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.

A process involving the steps in this order of: providing a waste plastics stream (A) comprising polyvinyl chloride (PVC); (i) supplying the waste plastics stream (A) to a reactor vessel; (ii) subjecting the waste plastics in the reactor vessel to a temperature of 250 C. and 350 C., preferably of 275 C. and 325 C., preferably for a period of 5-30 minutes, under applying a vacuum, preferably of 35 mbar, or using an inert gas sweep, and evacuating the generated hydrogen chloride (B) from the vessel, wherein the PVC is partially dechlorinated to form a waste plastics stream (C) comprising partially unsaturated PVC; (iii) removing the waste plastics stream (C) comprising partially unsaturated PVC from the reaction vessel; and (iv) separating the partially unsaturated PVC from the waste plastics stream to form a dechlorinated waste plastics stream (D).

Disclosed herein are embodiments of a method and system for producing a halogen gas. The method may comprise contacting a solid oxidizing agent with a vapor comprising a halide compound, to produce a gas stream comprising a halogen corresponding to the halide in the halide compound. The halide compound may be an acyl halide, such as an acetyl halide or an oxalyl halide. The oxidizing agent may be any suitable oxidizing agent, and in certain examples, potassium permanganate is used. The method may be performed under a reduced pressure. Also disclosed herein is a system suitable to perform the disclosed method. The system may comprise a reservoir, an oxidizing agent support and a gas stream outlet.

Disclosed herein are embodiments of a method and system for producing a halogen gas. The method may comprise contacting a solid oxidizing agent with a vapor comprising a halide compound, to produce a gas stream comprising a halogen corresponding to the halide in the halide compound. The halide compound may be an acyl halide, such as an acetyl halide or an oxalyl halide. The oxidizing agent may be any suitable oxidizing agent, and in certain examples, potassium permanganate is used. The method may be performed under a reduced pressure. Also disclosed herein is a system suitable to perform the disclosed method. The system may comprise a reservoir, an oxidizing agent support and a gas stream outlet.

Embodiments of the present disclosure are directed to systems and methods of removing carbon dioxide from a gaseous stream using magnesium hydroxide and then regenerating the magnesium hydroxide. In some embodiments, the systems and methods can further comprise using the waste heat from one or more gas streams to provide some or all of the heat needed to drive the reactions. In some embodiments, magnesium chloride is primarily in the form of magnesium chloride dihydrate and is fed to a decomposition reactor to generate magnesium hydrochloride, which is in turn fed to a second decomposition reactor to generate magnesium hydroxide.

A method for recovering hydrochloric acid and metal oxides from a chloride liquor is described. The method uses a chloride liquor including the metal and mixing the liquor and a matrix solution to produce a reaction mixture, wherein the matrix solution assists oxidation/hydrolysis of the metal with HCl production. In a preferred embodiment the matrix solution includes zinc chloride in various stages of hydration and an oxygen containing gas is added to the mix. A method where the improvement is the mixing of a liquor and a matrix solution where the solution assists hydrolysis of the metal with HCl production is also disclosed. The reactor is a column reactor in a preferred embodiment. Further disclosed is the method of using the matrix solution and a reactor for recovering hydrochloric acid and for oxidizing/hydrolysis of a metal.

A method for recovering hydrochloric acid and metal oxides from a chloride liquor is described. The method uses a chloride liquor including the metal and mixing the liquor and a matrix solution to produce a reaction mixture, wherein the matrix solution assists oxidation/hydrolysis of the metal with HCl production. In a preferred embodiment the matrix solution includes zinc chloride in various stages of hydration and an oxygen containing gas is added to the mix. A method where the improvement is the mixing of a liquor and a matrix solution where the solution assists hydrolysis of the metal with HCl production is also disclosed. The reactor is a column reactor in a preferred embodiment. Further disclosed is the method of using the matrix solution and a reactor for recovering hydrochloric acid and for oxidizing/hydrolysis of a metal.

The present invention discloses a method and system for conducting high temperature corrosion tests on metallic alloys without the need for extensive laboratory equipment and attendant safety measures through the use of a two-compartment ampoule where a vestibule connects these two compartments. A pre-selected mixture of salts is placed in one compartment in order to generate a specific partial pressure of halogen gas; and a metallic alloy is placed in the other compartment. The ampoule is then heated to a pre-determined temperature and held at this temperature for a pre-determined time period. A halogen gas of a specific partial pressure is thereby generated from the mixture of salts which comes into contact with the metallic alloy. Because the ampoule creates a sealed environment, the metallic alloy is under constant halogenation during the pre-determined time period. The metallic alloy is removed for examination when the pre-determined time period expires.

Embodiments of the present disclosure are directed to systems and methods of removing carbon dioxide from a gaseous stream using magnesium hydroxide and then regenerating the magnesium hydroxide. In some embodiments, the systems and methods can further comprise using the waste heat from one or more gas streams to provide some or all of the heat needed to drive the reactions. In some embodiments, magnesium chloride is primarily in the form of magnesium chloride dihydrate and is fed to a decomposition reactor to generate magnesium hydroxychloride, which is in turn fed to a second decomposition reactor to generate magnesium hydroxide.

The present relates to a method for producing calcium sulfate solid crystals and hydrochloric acid (HCl) from a calcium chloride solution comprising the steps of feeding a continuous stirred-tank reactor with a calcium chloride solution, sulfuric acid and water; mixing the calcium chloride solution, sulfuric acid and water in the reactor; and maintaining the reactor a temperature of less than about 70 C., converting the calcium chloride solution, sulfuric acid and water into HCl and calcium sulfate solid crystals. The method described herein can be incorporated as a means for regenerating HCl from CaCl.sub.2 solutions which are generated in the metallurgical industry when processing calcium-bearing ores for recovering metals like rare earth elements.