The present application pertains to processes for making calcium oxide and/or sulfuric acid from calcium sulfate. In some embodiments the processes comprise reacting a component comprising calcium sulfate with a second component comprising magnesium sulfite under conditions to form a solid comprising calcium sulfite and a solution comprising magnesium sulfate. Next, at least a portion of the solid comprising calcium sulfite is decomposed to form a second solid comprising calcium oxide, or calcium hydroxide, or cement, or clinker, or any combination thereof.

The electrochemical reactors disclosed herein provide novel oxidation and reduction chemistries and employ increased mass transport rates of materials to and from the surfaces of electrodes therein.

A method can include reducing calcium sulfate to calcium sulfide, converting calcium sulfide to calcium oxide, optionally using the calcium oxide to form a product, optionally oxidizing sulfur dioxide to sulfuric acid, and optionally using the sulfuric acid in fertilizer production.

The present application pertains to processes for making calcium oxide and/or sulfuric acid from calcium sulfate. In some embodiments the processes comprise reacting a component comprising calcium sulfate with a second component comprising magnesium sulfite under conditions to form a solid comprising calcium sulfite and a solution comprising magnesium sulfate. Next, at least a portion of the solid comprising calcium sulfite is decomposed to form a second solid comprising calcium oxide, or calcium hydroxide, or cement, or clinker, or any combination thereof.

The electrochemical reactors disclosed herein provide novel oxidation and reduction chemistries and employ increased mass transport rates of materials to and from the surfaces of electrodes therein.

The present application pertains to processes for making calcium oxide and/or sulfuric acid from calcium sulfate. In some embodiments the processes comprise reacting a component comprising calcium sulfate with a second component comprising magnesium sulfite under conditions to form a solid comprising calcium sulfite and a solution comprising magnesium sulfate. Next, at least a portion of the solid comprising calcium sulfite is decomposed to form a second solid comprising calcium oxide, or calcium hydroxide, or cement, or clinker, or any combination thereof.

Disclosed are methods and systems for capturing carbon dioxide and utilizing calcium sulfate to generate useful products.

The present disclosure provides a desulfurization and sulfur recovery method for sulfur dioxide flue gas, and belongs to the technical field of non-ferrous metal smelting. The method includes the following steps: desulfurizing the sulfur dioxide flue gas by taking slagging flux limestone or quicklime for smelting or converting process as a desulfurizer, and adsorbing SO.sub.2 in the gas to obtain gypsum residue, calcium sulfite, and the desulfurized flue gas, where SO.sub.2 in the sulfur dioxide flue gas before desulfurization is less than 1 vol %; and recycling the gypsum residue and the calcium sulfite to the smelting or converting furnace for slagging, resolving the SO.sub.2 into smelting off-gas, producing sulfuric acid in acid plant.