How Is Ferrock Made?

Published Categorized as Building Materials
Ferrock Concrete Mixer

Ferrock is a carbon-negative environmentally-friendly compound that is a suitable alternative to concrete. It is made up of 95% recycled materials and is cheap to manufacture, but how is it exactly made?

Ferrock is made by combining steel dust waste with silica. A chemical reaction between the iron in the dust and the carbon dioxide in the air causes the mixture to turn into iron carbonate. Once this is mixed with water and exposed to carbon dioxide, it hardens into a solid form, similar to concrete.

In this article, we will discuss the process of forming Ferrock, history, and potential uses. We’ll also look at the pros and cons of using Ferrock.

What Is Ferrock?

Ferrock is an iron-rich compound that can be made with mostly recycled materials. When mixed, the ingredients go through a chemical reaction that results in a strong, hard solid form, like concrete.

Ferrock is five times more sturdy than Portland concrete. And it’s flexible enough that it doesn’t crumble due to compression or seismic activity.

Concrete is a substance we’re all familiar with, as it’s used everywhere. This material is strong enough to build bridges and buildings hundreds of feet tall. Once cured, concrete can last for years without degrading or getting damaged.

But concrete does have its weaknesses, making it not the best option for specific projects, even though there is no suitable alternative.

Examples of where concrete might not work as well include saltwater, as the cement can erode over time. Or sewage pipes, where frequent exposure to the chemicals used in water treatment will cause erosion.

The issue with producing so much concrete is that the process produces carbon dioxide into the air. The production of concrete and cement accounts for 5% of the world’s CO2 emissions, causing a lot of pollution.

Ferrock emits carbon dioxide during production, but the exciting thing about this material is that it absorbs CO2 while hardening. The more CO2 it consumes, the stronger it becomes. So Ferrock can help reduce greenhouse gases, whereas concrete causes them.

How Is Ferrock Made?

Ferrock is formed by using the steel dust byproducts that come from multiple types of industrial processes. Usually, this dust gets thrown away, which is a waste of its potential. This action leads to heavy metals in landfills, which can cause toxins to seep into the ground.

In addition to the steel dust waste, you also need silica made by ground-up glass. This product is often found in your bags, jackets, and other large items when you purchase them, in the form of a small paper packet.

To create Ferrock, you mix steel dust and silica with ferrous rock, an iron-rich mineral, and other ingredients that cause corrosion or rusting. Then water is mixed in so that the mixture turns into a paste similar to the chalky goo of cement.

Once the Ferrock is mixed up, it can be used exactly like cement. You can pour it into any mold or trowel with it. Finally, the mix gets exposed to carbon dioxide gas.

During this process, the iron in the dust will start to rust as it absorbs CO2. The carbon dioxide gets fused into the mixture, forming iron carbonate. In a week, the material hardens into the solid form called Ferrock.

As the Ferrock hardens, it traps the carbon dioxide into the material. Surprisingly, the addition of CO2 actually makes the Ferrock stronger. Once Ferrock has set, it’s similar to concrete in that you can’t revert it to a liquid form.

Benefits of Ferrock

There are a lot of benefits to using Ferrock for construction purposes instead of concrete. We’re going to take a closer look at these benefits, including strength, flexibility, carbon neutrality, and chemically inactive.

Five Times Harder Than Concrete

Ferrock hardens into a solid form, making it similar to concrete. But once hardened, Ferrock has five times more strength than concrete. This means it can withstand more weight, compression, and damage without being destroyed.

This material has strengths ranging from 5,000 to 7,000 psi. Some tests achieved up to 10,000 psi. These values exceed the recommended OPC standard values of 4786 psi (OPC-33 MPa), 6236 psi (OPC-43), and 7687 psi (OPC-53) for concrete.

The durability and stability of Ferrock mean it can be used for the same purposes as cement, including building materials. This material can also withstand temperatures over 1000℉ (600℃), making it an excellent candidate for fireproofing or insulation when turned into foam.


Ferrock also has a bit of flexibility to it, meaning it can withstand more pressure and movement. Concrete is completely solid, so any slight movement can cause cracks that weaken the entire structure.

Ferrock, on the other hand, can withstand some movement without damage. This feature makes it great to use in areas where there is active seismic activity such as earthquakes. In flexural tests, it was found that Ferrock is four times stronger than Portland cement.

