Urea CAS 57-13-6
Chelora Chemicals supplies agricultural, technical and DEF-grade urea worldwide, in prilled and granular form. Every consignment leaves with a batch-specific COA covering nitrogen, biuret, moisture and particle size, the current SDS and full export documentation.
Also known as: Carbamide · Carbonyl diamide · Prilled urea · Granular urea · UREA 46%
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Price, lead time and a sample COA for Urea, usually within one working day. We ship worldwide.
Request a Quote Email the DeskDocumentation
- Batch-specific COA (nitrogen, biuret, moisture, size)
- Safety Data Sheet (SDS)
- Transport and export documents
- Third-party inspection on request
- Certificate of origin
What is Urea?
Urea is the diamide of carbonic acid, CH₄N₂O, a white crystalline solid with the highest nitrogen content of any solid fertiliser at 46%. It is highly soluble in water and non-hazardous in ordinary handling.
Most urea is made by reacting ammonia with carbon dioxide, usually using the CO₂ produced by the same ammonia plant, which is why the two units are almost always built together.
Agriculture takes the overwhelming majority, but technical grades go to urea-formaldehyde resins, melamine, and automotive diesel exhaust fluid, where the biuret and impurity limits are far tighter than fertiliser quality.
Why Urea specifically
- Highest solid nitrogen content. 46% nitrogen means lower freight and handling cost per unit of nutrient than any other solid fertiliser.
- Non-hazardous handling. Unlike ammonium nitrate, urea is not an oxidiser and is not subject to dangerous-goods or security controls.
- A resin feedstock. Condensation with formaldehyde gives the UF resins used in most wood panel production.
- The DEF reagent. Automotive-grade urea solution is the reductant for SCR systems on diesel vehicles.
How Urea is Manufactured
Urea is synthesised from ammonia and carbon dioxide at high pressure, then concentrated and shaped into prills or granules.
- Ammonia and CO₂ feed. Both come from the adjacent ammonia plant, which produces CO₂ as a by-product of reforming.
- Carbamate formation. Ammonia and CO₂ combine at about 150 bar and 180 °C to ammonium carbamate, a strongly exothermic reaction.
- Dehydration. Carbamate dehydrates to urea and water in an equilibrium reaction with incomplete conversion.
- Recycle and stripping. Unconverted carbamate is stripped and returned to the synthesis loop.
- Concentration. The urea solution is evaporated to melt, with biuret formation controlled by limiting time at temperature.
- Prilling or granulation. Melt is prilled in a tower or granulated in a fluid bed; granular product is harder and better suited to bulk blending.
Typical Commercial Specification
Figures below are representative of commercial agricultural grade urea. Technical and DEF grades carry much tighter biuret and metals limits — tell us the use and we will send the matching sheet.
| Parameter | Typical Value |
|---|---|
| Appearance | White prills or granules, free flowing |
| Nitrogen content | 46.0% min by weight |
| Biuret | 1.0% max agricultural; 0.3% max technical and DEF |
| Moisture | 0.5% max |
| Free ammonia | To grade, typically 150 ppm max |
| Formaldehyde (anti-caking) | To grade, typically 0.45% max |
| Particle size | 1 to 2.4 mm prilled; 2 to 4 mm granular, 90% min |
| Crushing strength | Granular, typically 2.5 kgf min |
| Insolubles | To grade, typically 10 ppm max for DEF grade |
Physical & Chemical Properties
| Property | Value |
|---|---|
| Chemical formula | CH₄N₂O (NH₂CONH₂) |
| Molecular weight | 60.06 g/mol |
| Appearance | White crystalline prills or granules, almost odourless |
| Melting point | 132.7 °C, with decomposition |
| Bulk density | About 0.74 to 0.78 g/cm³ |
| Solubility in water | Very high — about 1080 g/L at 20 °C |
| Heat of solution | Strongly endothermic — solution cools markedly |
| pH of 10% solution | About 7.5 to 9.5 |
| Hygroscopicity | Critical relative humidity about 73% at 30 °C |
| Decomposition | Above about 133 °C, releasing ammonia and forming biuret |
| Incompatibilities | Strong oxidisers, acids, nitrites, hypochlorites |
Behaviour in the process
Urea is chemically benign but physically demanding in storage:
- Hygroscopic. Above about 73% relative humidity urea absorbs moisture, cakes and loses free flow. Dry storage is essential.
