Process for the production of combined fertilizers

A process for making a combined fertilizer comprising:

• i) a first nitrogen-based fertilizer;
• ii) one or more second nitrogen-based fertilizer(s) different from said first nitrogen-based fertilizer, and/or one or more nutrient(s), collectively called one or more further components,
• wherein said combined fertilizer is made by a process of granulation in a fluid bed comprising the steps of:
• providing a first liquid feed to a first region of a granulation environment,
• providing a second liquid feed to a second region of said environment,
• wherein solid seeds acting as starting points for the granulation process are fed to said first region of the granulation environment, and said second region is downstream said first region;
• and wherein in the first region of the granulation environment, the first liquid feed solidifies on the solid seeds forming a binder layer around the solid seeds, and
• the second liquid feed has the form of a micronized slurry of said one or more further components in the first nitrogen-based fertilizer, spraying the second liquid feed over the granules previously formed in the first region;
• wherein the micronized slurry contains solid crystals of said one or more further components, and is sprayed in the form of droplets having an average size at least 5 times the average size of said crystals;
• and
• wherein the seeds have an average size of 500-1000 microns, the binder layer has a thickness of 200 to 400 microns, and said crystals have a size not greater than 100 microns.