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 for processing MgCl2 solutions including the steps of: providing an aqueous solution including 5-25 wt. % of MgCl2 and optionally organic contaminants to a step, wherein water and present, organic components are evaporated; withdrawing aqueous solution with a MgCl2 concentration of 25-35 wt. % from an evaporation step and providing it to a preconcentrator where it is contacted with a HCl containing gas stream at least 300 C.; providing aqueous solution with a MgCl2 concentration of 35-45 wt. % resulting from the preconcentrator to a thermohydrolysis reactor, being at at least 300 C.; withdrawing MgO from the thermohydrolysis reactor in solid form, and withdrawing a HCl containing gas stream from the thermohydrolysis reactor, said HCl-containing gas stream at least 300 C.; providing the HCl-containing gas stream with at least 300 C. to the preconcentrator; withdrawing a HCl-containing gas stream with a temperature of at most 150 C. from the preconcentrator.

A method for processing MgCl2 solutions including the steps of: providing an aqueous solution including 5-25 wt. % of MgCl2 and optionally organic contaminants to a step, wherein water and present, organic components are evaporated; withdrawing aqueous solution with a MgCl2 concentration of 25-35 wt. % from an evaporation step and providing it to a preconcentrator where it is contacted with a HCl containing gas stream at least 300 C.; providing aqueous solution with a MgCl2 concentration of 35-45 wt. % resulting from the preconcentrator to a thermohydrolysis reactor, being at at least 300 C.; withdrawing MgO from the thermohydrolysis reactor in solid form, and withdrawing a HCl containing gas stream from the thermohydrolysis reactor, said HCl-containing gas stream at least 300 C.; providing the HCl-containing gas stream with at least 300 C. to the preconcentrator; withdrawing a HCl-containing gas stream with a temperature of at most 150 C. from the preconcentrator.

The invention pertains to a method for preparing succinic acid which comprises providing an aqueous magnesium succinate solution to an acidification step, wherein the magnesium succinate solution is acidified by the addition of hydrogen chloride, thereby obtaining an aqueous solution comprising succinic acid and magnesium chloride and subjecting the aqueous solution comprising succinic acid and magnesium chloride derived from the acidification step to a treatment step with active carbon followed by precipitating succinic acid from an aqueous mixture comprising succinic acid and magnesium chloride resulting from the active carbon treatment step in a precipitation step to form solid succinic acid. It has been found that the method according to the invention leads to succinic acid crystals with better properties than a comparable method wherein no active carbon treatment is used.

The invention pertains to a method for preparing succinic acid which comprises providing an aqueous magnesium succinate solution to an acidification step, wherein the magnesium succinate solution is acidified by the addition of hydrogen chloride, thereby obtaining an aqueous solution comprising succinic acid and magnesium chloride and subjecting the aqueous solution comprising succinic acid and magnesium chloride derived from the acidification step to a treatment step with active carbon followed by precipitating succinic acid from an aqueous mixture comprising succinic acid and magnesium chloride resulting from the active carbon treatment step in a precipitation step to form solid succinic acid. It has been found that the method according to the invention leads to succinic acid crystals with better properties than a comparable method wherein no active carbon treatment is used.

The invention is directed to a method for recovering carboyxlic acid from an magnesium carboxylate containing aqueous mixture, including the steps of: contacting the aqueous mixture with an acidic ion exchanger, thereby forming a carboxylic acid mixture and an ion exchanger loaded with magnesium ions; contacting the ion exchanger loaded with magnesium ions with a hydrochloric acid solution, thereby forming a magnesium chloride solution; and thermally decomposing the magnesium chloride solution at a temperature of at least 300 C., thereby forming magnesium oxide (MgO) and hydrogen chloride (HCl).

The invention is directed to a method for recovering carboyxlic acid from an magnesium carboxylate containing aqueous mixture, including the steps of: contacting the aqueous mixture with an acidic ion exchanger, thereby forming a carboxylic acid mixture and an ion exchanger loaded with magnesium ions; contacting the ion exchanger loaded with magnesium ions with a hydrochloric acid solution, thereby forming a magnesium chloride solution; and thermally decomposing the magnesium chloride solution at a temperature of at least 300 C., thereby forming magnesium oxide (MgO) and hydrogen chloride (HCl).

The invention pertains to a method for providing a succinic acid solution, comprising the steps ofproviding a first magnesium succinate containing medium with a magnesium succinate concentration of 18-23 wt. % to a first acidification reactor where it is contacted with hydrogen chloride to form a solution of succinic acid, magnesium chloride and hydrogen chloride,providing a second magnesium succinate containing medium with a magnesium 3 succinate concentration of 25-50 wt. %, and contacting it in a second acidification reactor with the solution of succinic acid, magnesium chloride and hydrogen chloride withdrawn from the first acidification reactor, to form an aqueous mixture comprising magnesium chloride and succinic acid with a succinic acid concentration of at least 18 wt. %. the method according to the invention makes it possible to obtain a solution comprising succinic acid and magnesium 20 chloride with an increased succinic acid concentration.

The invention pertains to a method for preparing succinic acid comprising the steps of providing an aqueous magnesium succinate solution to an acidification step, wherein the magnesium succinate solution is acidified by the addition of hydrogen chloride, thereby obtaining an aqueous solution comprising succinic acid and magnesium chloride; subjecting an aqueous solution comprising succinic acid and magnesium chloride derived from the acidification step to a treatment step with active carbon, precipitating succinic acid from an aqueous mixture comprising succinic acid and magnesium chloride resulting from the active carbon treatment step in a precipitation step to form solid succinic acid and a magnesium chloride solution, separating the solid succinic acid from the magnesium chloride solution subjecting the magnesium chloride solution to a thermal decomposition at a temperature of at least 300 C., thereby decomposing the magnesium chloride to magnesium oxide and hydrogen chloride, and recycling the hydrogen chloride generated in the thermal decomposition step to the acidification step. It has been found the method according to the invention leads to succinic acid crystals with better properties than a comparable method wherein no active carbon treatment is used.