摘要 |
Process for the preparation of urea granules in a fluid-bed granulator, by using at least one feeding device to feed a urea melt in the form of a film to a fluidized bed of solid urea nuclei, upon which the nuclei grow by solidification of the urea melt on the nuclei, in which the amounts of biuret and water in the urea melt and in the urea granules fulfill the following relation <maths id="MATH-US-00001" num="00001"> <math overflow="scroll"> <mrow> <mfrac> <mrow> <msub> <mi>b</mi> <mi>m</mi> </msub> <mo>.</mo> <msub> <mi>b</mi> <mi>g</mi> </msub> </mrow> <mrow> <msub> <mi>w</mi> <mi>m</mi> </msub> <mo>.</mo> <mrow> <mo>(</mo> <mrow> <msub> <mi>w</mi> <mi>m</mi> </msub> <mo>-</mo> <msub> <mi>w</mi> <mi>g</mi> </msub> </mrow> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>=</mo> <mrow> <mn>0.1</mn> <mo>-</mo> <mn>20</mn> </mrow> </mrow> </math> </maths> wherein bm=the % by weight of biuret in the urea melt bg=the % by weight of biuret in the urea granules wm=the % by weight of water in the urea melt wg=the % by weight of water in the urea granules.
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