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Utilization of Coal-burning Powerplant Byproducts.

Muter-RB; Lawrence-WF
U S Pat 3 642 445 1972 Feb; :
A process is described in which a modified fly ash slurry at a ph 10- 13, formed in the reaction of s-containing combustion gases with limestone or dolomite and by coprecipitation with pulverized coal fly ash, can be converted into reusable carbonates by carbonization to a ph approximately 7.0 By the use of co2-containing gases (plant stack gases) on a slurry to which an anionic emulsifier has been added; the modified fly ash contains generally alkaline earth sulfates or sulfites 2-20, fly ash 25-65 pct, and unreacted alkaline earth oxides the rest. The carbonates formed are separated from the slurry by flotation, dried, and reinjected into the furnace; the flotation reject is dewatered and is converted in a reverberatory furnace into a molten mass, with a viscosity of up to 10 p, from which a fibrous mineral wool, high in si, is produced by air- blowing. The mineral wool produced is less corrosive to steel under humid conditions than other insulating materials; the so2 and so3 gases produced in the reverberatory furnace can be recovered for reprocessing to h2so4.
Publication Date
Document Type
Fiscal Year
NTIS Accession No.
NTIS Price
Identifying No.
PAT 3,642,445
NIOSH Division
Source Name
U.S. Pat. 3,642,445; Feb. 15, 1972; Chem Abstr. 76:89,733F