Process of producing hydrogen fluoride as a dry gas from clear fluosilicic acid-containing solutions

Claim 1

IN THE PROCESS OF PRODUCING HYDROGEN FLUORIDE AS A DRY VAPOR FROM CLEAR FLUOSILICIC ACID-CONTAINING SOLUTIONS; THE IMPROVEMTN WHICH COMPRISES SUBJECTING A CLEAR FLUOSILICIC ACID-CONTAINING SOLUTION TO THE ACTION OF HEATED CONCENTRATED SULFURIC ACID IN A CLOSED REACTOR IN THE ABSENCE OF FREE SILICA, CONTINUING SAID ACTION UNTIL A SUBSTANTIAL PORTION OF HYDROGEN FLUORIDE IS EVOLVED FROM SAID SOLUTION AS A VAPOR TOGETHER WITH SILICON TETRAFLUORIDE VAPOR, WITHDRAWING SAID VAPORS CONTAINING SAID HYDROGEN FLUORIDE AND SILICON TETRAFLUORIDE FROM SAID CLOSED REACTOR, SEPARATING HYDROGEN FLUORIDE IN SAID VAPORS FROM SILICON TETRAFLUORIDE WHEREBY HYDROGEN FLUORIDE IS PRODUCED ASN A SUBSTANTIALLY DRY VAPOR, REACTING SILICON TETRAFLUORIDE WITH WATER TO PRODUCE FLUOSILICIC ACID AND SILICA, REMOVING SILICA AND LIBERATING CLEAR FLUOSILICIC ACID SUBSTANTIALLY FREE FROM SILICA, AND RECYCLING CLEAR FLUOSILICIC ACID SUBSTANTIALLY FREE FROM SILICA TO THE FIRST OPERATION.