Abstract: The present invention relates to a process for decomposing calcium sulfide (CaS) into calcium oxide (CaO) and sulfur dioxide (SO2), comprising:—providing a reactor containing calcium sulfide and a source of carbon,—oxidizing the source of carbon so as to generate carbon dioxide (CO2),—reacting the calcium sulfide with said carbon dioxide so as to produce carbon oxide (CaO), sulfur dioxide (SO2) and carbon monoxide (CO) according to the following reaction: CaS+3CO2˜CaO+SO2+3CO wherein the oxygen and carbon contents in the oxidation step are chosen such that: (i) the mass ratio C/CaS is comprised between 0.15 and 0.35 and (ii) the mass ratio O2/C is comprised between 5 and 25.

Abstract: The present invention relates to a process for decomposing calcium sulfate (CaSO4) present in phosphogypsum (PG), comprising the following steps: a) providing a reactor containing phosphogypsum (PG) and a solid source of carbon (C), b) reacting a flow of dioxygen (Oz) with the source of carbon (C) so as to generate carbon oxide (CO), c) reacting carbon oxide (CO) obtained in step a) with calcium sulfate (CaSO4) of the phosphogypsum to produce calcium oxide (CaO) and sulfoxide (SO2) according to the following reaction: CaSO4+CO?CaO+SO2+CO2 wherein the mass ratio C/PG is between 0.2 and DA, and the mass ratio 15 O2/PG is between 0.5 and 1.5.

Abstract: The present invention relates to a process for decomposing calcium sulfide (CaS) into calcium oxide (CaO) and sulfur dioxide (SO2), comprising: —providing a reactor containing calcium sulfide and a source of carbon, —oxidizing the source of carbon so as to generate carbon dioxide (CO2), —reacting the calcium sulfide with said carbon dioxide so as to produce carbon oxide (CaO), sulfur dioxide (SO2) and carbon monoxide (CO) according to the following reaction: CaS+3CO2˜CaO+SO2+3CO wherein the oxygen and carbon contents in the oxidation step are chosen such that: (i) the mass ratio C/CaS is comprised between 0.15 and 0.35 and (ii) the mass ratio O2/C is comprised between 5 and 25.

Abstract: The present invention relates to a process for decomposing calcium sulfate (CaSO4) present in phosphogypsum (PG), comprising the following steps: a) providing a reactor containing phosphogypsum (PG) and a solid source of carbon (C), b) reacting a flow of dioxygen (Oz) with the source of carbon (C) so as to generate carbon oxide (CO), c) reacting carbon oxide (CO) obtained in step a) with calcium sulfate (CaSO4) of the phosphogypsum to produce calcium oxide (CaO) and sulfoxide (SO2) according to the following reaction: CaSO4+CO?CaO+SO2+CO2 wherein the mass ratio C/PG is between 0.2 and DA, and the mass ratio 15 O2/PG is between 0.5 and 1.5.