Purification of beryllium by acetylacetone EDTA solvent extraction: procedure and chemistry

Abstract

A procedure, described previously, for the preparation of high purity beryllium hydroxide has been improved and demonstrated on a kilogram scale, and a systematic study of its chemistry has been carried out. The Be(OH)2·xH2O starting material is dissolved in acetylacetone (HX) as BeX2, scrubbed with aqueous EDTA to remove metallic impurities, stripped with nitric acid, and precipitated with ammonia. The dried Be(OH)2 · 0.3 H2O, a granular, free-flowing powder, was obtained in 85% yield. Detectable metallic impurities totalled <5 parts/106. The variation of BeX+ and BeX2 formation quotients with ionic strength as well as the variation of BeX2 and HX distribution coefficients with both aqueous ionic strength and organic phase composition are summarized. Decontamination efficiencies for some 13 cations were estimated to be very high. Effective purification was demonstrated on a sample of Be(OH)2 starting material which was contaminated with 1000 parts/106 parts BeO of Na+, Mg2+, B(III), Cu2+, Al3+, Fe3+ and Cr3+