Embodiments relate to systems and methods directed towards arrangements of a preheater, a heat exchanger, a plasma recovery system, and at least one processing stage configured to use steam output of a calciner for heating incoming wastewater that is being processed.

A process for producing caustic calcined magnesia (CCM) includes calcining a magnesium containing material, such as magnesite, in a primary calciner to produce a primary calcined material and a primary exhaust comprising dust; subjecting the primary exhaust to separation to recover a dust material includes incompletely calcined dust particles; calcining the dust material in the secondary calciner to produce calcined dust, wherein the dust material is not co-calcined with the magnesium containing material or the primary calcined material. The primary calcined material and the calcined dues thus form two CCM products, which can be kept separate or combined. The primary calciner can be a multiple hearth furnace (MHF) while the secondary calciner can be a gas suspension calciner (GSC). Using a secondary calciner in such a manner can increase throughput of the primary calciner and provide other advantages for the calcination process.

The present application pertains to processes producing oxides using a weak acid intermediate. In one embodiment a material comprising calcium carbonate is reacted with a solution comprising aqueous carboxylic acid to form a gas comprising carbon dioxide and a solution comprising aqueous calcium carboxylate. The solution comprising aqueous calcium carboxylate is reacted with sodium sulfate to form a solution comprising aqueous sodium carboxylate and a solid comprising calcium sulfate. The solution comprising aqueous sodium carboxylate is reacted with sulfur dioxide to form sodium sulfite and an aqueous carboxylic acid. The sodium sulfite is separated from said aqueous carboxylic acid and reacted to form a solid comprising calcium sulfite which is decomposed to form calcium oxide and sulfur dioxide.

Digestion of a laterite with sulfuric acid dissolves all constituents except silica. The resulting sulfatesaluminum sulfate, ferric sulfate, titanyl sulfate, and magnesium sulfateremain in solution at approximately 90 C. Hot filtration separates silica. Solution flow over iron reduces ferric sulfate to ferrous sulfate. Controlled ammonia addition promotes hydrolysis and precipitation of hydrated titania from titanyl sulfate that is removed by filtration. Addition of ammonium sulfate forms ferrous ammonium sulfate and ammonium aluminum sulfate solutions. Alum is preferentially separated by crystallization. Addition of ammonium bicarbonate to an ammonium alum solution precipitates ammonium aluminum carbonate which may be heated to produce alumina, ammonia, and carbon dioxide. The addition of oxalic acid generates insoluble ferrous oxalate which thermally decomposes to ferrous oxide and carbon monoxide which is used to reduce the ferrous oxide to metallic iron. Further oxalic acid addition precipitates magnesium oxalate which is thermally decomposed to magnesium oxide.

Digestion of a laterite with sulfuric acid dissolves all constituents except silica. The resulting sulfatesaluminum sulfate, ferric sulfate, titanyl sulfate, and magnesium sulfateremain in solution at approximately 90 C. Hot filtration separates silica. Solution flow over iron reduces ferric sulfate to ferrous sulfate. Controlled ammonia addition promotes hydrolysis and precipitation of hydrated titania from titanyl sulfate that is removed by filtration. Addition of ammonium sulfate forms ferrous ammonium sulfate and ammonium aluminum sulfate solutions. Alum is preferentially separated by crystallization. Addition of ammonium bicarbonate to an ammonium alum solution precipitates ammonium aluminum carbonate which may be heated to produce alumina, ammonia, and carbon dioxide. The addition of oxalic acid generates insoluble ferrous oxalate which thermally decomposes to ferrous oxide and carbon monoxide which is used to reduce the ferrous oxide to metallic iron. Further oxalic acid addition precipitates magnesium oxalate which is thermally decomposed to magnesium oxide.

A catalyst-free synthesis method for the formation of a metalorganic compound comprising a desired (first) metal may include, for example, selecting another (second) metal and an organic solvent, with the second metal being selected to (i) be more reactive with respect to the organic solvent than the first metal and (ii) form, upon exposure of the second metal to the organic solvent, a reaction by-product that is more soluble in the organic solvent than the metalorganic compound. An alloy comprising the first metal and the second metal may be first produced (e.g., formed or otherwise obtained) and then treated with the organic solvent in a liquid phase or a vapor phase to form a mixture comprising (i) the reaction by-product comprising the second metal and (ii) the metalorganic compound comprising the first metal. The metalorganic compound may then be separated from the mixture in the form of a solid.

A catalyst-free synthesis method for the formation of a metalorganic compound comprising a desired (first) metal may include, for example, selecting another (second) metal and an organic solvent, with the second metal being selected to (i) be more reactive with respect to the organic solvent than the first metal and (ii) form, upon exposure of the second metal to the organic solvent, a reaction by-product that is more soluble in the organic solvent than the metalorganic compound. An alloy comprising the first metal and the second metal may be first produced (e.g., formed or otherwise obtained) and then treated with the organic solvent in a liquid phase or a vapor phase to form a mixture comprising (i) the reaction by-product comprising the second metal and (ii) the metalorganic compound comprising the first metal. The metalorganic compound may then be separated from the mixture in the form of a solid.

The invention provides a method for preparing a carboxylic acid, which method includes the steps of providing magnesium carboxylate, wherein the carboxylic acid corresponding with the carboxylate has a solubility in water at 20 C. of 80 g/100 g water or less; acidifying the magnesium carboxylate with HCl, thereby obtaining a solution comprising carboxylic acid and magnesium chloride (MgCl.sub.2); optionally a concentration step, wherein the solution comprising carboxylic acid and MgCl.sub.2 is concentrated; precipitating the carboxylic acid from the solution comprising the carboxylic acid and MgCl.sub.2, thereby obtaining a carboxylic acid precipitate and a MgCl.sub.2 solution.

The invention provides a method for preparing a carboxylic acid, which method includes the steps of providing magnesium carboxylate, wherein the carboxylic acid corresponding with the carboxylate has a solubility in water at 20 C. of 80 g/100 g water or less; acidifying the magnesium carboxylate with HCl, thereby obtaining a solution comprising carboxylic acid and magnesium chloride (MgCl.sub.2); optionally a concentration step, wherein the solution comprising carboxylic acid and MgCl.sub.2 is concentrated; precipitating the carboxylic acid from the solution comprising the carboxylic acid and MgCl.sub.2, thereby obtaining a carboxylic acid precipitate and a MgCl.sub.2 solution.

A method of transporting CO.sub.2 includes combining gaseous CO.sub.2 produced at a point of origin with a solid metal oxide salt and/or a solid metal hydroxide salt at the point of origin to form a solid metal carbonate salt that includes the CO.sub.2 from the point of origin and the metal from the metal oxide salt or the metal from the metal hydroxide salt. The method includes transporting the solid metal carbonate salt from the point of origin to a destination. The method also includes calcining the solid metal carbonate salt at the destination to generate gascous CO.sub.2 and to re-generate the solid metal oxide salt and/or the solid metal hydroxide salt.