Development Of Crystallizer Systems For Large Particles Schoenite

Application of potassium magnesium fertilizer can improve crop yields and quality.However, the small particle picromerite leads to agglomeration of the product, whichseriously affected its usability, so it is of great importance to develop the process ofproducing large particles potassium magnesium fertilizer.A comprehensive comparison of the average particle size and particle size distributionof products under conditions, including the feed flow rate; the liquid circulation flow rate;the quality of mother liquor; the amount of seed; the average particle size of seed; the liquidto solid ratio of slurry were determined. The optimum condition was shown as follows:liquid circulation flow rate--4L/min, the quality of mother liquor--6000g, the amount ofseed--10%, the liquid to solid ratio of slurry--9:1, the particle size of the product leading to618.897μm. It demonstrated crystal aggregation was caused by not only fine crystallineattached to the crystal surface, but also mostly fine crystalline embedded inside largecrystals.Under optimum conditions, fluent software simulated the distribution of the flow fieldwithin12-litre-large crystallizer. It was found that the distance from the bottom ofcrystallizer to the open mouth of the feeding pipe decided the turbulent region, increasingthe diameter of open mouth of the feeding pipe could improve the velocity distribution ofthe flow field. The liquid flow field distribution was substantially the same under differentliquid circulation flow rate. The speed was different with the flow rate increasing at thesame position. The velocity of the flow field in the bottom of crystallizer was betterdistributed when the distance from the bottom of crystallizer to open mouth of the feedingpipe is6cm, the diameter of open mouth is5cm, and enlarged section was located30cmabove the bottom of crystallizer.This paper realized the online observation of the crystallization process. Through theinvestigation of the schoenite crystallizer structure and the crystallization conditions, theparameters in crystallization process of large particle schoenite were acquired, laying thefoundations for the further development of industrialization.