USE OF PRECALCINERS TO REMOVE ALKALIES FROM RAW MATERIALS IN THE CEMENT INDUSTRY. QUARTERLY TECHNICAL PROGRESS REPORT, FEBRUARY--APRIL 1979

Laboratory tests designed to evaluate the volatility of alkalies in finely-ground argillaceous minerals are reported. A method used to determine the sintering points of these minerals is described. In addition to six pure minerals which were studied, argillaceous materials which are more typical of cement-plant raw feed components were studied. The conclusions of this report are: at 1000 exp 0 C, a combination of CaCO sub 3 and CaCl sub 2 additives enables volatilizion in one-half hour up to about 50% of the total alkali from high-alkali feldspars. However, much less alkali was lost from the typical cement plant raw materials under the same conditions; the atmosphere in which the experiment was conducted may have a significant effect on the results, especially if there is S present in the system. Absence of O can lead to decomposition ofnormally involatile alkali sulfates. Fe Cl sub 3 , may be lost from the sample. Losses are greatest in the absence of CaO and water vapor; sintering points of the pure minerals are above 1200 exp 0 C. Therefore, there is little danger of their sintering at 1000 exp 0 C, the presence of fluxing agents such as CaCl sub 2 may cause some sticking: and the use of vapor-phase compounds such as FeCl sub 3 and HCl is not an effective means of volatilizing alkalies under test conditions of (1000 exp O C for 30 minutes).

  • Corporate Authors:

    Portland Cement Association

    5420 Old Orchard Road
    Skokie, IL  USA  60077

    Department of Energy

    1000 Independence Avenue, SW
    Washington, DC  USA  20585
  • Authors:
    • Gartner, E M
  • Publication Date: 1979-5

Media Info

  • Pagination: 14 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00313027
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Contract Numbers: EM-78-C-02-4929
  • Files: TRIS
  • Created Date: May 7 1980 12:00AM