- Caking. Prills bond under pressure and humidity in stacked bags; anti-caking treatment and stack height control both matter.
- Endothermic dissolution. Dissolving urea cools the solution sharply, which is used in cold packs and matters in DEF blending.
- Biuret formation on heating. Any heating above the melting point during processing creates biuret and degrades the grade.
Urea Grades and Nitrogen Alternatives
Urea is bought by grade and by physical form, and the two decisions are independent of each other.
| Material | Origin / type | When it is the right choice |
|---|---|---|
| Prilled urea 46% | Smaller, softer particles | Direct application and solution preparation; the volume standard |
| Granular urea 46% | Larger, harder particles | Bulk blending, mechanical spreading and long-distance bulk handling |
| Technical grade urea | Biuret under 0.3% | UF resins, melamine and industrial chemistry |
| DEF / AUS 32 grade urea | Very low biuret, metals and insolubles | Diesel exhaust fluid for SCR systems |
| Ammonium nitrate | CAN or AN, 33 to 34.5% N | Where faster nitrogen release is wanted; subject to security controls |
Stated plainly: urea carries more nitrogen per tonne than any alternative and is far easier to ship and store than ammonium nitrate. Its drawback is volatilisation loss if it is surface applied without incorporation or a urease inhibitor.
Industries We Supply Urea To
Fertiliser dominates, but the technical and automotive grades are growing faster.
Where Urea is Used
Around 85% of urea goes to fertiliser. Resins, melamine and diesel exhaust fluid take most of the rest.
In fertiliser use
Urea hydrolyses in soil to ammonium carbonate under the action of urease, then nitrifies to nitrate. Surface application without incorporation can lose a significant share of the nitrogen as ammonia volatilisation, which is why urease inhibitors and incorporation practices matter more for urea than for nitrate fertilisers.
In diesel exhaust fluid
DEF is a 32.5% urea solution that decomposes in the hot exhaust to ammonia, which reduces NOx over the SCR catalyst. The specification is demanding: biuret, aldehydes, metals and insolubles all have very low limits because the injector and catalyst are intolerant of contamination.
Need a specific grade, purity and packing format?
Tell us the grade, the grade, the biuret limit and the particle form, the packing format you can receive and the annual quantity. We will come back with a price, a lead time, a sample COA and the full documentation set.
Quality Control & Testing
Every lot is released against a batch-specific Certificate of Analysis, with biuret and moisture reported alongside nitrogen because they determine which applications the lot suits.
- Nitrogen content — the primary grade measure, by Kjeldahl or equivalent.
- Biuret — reported because it limits use in foliar, resin and DEF applications.
- Moisture — measured because it drives caking and flow problems.
- Particle size distribution and crushing strength — confirming the physical grade for blending and spreading.
- Free ammonia — measured as an indicator of process and storage condition.
- Insolubles and metals — tested for DEF and technical grades.
Common Process Problems & Likely Causes
When urea causes trouble, it is usually moisture, caking, biuret or dust. This table is the shortcut our technical desk works through before anyone opens a complaint file.
| Symptom | Likely cause | What to check |
|---|---|---|
| Bags caking into solid blocks | Humidity above the critical level or excessive stack height | Moisture figure, warehouse humidity and stacking practice |
| Poor spreading pattern in the field | Particle size distribution or prill strength | Size analysis and crushing strength on the COA |
| Dust during handling | Prill attrition in repeated transfer | Crushing strength and number of transfer points |
| Leaf scorch after foliar application | Biuret above the foliar tolerance | Biuret figure against the grade required |
| DEF injector fouling | Insolubles, metals or biuret above the ISO limit | DEF-grade COA and blending water quality |
| Resin cure or colour problems | Biuret or free ammonia in technical grade urea | Biuret and free ammonia results |
Packaging, Storage & Shipping
- Standard packing. 50 kg PP bags, 500 to 1250 kg jumbo bags, and bulk vessel or truck loading.
