoorthy@gmail.com (D. Sathiyamoorthy). 0304-386X/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.hydromet.2011.05.003 Contents lists available at ScienceDirect Hydrometallurgy journal homepage: www.elsevier.com/locate/hydromet