CO2 mineralization and utilization by tailings sand in China for potential carbon sinks and spatial project layout

The use of tailings sand for CO2 mineralization and utilization (CMU) has been emerging globally, offering a sustainable solution for repurposing tailings sand while establishing a stable carbon sink. Despite several reports that evaluated process performance and project benefits, existing research has not delved into the project layout focusing on the tailings pond facility and the feasibility considerations from a cluster and ownership perspective. Conducting facility-scale refined mineralized carbon sink (MCS) and layout feasibility assessment is a key issue that needs to be addressed urgently. Here, we accounted for CMU potential (CMUP) of tailings sand using a sample of 6219 tailings pond ownerships in China, predicted future annual carbon sinks through an innovative ARIMA-cloud model, and analyzed the feasibility of project layouts within potential clusters concerning enterprise size. Our results indicate that the CMUP of accumulated tailings sand in China amounts to 1817.87 Mt. In a combined scenario involving future technological leapfrogging and increased utilization, the average annual carbon sink by 2030 is projected to be 24.73 Mt. A considerable reduction in project layout feasibility across all scenarios was observed due to the mismatch between carbon clusters and enterprise size. Our study reveals that CMU using tailings sand should be regarded as one of the essential green technologies in the portfolio of strategic Chinese CO2 mitigation. However, we highlight the necessity of aligning cluster programs with the support capacity of the ownership enterprise to ensure the optimal project success.