Patent EA-000476-B1 (EA)
Title: Liquid medium extraction purification method and use thereof
Inventor: TAKHIM MOHAMED
IPC: C01F11/46
Filed: 1996-06-21
Abstract: 1. A method of extraction purification phosphoric acid and/or derivatives thereof a from liquid medium comprising the steps of: - adding to the liquid medium a vapour-entrainable organic compound having a Lewis-type acid-base molecule, said compound being added in a sufficient amount to produce a reaction product from a balanced reaction between the organic compound and, at least, one substance to be isolated, when difference pKa of said organic compound and the substance to be isolated is from 0.1 to 5 and sufficient to precipitate the balanced reaction product, - separating by filtering into the precipitate and filtrate, - vapour-entraining organic compound therefrom and - collecting separated said phosphoric acid in a purified form and/or derivatives thereof to be isolated. 2. The method of Claim 1, wherein the organic compound is selected from the group comprising aromatic amines, pyrrole, thiophene, o-cresol, m-cresol, monochloro-2-methyl-2-pentene, ethiothiol-1-propene or dichloroacetate ethyl and derivatives or isomers thereof. 3. The method of Claim 1, wherein the aromatic amine is aniline, p-toluidine or 3-methyl-2-naphtylamine or salts thereof, for example, their phosphates, sulfates or chlorides or their derivatives, such as derivatives of lower alkyl or nitro derivatives, or their isomers. 4. The method of any Claims 1-3, wherein the step of adding comprises agitation of the liquid for diffusing an organic compound in it, which is introduced, if necessary, in the form of emulsion/solution. 5. The method of any Claims 1-4, wherein said adding is effected at a temperature between 10 and 80 degree C. 6. The method of any Claims 1-5, wherein said filtering is effected in vacuum. 7. The method of any Claims 1-6, wherein at the separating step the filtered precipitate is washed in an aqueous solution of said balanced reaction product. 8. The method of any Claims 1-7, wherein the vapour entraining step comprises an injection of vapour via the precipitate in the form of filtered cake and separating of the organic compound by the injecting vapour. 9. The method of Claim 8, wherein the vapour entraining step comprises the application of 1-2 kg water vapour/kg filtered cake at a temperature between 40-110 degree C. 10. The method of any Claims 1-7, wherein the vapour entraining step comprises mixing of the filtered precipitate with water, boiling the water, which, as vapour entrains said organic compound. 11. The method of any Claims 1-10, wherein comprises the treatment of said phosphoric acid and/of derivatives thereof collected in a purified form by hydrogen peroxide to remove traces of the organic compound and further by activated carbon to decolorize separated phosphoric acid and/or therefrom. 12. The method of any Claims 1-11, wherein further comprises a step of storing and/or transporting of said filtered precipitate after the separating step. 13. The method of any Claims 1-12, wherein comprises adding an organic compound into said liquid medium in a non-purified form and, if necessary, recycle said organic compound at the adding step and, if necessary, the organic compound is separated in the purified form from the entrained liquefied vapour, if the organic compound is not recycled after vapour entraing step. 14. The method of any Claims 1-13, wherein further comprises - an additional adding of said organic compound to said separated filtrate for precipitation and coprecipitation of salts of said organic compound with one or more impurities, present in the separated filtrate, - separating precipitated or coprecipitated substances in the form of filtered cake and a new filtrate, - vapour entraining of an organic compound from the filtered cake and removal of the impurities concentrate. 15. The method of any Claims 1-14, wherein comprises - a first step of adding said organic compound to a liquid medium in quantity sufficient to modify solubility of one or several impurities present in the liquid medium, provoking their precipitation and coprecipitation, - separating one or several precipitated impurities, - a second step of adding said organic compound into the remaining liquid medium total quantity of which, taking into account the first step of adding, is sufficient for precipitating the balanced reaction product, - separating by filtering the precipitate and filtrate, - vapour-entraining said organic compound from precipitation and - collecting separated said phosphoric acid in a purified form and/or derivatives thereof. 16. The method of any Claims 1-13 and 15, wherein the liquid medium is an aqueous solution of non-purified phosphoric acid and comprises - adding optionally non-purified aniline or derivatives thereof into said solution, to obtain concentration sufficient for precipitation aniline phosphate or derivatives thereof, - separating phosphate of the organic compound in the form of the filtered cake, - removal the filtrate, containing impurities, - vapour entraining of pure aniline or derivatives thereof from the filtered cake and - collecting purified phosphoric acid. 17. The method of any Claims 1-13 and 15, wherein further comprises sulfuric etching of phosphate ore to form etching solution, - adding the first portion of the above-said aniline quantity into the etching solution to obtain pH values between 1.3 and 5, preferably between 2.0 and 3.5, at which calcium sulphate is precipitated, - separating by filtering pure calcium sulphate and the filtrate as an aqueous solution of phosphoric acid and - adding the second portion of the above-said aniline quantity or derivatives thereof into the solution, the total quantity of which, taking into account the first portion, is sufficient for precipitation of aniline phosphate or derivatives thereof. 18. The method of any Claims 16 or 17, wherein comprises preliminary adjustment of H3PO4 concentration between 7% and 40% in aqueous solution of phosphoric acid into which aniline or derivatives thereof are added in quantity sufficient for precipitation of aniline phosphate or derivatives thereof. 19. The method of any Claims 1-13 and 15, wherein the liquid medium is an aqueous solution of non-purified phosphoric acid and comprises adding optionally non-purified aniline or derivatives thereof into said solution in quantity sufficient for precipitation of aniline phosphate or derivatives thereof, separating said aniline phosphate or derivatives thereof, removing aniline or derivatives thereof from the precipitation using alkaline or nitric compounds, vapour entraining pure aniline or derivatives thereof from precipitation and collecting purified phosphoric acid salt from said alkaline and nitric compounds. 20. The method of any Claims 16-18, wherein further comprises - adding optionally non-purified aniline or derivatives thereof in the filtrate to obtain concentration sufficient for precipitation aniline salts or derivatives thereof and one or several impurities; - separating precipitation and coprecipitation in the form of filtered cake and a new filtrate; - vapour entraining pure aniline or derivatives thereof from the filtered cake, and - collecting concentrate of said impurities.