After the urea granules and coating materials were mixed in the rotarypan, water was introduced as a mist onto the surface of the bed by setting a solenoid valve timer on or off. These steps were continued until all the urea and coating mixture were used. Finally, by over loading the rotary pan, the coated urea granules that flowed through a vibration tray were dried with a small fan and collected. The operational parameters are listed in Table 2.