PHNX Materials Found a Way to Cut Concrete’s Carbon Footprint Using Coal Waste

Coal-fired power plants have caused considerable harm over the last hundred years, contributing to everything from climate change and acid rain to black lung disease and heart conditions. Overall, their impact has been overwhelmingly negative.

However, hidden within the ashes they produce lies a surprising environmental benefit.

Up to 30% Cement Replacement: How Fly Ash Helps Curb Carbon Emissions

“Fly ash can substitute for up to 30% of cement,” explained Krish Mehta, co-founder and CEO of PHNX Materials, in an interview with TechCrunch. Since cement production is highly carbon-intensive, using fly ash in its place can substantially lower concrete’s carbon emissions.

PHNX Materials has developed a method to remove sulfur and carbon—unwanted impurities for concrete manufacturers—from fly ash. This not only makes the ash more suitable for use in concrete but also yields recoverable sulfur and aluminum, both valuable byproducts found in the ash.

PHNX Materials Secures $2.5M Seed Round Backed by Top Climate Investors

TechCrunch has learned exclusively that the startup recently secured a $2.5 million seed investment. The funding round was led by Divergent Capital, KdT Ventures, and Overture, with additional backing from Jane Woodward.

Ash has played a role in concrete production for thousands of years. The Ancient Romans utilized volcanic ash, and more recently, fly ash from coal-fired power plants has been adopted by state transportation agencies. For instance, Caltrans mandates that concrete used in its projects contain at least 25% fly ash.

According to Jorge Osio-Norgaard, co-founder and CTO of PHNX Materials, fly ash contributes to the stability of concrete mixtures. Without it, a specific chemical reaction may cause the aggregate—the small stones within the concrete—to transform into a gel that expands and ultimately cracks the structure.

Fly Ash Enhances Infrastructure Longevity, Says PHNX Co-Founder

“When you’re investing a billion dollars into infrastructure like highways or bridges, you expect it to endure for a century,” said Osio-Norgaard. “Fly ash plays a key role in making that possible.”

The shutdown of coal-fired power plants has significantly reduced the supply of ash available to the concrete industry. While coal once accounted for 51% of electricity production in the U.S., it now contributes only 15%.

This decline has given rise to a new sector focused on recovering coal ash. Companies are now excavating ash pits to extract usable fly ash, lightly processing it, and selling it to concrete producers. However, not all of the recovered ash meets quality standards, according to Mehta, which has led to a supply shortage and rising prices.

As a consequence, concrete manufacturers have been reducing the amount of fly ash in their mixes to around 8%, Mehta said. Though they could incorporate as much as 30%, they’re compensating for the shortfall with extra cement — a substitute that costs nearly twice as much per ton as fly ash.

That trade-off not only compromises the longevity of concrete but also contributes significantly to its carbon emissions. Cement production emits CO2 both from the chemical reaction involved in its creation and from the burning of fossil fuels needed to generate the high temperatures required. According to the EPA, manufacturing one ton of cement in the U.S. results in about 0.8 tons of carbon dioxide emissions.

“We saw the potential to decarbonize the industry quickly and at scale by tapping into a new source of ash,” Mehta explained.

PHNX Unlocks Value from Landfill Fly Ash, Recovering Key Materials for Multiple Industries

PHNX’s method involves recovering fly ash from landfills and extracting materials like sulfur and aluminum. The company is also exploring the recovery of rare earth elements. The processed ash will be sold to concrete producers, while the extracted compounds—such as sulfur, which has applications in fertilizer—will be marketed to other industries.

By turning the contaminants found in the roughly 843 fly ash landfills across the U.S. into valuable resources, PHNX believes it can provide the concrete industry with a more sustainable, lower-emission alternative. “We saw the potential to decarbonize the industry quickly and at scale by tapping into a new source of ash,” Mehta reiterated.

Read the original article on: TechCrunch

Read more: How to Greatly Reduce Industrial Mercury Emissions