Process for the production of high strength, high purity hydrofluoric acid

Claim 1

A PROCESS FOR THE PRODUCTION OF HIGH-STRENGTH HIGHPURITY HYDROFLUORIC ACID WHICH COMPRISES THE STEPS OF: (A) REACTING FLUORITE WITH A MIXTURE OF CONCENTRATED SULPHURIC ACID AND SULPHUR TRIOIXIDE UNDER ANHYDROUS CONDITIONS TO PRODUCE A GGASEOUS REACTION PRODUCT CONTAINING SOLID IMPURITIES, HYDROGEN FLUORIDE AND HIGHBOILING IMPURITY COMPONENTS INCLUDING WATER AND SULPHURIC ACID; (B) CONVEYING THE RESULTING GASEOUS REACTION PRODUCT INTO A CONDENSING ZONE CONTAINING A LIQUID OF HIGHBOILING COMPONENTS, CONSISTING ESSENTIALLY OF ABOUT 20 TO 40 WEIGHT-PERCENT OF SULPHURIC ACID, FROM ABOUT 20 TO 40 WEIGHT-PERCENT OF WATER AND FROM ABOUT 20 TO 60 WEIGHT-PERCENT OF HYDROGEN FLUORIDE; (C) PASSING THE GASEOUS REACTION PRODUCT OVER THE SURFACE OF SAID LIQUID TO SCRUB SAID SOLID IMPURITIES FROM SAID GASEOUS PRODUCT AND TO EFFECT ABSORPTION OF THE SULPHURIC ACID AND WATER CONTAINED IN SAID GASEOUS PRODUCT BY SAID LIQUID;