Reaction Mechanism and Process Control of Hydrogen Reduction of Ammonium Perrhenate

Junjie Tang,Yuan Sun,Chunwei Zhang,Yan Liu,Long Wang,Dawei Fang,Yizhou Zhou

doi:10.3390/met10050640

Junjie Tang, Yuan Sun + Show 5 more

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https://doi.org/10.3390/met10050640

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Abstract

The preparation of rhenium powder by a hydrogen reduction of ammonium perrhenate is the only industrial production method. However, due to the uneven particle size distribution and large particle size of rhenium powder, it is difficult to prepare high-density rhenium ingot. Moreover, the existing process requires a secondary high-temperature reduction and the deoxidization process is complex and requires a high-temperature resistance of the equipment. Attempting to tackle the difficulties, this paper described a novel process to improve the particle size distribution uniformity and reduce the particle size of rhenium powder, aiming to produce a high-density rhenium ingot, and ammonium perrhenate is completely reduced by hydrogen at a low temperature. When the particle size of the rhenium powder was 19.74 µm, the density of the pressed rhenium ingot was 20.106 g/cm3, which was close to the theoretical density of rhenium. In addition, the hydrogen reduction mechanism of ammonium perrhenate was investigated in this paper. The results showed that the disproportionation of ReO3 decreased the rate of the reduction reaction, and the XRD and XPS patterns showed that the increase in the reduction temperature was conducive to increasing the reduction reaction rate and reducing the influence of disproportionation on the reduction process. At the same reduction temperature, reducing the particle sizes of ammonium perrhenate was conducive to increasing the hydrogen reduction rate and reducing the influence of the disproportionation.

Highlights

Rhenium as an important rare metal is widely used in metallurgy and the aerospace industry [1].The plasma method, electrolysis method, vapor deposition method, and powder metallurgy are the main processes for the preparation of rhenium [2,3]
ReO3 decreased the rate of the reduction reaction, and the increase in the reduction temperature was conducive to increasing the reduction reaction rate and reducing the influence of disproportionation conducive to increasing the reduction reaction rate and reducing the influence of disproportionation on the reduction process
(2) At the same reduction temperature, reducing the particle sizes of ammonium perrhenate was conducive to increasing the hydrogen reduction rate and reducing the influence of the was conducive to increasing the hydrogen reduction rate and reducing the influence of the disproportionation on the reduction process

Summary

Introduction

Rhenium as an important rare metal is widely used in metallurgy and the aerospace industry [1]. The plasma method, electrolysis method, vapor deposition method, and powder metallurgy are the main processes for the preparation of rhenium [2,3]. Jurewicz et al [4] prepared a high-purity nanometer rhenium powder by the plasma method. Leonhardt et al [5] used plasma spray spheroidization to control the microstructure of rhenium and obtained spherical rhenium powders. Schrebler et al [6] prepared spherical rhenium powder from a mixture of rhenic acid and sodium sulfate by electrolysis. Liu et al [7] prepared small particles of superfine spherical rhenium powder by vapor deposition

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