Abatement and selective recovery of acid gas emissions

Claim 1

A PROCESS FOR THE SELECTIVE AND SEPARATE REMOVAL OF HYDROGEN FLUORIDE AND SULFUR DIOXIDE FROM A GASEOUS MIXTURE COMPRISING THE STEPS OF: A. PASSING SAID GASEOUS MIXTURE THROUGH A FIRST SORPTIONZONE IN CROSSFLOW CONTACT WITH A FIRST AQUEOUS SOLUTION OF A BASIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF SODIUM HYDROXIDE, POTASSIUM HYDROXIDE, SODIUM CARBONATE, POTASSIUM CARBONATE AND MIXTURES THEREOF, WHILE MAINTAINING THE PH OF THE SOLUTION EFFLUENT FROM SAID FIRST SORPTION ZONE AT NOT GREATER THAN 6 AND MAINTAINING THE TEMPERATURE OF THE GASEOUS MIXTURE AT NOT GREATE THAN 100*F WHILE PASSING THROUGH SAID SORPTION ZONE SO AS TO SELECTIVELY REMOVE HYDROGEN FLUORIDE FROM THE GASEOUS MIXTURE AND FORM A SOLUBLE FLUORIDE SALT IN SAID FIRST AQUEOUS SOLUTION, B. RECOVERING SAID FIRST AQUEOUS SOLUTION TOGETHER WITH FLUORIDE DISSOLVED THEREIN AS A LIQUIID EFFLUENT FROM SAID FIRST SORPTION ZONE, C. DIVERTING A LARGE PORTION OF ABOUT 50-90 PERCENT OF SAID LIQUID EFFLUENT WILE PASSING THE REMAINING PORTION TO A REACTIN VESSEL FOR REACTION WITH CALCIUM HYDROXIDE, D. NEUTRALIZING A PORTION OF ABOUT 50-90 PERCENT OF THE FLLUORIDE INTRODUCED INTO THE REACTION VESSEL BY THE ADDITION OF CALCIUM HYDROXIDE TO PRECIPITATE CALCIUM FLUORIDE AND REGENERATE A HYDROXIDE SLUTION, E. SEPARATNG THE LIQUID AND PRECIPITATE FROM SAID REACTION VESSEL BY MECHANICAL MANS AND RECOVERING A SOLID-FREE HYDOXIDE SOLUTION, F. MIXING SAID RECOVERED, SOLIDS-FREE HYDROXIDE SOLUTION WITH AID DIVERTED LARGE PORTION OF SAID LIQUID EFFLUENT FROM SAID FIRST SORPTION ZONE, G. RECYCLING SAID MIXED SOLUTION AS THE AQUEOUS SOLUTION FOR SAID FIRST SORPTION ZONE, H. RECOVERING SAID GASEOUS MIXTURE FROM SAID FIRST SORPTION ZONE SUBSTANTIALLY FREE OF HDROGEN FLUORIDE AND PASSING IT THROUGH A SECOND SORPTION ZONE IN CROSSFLOW CONTACT WITH A SECOND AQUEOUS SOLUTION OF A BASIC COMPOUND SELECTD FROM THE GROUP CONSISTING OF SODIUM HYDROXIDE, POTASIUM HYROXIDE, SODIUM CARBONATE, POTASSIUM CARBONATE AND MIXTURES THEREOF, WHILE MAINTAINING THE PH OF THE SOLUTION EFFLUENT FROM SAID SECOND SCRUBBING BED AT BETWEEN 6 AND 16 SO AS TO SELECTIVELY REMOVE SULFUR DIOXIDE FROM THE GASEOUS MIXTURE AND FROM A SOLUBLE SULFITE SALT IN SAID AQUEOUS SOLUION, AND I. RECOVERING SAID GASEOUS MIXTURE SUBSTANTIALLY FREE OF BOTH HYDROGEN FLUORIDE AND SULFUR DIOXIDE.