Mineral carbonation of materials

Methodology name	Mineral carbonation of materials
Version	1.0
Methodology ID	RIV-CDR-MIN-V1.0
Release date	June 2025
Status	Public consultation

Introduction

It is widely acknowledged that in addition to reducing global greenhouse gas (GHG) emissions, and permanently sequestered. One way to do this is through of concrete and alkaline wastes that contain metal ions, destined for permanent incorporation into building products. In this process, captured CO₂ is exposed to and reacts with alkaline materials, generating stable carbonates that can store the CO₂.

This methodology document outlines the general requirements for mineral carbonation of materials projects certified under the Riverse Standard Rules.

Acknowledgements 🤝

This methodology was developed by Riverse with valuable input and support from the Riverse Mineral Carbonation Methodology Working Group members and other expert contributors.

We would like to thank Christina Stavridi, Bernardo Martinez, and Gabriel Carrero (Carbon Limit), Colin Hills (University of Greenwich), Jamie Rogers (CarbonCure), Paula Carey and Aaron Lyons (Carbon8), and Stephen Roscoe (O.C.O) for their insights and contributions throughout the development process.

Glossary

Mineral Carbonation	A chemical process where CO2 reacts with alkaline materials (e.g., concrete, cement, industrial residues) to form stable carbonates (e.g. CaCO3), permanently storing CO2.
Carbonated Material	The solid product resulting from mineral carbonation, containing CO2 locked in stable carbonate form (e.g., carbonated concrete or aggregate).
Carbonation curing	A process where CO2 is introduced to concrete or cement-based materials during the curing stage, to accelerate strength development and chemically bind CO2 into the material.
Carbonation batch	The carbonated material produced using the same input materials (alkaline feedstock and CO2) and operating conditions. It is assumed that all carbonated material from the same carbonation batch has similar characteristics.
Alkaline Feedstock	Materials that contain metal oxides (e.g., calcium, magnesium, iron) that react with CO2 to form carbonates.
Biogenic CO2	CO2 originating from biomass sources. Its carbonation leads to net carbon removals, and is eligible for removal carbon credits.
Atmospheric CO2	CO2 captured directly from the atmosphere, typically from Direct Air Capture (DAC) or ambient air. Its carbonation leads to net carbon removals, and is eligible for removal carbon credits.
Fossil CO2	CO2 originating from fossil fuels. Its carbonation leads to carbon storage, and is eligible for avoidance carbon credits.
Calcination CO2	CO2 originating from lime that is calcinated in cement production, from breaking up CaCO3 into CO2 and calcium silicates. Its carbonation leads to carbon storage, and is eligible for avoidance carbon credits.
Fugitive CO2 Emissions	Unintended leaks of CO2 from equipment (e.g., reactors, pipelines). Not to be confused with the Leakage eligibility criteria.
Ordinary Portland Cement (OPC)	The most common type of cement, produced by heating limestone and other materials to form clinker, which is then ground into a fine powder.
Supplementary cementitious materials (SCM)	Industrial by-products (e.g. fly ash, slag) or natural pozzolans used to partially replace OPC in concrete. They can both replace and reduce clinker-related emissions, and serve as reactive alkaline materials that bind CO2 into stable carbonates.

Glossary