Multistage mineral carbonation

The present invention provides an integrated process for carbon dioxide capture, sequestration and utilisation, which comprises:a) providing an aqueous slurry comprising an aqueous liquid and a particulate solid comprising an activated magnesium silicate mineral;b) in a dissolution stage, contacting a CO2-containing gas stream with the aqueous slurry at a first pressure to dissolve magnesium from the mineral to provide a slurry comprising a magnesium ion enriched carbonated aqueous liquid and a magnesium depleted solid residue; andc) in a precipitation stage, precipitating magnesium carbonate from magnesium ions dissolved in step b) by multiple successive stage-wise reductions in pressure, with each stage being at a lower pressure than the preceding stage;wherein each successive stage-wise reduction in pressure releases CO2 which is correspondingly stage-wise compressed and recycled back into the dissolution stage.