Production and recovery of ammonium sulfate

Claim 1

A PROCESS FOR THE PRODUCTION AND CONCENTRATION OF AMMONIUM SULFATE WHICH COMPRISES, PASSING A WATER SOLUTION OF AMMONIUM SULFATE CONTAINING FROM 10 TO 30 WEIGHT PER CENT AMMONIUM SULFATE INTO THE UPPER 2/3 PORTION OF A LIQUID ZONE CONTAINED IN A REACTION ZONE, SAID REACTION ZONE CONTAINING A VAPOR ZONE ABOVE SAID LIQUID ZONE, BURNING WITHIN SAID LIQUID ZONE A COMBUSTIBLE MIXTURE OF FUEL GAS, HAVING A HEATING VALUE OF FROM 750 TO 1250 B.T.U./FT.3 NET AT 60* F. AND 760 MM. OF MERCURY, AND AIR, SAID AIR BEING PRESENT IN SAID MIXTURE IN AN AMOUNT NOT EXCEEDING 25 VOLUME PER CENT MORE THAN THAT REQUIRED TO COMPLETELY COMBUST SAID FUEL GAS, DIRECTLY CONTACTING SAID WATER SOLUTION OF AMMONIUM SULFATE AND RESULTING HOT PRODUCTS OF SAID BURNING IN SAID LIQUID ZONE SO AS THE VAPORATE WATER FROM SAID SOLUTION, WITHDRAWING WATER VAPOR FROM SAID VAPOR ZONE, INTRODUCING GASEOUS AMMONIA HAVING A PURITY OF AT LEAST 90 WEIGHT PER CENT INTO THE LOWER 1/3 PORTION OF SAID LIQUID ZONE, INTRODUCING SULFURIC ACID HAVING A PURITY OF AT LEAST 90 WEIGHT PER CENT INTO THE LOWER PORTION OF THE UPPER 2/3 PORTION OF SAID LIQUID ZONE, REACTING AMMONIA WITH SULFURIC ACID IN SAID LIQUID ZONE TO PRODUCE AMMONIUM SULFATE, WITHDRAWING A WATER SOLUTION OF AMMONIUM SULFATE FROM THE LOWER PORTION OF SAID LIQUID ZONE CONTAINING FROM 30 TO 50 WEIGHT PER CENT AMMONIUM SULFATE, SUCH WATER SOLUTION CONTAINING NO CRYSTALLIZED AMMONIUM SULFATE, INTRODUCING SAID WITHDRAWN AMMONIUM SULFATE SOLUTION INTO THE UPPER 2/3 PORTION OF A LIQUID ZONE CONTAINED IN A CONCENTRATION ZONE, SAID CONCENTRATION ZONE CONTAINING A VAPOR ZONE ABOVE SAID LIQUID ZONE, BURNING WITHIN SAID LIQUID ZONE A SECOND COMBUSTIBLE MIXTURE OF FUEL GAS, HAVING A HEATING VALUE OF FROM 750 TO 1250 B.T.U./FT.3 NET AT 60* F. AND 760 MM. OF MERCURY, AND AIR, DIRECTLY CONTACTING SAID LAST-MENTIONED AMMONIUM SULFATE SOLUTION AND RESULTING HOT PRODUCTS OF SAID LAST-MENTIONED BURNING IN THE LAST SAID LIQUID ZONE SO AS TO EVAPORATE WATER, WITHDRAWING WATER VAPOR FROM THE UPPER PORTION OF THE LAST SAID VAPOR ZONE, AND WITHDRAWING AN AMMONIUM SULFATE-WATER SLURRY FROM THE BOTTOM PORTION OF THE LAST SAID LIQUID ZONE CONTAINING FROM 75-80 WEIGHT PER CENT TOTAL AMMONIUM SULFATE.