A method for carbon sequestration comprising the steps of: (i) providing a solid feedstock having a first moisture content and a mass-based D95 determined by sieve analysis of less than 20 mm; (ii) providing a first carbon-rich gas comprising at least 1 vol% CO 2 and a second carbon-rich gas comprising at least 1 vol% CO 2; (iii) subjecting the solid feedstock of step (i) in a size-reduction apparatus to a size-reduction operation in the presence of the first carbon-rich gas of step (ii) to obtain a first CO 2 -enriched material and recovering the first CO 2 -enriched material; (iv) increasing the moisture content of said first CO 2 -enriched material to a second moisture content higher than the first moisture content to obtain wetted CO 2 -enriched material; (v) submitting the wetted CO 2 -enriched material to a further CO 2 -enrichment treatment outside the size-reduction apparatus by contacting it with the second carbon-rich gas comprising at least 1 vol% CO 2; to obtain a second CO 2 -enriched material and recovering the second CO 2 -enriched material; wherein the second CO 2 -enriched material recovered in step (v) has a D50, determined with a laser light scattering particle size analyzer utilizing the Mie theory of light scattering, within the range of 0.1 to 100 μm, wherein the first moisture content is less than 8 wt.% (by total weight of the solid feedstock), and wherein the second moisture content is more than 10 wt.% (by total weight of the wetted CO 2 -enriched material), and wherein the ratio of the D50 of the first CO 2 -enriched material recovered in step (iii), to the D50 of the second CO 2 -enriched material recovered in step (v), is within the range of 0.8-1.2, wherein the D50 is the mass median diameter. (i) providing a solid feedstock having a first moisture content and a mass-based D95 determined by sieve analysis of less than 20 mm; (ii) providing a first carbon-rich gas comprising at least 1 vol% CO 2 and a second carbon-rich gas comprising at least 1 vol% CO 2; (iii) subjecting the solid feedstock of step (i) in a size-reduction apparatus to a size-reduction operation in the presence of the first carbon-rich gas of step (ii) to obtain a first CO 2 -enriched material and recovering the first CO 2 -enriched material; (iv) increasing the moisture content of said first CO 2 -enriched material to a second moisture content higher than the first moisture content to obtain wetted CO 2 -enriched material; (v) submitting the wetted CO 2 -enriched material to a further CO 2 -enrichment treatment outside the size-reduction apparatus by contacting it with the second carbon-rich gas comprising at least 1 vol% CO 2; to obtain a second CO 2 -enriched material and recovering the second CO 2 -enriched material; wherein the second CO 2 -enriched material recovered in step (v) has a D50, determined with a laser light scattering particle size analyzer utilizing the Mie theory of light scattering, within the range of 0.1 to 100 μm, wherein the first moisture content is less than 8 wt.% (by total weight of the solid feedstock), and wherein the second moisture content is more than 10 wt.% (by total weight of the wetted CO 2 -enriched material), and wherein the ratio of the D50 of the first CO 2 -enriched material recovered in step (iii), to the D50 of the second CO 2 -enriched material recovered in step (v), is within the range of 0.8-1.2, wherein the D50 is the mass median diameter.