METHOD OF PRODUCING GRANULAR INDUSTRIAL NITROGEN-CALCIUM FERTILISER Russian patent published in 2013 - IPC C01F11/38 C05C5/04 

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical industry. A reaction mixture obtained from decomposition of calcium mineral salts with nitric acid is exposed to an alkaline reagent with pH from 6 to 10 and at temperature of 50°C to 120°C. Undesirable cations are precipitated and separated; in the obtained solution, the ratio Ca²⁺:NH₄ ⁺ is adjusted to 4.5 to 9.4 by adding nitric acid and gaseous and/or liquid ammonia and/or ammonium nitrate. The obtained solution is thickened. Superheated solution at temperature from 100°C to 170°C is injected into a granulator. A powder phase is added. The solution is granulated at temperature from 40°C to 135°C and temperature of the obtained granulate is brought to a value not higher than 110°C. The granular material is sieved. The suitable fraction of the granular fertiliser is separated. The coarse fraction is ground and, along with the finer fraction, is cooled and returned into the granulator.

EFFECT: present invention enables to obtain granular fertiliser containing water-soluble calcium and nitrogen salts, which is suitable for droplet irrigation and hydroponics.

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