Nitride Intermediates in the Preparation of Columbium, Vanadium, and Tantalum Metals (in Two Parts): 1. Nitride Preparation

Details

• Personal Author:
  Atkinson, Gary B. ; Guidotti RA ; Kesterke DG
• Description:
  The federal Bureau of Mines has studied the reaction of oxides of columbium, vanadium, and tantalum with ammonia in vertical, gas- solids reactors at temperatures ranging from 300 deg to 1,300 deg c with the goal of preparing nitride intermediates for subsequent preparation of the metals by a thermal-decomposition step. The best nitride conversions were obtained in nonmetal reactors. With cb2o5, v2o3, and v2o5, low-temperature maxima in reaction rates occurred at 800 deg, 800 deg, and 450 deg c, respectively, during oxynitride formation (in al2o3) in 1 atm of pure ammonia. Conversion of the oxynitride, in a second step, to the mononitride was optimum at 1,200 deg c for columbium and 1,050 deg c for vanadium. In the case of ta2o5, the rate of reaction to form ta3n5 (in a single step) was highest at 900 deg c, where the presence of up to 5 percent methane was found to be beneficial; improved results were obtained by conducting the nitriding in a rotary kiln. Optimum space velocities (in the vertical al2o3 reactor) ranged from 5,280 hr-1 for cb2o5 to 7,950 hr-1 for v2o3. Oxide particle size had little effect upon reaction rates. Under fully optimized conditions, products containing less than 1 percent oxygen were readily obtained in under 6 hours. [Description provided by NIOSH]
• Subjects:
  Occupational Health Safety
• Series:
  Mining Publications
• Subseries:
  Report of Investigations
• Document Type:
  Text
• Genre:
  Conference Publications ; Case Report
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  RERC - Reno Research Center
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-25
• NIOSHTIC Number:
  nn:10007588
• NTIS Accession Number:
  PB248108
• Citation:
  NTIS: PB 248 108 :25 pages
• Federal Fiscal Year:
  1975
• Peer Reviewed:
  False
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:b3e4f393aee5df2e26a6fa425282259795b1c0d5e5d5321a36605901864751e67f219e7f5e707e119ed176ee08ad408ec3767cfd00d56a829425c36f543a1fa5
• Download URL:
  https://stacks.cdc.gov/view/cdc/237179/cdc_237179_DS1.pdf
• File Type:
  [PDF - 2.25 MB ]