METHOD FOR PRODUCING COMPLEX NITROGEN FERTILIZER WITH PROLONGED ACTION Russian patent published in 2023 - IPC C05C9/02 

FIELD: fertilizers.

SUBSTANCE: invention relates to methods for producing complex nitrogen fertilizers comprising microelements, used in various soil and climatic conditions for a variety of agricultural crops. A method has been proposed for producing a complex nitrogen fertilizer with prolonged action, which involves mixing prilled urea with an inorganic salt in the form of sodium tetraborate, or magnesium sulfate, or zinc sulfate, or a mixture thereof, with heating to 40°C, then urea-formaldehyde concentrate “КФК-85” is added to the mixture with the addition of orthophosphoric acid, the reaction mass is continuously stirred and heated to 90±2°C and held under these conditions for 30 minutes, followed by cooling the product to room temperature and grinding, while the mass ratio of the initial components is as follows: prilled urea : inorganic salt : urea-formaldehyde concentrate “КФК-85” : orthophosphoric acid – 100: (3-8) : (3-7) : (1.4-2.2).

EFFECT: improving the method for producing complex nitrogen fertilizer, eliminating residual formaldehyde from its composition with expanding the areas of its use in agriculture, while the developed complex fertilizers more effectively increase productivity, are not washed out of the soil by precipitation and are characterized by a slow release of bound nitrogen both alone and in combination with other products.

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