Prolonged-action magnesium-bearing urea from thermally activated dolomite: effect of additive content and calcination temperature on granule properties

Khosimov, B. T

Innovative Multidisciplinary Journal of Applied Technology · 2026-yil

Annotatsiya

This study quantifies how the amount of thermally activated dolomite added to a urea melt and the temperature at which that dolomite is calcined jointly govern the properties of the resulting granules. Local dolomite ( 27.52 %, 20.24 %, 43.21 %) was calcined at , , , , and 900 °C and introduced into molten urea at ten levels from 0.5 to 5.0 wt %, giving a two-factor full factorial design of 60 compositions plus a dolomite-free control. Dissolution time, melt crystallisation temperature, hygroscopic point, porosity and crushing strength were measured for every composition. Dolomite raised the dissolution time in all 60 cases, from 93.8 s for the control to 94.28–207.62 s, raised the crushing strength to 2.56–3.46 MPa and lowered the porosity below the control value of 5.75 % throughout. Each response was described by an additive linear model in the two factors (–; the interaction term was insignificant, –). Grouping the model residuals by calcination temperature revealed that three independent responses reach an extremum at exactly 700 °C and change sign between and 800 °C, coinciding with the calculated appearance of free and marking the transition of dolomite from a comparatively inert filler to a reactive additive. Four criteria complete activation of the magnesium component, limitation of free , at least 45.5 % total nitrogen and at least 2.5 MPa crushing strength identify a single regime: 2 g of dolomite calcined at 700 °C per 98 g of urea, a product that dissolves 1.38 times more slowly than unmodified urea, is 12.6 % stronger, 9.9 % less porous and contains 45.72 % N and 0.55 % entirely in the active form, with only 0.10 % free . Compared with a urea–formaldehyde system studied under the same criteria it is 6.7 % stronger, carries 4.5 absolute per cent more nitrogen and requires no imported formalin. This study quantifies how the amount of thermally activated dolomite added to a urea melt and the temperature at which that dolomite is calcined jointly govern the properties of the resulting granules. Local dolomite ( 27.52 %, 20.24 %, 43.21 %) was calcined at , , , , and 900 °C and introduced into molten urea at ten levels from 0.5 to 5.0 wt %, giving a two-factor full factorial design of 60 compositions plus a dolomite-free control. Dissolution time, melt crystallisation temperature, hygroscopic point, porosity and crushing strength were measured for every composition. Dolomite raised the dissolution time in all 60 cases, from 93.8 s for the control to 94.28–207.62 s, raised the crushing strength to 2.56–3.46 MPa and lowered the porosity below the control value of 5.75 % throughout. Each response was described by an additive linear model in the two factors (–; the interaction term was insignificant, –). Grouping the model residuals by calcination temperature revealed that three independent responses reach an extremum at exactly 700 °C and change sign between and 800 °C, coinciding with the calculated appearance of free and marking the transition of dolomite from a comparatively inert filler to a reactive additive. Four criteria complete activation of the magnesium component, limitation of free , at least 45.5 % total nitrogen and at least 2.5 MPa crushing strength identify a single regime: 2 g of dolomite calcined at 700 °C per 98 g of urea, a product that dissolves 1.38 times more slowly than unmodified urea, is 12.6 % stronger, 9.9 % less porous and contains 45.72 % N and 0.55 % entirely in the active form, with only 0.10 % free . Compared with a urea–formaldehyde system studied under the same criteria it is 6.7 % stronger, carries 4.5 absolute per cent more nitrogen and requires no imported formalin.

Maqola ma’lumotlari
MualliflarKhosimov, B. T
JurnalInnovative Multidisciplinary Journal of Applied Technology
NashriyotТДТУ Қўқон филиали
ISSN2995-486X, 2995-486x
Nashr sanasi2026-09-21
Jild4
Son9
Betlar33-40
TilIngliz
DOI10.51699/y4qbv566
Indeksga qo‘shilgan2026-09-22

DOI: 10.51699/y4qbv566 · Maqolaning asl sahifasi

Kalit so‘zlar

ureadolomite, thermal activation, slow-release fertilizer, prolongation, dissolution time, hygroscopic point, granule strength, free calcium oxide, full factorial design

Iqtibos keltirish

APAKhosimov, B. T (2026). PROLONGED-ACTION MAGNESIUM-BEARING UREA FROM THERMALLY ACTIVATED DOLOMITE: EFFECT OF ADDITIVE CONTENT AND CALCINATION TEMPERATURE ON GRANULE PROPERTIES. Innovative Multidisciplinary Journal of Applied Technology, 4(9), 33-40. https://doi.org/10.51699/y4qbv566
GOST (OAK)Khosimov, B. T PROLONGED-ACTION MAGNESIUM-BEARING UREA FROM THERMALLY ACTIVATED DOLOMITE: EFFECT OF ADDITIVE CONTENT AND CALCINATION TEMPERATURE ON GRANULE PROPERTIES // Innovative Multidisciplinary Journal of Applied Technology. – 2026. – T. 4, № 9. – P. 33-40. – DOI: 10.51699/y4qbv566.
MLAKhosimov, B. T. “PROLONGED-ACTION MAGNESIUM-BEARING UREA FROM THERMALLY ACTIVATED DOLOMITE: EFFECT OF ADDITIVE CONTENT AND CALCINATION TEMPERATURE ON GRANULE PROPERTIES.” Innovative Multidisciplinary Journal of Applied Technology, 4(9), 33-40, 2026. https://doi.org/10.51699/y4qbv566
ChicagoKhosimov, B. T. “PROLONGED-ACTION MAGNESIUM-BEARING UREA FROM THERMALLY ACTIVATED DOLOMITE: EFFECT OF ADDITIVE CONTENT AND CALCINATION TEMPERATURE ON GRANULE PROPERTIES.” Innovative Multidisciplinary Journal of Applied Technology, 4(9), 33-40 (2026). https://doi.org/10.51699/y4qbv566
HarvardKhosimov, B. T (2026) ‘PROLONGED-ACTION MAGNESIUM-BEARING UREA FROM THERMALLY ACTIVATED DOLOMITE: EFFECT OF ADDITIVE CONTENT AND CALCINATION TEMPERATURE ON GRANULE PROPERTIES’, Innovative Multidisciplinary Journal of Applied Technology, 4(9), 33-40. https://doi.org/10.51699/y4qbv566
BibTeX
@article{khosimovbt2026,
  title = {PROLONGED-ACTION MAGNESIUM-BEARING UREA FROM THERMALLY ACTIVATED DOLOMITE: EFFECT OF ADDITIVE CONTENT AND CALCINATION TEMPERATURE ON GRANULE PROPERTIES},
  author = {Khosimov, B. T},
  journal = {Innovative Multidisciplinary Journal of Applied Technology},
  year = {2026},
  volume = {4},
  number = {9},
  pages = {33-40},
  doi = {10.51699/y4qbv566},
  url = {https://doi.org/10.51699/y4qbv566}
}

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