kpmi
Search
- Page Path
- HOME > Search
- [Korean]
- Basic Study on the Recycling of Waste Tungsten Scraps by the Oxidation and Reduction Process
- Sang-Uk Kim, Ji-seok Yun, Tae-Wook Kim, Bong-Hwi Cho, In-Ho Kim, Sang-Mu Kim, Chang-Bin Song
- J Korean Powder Metall Inst. 2017;24(1):34-40. Published online February 1, 2017
- DOI: https://doi.org/10.4150/KPMI.2017.24.1.34
- 272 View
- 1 Download
- 1 Citations
-
Abstract
PDF This study is carried out to obtain basic data regarding oxidation and reduction reactions, originated on the recycling of waste tungsten hard scraps by oxidation and reduction processes. First, it is estimated that the theoretical Gibbs free energy for the formation reaction of WO2 and WO3 are calculated as ΔG1,000K= -407.335 kJ/mol and ΔG1,000K = -585.679 kJ/mol, from the thermodynamics data reported by Ihsan Barin. In the experiments, the oxidation of pure tungsten rod by oxygen is carried out over a temperature range of 700-1,000°C for 1 h, and it is possible to conclude that the oxidation reaction can be represented by a relatively linear relationship. Second, the reduction of WO2 and WO3 powder by hydrogen is also calculated from the same thermodynamics data, and it can be found that it was difficult for the reduction reaction to occur at 1,027°C, in the case of WO2, but it can happen for temperatures higher than 1127°C. On the other hand, WO3 reduction reaction occurs at the relatively low temperature of 827oC. Based on these results, the reduction experiments are carried out at a temperature range of 500-1,000°C for 15 min to 4 h, in the case of WO3 powder, and it is possible to conclude that the reduction at 900°C for 2h is needed for a perfect reduction reaction.
-
Citations
Citations to this article as recorded by
- A Basic Study on the Recycling of Wasted Cemented Carbide by the Zn Bath Process(Ⅰ)
Kyung-Sik Kim, In-Ho Kim, Chan-Gi Lee, Chang-Bin Song
Journal of the Korean Institute of Resources Recycling.2020; 29(6): 35. CrossRef
- A Basic Study on the Recycling of Wasted Cemented Carbide by the Zn Bath Process(Ⅰ)
- [Korean]
- A Basic Study on the Fabrication of W-M(M=Cu, Sn, Ni) System High Density Composite (I)
- Tak-Soon Jang, Jun-Hee Hong, Tae-Haeng Lee, Jar-Myung Koo, Chang-Bin Song
- J Korean Powder Metall Inst. 2009;16(4):268-274.
- DOI: https://doi.org/10.4150/KPMI.2009.16.4.268
- 206 View
- 0 Download
- 2 Citations
-
Abstract
PDF
- For the purpose of obtaining basic information on the development of lead-free materials, a high density composites (a) W-Cu, (b) W-Sn (c)W-Cu-Sn and (d) W-Cu-Ni were fabricated by the P/M method. The particle size of used metal powders were under 325 mesh, inner size of compaction mould was phi8 mm, and compaction pressure was 400 MPa. A High density composite samples were sintered at a temperature between 140°C and 1050°C for 1 hour under Ar atmosphere. The microstructure, phase transformation and physical properties of the sintered samples were investigated. As the results, the highest relative density of 95.86% (10.87 g/cm3) was obtained particularly in the sintered W-Cu-Sn ternary system sample sintered at 450 for 1hr. And, Rockwell hardness (HRB) of 70.0 was obtained in this system.
-
Citations
Citations to this article as recorded by- Fabrication and Performance Analysis of Environment Friendly Double Core Bullets for Small Arms
Jun-Hee Hong, Tak-Soon Jang, Chang-Bin Song, Dae-Wha Kang
Journal of the Korea Institute of Military Science and Technology.2011; 14(3): 345. CrossRef - Design and Performance Analysis of Environment Friendly Double Core Bullets for Small Arms
Jun-Hee Hong, Tak-Soon Jang, Chang-Bin Song, Byung-In Kim
Journal of the Korea Institute of Military Science and Technology.2011; 14(2): 264. CrossRef
- Fabrication and Performance Analysis of Environment Friendly Double Core Bullets for Small Arms
First
Prev
TOP
