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Method for scrubbing pollutants from an exhaust gas stream

  • US 5,100,633 A
  • Filed: 10/25/1990
  • Issued: 03/31/1992
  • Est. Priority Date: 11/07/1985
  • Status: Expired due to Term
First Claim
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1. A method of treatment of an exhaust gas stream containing as pollutants at least one of the acidic oxides of sulfur, nitrogen, carbon, and halogens and acidic halogen compounds, whose temperature exceeds the dew point of the gas, for producing scrubbed exhaust and useful or benign by-products, said method comprising:

  • providing a basic aqueous slurry of ash, said ash containing alkali and alkaline earth metal salts,contacting the exhaust gas stream with the slurry in a manner to scrub said exhaust gas stream and to cause the pollutants therein to react with the water in the slurry to produce acids,allowing said acids to react with any oxides, hydroxides and carbonates of alkali and alkaline metal salts in said slurry, thereby to produce a solution with soluble alkali metal salts and a precipitate of any insoluble alkali and alkaline earth metal salts comprising at least one of halogen compounds, carbonate, sulfate, sulfite, nitrate, and nitrite of calcium, magnesium, potassium and sodium in said slurry,recovering said precipitate from said solution,evaporating said solution freed of said precipitate,recovering in solid form any soluble alkali and alkaline earth metal salts present in said solution, andexpelling the scrubbed exhaust gas stream.

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