Abstract��
In the prepration of oxalic acid by calcification method, the main reaction is the acidolysis of oxacalcite by sulphuric acid. The phase diagram of SO 2- 4-Ca 2+ were determined by experiments,thus the crystal area and spontaneous nucleation area of CaSO 4��2H 2O were found.Using mathematical model to direct feeding of raw material we can get rather ideal crystal grain,and the filtering rate achieved is as high as 0 75m 3/m 2��min.
1997, Vol. 14 
