The Influences of Stirring on the Recrystallization of Ammonium Perrhenate

Abstract

Ammonium perrhenate is widely used in alloy manufacturing, powder processing, the catalytic industry, and other fields. Recrystallization can improve the specific surface area of ammonium perrhenate, reduce its particle size, and improve its particle size distribution uniformity. Therefore, recrystallized ammonium perrhenate can obtain better application benefits in the above fields. Stirring is an important factor that affects the recrystallization of ammonium perrhenate, and this paper systematically analyzes the influence of the stirring paddle types and stirring intensities on ammonium perrhenate during the homogeneous recrystallization process, ultimately revealing the relationship between the growth rate of ammonium perrhenate and the stirring process. Particle image velocimetry physical simulation results showed that the flow field in the reactor was more evenly distributed when using the disc turbine impeller, and a relatively uniform velocity liquid flow area was formed in the whole reactor, while the low-velocity liquid flow area was smaller. Therefore, this information, combined with SEM test results, suggests that under the same recrystallization time and stirring intensity, the stirring effect of a disc turbine impeller is more suitable than a propelling propeller and an Intermig impeller for the recrystallization process of ammonium perrhenate. Moreover, the XRD patterns and SEM analysis showed that if the agglomeration in the systems was too strong or too weak, the growths of the (101) crystal plane and (112) crystal plane were restrained, which caused an attenuation in the growth rates along the crystallographic directions that were orthogonal to the crystal faces. Finally, the reduction experiments show that the recrystallization of ammonium perrhenate could improve the phase parameters of rhenium powders.

Reaction of Perrhenate with Phthalocyanine Derivatives in the Presence of Reducing Agents and Rhenium Oxide Nanoparticles in Biomedical Applications

“…The PXRD analysis further confirmed the presence of Re IV , Re VI , and Re VII , corresponding to ReO 2 , ReO 3 , NH 4 ReO 4 and H 0.57 ReO 3 , respectively (Figure 7). [39][40][41] However, the PXRD profiles (Figure 7) showed multiple phases of amorphous rhenium oxides as expected for mixed-valence rhenium oxide nanoparticles. [28,42] FolateÀ Tetraaminophthalocyanine-Capped Nanoparticles (Re x O y À TAPcÀ FA NPs).…”

Reaction Mechanism and Process Control of Hydrogen Reduction of Ammonium Perrhenate

“…The thermally saturated solution of ammonium perrhenate was introduced into the recrystallization condensation reactor; the stirring speed and cooling temperature were adjusted and recrystallized at 5 • C for 3 h. Finally, the cooled solid-liquid mixture was filtered and dried to obtain ammonium perrhenate crystals. The SEM diagrams of the recrystallized ammonium perrhenate are shown in Figure 3 [29], and the median diameters (D 50 ) and specific surface area are shown in Table 1. The recrystallization ammonium perrhenate particles (60 g) were reduced with the different temperatures (300-900 • C) in the high-temperature vacuum sintering furnace; the hydrogen flow rate was 500 mL/min, and the heating rate was 10 • C/min.…”

Investigations of the Density and Solubility of Ammonium Perrhenate and Potassium Perrhenate Aqueous Solutions

“…There is one publication about the multistage recrystallization of CAP to remove potassium [41]. Apart from that, the influence of stirring on the recrystallization of ammonium perrhenate has been examined [42]. Other properties, the thermal expansion coefficient, the standard enthalpies formation, and the heat capacity single crystals APR and PPR, have also been determined [43][44][45][46].…”