Chemically Inactive

Ferrock is considered chemically inactive, which means the material does not degrade when exposed to gases or chemicals. Concrete can deteriorate over time and exposure to chemicals.

For this reason, Ferrock is often used in marine construction, as it is immune to the effects of saltwater. In fact, Ferrock actually gets more durable when exposed to seawater, so it’s excellent for underground environments.

It is also resistant to conditions like UV radiation, corrosion, rotting, rust, and oxidation. Nor can it be damaged by chemicals, making it a viable option for pipes and tubes.

Carbon Neutral

Ferrock is also considered carbon-neutral, which means it does not emit a lot of carbon dioxide during manufacturing. This material does put out a bit of CO2 during production.

However, while Ferrock is in the liquid form, it uses carbon dioxide to help it harden. CO2 fuses into the mixture, trapping the gas inside the rock as it turns into a solid.

So, in essence, Ferrock works as a carbon dioxide filter, removing some of the CO2 in the atmosphere. It uses the absorbed CO2 to form its final shape, a sheet of solid hard Ferrock.

Cons of Ferrock

By this point, you’re probably completely sold on the idea of using Ferrock in place of concrete. We’re right there with you. But there are some downsides to this material that make it unsuitable for extended use.


Ferrock is an eco-friendly alternative to using concrete. 95% of the ingredients of Ferrock are recycled materials, which means you won’t be using up natural resources, as you would do with concrete.

But herein lies the problem. Ferrock needs steel dust waste and silica, both of which are the byproducts or leftover scraps of another process. Therefore, both of these products are in limited supply.

The production of Ferrock is mostly dependent on the creation of other goods. What this means for Ferrock manufacturers is that they are limited in much rock they can make, based on the availability of ingredients.

It takes a lot of silica and metal shavings to make Ferrock, which makes it challenging to do large projects. Currently, there are limited applications for what you can build with Ferrock.


Right now, Ferrock hasn’t become widely used, so it’s still pretty easy to find the necessary materials. Therefore, you can create Ferrock for a low over cost. But concrete will usually be cheaper to make or purchase than Ferrock, due to the manufacturing.

But if companies start to realize there’s a profit to be made by their wastes, it could drive costs up, and make it more challenging to find the necessary materials.

Over time, it could become too expensive to use Ferrock over concrete, despite the growing environmental issues connected to the greenhouse gases caused by concrete manufacturing.


One of the most significant issues preventing Ferrock from replacing concrete entirely is the fact that it’s quite new. Concrete has been around for over 200 years, and there’s still plenty that hasn’t been figured out.

We do know that Ferrock is strong enough to withstand more compression and weight than concrete. But we don’t know how long the life cycle the material is, as it has only been around since the early 2000s.

It’s also unknown how well Ferrock will work in relation to building conditions, as it needs specific techniques to harden. It’s also unclear if you can use the same types of concrete methods on Ferrock.

History of Ferrock

Ferrock was invented by Dr. David Stone, founder and owner of Iron Shell Media Technologies, and former University of Arizona Ph.D. student in the Department of Soil, Water, and Environmental Science Department.

Stone accidentally made Ferrock while he was working on a project back in 2002. At the time, he was researching ways to prevent iron from rusting and hardening.

At first, he didn’t think much of the material he created and abandoned the test. However, he soon changed his mind and decided to focus on finding a material with the same physical capabilities of concrete, but in an eco-friendly version.

To test his new idea, he worked with the Tohono O’odham Nation Reservation in Southern Arizona to source the silica he needed to do his tests.

He also received $200,000 in grants by the Environmental Protection Agency (EPA), which allowed him to create demonstrative projects, along with assistance from the tribe.

Once Stone had the Ferrock manufacturing process figured out, he entered his eco-friendly alternative to concrete in a competition, which he won.

In 2013, the US Patent and Trademark Office issued a patent for the invention. Although Stone is the one who invented Ferrock, the copyright belongs to the University of Arizona, since he was working for them at the time of his discovery.

A year later, in 2014, Stone worked out a contract to hold a license that allowed him to commercialize his invention. This license was done in collaboration with Tech Launch Arizona (TLA).

Iron Shell Material Technologies

Currently, the University of Arizona holds a patent for Ferrock. They have given an exclusive license to Iron Shell Material Technologies. This license allows for the commercialization of Ferrock, meaning it can be manufactured and sold. Ferrock is now a trademarked name.

