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 process method for preparing magnesium oxide from dolomite includes the following steps: S1, pretreating dolomite to obtain the calcined dolomite; S2, hydrating the calcined dolomite according to the solid-liquid ratio, controlling the hydration temperature and the hydration time, filtering, washing and drying after hydration to obtain the hydration product; S3, configuring a complex solution, using the sodium hydroxide solution to adjust the pH value to 8-10; S4, performing the complexation reaction by mixing the hydration product in S2 with the complex solution in S3, and controlling the complexation temperature and the complexation time, obtaining the magnesium oxide by filtration, washing and drying after the reaction is completed. The invention uses dolomite as raw material, and the amount of magnesium hydroxide produced by magnesium oxide at a specific hydration temperature and hydration time can be ignored.

A process method for preparing magnesium oxide from dolomite includes the following steps: S1, pretreating dolomite to obtain the calcined dolomite; S2, hydrating the calcined dolomite according to the solid-liquid ratio, controlling the hydration temperature and the hydration time, filtering, washing and drying after hydration to obtain the hydration product; S3, configuring a complex solution, using the sodium hydroxide solution to adjust the pH value to 8-10; S4, performing the complexation reaction by mixing the hydration product in S2 with the complex solution in S3, and controlling the complexation temperature and the complexation time, obtaining the magnesium oxide by filtration, washing and drying after the reaction is completed. The invention uses dolomite as raw material, and the amount of magnesium hydroxide produced by magnesium oxide at a specific hydration temperature and hydration time can be ignored.

A Process for producing a coated mixed lithium transition metal oxide starts with dry mixing of a mixed lithium transition metal oxide and a pyrogenically produced, nanostructured magnesium oxide in a mixing unit having a specific electrical power of 0.05-1.5 KW per kg of the mixed lithium transition metal oxide. The coated mixed lithium transition metal oxide finds application as an active positive electrode material for a lithium-ion battery, and electric and/or electronic devices.

A Process for producing a coated mixed lithium transition metal oxide starts with dry mixing of a mixed lithium transition metal oxide and a pyrogenically produced, nanostructured magnesium oxide in a mixing unit having a specific electrical power of 0.05-1.5 KW per kg of the mixed lithium transition metal oxide. The coated mixed lithium transition metal oxide finds application as an active positive electrode material for a lithium-ion battery, and electric and/or electronic devices.

A process for producing magnesia can include contacting CO.sub.2-containing emissions with a magnesium-containing material to produce magnesium carbonate; subjecting the magnesium carbonate to calcination to produce a CO.sub.2 by-product and magnesia; and recycling at least a portion of the CO.sub.2 by-product for contacting the magnesium-containing material to produce the magnesium carbonate. The magnesium-containing material can include mining residues, such as phyllosilicate or chrysotile mining residue, and the magnesium carbonate produced can include precipitated nesquehonite that is subjected to calcination to produce the magnesia.

A process for producing magnesia can include contacting CO.sub.2-containing emissions with a magnesium-containing material to produce magnesium carbonate; subjecting the magnesium carbonate to calcination to produce a CO.sub.2 by-product and magnesia; and recycling at least a portion of the CO.sub.2 by-product for contacting the magnesium-containing material to produce the magnesium carbonate. The magnesium-containing material can include mining residues, such as phyllosilicate or chrysotile mining residue, and the magnesium carbonate produced can include precipitated nesquehonite that is subjected to calcination to produce the magnesia.

A pyrogenically prepared surface modified magnesium oxide finds application in electronics, catalysis, paints and oils and as cathode and/or anode active material coating for the production of cathodes and/or anodes in lithium-ion and sodium-ion batteries. In a process for the preparation of a pyrogenically prepared surface modified magnesium oxide, a surface modification and a thermal treatment at elevated temperatures adapts the physical and chemical properties of the magnesium oxide.

A pyrogenically prepared surface modified magnesium oxide finds application in electronics, catalysis, paints and oils and as cathode and/or anode active material coating for the production of cathodes and/or anodes in lithium-ion and sodium-ion batteries. In a process for the preparation of a pyrogenically prepared surface modified magnesium oxide, a surface modification and a thermal treatment at elevated temperatures adapts the physical and chemical properties of the magnesium oxide.

A process for producing magnesia can include contacting CO.sub.2-containing emissions with a magnesium-containing material to produce magnesium carbonate; subjecting the magnesium carbonate to calcination to produce a CO.sub.2 by-product and magnesia; and recycling at least a portion of the CO.sub.2 by-product for contacting the magnesium-containing material to produce the magnesium carbonate. The magnesium-containing material can include mining residues, such as phyllosilicate or chrysotile mining residue, and the magnesium carbonate produced can include precipitated nesquehonite that is subjected to calcination to produce the magnesia.