PROCESS OF CONCENTRATING DILUTE SULFURIC ACID IN A THREE-STAGE FORCED-CIRCULATION VACUUM EVAPORATION PLANT USING FORCED CIRCULATION

摘要

A PROCESS IS DESCRIBED BY WHICH DILUTE SULFURIC ACID (4) IS CONCENTRATED IN A THREE-STAGE VACUUM EVAPORATION PLANT USING FORCED CIRCULATION. DILUTE SULFURIC ACID IS FED TO THE FIRST STAGE (1) AND CONCENTRATED SULFURIC ACID (7) IS WITHDRAWN FROM THE THIRD STAGE (3). STEAM (5) AND/OR OVERHEAD VAPOR (6) ARE USED AS HEATING FLUIDS. THAT PROCESS IS CHARACTERIZED IN THAT 30 TO 95% OF THE DILUTE SULFURIC ACID (4) ARE CONTINUOUSLY FED TO THE EVAPORATING VESSEL (1B) OF THE FIRST STAGE (1). IN THAT PROCESS A FORMATION OF DIFFICULTLY REMOVABLE GYPSUM DEPOSITS IN THE FIRST STAGE (1) WILL BE AVOIDED. (FIG. 2)