Abstract: A process for simultaneous removal of SO.sub.2 and NO.sub.x from a gas stream that includes flowing the gas stream to a spray dryer and absorbing a portion of the SO.sub.2 content of the gas stream and a portion of the NO.sub.x content of the gas stream with ZnO by contacting the gas stream with a spray of an aqueous ZnO slurry; controlling the gas outlet temperature of the spray dryer to within the range of about a 0.degree. to 125.degree. F. approach to the adiabatic saturation temperature; flowing the gas, unreacted ZnO and absorbed SO.sub.2 and NO.sub.x from the spray dryer to a fabric filter and collecting any solids therein and absorbing a portion of the SO.sub.2 remaining in the gas stream and a portion of the NO.sub.x remaining in the gas stream with ZnO; and controlling the ZnO content of the aqueous slurry so that sufficient unreacted ZnO is present in the solids collected in the fabric filter to react with SO.sub.2 and NO.sub.

Abstract: Improved combination wet absorber/spray-dry dry wastes collection air pollution control process and apparatus therefor, employing aqueous solutions of sodium or ammonium alkali sorbents injected in an absorber through which SO.sub.x -containing flue or process gases containing fly ash are passed. Fly ash is collected in the absorber wherein the alkali reacts with the SO.sub.x to form sodium and ammonium sulfur oxide salts liquor containing collected fly ash in slurry form, which is passed back upstream and injected into a spray dryer through which the gases pass. The heat of the gases in the spray dryer dries the slurry to a powder of salts and fly ash which is removed. The spray dryer simultaneously provides some added preliminary SO.sub.x removal.

Abstract: Improved combination wet absorber/spray-dry dry wastes collection air pollution control process and apparatus therefor, employing aqueous solutions of sodium or ammonium alkali sorbents injected in an absorber through which SO.sub.x -containing flue or process gases containing fly ash are passed. Fly ash is collected in the absorber wherein the alkali reacts with the SO.sub.x to form sodium and ammonium sulfur oxide salts liquor containing collected fly ash in slurry form, which is passed back upstream and injected into a spray dryer through which the gases pass. The heat of the gases in the spray dryer dries the slurry to a powder of salts and fly ash which is removed. The spray dryer simultaneously provides some added preliminary SO.sub.x removal.

Abstract: Suppression of calcium sulfate scale in wet lime and limestone flue gas desulfurization (FGD) scrubbers and mist eliminators is accomplished by scrubbing in the presence of an oxidation inhibitor comprising gaseous nitric oxide (NO).

Abstract: Process for control of SO.sub.x emissions from copper smelter operations involving pyrometallurgical reduction of copper ores to elemental copper in which the gases from reverberatory furnaces, roasters, and/or converters are scrubbed with a sodium alkali sorbent to produce sodium sulfate and sulfite wastes. The cleaned flue gases are exhausted to the atmosphere. The waste sodium sulfate/sulfite material is then reacted with excess acid from the smelter acid plant and ferrous ion-rich barren solution from the associated cement copper operations to produce co-precipitated double salts of sodium ferric hydroxy-disulfates and/or sulfites (SFH), having low water solubility and being suitable for landfill type disposal without posing serious water pollution problems. This disposes of the sodium sulfite/sulfate waste materials from the air pollution control process and also strips the barren solution of iron prior to its recycle to heap or dump leaching operations.

Abstract: Process for insolubilizing water soluble wastes from alkaline sodium or ammonium type sulfur dioxide control systems used in conjunction with industrial or power plants. The sodium or ammonium sulfite or sulfate wastes are reacted in solution with ferric ions and sulfuric acid to produce an insoluble basic, hydrous or anhydrous, sodium and/or ammonium hydroxy ferric sulfate or sulfite compounds of the generic type M.sub.v (Na, NH.sub.4).sub.w Fe.sub.x (SO.sub.u).sub.y (OH.sub.z)nH.sub.2 O, wherein M is selected from an alkali metal other than sodium, or an authigenic metal or other cation present in industrial or power plant wastes, v is selected from zero to six, w is selected from zero to five, x is selected from zero to six, y is selected from one to five, u is 3 and/or 4, z is selected from zero to 12, and n is selected from zero to 20. Principal end product compounds include Natrojarosite, Ammoniojarosite, Metasideronatrite, Sideronatrite, Depegite, Rosarite, Iriite, and mixtures thereof.

Abstract: Method for disposal of water soluble sodium sulfur oxide-containing wastes resulting from industrial processes producing fly and/or bottom ash from fossil fuel utilization and waste or excess sodium sulfur oxide compounds, particularly disposal of sodium sulfite and/or sodium sulfate resulting from wet or dry sodium alkali scrubbing of tail or flue gases to reduce SO.sub.x emissions therefrom as from smelters, power plants, paper plants, glass plants and industrial boiler operations. Process involves mixing sodium sulfur oxide wastes with an alumina and silica-containing fly ash and/or bottom ash, forming an agglomerate, such as a pellet or briquette, and sintering in the range of about (1000.degree.-2300.degree.F). The resultant sintered particle shows lower solubility than the current standard of calcium sulfate, being 10.sup..sup.-2 to 10.sup..sup.-4 as soluble as the starting sodium sulfur oxides, has increased density (as high as 2.