Premium
Single‐pass flow‐through reaction cell for high‐temperature and high‐pressure in situ neutron diffraction studies of hydrothermal crystallization processes
Author(s) -
Xia Fang,
Brugger Joël,
Qian Gujie,
Ngothai Yung,
O'Neill Brian,
Zhao Jing,
Pullen Stewart,
Olsen Scott,
Pring Allan
Publication year - 2012
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889812002300
Subject(s) - hydrothermal circulation , crystallization , supercritical fluid , volumetric flow rate , ambient pressure , materials science , volume (thermodynamics) , analytical chemistry (journal) , hydrothermal synthesis , neutron diffraction , powder diffractometer , mineralogy , chemistry , diffraction , chemical engineering , thermodynamics , crystallography , optics , crystal structure , chromatography , physics , organic chemistry , engineering
A large‐volume single‐pass flow‐through cell for in situ neutron diffraction investigation of hydrothermal crystallization processes is reported. The cell is much more versatile than previous designs owing to the ability to control independently and precisely temperature (up to 673 K), pressure (up to 46 MPa), flow rate (0.01–10 ml min −1 ) and reaction‐fluid volume (≥65 ml). Such versatility is realized by an innovative design consisting of a room‐temperature and ambient‐pressure external fluid supply module, a high‐pressure reaction module which includes a high‐temperature sample compartment enclosed in a vacuum furnace, and a room‐temperature and high‐pressure backpressure regulation module for pressure control. The cell provides a new avenue for studying various parameters of hydrothermal crystallizations independently, in situ and in real time at extreme hydrothermal conditions ( e.g. supercritical). The cell was successfully commissioned on the high‐intensity powder diffractometer beamline, Wombat, at the Australian Nuclear Science and Technology Organisation by investigating the effect of pressure on the hydrothermal pseudomorphic conversion from SrSO 4 (celestine) to SrCO 3 (strontianite) at a constant temperature of 473 K and flow rate of 5 ml min −1 . The results show that the increase of pressure exerts a nonlinear effect on the conversion rate, which first increases with increasing pressure from 14 to 20 MPa, and then decreases when pressure further increases to 24 MPa.