Abstract: SO.sub.x /NO.sub.x pollution control reagent composition comprising from 0.1 to 25% urea in intimate admixture with dry, finely divided Nahcolite, a naturally occurring form of sodium bicarbonate. The composition is used in a process of removing SO.sub.x /NO.sub.x from the flue gases of utility and industrial plants, incinerators and the like by dry injection into a flue gas duct a sufficient distance upstream of a spent reagent collection device to provide above about 0.25 seconds of residence time of the reagent composition in the flue gas duct at temperatures in the range of above about 200.degree. F. followed by collection, preferably in an electrostatic precipitator. The Nahcolite reacts with the SO.sub.2 to form sodium sulfate and also removes NO.sub.x in the form of NO. The urea prevents the conversion of NO to NO.sub.2 by the Nahcolite, and maintains the concentration of the NO.sub.2 in the exit flu gases below the 50 parts per million visibility threshold (depending on ambient conditions).

Abstract: Nahcolite solution mining process comprising drilling at least one well into a Nahcolite bed, circulating hot barren aqueous liquor in a cavity in said Nahcolite bed for a time sufficient to produce a pregnant liquor having an increase in the concentration of NaHCO.sub.3 in the range of from about 3 to about 20% while maintaining Na.sub.2 CO.sub.3 concentration in the range of about 0.25-4%, preferably less than 2.5%, withdrawing said pregnant liquor, cooling said pregnant liquor to preferentially precipitate NaHCO.sub.3 therefrom and to produce a barren liquor, recovering said NaHCO.sub.3, and reheating and re-injecting said barren liquor in said well. The cavity temperature is maintained below about 250.degree. F. and preferably below about 200.degree. F. The barren liquor is injected at a pressure of below about 150 psig. The pregnant liquor is extracted at a temperature in the range of from about 85.degree. F. to about 200.degree. F., and the cystallization occurs at a temperature of about 25.degree.-120.