• Title/Summary/Keyword: Rare metals

Search Result 213, Processing Time 0.032 seconds

Refinement Behavior of Coarse Magnesium Powder by High Energy Ball Milling (HEBM) (고에너지 밀링공정을 이용한 조대 마그네슘 분말의 미세화 거동)

  • Song, Joon-Woo;Kim, Hyo-Seob;Kim, Hong-Moule;Kim, Taek-Soo;Hong, Soon-Jik
    • Journal of Powder Materials
    • /
    • v.17 no.4
    • /
    • pp.302-311
    • /
    • 2010
  • In this research, the refinement behavior of the coarse magnesium powders fabricated by gas atomization was investigated as a function of milling time using a short duration high-energy ball milling equipment, which produces fine powders by means of an ultra high-energy within a short duration. The microstructure, hardness, and formability of the powders were investigated as a function of milling time using X-ray diffraction, scanning electron microscopy, Vickers micro-hardness tester and magnetic pulsed compaction. The particle morphology of Mg powders changed from spherical particles of feed metals to irregular oval particles, then platetype particles, with increasing milling time. Due to having HCP structure, deformation occurs due to the existence of the easily breakable C-axis perpendicular to the base, resulting in producing plate-type powders. With increasing milling time, the particle size increased until 5 minutes, then decreased gradually reaching a uniform size of about 50 micrometer after 20 minutes. The relative density of the initial power was 98% before milling, and mechanically milled powder was 92~94% with increase milling time (1~5 min) then it increased to 99% after milling for 20 minutes because of the change in particle shapes.

Recovery of Rare Metals from the Waste Secondary Lithium Ion Battery Cathode Active Materials Using Lactic Acid and Oxalic acid (젖산과 옥살산을 이용한 폐 이차 리튬이온 전지 양극 활물질로부터 희유금속들의 회수)

  • Kim, Younjung;Han, Ji Sun;Choi, Sik Young;Oh, In-Gyung;Hong, Yong Pyo;Ryoo, Keon Sang
    • Journal of the Korean Chemical Society
    • /
    • v.63 no.6
    • /
    • pp.446-452
    • /
    • 2019
  • We have developed a method that can leach Co, Mn, and Ni in the cathode active material safely using lactic acid. When cathode active material was leached by lactic acid, lactic acid showed the highest efficiency at 2 N than 1 N and above 4 N concentration. When the cathode active material was added incrementally into the solution of lactic acid, the maximum solubility was 30 g/L at 2 N concentration. Oxalic acid was added in the solution of lactic acid and it showed that rare metals represent the most economical recovery efficiency at 4 g/L. Based on this study, it was found that the optimal condition for recovery of rare metals from cathode active material is oxalic acid : cathode active material = 7 : 1 as a ratio of weight. In addition, it was observed that the precipitate produced by oxalic acid is a polynuclear crystalline material bonded with 3 components of Co, Ni, and Mn.

R&D Trends of Rare Metals Recovery from Seawater (해수(海水)로부터 희유금속(稀有金屬) 회수(回收) 연구동향(硏究動向))

  • Kim, Jong-Heon;Noh, Kyung-Ran;Kim, Sang-Woo;Choi, Sung-Bae;Kil, Sang-Cheol
    • Resources Recycling
    • /
    • v.22 no.6
    • /
    • pp.73-80
    • /
    • 2013
  • Marine mineral resources are classified into submarine and seawater mineral resources. In seawater, huge amounts of useful minerals, such as uranium, lithium, magnesium, aluminum, zinc, iron, silver, copper, vanadium, nickel, titanium and cobalt are present. If the rare metals recovery technology from seawater is developed, the commercialization of the precess will be possible. For the 21st century, countries rich in resoures tend to weaponize the resources, according to the depletion of reserves and quality degradation of metal resources in the land. Therefore, Korea that relies on imports for most of the metal resources, should focus on the research and development of the rare metals recovery technology from seawater by using the geographical characteristics of the country that is on three sea-sides.

The Production of Tantalum Powder by MR and EMR Method (MR법 및 EMR법에 의한 탄탈륨 분말 제조)

  • Bae, In Seong;Park, Hyeoung Ho;Kim, Byung Il
    • Journal of the Korean Society for Heat Treatment
    • /
    • v.15 no.1
    • /
    • pp.16-20
    • /
    • 2002
  • In conventional metallothermic reduction(MR) for obtaining tantalum powder in batch-type operation, it is difficult to control morphology and location of deposits because the reaction occurs by direct physical contact between reductants and feed materials. On the other hand, a electronically mediated reaction(EMR) is capable to overcome these difficulties through the reaction by electron transfer and have a merit of continuous process. In this study an MR and EMR method has been applied to the production of a tantalum powder by sodium reduction of $K_2TaF_7$. As the reduction temperature increases, the particle size and yield of tantalum powder obtained by MR and EMR method is increased.

Fabrication and Dynamic Consolidation Behaviors of Rapidly Solidified Mg Alloy Powders (급속응고 Mg 합금분말의 제조 및 동적성형특성)

  • Chae, Hong-Jun;Kim, Young-Do;Kim, Taek-Soo
    • Journal of Powder Materials
    • /
    • v.18 no.4
    • /
    • pp.340-346
    • /
    • 2011
  • In order to improve the weak mechanical properties of cast Mg alloys, Mg-$Zn_1Y_2$ (at%) alloy powders were synthesized using gas atomization, a typical rapid solidification process. The powders consist of fine dendrite structures less than 3 ${\mu}m$ in arm spacing. In order to fabricate a bulk form, the Mg powders were compacted using magnetic pulse compaction (MPC) under various processing parameters of pressure and temperature. The effects of the processing parameters on the microstructure and mechanical properties were systematically investigated.