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.

A chemical looping combustion (CLC) process for sour gas combustion is integrated with a gas turbine combined cycle and a steam generation unit, and is configured to provide in-situ removal of H.sub.2S from the sour gas fuel by reacting the H.sub.2S with a oxygen carrier at a location within the fuel reactor of the CLC unit. The process is also configured such that oxygen-rich exhaust gases from the gas turbine combined cycle is used to feed the air reactor of the CLC unit and re-oxidize oxygen carriers for recirculation in the CLC unit.

A chemical looping combustion (CLC) process for sour gas combustion is integrated with a gas turbine combined cycle and a steam generation unit, and is configured to provide in-situ removal of H.sub.2S from the sour gas fuel by reacting the H.sub.2S with a oxygen carrier at a location within the fuel reactor of the CLC unit. The process is also configured such that oxygen-rich exhaust gases from the gas turbine combined cycle is used to feed the air reactor of the CLC unit and re-oxidize oxygen carriers for recirculation in the CLC unit.

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.

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.

A chemical looping combustion (CLC) process for sour gas combustion includes a number of reaction zones and is configured to provide in-situ oxygen production and in-situ removal of SO.sub.2 from a product gas stream by reacting the SO.sub.2 with a calcium-based sorbent at a location within one reaction zone. The CLC process is also configured such that the in-situ oxygen production results from the use of a metal oxide oxygen carrier which is purposely located such that it does not directly contact the sour gas, thereby eliminating the generation of undesirable sulfur-based metal oxides.

A chemical looping combustion (CLC) process for sour gas combustion includes a number of reaction zones and is configured to provide in-situ oxygen production and in-situ removal of SO.sub.2 from a product gas stream by reacting the SO.sub.2 with a calcium-based sorbent at a location within one reaction zone. The CLC process is also configured such that the in-situ oxygen production results from the use of a metal oxide oxygen carrier which is purposely located such that it does not directly contact the sour gas, thereby eliminating the generation of undesirable sulfur-based metal oxides.

In some embodiments the application pertains to processes comprising reacting a component comprising an alkaline earth weak acid with a component comprising an acid to form a component comprising an alkaline earth acid anion and a component comprising a weak acid derivative. At least a portion of the component comprising the alkaline earth acid anion is reacted with a component comprising an alkali sulfate to form a component comprising alkaline earth sulfate and a component comprising an alkali acid anion. At least a portion of the component comprising alkaline earth sulfate is decomposed to form a component comprising alkaline earth oxide, or alkaline earth hydroxide, or alkaline earth carbonate, or alkaline earth sulfide, or a derivative thereof, or any combination thereof, and a component comprising sulfur dioxide, or oxygen, or sulfur trioxide, or a derivative thereof, or any combination thereof.

In some embodiments the application pertains to processes comprising reacting a component comprising an alkaline earth weak acid with a component comprising an acid to form a component comprising an alkaline earth acid anion and a component comprising a weak acid derivative. At least a portion of the component comprising the alkaline earth acid anion is reacted with a component comprising an alkali sulfate to form a component comprising alkaline earth sulfate and a component comprising an alkali acid anion. At least a portion of the component comprising alkaline earth sulfate is decomposed to form a component comprising alkaline earth oxide, or alkaline earth hydroxide, or alkaline earth carbonate, or alkaline earth sulfide, or a derivative thereof, or any combination thereof, and a component comprising sulfur dioxide, or oxygen, or sulfur trioxide, or a derivative thereof, or any combination thereof.

In some embodiments the application pertains to processes comprising reacting a component comprising an alkaline earth weak acid with a component comprising an acid to form a component comprising an alkaline earth acid anion and a component comprising a weak acid derivative. At least a portion of the component comprising the alkaline earth acid anion is reacted with a component comprising an alkali sulfate to form a component comprising alkaline earth sulfate and a component comprising an alkali acid anion. At least a portion of the component comprising alkaline earth sulfate is decomposed to form a component comprising alkaline earth oxide, or alkaline earth hydroxide, or alkaline earth carbonate, or alkaline earth sulfide, or a derivative thereof, or any combination thereof, and a component comprising sulfur dioxide, or oxygen, or sulfur trioxide, or a derivative thereof, or any combination thereof.