| 摘要 |
PROBLEM TO BE SOLVED: To inexpensively and stably produce a time interval elution type coated fertilizer reduced in initial suppression down to a satisfactory level on an industrial scale by disposing a dust removing device having performance of a removal rate above a specific value between a gas outlet from a coating device and a gas cooling condenser disposed in a circulation system for gas and removing the dust used for drying. SOLUTION: The performance of the dust removing device is >=95% in the removal rate of 1 to 10-micron particles and >=99.5% in the removal rate of 10 to 100-micron particles. The coated fertilizer is produced by using the device for coating the fertilizer surface with a polymer solution and reintroducing the gas used for drying discharged from the coating device into the coating device. Not only the shape of the particles of the fertilizer but the dust derived from the particles of the fertilizer exert a significant influence on the initial elution of the coated fertilizer and the dust removing device is built into the gas circulation system for solvent drying. The dust removing device is a bag filter, an electrostatic precipitator, etc. The material that exerts the significant influence on the elution is the water-soluble particles of 1 to 100 microns. |