Iron Shell is a company founded by Dr. Stone to allow him to sell his invention. His company focuses on finding new, environmentally-friendly, carbon-negative, iron-based materials to use in construction.

Given the company’s goal, it’s no surprise that Stone uses steel dust that he gets for free from plants that do not participate in recycling the leftover steel particles. This saves the landfills from being filled with heavy metal toxins.

He also spends his time collecting empty bottles from the Tohono O’odham Nation reservation. Stone doesn’t just get the leftover bottles from the drink dispensaries through the assistance of tribe member Richard Pablo and others.

Dr. Stone also does his part to help clean up litter by picking up bottles off the side of the road. These bottles are then put into a glass crusher where they are turned into silica.


In addition to the creation and patent of Ferrock, Iron Shell has also invented polymiron, a carbon-negative ionomer that is iron-rich. Dr. Stone and his colleagues hope to be able to use this biopolymer as a sealer, resin, tar, and other ventures.

This product is electrically conductive, so there’s the hope of using it in energy conversion systems. However, this product is still in the development phase.

Uses of Ferrock

Currently, Ferrock is being used as a substitute for multiple small projects, such as pavers, tile, and bricks. It has also been tested and approved for larger items such as slabs, sidewalks, walls, and benches.

However, there have not been significant advancements, such as large structures, roads, or any potential projects that could arise in the future.

There have been some promising results that open Ferrock up for a marine-based construction market. This is due to its astounding ability to get more durable with exposure to saltwater, instead of degrading like concrete, which is just clay and chalk mixed together.

Ferrock can also be used for marine structures such as structural pilings, seawalls, piers, breakwaters, and foundations. It is also possible to apply for the construction of piping, as it is resistant to chemicals found in sewage such as sulfuric acid.

Why Choose Ferrock Over Concrete?

Concrete is a tried and true product that has been around for hundreds of years. We know what we can do with it. And you see it everywhere you go.

But despite the extensive use of concrete, there is a good reason we should want to find other possible building materials.

Manufacturing concrete and cement – which is produced separately and is added to the concrete to make it firm up and bind together to form a hard shape -, releases a ton of carbon dioxide into the air.

The reason why there’s so much CO2 is that cement has to be heated to extremely high temperatures in order to break down the limestone. And when we say high, we mean scorching, as in 2,800℉ (1537.778℃).

To give you an idea of how much carbon dioxide we’re talking about, for every 1000 kilograms of cement, 900 kilograms of carbon dioxide is released from the factories and into the air.

Now let’s look at Ferrock, which has been found to absorb carbon dioxide and fuse it into the matrix. It seems like a no-brainer that we would want to use more of a product that can do the same things as concrete, but that cleans up our air too.

Set Time

Another advantage that Ferrock has over concrete is that it does not take as long to set and harden. Concrete takes 24 to 48 hours to harden. But it takes up to 28 days before it reaches its full strength. Before this time, the concrete can still be damaged by hard impacts.

Ferrock needs at least a week to finish expanding. During this time, all the small glass fragments fuse together, and the material hardens. It also continues to pull in carbon dioxide, which also helps strengthen the durability.

Final Verdict

Ferrock seems to be a viable solution for a carbon negative, recycled, durable material that could replace concrete. Given the changes in global warming over the last few hundred years, it’s nice to see that there are people out there trying to find ways to reduce our carbon footprint.

And what better way to do that than to use an eco-friendly material made of recycled materials? And the fact that Ferrock can actually absorb carbon dioxide out of the atmosphere, reducing greenhouse gasses makes it an even better product.

We look forward to seeing the future uses of Ferrock and we hope that there will continue to be other inventions developed that will be better for the environment. With the huge advances in technology, we’re sure there’s going to be great creations in the future. Thanks for reading!


By Giovanni Valle

Giovanni Valle is a licensed architect and LEED-accredited professional and is certified by the National Council of Architectural Registration Boards (NCARB). He is the author and managing editor of various digital publications, including BuilderSpace, Your Own Architect, and Interiors Place.


  1. Do some research- concrete has been used for more than 2000 years. The Romans and others used it extensively.

    Wikipedia has a link- I used ‘concrete history’ in my search.

    1. While true that Roman concrete dates back more than 2,000 years and there are other civilizations that used variations of it even before that time, the 200 year timeframe refers to modern concrete which uses Portland cement as a binder and was invented in 1824 by Joseph Aspdin. This mixture is what is used today in most contemporary structures and what we commonly refer to as “concrete”.

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