NZ Start-Up Harnesses Olivine Rocks for Carbon Removal

The Earth’s carbon dioxide in the atmosphere was in perfect balance until the Industrial Revolution when vast amounts of carbon dioxide emitted into the atmosphere threw the carbon cycle out of balance.

Human activities have released more carbon dioxide than the Earth’s carbon cycle can absorb. Since the beginning of the Industrial Revolution, carbon dioxide concentrations in the atmosphere have risen from about 280 parts per million to 387 parts per million, a 39 per cent increase.

This means that of every million molecules in the atmosphere, 387 are carbon dioxide—the highest concentration in two million years. The latest measurement taken in September 2023 is 419 ppm.

This excess carbon dioxide warms the planet, causing climate change. But what if there is a solution to help restore the Earth’s carbon cycle balance?

The idea of breaking down rocks to accelerate carbon capture has been well-known for many years. Weathering is a natural process whereby when certain types of rocks, those rich in silicate and magnesium, break down, they react with water and the atmosphere to capture carbon and lock it up in solid form.

Scientists have proposed using olivine rock, a green-coloured rock that, when grounded, could speed up carbon dioxide removal from the atmosphere. Olivine is mainly found in the Earth’s mantle and is widely abundant globally. In New Zealand, it is a standard construction material used as an aggregate to make roads.

But what if they could develop a process that could accelerate the timescale of rocks like olivine to capture carbon?

A New Zealand-based start-up mineral conversion company, Aspiring Materials, has found an extraordinary way to use olivine, an ordinary rock, to combat climate change. In the video below, Aspiring’s Megan Danczyk, a chemical process engineer at Aspiring Material, explains how the company has developed a breakthrough process that can capture carbon at an unprecedented concentration. She says they are unlocking nature’s power to capture carbon in an accelerated timescale, which the world needs now to fight climate change. 

Chris Oze, Aspiring Material Co-Founder, says that for every ton of rock, their process could displace up to three tons of CO2.

The method includes grounding the rock, which is then dissolved in acid. The elemental soup produces minerals like iron, silica, and magnesium. When water is added to the magnesium powder, it immediately captures CO2 from the air and turns into a solid form. The magnesium and carbon dioxide compound can be used to form many other materials, including a zero-emissions gib board, a commonly used construction material in New Zealand (Brownlie, 2023).

Coastal carbon capture using green sand

In the US, a private company called Vesta believes they could speed up the ocean’s long-term carbon sequestration process by spreading crushed olivine into beaches and sand seafloor. Crushing olivine can accelerate its weathering process by increasing the surface areas of the mineral available for chemical reaction with seawater.

Global emissions are around 32 billion metric tons of CO2 annually, and whether speeding up rock weatherisation could significantly dent our carbon emissions remains to be seen. Vesta says its technique would remove at least a gigaton of atmospheric CO2 annually.

Learn more about coastal carbon capture using olivine: Can These Rocks Help Rein in Climate Change?