- Storage. Dry, covered, well-ventilated warehousing on pallets, away from direct ground contact and rain ingress.
- Humidity control. Keep relative humidity below about 70%. Urea absorbs moisture rapidly above its critical humidity and cakes.
- Stack height. Limit stack height and storage time; compression plus humidity is what turns bagged urea into blocks.
- Material compatibility. Non-corrosive to most materials when dry; solutions are mildly corrosive to carbon steel.
- Segregation. Keep apart from strong oxidisers, acids, nitrites and hypochlorites.
- Shelf life. Typically 12 months or more in dry storage. Caking, not chemistry, is the limiting factor.
- Transport classification. Not classified as dangerous goods for transport.
Hazards & Safe Handling
Urea is one of the least hazardous products we supply. It is not classified as dangerous for transport and presents only mild irritant and dust hazards in normal handling.
- Low acute toxicity. Urea is not classified as harmful by ingestion, inhalation or skin contact in normal industrial handling.
- Dust and eye irritation. Dust can irritate eyes and the respiratory tract. Use dust control and eye protection during bulk handling.
- Ammonia on decomposition. Heating above about 133 °C releases ammonia; ventilate melting and processing areas.
- Skin and eyes. Prolonged contact with solutions can dry and irritate skin. Use gloves and eye protection when handling solutions.
- Manual handling. 50 kg bags present an ergonomic rather than chemical hazard; use mechanical handling where possible.
- Environment. Nitrogen release to watercourses causes eutrophication. Contain spills and prevent drainage runoff.
Regulatory & Compliance Notes
Urea is unregulated for transport but is subject to fertiliser quality and, for DEF grades, automotive specification rules. The notes below are orientation rather than legal advice.
- GHS classification. Not classified as hazardous in most jurisdictions, though some apply an eye irritation classification.
- Fertiliser regulation. Nitrogen content, biuret and labelling are governed by national fertiliser quality rules and import registration requirements.
- DEF specification. Automotive urea solution must meet ISO 22241, which sets limits on biuret, aldehydes, insolubles and metals.
- Transport. Not classified as dangerous goods. Standard bulk and bagged cargo documentation applies.
- REACH and inventories. Registered under EU REACH and listed on the major chemical inventories.
- Feed use. Where urea is sold as a non-protein nitrogen feed supplement, feed-grade registration and labelling requirements apply.
We Supply Urea Worldwide
Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship Urea from India and from partner sources to customers across Asia, Europe, the Middle East, Africa, and North and South America, handling the export documentation, transport paperwork and freight so the material arrives ready to use.
- Incoterms. EXW, FOB, CIF, CFR and DAP quoted to suit your purchasing terms and freight arrangements.
- Ports. Regular shipments through Nhava Sheva (JNPT) and Mundra, with other ports arranged where routing and cargo rules allow.
- Documentation. Commercial invoice, packing list, certificate of origin, COA, SDS and the transport declaration issued as a complete set.
- Flexible volumes. From a container of bagged product up to repeat bulk shipments on a supply contract.
- Supply continuity. Because we are independent of any one producer, a plant turnaround or a shipping disruption at one source does not have to become your stock-out.
Buying Urea from Chelora
We are an independent sourcing and supply partner. For urea that means settling three things at enquiry: the grade and biuret limit, prilled or granular form, and the packing and shipment schedule against your season or production plan.
- Documentation on every lot. Batch-specific COA (nitrogen, biuret, moisture, size), plus SDS and the full transport paperwork.
- Analysis before commitment. Representative analysis shared ahead of a commercial order so your lab can qualify the material.
