SIZE-DEPENDENT GROWTH-BEHAVIOR RELATED TO THE MOSAIC SPREAD IN AMMONIUM-SULFATE CRYSTALS

The growth rate of small (1-120 mu m) ammonium sulphate crystals, whic h were removed from a 970 L crystallizer via a fines classification li ne, were measured in a 2 L growth cell. An exponential size dependent growth (SDG) curve was used to model the data, revealing a size depend ent growth rate up to a size of 220 mu m. The same crystals were dried and sieved and the level of internal strain (''mosaic spread'') measu red using the high intensity synchrotron radiation source. The results showed that the average mosaic spread and also the spread in mosaic s preads reduced with increasing crystal length. These results are consi stent with the SDG rate measured for the small particles in suspension and points to internal lattice strain as being the cause of the SDG.