From Theory to Reality: Why Brown Coal-Urea Blends Struggled. Until Now.

The idea of blending brown coal with urea to create a slow-release nitrogen fertiliser isn’t new.
For decades, researchers have recognised that lignite, due to its porous structure and high organic carbon content, can help mitigate nitrogen loss to the environment, enhance nitrogen use efficiency, reduce emissions, and improve crop performance.
So why isn’t this fertiliser on the market already?
The short answer: manufacturing challenges.
The long answer? Let’s explore why the concept struggled and how COLDry Fertiliser is turning long-standing scientific promise into commercial reality.
The Scientific Case Has Always Been Strong

Peer-reviewed studies have long demonstrated that combining urea with treated brown coal:

• Reduces leaching and volatilisation
• Slows nitrogen release, synchronising it with crop uptake
• Improves soil organic matter and microbial activity
• Lowers greenhouse gas emissions (especially N₂O)

“Brown coal-urea fertiliser reduced nitrogen loss compared to urea alone by over 50%.”
— Hybrid Brown Coal-Urea Fertiliser Study, Flinders University (2023)
A 15N tracer study published in Environmental Science: Processes & Impacts confirmed:

• 21% increase in nitrogen uptake by plants
• 64% decrease in nitrogen oxide emissions
• 59% less nitrogen leaching
• 23% yield improvement

The Manufacturing Problem

Despite these promising results, commercialisation has historically failed. Why?
Urea and lignite have opposing material properties:

• Urea is dry and crystalline, sensitive to heat
• Lignite is moist and porous, prone to clumping and requires drying

The main issues:

• Clumping during blending, due to lignite’s high moisture
• Nitrogen loss during drying, as high temperatures cause urea to break down
• Inconsistent granule size, making application unreliable
• High energy costs, making production uneconomical at scale

Put simply, the tech to manufacture a stable, cost-effective lignite-urea granule didn’t exist. Until now.
The COLDry Breakthrough

The game-changer is ECT’s patented COLDry process, a low-temperature drying method designed initially for upgrading Victorian brown coal into a cleaner energy product.
Repurposed for fertiliser, COLDry enables:

• Uniform blending of lignite and urea
• Low-temperature (<40°C) drying, preserving nitrogen
• Stable, granulated product, easy to store, transport, and spread
• High scalability, without the energy burden of traditional drying

The result is COLDry Fertiliser, a lignite-nitrogen blend that delivers on the theory with:

• Lower cost than urea
• Higher nitrogen retention
• Carbon-rich soil benefits
• Compatibility with standard farming equipment

The Fertiliser the Market’s Been Waiting For

Until now, the choice was binary:

• Use urea and accept the losses, or
• Explore niche slow-release products that were expensive.

COLDry Fertiliser changes that dynamic. It delivers:

• Low-emission performance
• Lower overall cost per unit of nitrogen absorbed
• Improved soil health, thanks to added organic carbon
• Farmer-friendly form factor: spread it like urea, no new systems needed

And it’s manufactured right here in Australia, reducing dependence on volatile global markets.
From Research to Paddock

Field trials are due to commence.
The goal: validate performance under real-world conditions and finalise off-take partnerships for commercial rollout.
“The science has always been strong. What we’ve done is solve the engineering problem.”
— John Tranfield, CEO, Environmental Clean Technologies
What’s Next?

With the technology now in place, we are working with ESG Agriculture via our 'Zero Quest' joint venture to:

• Scale production capacity to 30,000–50,000 tonnes per annum
• Expand field trials
• Engage with regional producers to reduce reliance on imports and cut on-farm emissions

It’s the start of a new chapter where good science meets practical execution.

What's Next???.....