Process for the production of chlorine dioxide

Claim 1

IN A PROCESS FOR THE PRODUCTION OF CHLORINE DIOXIDE OF A TYPE IN WHICH AN AQUEOUS SOLUTION OF AN ALKALI METAL CHLORATE IS REACTED WITH HYDROCHLORIC ACID IN A REACTION ZONE TO PRODUCE CHLORINE DIOXIDE AND AN ALKALI METAL CHLORIDE, AT LEAST A PORTION OF THE SOLUTION IN SAID REACTION ZONE IS PASSED TO AN ENRICHING ZONE TO INCREASE THE CHLORATE CONTENT OF THE LAST-MENTIONED SOLUTION AND THEN CONDUCTED AFTER ENRICHMENT TO SAID REACTION ZONE FOR REACTION WITH HYDROCHLORIC ACID TO GENERATE CHLORINE DIOXIDE; THE IMPROVEMENT CHARACTERIZED BY PROVIDING IN SAID ENRICHING ZONE ALKALI METAL CHLORATE IN AN AMOUNT IN EXCESS OF THE AMOUNT OF CHLORATE REQUIRED TO SATURATE SAID LASTMENTIONED SOLUTION WITH RESPECT TO SAID ALKALI METAL CHLORIDE, WHEREBY CONDITIONS FAVOURABLE TO THE PRECIPITATION OF SAID ALKALI METAL CHLORIDE ARE ESTABLISHED IN SAID ENRICHING ZONE, AND INCREASING THE CHLORATE CONTENT OF SAID LAST-MENTIONED SOLUTION AND PRECIPITATING SAID ALKALI METAL CHLORIDE THEREFROM IN SAID ENRICHING ZONE BY PASSING SAID LAST-MENTIONED SOLUTION THROUGH SAID ENRICHING ZONE.