Continuous production of hydroxyl-ammonium salts

Claim 1

IN A PROCESS FOR THE CONTINUOUS PRODUCTION OF HYDROXYLAMMONIUM SULFATE BY CATALYTIC REDUCTION OF NITRIC OXIDE WITH HYDROGEN IN CONTACT WITH A PLATINUM CATALYST AND DILUTE SULFURIC ACID, THE IMPROVEMENT WHICH COMPRISES CARRYING OUT SAID REDUCTION IN A SYSTEM OF AT LEAST TWO SEPARATE SUCCESSIVE STAGES WHEREIN THE DILUTE SULFURIC ACID IS SUPPLIED TO THE FIRST STAGE AND CONTINUOUSLY PASSED THROUGH EACH SUCCEEDING STAGE, A MIXTURE OF SAID HYDROGEN AND NITRIC OXIDE IS GASSED INTO EACH SEPARATE STAGE AND THE RESULTING HYDROXYLAMMONIUM SULFATE SOLUTION IS WITHDRAWN FROM THE LAST STAGE, BOTH THE AMOUNT OF SAID ACID INTRODUCED INTO THE FIRST STAGE AND THE INPUT GASEOUS HYDROGEN AND NITRIC OXIDE INTO EACH STAGE BEING ADJUSTED SO AS TO MAINTAIN A DECREASING ACID CONCENTRATION FROM STATGE TO STAGE, THE ACID CONCENTRATION IN THE LAST STAGE BEING SUCH THAT THE PH DOES NOT RISE ABOVE 2.5 AND THE ACID CONCENTRATION IN THE FIRST STAGE BEING AT LEAST ABOUT FIVE TIMES HIGHER THAN THE ACID CONCENTRATION IN THE LAST STAGE.