FLUORINE BALANCE AND FLUORINE EMISSION FROM CEMENT KILNS

IN THE BURINING OF PORTLAND CEMENT CLINKER THE FLUORINE IS PARTLY DRIVEN OUT OF THE RAW MATERIAL AND FUEL. IN ORDER TO ELUCIDATE THE QUESTION WHETHER THE FLUORINE IS EMITTED IN GASEOUS FORM WITH THE KILN EXIT GASES OR IS COMBINED IN SOLID FORM IN THE CLINKER OR IN THE DUST, COMPLETE FLUORINE BALANCES FOR ELEVEN CEMENT KILNS OF VARYING DESIGN WERE ESTABLISHED, IN ADDITION TO EXIT GAS INVESTIGATIONS. NO GASEOUS FLUORIDES COULD BE DETECTED IN THE CLEANED GAS FROM THE CEMENT KILN. FROM THERMODYNAMIC CONSIDERATIONS AND MORE PARTICULARLY ALSO FROM THE RESULTS OF THE FLUORINE BALANCE INVESTIGATIONS IT EMERGES THAT CEMENT KILNS CANNOT EMIT FLUORIDES IN GASEOUS FORM, THIS BEING SO BECAUSE, WITH THE LARGE EXCESS OF CALCIUM OXIDE OCCURRING, THEY ARE ENTIRELY COMBINED AS CALCIUM FLUORIDE. THE SLIGHT FLUORIDE EMISSION FOUND IN THE DUST CONTAINED IN THE CLEANED GAS-AMOUNTING FROM 0.009 TO 1.420 MG FLUORINE PER CUBIC METER (?) --IS THEREFORE NOT DEPENDENT ON THE MAGNITUDE OF THE FLUORINE BALANCE, BUT ON THE PRECIPITATION EFFICIENCY OF THE ELECTROSTATIC PRECIPITATORS INSTALLED AFTER KILNS. THE AMOUNT OF FLUORINE COMBINED IN THE CLINKER RANGES FROM 88 TO 98% OF THE TOTAL FLUORINE INTAKE, AND THIS PERCENTAGE IS HIGHER ACCORDING AS THE DUST LOAD ON THE KILN EXIT GAS IS SMALLER. FROM THE STRICTLY LINEAR RELATIONSHIP BETWEEN THE AMOUNT OF FLUORINE COMBINED IN THE CLINKER IN % OF THE BALANCE SUM AND THE EXTERNAL DUST CYCLE IN GRAMMES OF DUST PER KG OF CLINKER IT FOLLOWS THAT THE FLUORINE IS COMBINED SOLELY IN SOLID FORM AS CALCIUM FLUORIDE IN THE CLINKER AND IN THE KILN DUST. CALCIUM FLUORIDE IS HARMLESS, AS IT IS DIFFICULTY SOLUBLE IN WATET. /AUTHOR/

• Supplemental Notes:
  • Vol 57, No 1, PP 1-8
• Authors:
  • Sprung, S
  • Seebach, H M
• Publication Date: 1968-1

Media Info

• Serial:
  • Zement-Kalk-Gips

Subject/Index Terms

• TRT Terms: Calcium compounds; Cement kilns; Clinkers; Combustion; Electrostatic precipitators; Electrostatics; Fluorides; Fluorine; Gas analysis; Mathematical analysis; Ovens; Oxides; Portland cement; Thermodynamics
• Old TRIS Terms: Precipitators
• Subject Areas: Highways; Materials;

Filing Info

• Accession Number: 00212630
• Record Type: Publication
• Files: TRIS
• Created Date: Jul 8 2000 12:00AM