Mineralization of CO2
Mineralization of CO2 is a natural process to permanently remove CO2 from the air and lock the resulting carbon into minerals. Mineralization is basically the natural process of rock weathering. It occurs when water and air get into contact with the surface of volcanic rock. In nature, this process is very slow as the exposed surface of the rock is small. By crushing rocks and grinding them into tiny particles, the surface becomes magnified and all of the rock weathers in a timeframe of one year. RockFarm uses volcanic rock with both a high capacity to store carbon and high availability on the market in Europe. This rock is called dunite and is already being mined in Europe on a scale of megatons per year in Europe. Big mines are indicating their ability to ramp up production considerably without having to invest in further mining infrastructure.
At RockFarm, crushed and grinded particles of volcanic rock are inserted into enclosed carbon removal walls. Automation technology is applied to control weathering conditions inside of a closed system. Optimized weathering is an engineered process to improve the quality, quantity and duration of mineralization. Our robots are artificial, but the applied chemical processes to fight global warming are still based on the natural weathering of volcanic rock. Our technology speeds up the natural process of rock weathering.
Rinse and Refill
Mineralization requires moderate temperatures, moisture and a lot of rock surface. RockFarm rock walls can offer optimized conditions for that. But most important for efficient carbon removal is a strategy for how to fill material into the wall and how to remove carbonized material. Nature provides us with an elegant solution for that. Both minerals and CO2 can dissolve in water. And as they are interdependent, it is possible to control the mineralization rate of water by controlling the amount of CO2 (carbonic acid) in that water. Thus, we use a dispersion of water and minerals to fill minerals through pipes into the wall and sedimentation to aggregate it. Carbonized minerals are basically carbonates. Carbonates dissolve in water into hydrocarbons. Thus, it is easy to flush carbonates out of the wet wall center. And to remove hydrocarbonates from water, the process of precipitation can be controlled through control of the amount of carbonic acid (CO2) in water. As you might notice, this is a beautiful process of water chemistry as being applied today for public freshwater treatment. It works basically without filtering, is scalable and ready for water reuse.
Closed box
A typical question from experts in enhanced weathering is about the aggregation of carbon in a wall. The CO2 concentration in the air is below 1% and that is far from optimal for enhanced weathering. We solve that by means of our closed box technology. We have identified a simple solution to seal our wall against the atmosphere. By adding carbonated water to the wall, the concentration of CO2 can be increased far above atmospheric level (at the same pressure). Our goal is to reach faster weathering of rock in our walls compared to weathering in soil.
Summary
RockFarm teaches its robots to build closed box enhanced weathering devices at the lowest cost and with the added value of being a beautiful natural stone wall. The carbon removal rate is increased by a factor of magnitude towards natural rock weathering. RockFarm applies fine rock grinding and conventional freshwater treatment to achieve that.
