Types of Urea and What Urea Is Used For: From Fertilizer to AdBlue

Urea — also called carbamide, chemical formula CO(NH₂)₂ — is the most widely produced nitrogen compound in the world, with global output of around 180 million tonnes a year. At 46% nitrogen it carries more nitrogen than any other solid fertilizer, which is why farmers know it simply as urea 46-0-0. But fertilizer is only part of the story: the same molecule binds the plywood in your furniture, feeds cattle, and — as AdBlue — cleans the exhaust of nearly every modern diesel engine.

This guide explains the different types of urea, what each grade is used for, and why the urea that grows wheat cannot go into a diesel tank's AdBlue filler.

What is urea and how is it made?

Industrial urea is synthesised from ammonia and carbon dioxide at high pressure and temperature. The ammonia comes from the Haber–Bosch process, which is why urea plants sit on top of cheap natural gas — the Middle East, Russia, Egypt, Nigeria and the US Gulf dominate export supply. The molten urea leaving the synthesis loop is then finished into one of the physical forms below, and the finishing step is what separates one commercial type of urea from another.

The five main types of urea

1. Prilled urea (fertilizer grade)

Molten urea sprayed from the top of a prilling tower solidifies into small spheres of roughly 1–2.4 mm. Prilled urea is the classic fertilizer form: cheapest to produce, quick to dissolve, well suited to direct application and to flooded rice. Its drawbacks are softer particles and more dust, which matters once cargo is handled in bulk several times. Typical spec: nitrogen 46% min, biuret 1% max, moisture 0.5% max.

2. Granular urea

Formed in a granulation drum or fluidised bed into harder, larger granules of roughly 2–4 mm. Granular urea withstands bulk handling, blends cleanly with DAP and potash in NPK blending plants, and spreads evenly from mechanical spreaders over wide bouts — which is why large broadacre markets such as the US, Brazil and Australia buy granular by preference. It usually commands a small premium over prills. For the commercial differences — specifications, HS codes and how cargoes are priced — see our urea N46 buying guide: prilled vs granular.

3. Technical grade urea

Higher purity, tightly controlled moisture and low free ammonia, sold to industry rather than agriculture. Technical urea is the feedstock for urea-formaldehyde (UF) resins — the adhesive in plywood, MDF and particleboard — as well as for melamine, glues, and NOx-control solutions. Buyers here care about parameters a farmer never asks about: aldehydes, insolubles and trace metals.

4. Feed grade urea

A controlled-purity urea used as non-protein nitrogen (NPN) in ruminant feed. Microbes in the rumen of cattle and sheep convert urea into microbial protein, letting formulators replace part of an expensive protein meal. Feed urea demands strict quality control and careful dosing — it is only for ruminants, and overdosing is dangerous — so it trades as a distinct, certified product, not as repurposed fertilizer.

5. Automotive grade urea (AUS 32 — the urea in AdBlue)

The purest commercial grade, defined by ISO 22241. Automotive urea is dissolved into demineralised water at exactly 32.5% to make AUS 32 — sold in Europe as AdBlue and in North America as diesel exhaust fluid (DEF). The specification limits biuret, aldehydes, insoluble matter and metals to levels far below fertilizer tolerances, because everything in the fluid ends up passing across an SCR catalyst.

What is urea used for?

• Fertilizer — roughly 90% of world demand. Applied directly, in NPK blends, or dissolved into UAN solution. Urea supplies the nitrogen behind wheat, corn, rice and pasture worldwide.
• Wood panels and adhesives. Urea-formaldehyde resin is the binder in most plywood, MDF and particleboard, and the base for laminates and moulding compounds.
• Melamine. Produced from urea, then turned into durable surfaces, laminates and dinnerware.
• Emissions control. As AdBlue/DEF in vehicle SCR systems, and as 40–50% urea solution in SNCR systems at power stations, cement kilns and waste incinerators.
• Animal feed. NPN nitrogen source for cattle and sheep rations.
• Cosmetics and pharmaceuticals. Urea creams (typically 10–40%) as a moisturiser and keratolytic.
• De-icing. Used on airport aprons and runways where chloride salts would corrode aluminium airframes.

AdBlue and DEF: urea's fastest-growing use

AdBlue is a 32.5% solution of automotive grade urea in demineralised water. Injected into the hot exhaust stream, the urea hydrolyses to ammonia, and over the selective catalytic reduction (SCR) catalyst that ammonia converts nitrogen oxides (NOx) into harmless nitrogen and water vapour. SCR is how diesel vehicles meet Euro 6 (cars), Euro VI (trucks and buses) and equivalent standards — which is why virtually every modern diesel truck, bus, tractor and many passenger cars carry a separate AdBlue tank. A truck typically consumes AdBlue at around 4–6% of its diesel consumption.

Three details worth knowing:

• Why exactly 32.5%? It is the eutectic concentration — the mix with the lowest freezing point, around −11 °C — and the concentration SCR dosing systems are calibrated for.
• Fertilizer urea cannot be used to make AdBlue. Fertilizer prills and granules are commonly treated with formaldehyde-based anti-caking agents and carry biuret and metal levels that would poison an SCR catalyst. AdBlue plants start from automotive/technical grade urea or take urea melt straight off the synthesis line.
• Quality is certified, not assumed. Genuine AdBlue is produced and tested to ISO 22241; off-spec fluid can mean deposit build-up, dosing faults and an expensive catalyst replacement.

Urea grades compared

Type	Form	Nitrogen	Biuret	Main use
Prilled urea	Prills 1–2.4 mm	46% min	≤1%	Direct-application fertilizer
Granular urea	Granules 2–4 mm	46% min	≤1%	Bulk fertilizer, NPK blending
Technical grade	Prills / crystals	46% min	Low, agreed per contract	UF resins, melamine, glues
Feed grade	Prills / granules	46% min	Controlled	Ruminant feed (NPN)
Automotive (AUS 32)	Solution 32.5%	—	ISO 22241 limits	AdBlue / DEF for SCR

Where urea comes from and how it is traded

Because natural gas is the feedstock, export capacity clusters in the Middle East (Qatar, Saudi Arabia, Oman, the UAE, Iran), Russia, Egypt and Nigeria, with China swinging between exporter and closed market depending on policy. India, Brazil, the US and Australia are the major importers, and Indian purchase tenders regularly set the tone for world prices. Benchmarks are quoted FOB Arab Gulf, FOB Egypt and CFR India; cargoes move in bulk vessels or in 50 kg bags, big bags and containers. Urea for fertilizer use enters most customs codes under HS 3102.10 — our HS code reference guide covers the details.

CommoFlow trades prilled and granular urea 46% N from Gulf and Central Asian producers, delivered CFR worldwide in bulk and bags, alongside the sulphur that the same fertilizer buyers often need. Whether you are blending NPK, casting panels or filling AdBlue, tell our desk the grade and volume and we will quote delivered.