New Approach for Trace Thallium Removal in High Purity Ammonium Rhenate Solution by P204 Extraction
Aifei Yi,
Ying Liu,
Xingwu Lu,
Song Chen,
Honglin Jiang,
Chuanbing Shao,
Xuetao Yuan,
Yanxi Yin
Affiliations
Aifei Yi
Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, Resources and Environmental Technology Corporation Limited, Beijing 101407, China
Ying Liu
Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, Resources and Environmental Technology Corporation Limited, Beijing 101407, China
Xingwu Lu
Northwest Research Institute of Mining and Metallurgy, Baiyin 730900, China
Song Chen
Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, Resources and Environmental Technology Corporation Limited, Beijing 101407, China
Honglin Jiang
Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, Resources and Environmental Technology Corporation Limited, Beijing 101407, China
Chuanbing Shao
Northwest Research Institute of Mining and Metallurgy, Baiyin 730900, China
Xuetao Yuan
Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, Resources and Environmental Technology Corporation Limited, Beijing 101407, China
Yanxi Yin
Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, Resources and Environmental Technology Corporation Limited, Beijing 101407, China
Thallium (Tl) is an extremely toxic rare metal to the eco-environment. Trace thallium impurity in ammonium perrhenate is harmful to the high-temperature mechanical properties of rhenium metal used for aeroengine single crystal blade. The di(2-ethylhexyl) phosphoric acid (P204) extraction to remove thallium in ammonium perrhenate solution without additive was innovatively proposed. The migration behavior of trace thallium with the concentration of P204, saponification degree and organic/aqueous phase (O/A) ratio, distribution law of thallium in the extraction system of P204, and mechanism of thallium removal were revealed. It was found Tl removal was rapidly increased to 98.5%, at conditions of P204 0.75 mol/L saponified 70% by ammonia, Tl 3.27 mg/L, O/A 1:1, T 298.15 ± 2 K, 250 rpm, and 3 min. McCabe-Thiele Tl extraction equilibrium isotherms indicates Tl concentration of raffinate less than 18.7 μg/L, a theoretical extraction of two stages and a theoretical stripping of two stages are required when both O/A work lines were at 1.0. Therefore, the method of the P204 solvent extraction system can effectively extract Tl in the forms of TlA(org), TlA3(org), TlOHA2(org), and Tl(OH)2A(org). Meanwhile, the new approach can be a promising process for ammonium rhenate refining.
