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AssigneeImi Tami Institute for Research and Development Ltd.
InventorsAvraham M. Baniel, Ruth Blumberg, Klara Hajdu
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Acids are recovered from their aqueous solution by an extraction process comprising a first extraction stage at which the aqueous solution is contacted with a water-immiscible extractant comprising a water-immiscible organic solvent and, dissolved therein, at least one secondary or tertiary amine in which the aggregate number of carbon atoms is at least 20; and a back-extraction stage in which the organic extract, separated from the original aqueous solution, is stripped with an aqueous liquid at a temperature which is higher by at least 20.degree. C. than the temperature of the first extraction stage. The stripped extractant can be recycled to the first extraction stage for making the process continuous, and if so recycled, is cooled on its way to the extraction stage. A preferred field of application is the recovery of organic acids produced by fermentation from the fermentation broth, e.g. citric acid.
A process for the recovery of an acid selected from the class consisting of citric acid, lactic acid, oxalic acid and phosphoric acid from an aqueous solution of the same acid comprising the steps of subjecting such aqueous acid solution to extraction with a water-immiscible organic extractant which comprises a solution of at least one secondary or tertiary amine in which the aggregate number of carbon atoms is at least 20 and a water-immiscible organic solvent selected from the class consisting of aliphatic hydrocarbons, aromatic hydrocarbons, petroleum fractions, hydrocarbons carrying nitro or halo substituents, alcohols and mixtures thereof to form an organic extract;
Dependencies are inferred from the claim text.