Carbon Into Stone: Onboard CO₂ Mineralization Gains Momentum

Shanghai Qiyao Technology Group Co., Ltd. has received in-principle support from the International Maritime Organization (IMO) for its proposal to treat onboard carbon mineralization as a form of permanent CO₂ storage.

The decision emerged during MEPC 84, where the IMO working group welcomed two joint submissions from the company and its partners. The concept allows captured ship emissions to be converted into stable minerals, such as calcium carbonate, which can be used in construction materials, effectively storing carbon permanently without leakage.

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Carbon mineralization is the process of accelerating natural chemical weathering to react captured (CO_{2}) with calcium- or magnesium-rich minerals. This permanently transforms the gas into solid, stable carbonates (like limestone) that cannot leak back into the atmosphere.

The company argues that mineralization offers a practical alternative to conventional onboard carbon capture and storage (OCCS), which typically depends on geological storage and is constrained by high costs and limited infrastructure.

Instead of treating captured CO₂ as waste requiring disposal, the proposed approach turns it into a usable industrial input, potentially improving both the economics and scalability of maritime decarbonization.

We see this IMO attention as an important step. Closing the loop from shipboard capture to onshore mineralization can make carbon accounting more practical and economically attractive for the industry
… said the head of Qiyao’s OCCS team.

One submission (MEPC 84/7/18) presents the technical and environmental justification for classifying mineralization as equivalent to permanent sequestration, while the second (MEPC 84/INF.8) is based on Qiyao’s demonstration project.

According to the second submission, the system was deployed on the EVER TOP, a 14,000 TEU container vessel operated by Evergreen Marine Corp., equipped with a full OCCS system covering absorption, compression, liquefaction, and onboard storage. After stable operation, the captured CO₂ was handled through a structured offshore-to-onshore logistics chain.

On 19 June 2025, the vessel completed a ship-to-ship transfer at Yangshan Port, Shanghai, offloading liquefied CO₂ to a dedicated carrier vessel (Dejin 26). The transfer was conducted via a multi-stage procedure including preparation, berthing, pipeline connection, tightness testing, controlled pressure equalisation, and gravity-assisted liquid flow transfer, achieving a total transfer of approximately 25.44 tonnes of CO₂.

Following transfer, the CO₂ was transported by sea and land to an industrial facility in Zhoushan, Zhejiang Province, where it was offloaded into tank trucks and ultimately delivered to Baorong Corporation.

There, it was used as a feedstock in a mineralization process producing construction materials, such as concrete derived from CO₂-reacted steel slag. This final step demonstrated conversion of captured emissions into stable mineral carbonates, effectively locking carbon into a solid, non-leaking form.