Utilization of Waste Fluosilicic Acid (in Two Sections). 1. Laboratory Investigations. 2. Cost Evaluation

Details

• Personal Author:
  Blake HE Jr. ; Dolezal, Henry ; Moser KW ; Reuss, John L. ; Thomas WS
• Description:
  This report describes two processes for utilizing the waste fluosilicic acid (H2SiF6) generated by the manufacture of phosphatic fertilizers. The first process involves conversion of fluosilicic acid to an acid-grade fluorspar (CaF2) by first precipitating the silica with ammonia and filtering, and then reacting the ammonium fluoride (NH4F) filtrate with Ca(OH)2. Over 95 percent of the fluoride is converted to CaF2. The second process involves neutralizing the H2SiF6 with Ca(OH)2 and silica and filtering and then volatilizing HF from the dry precipitate by pyrohydrolytic action at 1,050C. By this method, over 80 percent of the fluoride in H2SiF6 is recovered as anhydrous HF. Preliminary tests on the synthesis of cell-grade aluminum fluoride (AlF3) from the rotary reactor offgases and activated alumina showed that an 82-percent AlF3 product could be produced. An evaluation was made to determine the economics of utilizing waste fluosilicic acid for production of (1) calcium fluoride, and (2) anhydrous hydrogen fluoride. The evaluation showed that both products could be produced and marketed competitively. [Description provided by NIOSH]
• Subjects:
  Aluminum Silicates Fertilizers Fluorides Hydrofluoric Acid Occupational Health Safety
• Keywords:
  Fertilizers; Hydrogen fluoride; Calcium fluorides; Production; Materials recovery; Silicates; Fluorides; Chemical industry; Cost estimates; Fluorite; Capitalized costs; Ammonia; Operating costs; Hydrogen hexafluorosilicate; Silicate/hexafluoro; Waste gas recovery
• Series:
  Mining Publications
• Subseries:
  Report of Investigations
• Document Type:
  Text
• Genre:
  Conference Publications ; Case Report
• Place as Subject:
  Oregon ; OSHA Region 10
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  ALRC - Albany Research Center
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-60
• NIOSHTIC Number:
  nn:10008742
• NTIS Accession Number:
  PB-199045
• Citation:
  Albany, OR: U.S. Department of the Interior, Bureau of Mines, RI 7502, 1971 Jan; :1-60
• Federal Fiscal Year:
  1971
• Peer Reviewed:
  False
• Source Full Name:
  Albany, OR: U.S. Department of the Interior, Bureau of Mines, RI 7502
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:3cdf65eb8f46e156d8b856b0dcf26299f520b4200b1bf0832041b23f8a93e88146a72141b4dee24658a5e2400bf29849404c67ce68e7d9aeb1ccdac2f1a6596c
• Download URL:
  https://stacks.cdc.gov/view/cdc/237269/cdc_237269_DS1.pdf
• File Type:
  [PDF - 21.36 MB ]