Portal de Periódicos da CAPES

Development of a SISAK extraction system for chemical studies of element 108, hassium

2010; R. Oldenbourg Verlag; Volume: 98; Issue: 12 Linguagem: Inglês

10.1524/ract.2010.1787

2193-3405

F. Samadani, J. Alstad, T. Bjørnstad, L. Stavsetra, J. P. Omtvedt,

Nuclear physics research studies

Abstract A liquid–liquid extraction system suitable for studies of chemical properties of Hs (element 108), in the form of HsO 4 , was developed using γ-emitting isotopes of its homologue Os. The system is targeted for the fast on-line extraction system SISAK, which operates in a continuous manner and is suitable for liquid-phase studies of transactinide elements. The distribution of OsO 4 between various dilute NaOH solutions and toluene was studied. Both batch and SISAK on-line experiments were performed to develop an appropriate system. From analysis of the extraction curves equilibrium constants for the formation of the presumed complexes, Na[OsO 4 (OH)] and Na 2 [OsO 4 (OH) 2 ], were obtained: K 1 =(1±0.5)×10 4 and K 2 =12±8, respectively. The SISAK system includes a liquid-scintillation detection system for α measurements. Due to quenching effects it is not possible to perform direct measurement of the aqueous phase α´s. Therefore, a two-stage extraction method that provides an indirect measurement of the activity in the aqueous phase was developed as part of the proposed system for Hs: Acidification of the raffinate from the first stage result in recovery of OsO 4 , which is highly extractable into toluene. The yield of extraction in the second step, from 0.01 M NaOH solution after acidification with H 2 SO 4 solution, was (90±3) %.