- Quantities. From a container of bagged product through to full bulk shipments on contract supply.
- Grade matching. Agricultural, technical or DEF grade in prilled or granular form, to the biuret, moisture and size limits your use requires.
- Inspection. Independent third-party inspection available at loading when the contract requires it.
- Related products. Ammonia, Formaldehyde, Nitric Acid and other feedstocks alongside Urea from one supplier.
How ordering works
- Send the enquiry. Product, grade or purity, quantity, destination port and the Incoterm you buy on. If you have a spec sheet, attach it — it saves a round trip.
- We quote. Price, lead time, packing format and a sample COA, normally within one working day.
- Qualify the supply. For first orders or critical applications, we share the analysis and handling documentation so your technical and safety teams can sign off before you commit.
- Confirm the order. Proforma invoice issued; payment terms agreed against the volume and the relationship.
- Allocation and QC. Material allocated and released against a batch-specific COA, with an independent inspection where the contract calls for it.
- Ship and document. Filled, labelled and loaded with the full export document set, and tracked through to arrival.
Urea — Common Questions
The questions our technical desk is asked most often about Urea. If yours isn't here, call or email and you will reach someone who knows the chemistry.
What is the CAS number of urea?
The CAS number for urea is 57-13-6, and its EC number is 200-315-5. Its molecular formula is CH₄N₂O with a molecular weight of 60.06 g/mol, and it is classified under HS code 3102.10.
What is urea used for?
Mainly as nitrogen fertiliser at 46% N. Technical grades go to urea-formaldehyde resins and melamine, and automotive grade is the basis of diesel exhaust fluid for SCR systems. Smaller volumes go to animal feed and industrial uses.
Do you supply urea worldwide?
Yes. Chelora Chemicals supplies and exports urea worldwide — across Asia Pacific, Europe, the Middle East, Africa and the Americas, as well as throughout India, in bags, jumbo bags and bulk.
What is the difference between prilled and granular urea?
Prills are smaller and softer, made by spraying melt down a tower; granules are larger and harder, made in a fluid bed. Granular urea handles bulk blending and mechanical spreading better; prilled is common for direct application and solution making.
What is biuret and why does it matter?
Biuret forms when urea melt is held too hot for too long. Above about 0.3% it damages foliage in foliar application and causes problems in resins and diesel exhaust fluid. Agricultural grade allows up to 1%; technical and DEF grades do not.
How is urea manufactured?
By reacting ammonia with carbon dioxide at about 150 bar to form ammonium carbamate, which dehydrates to urea and water. The CO₂ comes from the adjacent ammonia plant, which is why the two units are always built together.
Is urea hazardous?
No, in normal handling it is one of the least hazardous industrial chemicals. It is not classified as dangerous goods for transport and presents only dust and mild irritant concerns. Heating above its melting point releases ammonia.
Is urea classified as dangerous goods?
No. Unlike ammonium nitrate, urea is not an oxidiser and is not subject to dangerous-goods transport rules or explosives-precursor security controls.
How should urea be stored?
Dry, covered and ventilated, on pallets, with relative humidity kept below about 70%. Urea is hygroscopic above its critical humidity and will cake, especially under the pressure of tall bag stacks.
What packing sizes are available?
50 kg PP bags, 500 to 1250 kg jumbo bags, and bulk truck or vessel loading. Orders run from a container of bagged product up to full bulk cargoes.
What is DEF or AUS 32 grade urea?
A very high purity urea used to make the 32.5% solution injected into diesel exhaust for NOx reduction. It must meet ISO 22241, with very low biuret, aldehyde, metal and insoluble content, because the injector and SCR catalyst are intolerant of contamination.
What is the typical shelf life?
12 months or more in dry storage. The limiting factor is caking from moisture pick-up and stack compression rather than chemical degradation.
Ready to source Urea?
Send us your specification, grade and annual volume. You will get a price, a realistic lead time and a sample COA from someone who understands what the material has to do in your process — delivered anywhere in the world.