Urea is a highly soluble compound used in agriculture, industry, and research, but its solubility can vary based on conditions like temperature, water quality, and purity. A urea solubility test helps determine how well urea dissolves in water, which is critical for applications ranging from fertilizer mixing to industrial processes.
Urea is one of the most water-soluble solid nitrogen compounds, with a solubility of approximately 108 grams per 100 milliliters of water at 20°C (68°F). This means 108g of urea will dissolve completely in 100mL of water at room temperature, forming a clear solution.
Prepare water and urea
Dissolve urea
Check for undissolved solids
Test at different temperatures (optional)
Solubility increases significantly with temperature | |
20℃ | ~108g/100mL |
40℃ | ~137g/100mL |
60℃ | ~167g/100mL |
80℃ | ~202g/100mL |
Pure urea (99.5%+) dissolves completely.
Impurities like biuret, ammonium nitrate, or dust can reduce solubility, leaving residues. Industrial-grade urea may have lower purity than agricultural or pharmaceutical grades.
Tap water with high mineral content (e.g., calcium, magnesium) can reduce solubility by forming insoluble complexes with urea. Always use distilled or deionized water for accurate tests.
Fine urea powder dissolves faster than large granules or prills, as it has a larger surface area in contact with water.
Agriculture: Ensures urea fertilizers dissolve properly in irrigation water or foliar sprays, preventing undissolved particles that clog equipment or burn plants.
Industrial Uses: Critical for diesel exhaust fluid (DEF) production, where urea must dissolve completely to avoid nozzle clogs in SCR systems.
Laboratory Research: Guarantees precise urea concentrations in experiments (e.g., protein denaturation, dialysis solutions).
Quality Control: Identifies impure urea (e.g., contaminated with biuret or salts), which dissolves more slowly or leaves residues.
Can urea dissolve in cold water?
Yes, but slowly. At 0°C, urea solubility drops to ~67g/100mL, so cold water may leave undissolved solids.
Is urea more soluble than ammonium nitrate?
No—ammonium nitrate is more soluble (~190g/100mL at 20°C), but urea is preferred for its lower explosion risk.
How does solubility affect urea fertilizer effectiveness?
Poorly soluble urea may not distribute evenly in soil or water, leading to uneven crop growth or fertilizer burn in concentrated areas.
A urea solubility test is a simple yet critical step in ensuring urea quality for agricultural, industrial, and research use. By understanding how temperature, purity, and water quality affect dissolution, you can select the right urea for your needs and avoid costly issues like equipment clogs or crop damage. Always test solubility when working with new urea batches, especially for high-precision applications.
News China Melamine Raw Material Price Analysis In JUN.2025 1. China Melamine Raw Material Price Focus This Month In June 2025, melamine exports were 56,900
News China Melamine Analysis In May.2025 1. China Melamine Powder Export date In May 2025, melamine powder exports reached 63,000 tons, up 38.16% from the
Tech Blog How Melamine Molding Compound Powder Is Revolutionizing Industrial and Household Products Melamine molding compound powder (MMC powder)-thermosetting polymers synthesized from melamine formaldehyde (MF)
JINGJIANG MELAMINE POWDER
© JINJIANG MELAMINE