DYNAMIC BEHAVIOR OF PARTICLE AGGLOMERATION OF EUROPIUM OXALATE DURING REACTION CRYSTALLIZATION IN SEMI-BATCH REACTOR

During reaction crystallization of europium oxalate in a semi-batch reactor, a monotonical increase in the mean particle size and corresponding reduction in the total particle population were observed due to particle agglomeration occurring simultaneously with particle nucleation and growth. However, since particle agglomeration was achieved via particle aggregation and molecular growth, the mean particle size and total particle population in the product suspension were significantly influenced by the crystallization conditions of the feed concentration, agitation speed, and feeding time. A higher feed concentration and feeding time resulted in a larger mean particle size and smaller total particle population due to the higher supersaturation and longer holding time in the reactor. Meanwhile, agitation was found to exhibit a rather complicated influence on particle agglomeration because particle collision and a turbulent fluid shear were both promoted at the same time. In the semi-batch reactor, the reduction in total particle population during crystallization clearly reflected particle agglomeration.