公开(公告)号：AT3529T

公开(公告)日：1983-06-15

申请号：AT79200755

申请日：1979-12-12

Applicant: STAMICARBON B.V.

Inventor： WETERINGS, CORNELIS ANTONIUS MARIA ,  JANSSEN, JOHANNES ANNA

IPC: C01F11/46 ,  C04B11/02

公开(公告)号：AT957T

公开(公告)日：1982-05-15

申请号：AT79200754

申请日：1979-12-12

Applicant: STAMICARBON B.V.

Inventor： WETERINGS, CORNELIS ANTONIUS MARIA ,  JANSSEN, JOHANNES ANNA

IPC: C01F11/46 ,  C04B11/02 ,  C04B11/05 ,  C09C1/02

Abstract: The invention relates to a process for the preparation of calcium sulphate anhydrite in which calcium sulphate dihydrate is recrystallized at elevated temperature using concentrated sulphuric acid. … The recrystallization is performed using sulphuric acid at an H2SO2-concentration of 40-65 wt. %, calculated relative to the quantity of liquid phase in the recrystallization mixture. A temperature of between 40 and 90 DEG C and a residence time of 5-30 minutes is applied for the preparation of calcium sulphate anhydrite with an average particle size of 0.5-3 mu , and a temperature of between 20 and 45 DEG C and a residence time of 30 minutes to 3 hours is applied for the preparation of calcium sulphate anhydrite with an average particle size of 10-20 mu . … According to the invention a very pure calcium sulphate anhydrite is obtained, which is suitable for industrial application, for example in the building or paper industry.