Method for granulating a melt of an hydrous nitrate mineral salt-based composition, system and use thereof
AssigneeYara International Asa
InventorsPer Stokka, Olav Kjøhl
Life of this patent
Estimating the term…
Abstract
The present disclosure relates to a method for controlling the temperature in a granulator in which a melt of an hydrous nitrate mineral salt-based composition is granulated. The method comprises the steps of granulating the melt, separating out the undersized and oversized particles at the outlet of the granulator and recycling the undersized and oversized particles to the granulator, measuring the temperature in the granulator, adjusting the amounts of undersized and oversized particles recycled to the granulator according to the measured temperature in the granulator. The present disclosure further relates to low dust producing uncoated granules of a hydrous nitrate mineral salt-based composition.
Claims12
A method for granulating a melt of an hydrous calcium nitrate mineral salt-based composition comprising from 15 to 30 weight % of water, the method comprising the steps of:
- a) granulating a melt of the nitrate mineral salt-based composition by a granulator operating according to the agglomeration granulation principle to obtain a set of granules wherein the granulator has an amount of water in a liquid phase;
- b) separating out oversized and undersized granules from the granules obtained from step a) to obtain at least a set of oversized granules, a set of undersized granules and a set of granules having a suitable size;
- c) crushing the oversized granules obtained from step b);
- d) recycling the granules obtained from step c) to the granulator;
- e) recycling the undersized granules obtained from step b) to the granulator;
- f) during step a) measuring a temperature in the granulator and
- g) based on the temperature measured in step f), adjusting the amounts of granules recycled in steps d) and/or e) so as to control the amount of water in the liquid phase and maintain the temperature measured in step f) within a range of 90 to 96° C.
Uncoated granules having a sieve diameter ranging from 2 mm to 4 mm, comprising an hydrous calcium nitrate mineral salt-based composition, characterized in that they produce less than 1000 mg of dust per kg of granules, determined according to the Yara YTC-LAB-132 fluidization method.
Dependencies are inferred from the claim text.