Calcium sulfide decomposition process

1. A process for decomposing calcium sulfide (CaS) into calcium oxide (CaO) and sulfur dioxide (SO 2 ), comprising:

providing a reactor containing calcium sulfide and a source of carbon,

oxidizing the source of carbon so as to generate carbon dioxide (CO 2 ),

reacting the calcium sulfide with said carbon dioxide so as to produce calcium oxide (CaO), sulfur dioxide (SO 2 ) and carbon monoxide (CO) according to the following reaction:

CaS+3CO 2 →CaO+SO 2 +3CO

wherein the oxygen (O 2 ) and carbon (C) 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 O 2 /C is comprised between 5 and 25.

2. The process of claim 1 , wherein the ratio C/CaS is equal to 0.25.

3. The process of claim 1 , wherein the ratio O 2 /C is equal to 8.

4. The process of claim 1 , wherein in the oxidation step the reactor is heated to a temperature comprised between 900° C. and 1200° C.

5. The process of claim 4 , wherein the reactor is heated by induction.

6. The process of claim 1 , wherein the source of carbon comprises at least one of: coal, coke, charcoal, and shale oil.

7. The process of claim 1 , wherein the reactor is a continuous reactor comprising an inlet and an outlet for flowing O 2 through the calcium sulfide and the source of carbon.

8. The process of claim 1 , wherein the reactor is a fluidized bed reactor or a rotary kiln.