Process for the crystallization of an inorganic substance

A process for crystallization of an inorganic substance in a fluidized bed to provide monolithic spherical beads having a diameter of greater than 3 mm and reduced fines, the process comprising:

• a. preparing a supersaturated solution of the inorganic substance to be crystallized in a solvent which is a liquid;
• b. forcing a stream of the supersaturated solution upwardly through successively a fluidized bed distributor of a fluidized bed reactor and a bed of crystals arranged above the fluidized bed distributor, with a pressure effective to cause fluidization of the bed of crystals, the fluidized bed distributor dividing the stream of supersaturated solution into thin, substantially parallel and vertical jets;
• c. maintaining the distributor at a temperature which is uniform and at which the concentration of the inorganic substance to be crystallized from the supersaturated solution is lower than or equal to the concentration corresponding to saturation whereby spontaneous crystallization of the inorganic substance onto the distributor is substantially prevented;
• d. controlling the temperature of the distributor to cause the stream of supersaturated solution in the distributor to undergo a temperature change which is at most insufficient to desupersaturate it completely;
• and
• e. allowing crystallization to proceed and thereby provide monolithic spherical beads of the inorganic substance which have a diameter of greater than 3 mm, which diameter of greater than 3 mm is greater than that obtainable in a non-fluidized bed.

A process for crystallization of an inorganic substance in a fluidized bed to provide monolithic spherical beads having a diameter of greater than 3 mm and reduced fines, the process comprising:

• a. preparing a supersaturated solution of an inorganic substance to be crystallized in a solvent which is a liquid, which inorganic substance has a solubility which varies inversely with temperature;
• b. forcing a stream of the supersaturated solution upwardly through successively a fluidized bed distributor of a fluidized bed reactor and a bed of crystals arranged above the fluidized bed distributor, with a pressure effective to cause fluidization of the bed of crystals, the fluidized bed distributor dividing the stream of supersaturated solution into thin, substantially parallel and vertical jets;
• c. maintaining the fluidized bed distributor at a temperature which is uniform, which is less than that of the stream being forces therethrough, and at which the concentration of the inorganic substance to be crystallized from the supersaturated solution is lower than or equal to the concentration corresponding to saturation whereby spontaneous crystallization of the inorganic substance onto the fluidized bed distributor is substantially prevented;
• d. controlling the temperature of the distributor to cause the stream of supersaturated solution in the distributor to undergo a temperature change which is at most insufficient to desupersaturate it completely;
• and
• e. allowing crystallization to proceed and thereby provide monolithic spherical beads of the inorganic substance which have a diameter of greater than 3 mm, which diameter of greater than 3 mm is greater than that obtainable in a non-fluidized bed.