A process for the surface treatment of a surface-modified calcium carbonate, the process comprising the steps of: a) providing an aqueous suspension of at least one surface-modified calcium carbonate having solids content in the range from 5 to 80 wt.-%, based on the total weight of the aqueous suspension, wherein the surface-modified calcium carbonate is a reaction product of natural ground calcium carbonate or precipitated calcium carbonate with carbon dioxide and one or more H 3 O + ion donors, wherein the carbon dioxide is formed in situ by the H 3 O + ion donors treatment and/or is supplied from an external source; b) adjusting the pH-value of the aqueous suspension of step a) to a range from 7.5 to 12; c) adding at least one surface treatment agent to the aqueous suspension obtained in step b) in an amount ranging from 0.05 to 10 mg surface treatment agent per m 2 of the accessible surface area of the surface-modified calcium carbonate as provided in step a), the at least one surface treatment agent is selected from the group consisting of mono- or di-substituted succinic anhydride containing compounds, mono- or di-substituted succinic acid containing compounds, mono- or di-substituted succinic acid salts containing compounds; unsaturated fatty acids, salts of unsaturated fatty acids; unsaturated esters of phosphoric acid, salts of unsaturated phosphoric acid esters; abietic acid, salts of abietic acid and mixtures thereof; d) mixing the aqueous suspension obtained in step c) at a temperature in the range from 30 to 120°C; and e) drying the aqueous suspension during or after step d) at a temperature in the range from 40 to 160°C at ambient or reduced pressure until the moisture content of the obtained surface-treated calcium carbonate is in the range from 0.001 to 20 wt.-%, based on the total weight of the surface-treated calcium carbonate. a) providing an aqueous suspension of at least one surface-modified calcium carbonate having solids content in the range from 5 to 80 wt.-%, based on the total weight of the aqueous suspension, wherein the surface-modified calcium carbonate is a reaction product of natural ground calcium carbonate or precipitated calcium carbonate with carbon dioxide and one or more H 3 O + ion donors, wherein the carbon dioxide is formed in situ by the H 3 O + ion donors treatment and/or is supplied from an external source; b) adjusting the pH-value of the aqueous suspension of step a) to a range from 7.5 to 12; c) adding at least one surface treatment agent to the aqueous suspension obtained in step b) in an amount ranging from 0.05 to 10 mg surface treatment agent per m 2 of the accessible surface area of the surface-modified calcium carbonate as provided in step a), the at least one surface treatment agent is selected from the group consisting of mono- or di-substituted succinic anhydride containing compounds, mono- or di-substituted succinic acid containing compounds, mono- or di-substituted succinic acid salts containing compounds; unsaturated fatty acids, salts of unsaturated fatty acids; unsaturated esters of phosphoric acid, salts of unsaturated phosphoric acid esters; abietic acid, salts of abietic acid and mixtures thereof; d) mixing the aqueous suspension obtained in step c) at a temperature in the range from 30 to 120°C; and e) drying the aqueous suspension during or after step d) at a temperature in the range from 40 to 160°C at ambient or reduced pressure until the moisture content of the obtained surface-treated calcium carbonate is in the range from 0.001 to 20 wt.-%, based on the total weight of the surface-treated calcium carbonate.