Provided is a sulfur dioxide mixture that hardly corrodes metals. A sulfur dioxide mixture contains sulfur dioxide and water. The sulfur dioxide mixture is filled in a filling container in such a manner that a gas phase and a liquid phase exist, and the moisture concentration of the gas phase is from 0.005 mole ppm to less than 5,000 mole ppm.

The present application pertains to methods for making metal oxides and/or citric acid and/or capturing carbon dioxide. In one embodiment, the application pertains to a process for producing calcium oxide, magnesium oxide, or both from a material comprising calcium and magnesium. The process may include reacting a material comprising calcium carbonate and magnesium carbonate. Separating, concentrating, and calcining may lead to the production of oxides such as calcium oxide or magnesium oxide. In other embodiments the application pertains to methods for producing an alkaline-earth oxide and a carboxylic acid from an alkaline earth cation-carboxylic acid anion salt. Such processes may include, for example, reacting an alkaline-earth cation-carboxylic acid anion salt with aqueous sulfur dioxide to produce aqueous alkaline-earth sulfite or bisulfate and an aqueous carboxylic acid solution. Other useful steps may include desorbing, separating, and/or calcining.

The present application pertains to methods for making alkali hydroxide, or alkali carbonates, or alkali bicarbonates, or alkaline—earth sulfates. In one embodiment, a material comprising an alkaline earth is converted to an alkaline earth sulfite or bisulfite and reacted with an alkali sulfate to form an alkaline earth sulfate and alkali sulfite or bisulfite. The alkali sulfite or bisulfite is converted into an alkali hydroxide, or an alkali carbonate, or an alkali bicarbonate. In another embodiment, ammonium carbonate or ammonium bicarbonate is reacted with an alkali sulfate, to form ammonium sulfate and an alkali carbonate or alkali bicarbonate. A material comprising an alkaline earth is converted to an alkaline earth sulfite or bisulfite and reacted with the ammonium sulfate to form an alkaline earth sulfate and ammonium sulfite or ammonium bisulfite. The ammonium sulfite or bisulfite is regenerated into ammonia, or ammonium hydroxide, or ammonium carbonate, or ammonium bicarbonate.

The present invention relates to a process for decomposing calcium sulfide (CaS) into calcium oxide (CaO) and sulfur dioxide (SO.sub.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.sub.2), —reacting the calcium sulfide with said carbon dioxide so as to produce carbon oxide (CaO), sulfur dioxide (SO.sub.2) and carbon monoxide (CO) according to the following reaction: CaS+3CO.sub.2˜CaO+SO.sub.2+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 O.sub.2/C is comprised between 5 and 25.

The present disclosure relates to a process for decomposition of sulfuric acid, particularly a process for catalytically decomposing sulfuric acid, to obtain sulfur dioxide therefrom. In the present process, catalysts play a major role for improving the dissociation efficiency by lowering the activation energy barrier for the reaction.

The present disclosure relates to a catalyst composition for conversion of sulphur trioxide to sulphur dioxide and oxygen comprising an active material selected from the group consisting of transitional metal oxide, mixed transitional metal oxide, and combinations thereof; and a support material selected from the group consisting of silica, titania, zirconia, carbides, and combinations thereof. The subject matter also relates to a process for the preparation of the catalyst composition for conversion of sulphur trioxide to sulphur dioxide and oxygen.

The present disclosure describes a hydrogen sulfide decomposition process for converting hydrogen sulfide into hydrogen gas and sulfur dioxide. Such a process can significantly increase the amount of available hydrogen gas. In fact, if each Claus unit in the U.S. creating elemental sulfur in traditional systems were replaced by this hydrogen sulfide decomposition process, 1.83 million metric tons of hydrogen gas could be produced. This represents about 20% of the annual hydrogen produced in the U.S. for any purpose, recovered and available for reuse. Additionally, if desired, the sulfur dioxide can be further processed to form sulfuric acid.

A process for producing sulfuric acid and cement clinker may use calcium sulfate that is formed as a solid by-product and separated off in phosphoric acid production in a reaction of raw phosphate with sulfuric acid to form phosphoric acid. The process comprises treating calcium sulfate separated from the phosphoric acid with an acid to obtain a suspension comprising purified calcium sulfate, separating the purified calcium sulfate in solid form from the liquid phase of the suspension, mixing the purified calcium sulfate with admixtures and reducing agents to obtain a raw meal mixture for cement clinker production, burning the raw meal mixture to obtain the cement clinker, with formation of sulfur dioxide as offgas, and subjecting the sulfur dioxide formed to offgas purification and feeding the sulfur dioxide as raw material to sulfuric acid production to produce the sulfuric acid. The sulfuric acid produced may be used as starting material in phosphoric acid production.

A method of managing sulfur in a sulfur-containing stream may include steps of providing a sulfur-containing stream; converting sulfur within the sulfur-containing stream to elemental sulfur; transporting the elemental sulfur to a location at or near a sulfur oxide injection location; converting the elemental sulfur to sulfur oxides; recovering electrical energy from said step of converting the elemental sulfur to sulfur oxides; injecting the sulfur oxides into the sulfur oxide injection location. The method may include steps of screening a plurality of injection locations and selecting, from the screened plurality of injection locations, a particular sulfur dioxide injection location with specific reservoir characteristics for the sulfur oxides.

A method of managing sulfur in a sulfur-containing stream may include steps of providing a sulfur-containing stream; converting sulfur within the sulfur-containing stream to elemental sulfur; transporting the elemental sulfur to a location at or near a sulfur oxide injection location; converting the elemental sulfur to sulfur oxides; recovering electrical energy from said step of converting the elemental sulfur to sulfur oxides; injecting the sulfur oxides into the sulfur oxide injection location. The method may include steps of screening a plurality of injection locations and selecting, from the screened plurality of injection locations, a particular sulfur dioxide injection location with specific reservoir characteristics for the sulfur oxides.