Rhone-Poulenc Industries

Rhone-Poulenc Chimie

Rhone-Poulenc Specialites Chimiques

Rhone-Poulenc S.a.

Alain Leveque

Jacques Helgorsky

Jean-Louis Sabot

Richard Fitoussi

Michel Triollier

Jean-Luc Le Loarer

Thierry Delloye

Francinet Cailly

Dominique Foraison

Environmental pollution stemming from the industrial discharge and/or storage of water-soluble thorium compounds is avoided by converting same into essentially innocuous water-insoluble thorium phosphates, notably orthorhombic thorium phosphates, by (i) reacting such water-soluble thorium compounds, e.g., the nitrates and/or chlorides, with a base, for example aqueous ammonia, in an aqueous reaction medium, to precipitate a thorium hydroxide therein, (ii) next reacting the precipitate thus formed with a phosphating compound, e.g., phosphoric acid or a soluble phosphate salt, also in an aqueous reaction medium, to precipitate a thorium phosphate therein, and then (iii) separating such thorium phosphate precipitate.

Thorium phosphates prepared by insolubilization of soluble thorium

Neodymium or didymium values are selectively recovered from bastnaesite ores, essentially to the exclusion of cerium and trace amounts of thorium, by (i) calcining the bastnaesite ore, (ii) selectively leaching the calcined bastnaesite with an aqueous solution of nitric acid to solubilize therein neodymium and trivalent rare earth values, and thereby producing an insoluble residue which comprises cerium and thorium values, (iii) separating the insoluble residue, and (iv) liquid/liquid extracting desired neodymium or didymium values from the nitric acid solution.

Recovery of neodymium/didymium values from bastnaesite ores

Prohibited radioactivity is removed from contaminated aqueous effluents containing both nitrate and radium values, by liquid/liquid extracting such effluents with an organic phase comprising at least one halogenated, preferably fluorinated .beta.-diketone.

Reducing the radium radioactivity of aqueous effluents

Rare earth and cobalt values are separated and recovered from residue materials containing them, e.g., the waste residue from the production of samarium/cobalt magnets, by (a) dissolving such residues with nitric acid, (b) liquid/liquid extracting the resulting aqueous nitric phase with an organic phase including at least one water-insoluble neutral organophosphoric extractant, whereby the rare earth values are transferred into the organic phase, and (c) recovering the rare earth values from the organic phase.

Liquid/liquid extraction of rare earth/cobalt values

Rare earth and cobalt values are separated and recovered from residue materials containing them, e.g., the waste residues from the production of samarium/cobalt magnets, by (a) dissolving such residues with nitric acid, (b) liquid/liquid extracting the resulting aqueous nitric phase with an organic phase including at least one water-insoluble organic extractant having at least one primary, secondary, tertiary or quaternary amine function, whereby the rare earth values are transferred into the organic phase, and (c) recovering the rare earth values from the organic phase.

Gallium and rare earth values are recovered from oxide mixtures thereof by acidulating/dissolving such admixtures in an acid medium, and then liquid/liquid extracting the resulting solution and ultimately recovering said values from the phases which separate. The subject process is advantageously applied, for example, to the recovery of gallium and gadolinium from the waste fines resulting from the production of the garnets Gd.sub.3 Ga.sub.5 O.sub.12.

Recovery of gallium/rare earth values from oxide mixtures thereof

The method of recovering gallium from very basic solutions such as sodium aluminum liquors from the Bayer process by liquid/liquid extraction by means of an organic phase, preferably formed of an organic solvent and water-insoluble alkylhydroxyquinolines of the general formula ##STR1## in which n is a number between 5 and 20.

Method of recovering gallium from very basic solutions by liquid/liquid

Acidic aqueous phases comprising sulfate ion and particularly sulfuric acid values, titanium ion and particularly titanium (IV) values, and iron ion, particularly iron (II) values, and advantageously waste streams emanating from a sulfate process for the production of TiO.sub.2, are extracted with an initial organic phase which comprises at least one neutral organic extractant having the general formula: ##STR1## in which A and B, which may be the same or different, are the groups R.sub.1 or OR.sub.2, wherein R.sub.1 and R.sub.2 are straight or branched chain alkyl, alkenyl, alkynyl, alkoxyalkyl, aryl or alkylaryl radicals, or halogen substituted such radicals; and R is either R.sub.1 or R.sub.2 as above-defined, with R, R.sub.1 and R.sub.2 either being the same or different, or R is a group having the general formula: ##STR2## in which Y is a straight or branched chain alkylene radical, and A and B are as defined above, to provide a final aqueous phase comprising substantially all of said iron (II) values present in said initial aqueous phase and a final organic phase comprising substantially all of said sulfuric acid values and substantially all of said titanium values present in said initial aqueous phase; the respective iron/sulfate/titanium values may then be facilely recovered from their respective final phases.

Liquid/liquid extraction of acidic aqueous streams comprising

Rare earth, uranium and thorium values are separated and recovered from aqueous solutions of the chlorides thereof, said aqueous solutions having an acidity of less than 2 N and a concentration in such values, expressed as the oxides thereof, of at least 50 g/l, by liquid-liquid extracting said aqueous solutions with an organic extractant comprising at least one neutral organophosphorus compound.

Liquid-liquid extraction of rare earth/uranium/thorium values

Uranium values are recovered from a wet-process phosphoric acid solution by extracting said solution with a first organic extractant, reductively stripping the resulting first organic phase of its uranium values with a strip solution including and in which ferrous ion is utilized to reduce uranyl ions in said first organic phase to uranous ions therein, disengaging the strip solution from said first organic extractant and oxidizing same to convert the uranous ions therein to uranyl ions, next extracting said oxidized strip solution and the uranium values contained therein with a second organic extractant, and then stripping said uranium values from the resulting second organic phase, said recovery featuring (i) washing with an iron-free aqueous wash solution, and upstream of the reductive stripping thereof, the organic phase resulting from said first extraction, and (ii) utilizing effluent, iron-free wash solution from the step (i) to wash the organic phase resulting from said second extraction and concomitantly to strip any iron values therefrom, upstream of the stripping of the uranium values therefrom.

Reductive stripping of uranium values from wet-process phosphoric acid

Highly pure (&gt;99.99%) aqueous solutions of gallium chloride are obtained by a process having two major stages. The first stage, effected by passage of an aqueous acid solution containing gallium over a strongly basic ion exchange resin, makes it possible to eliminate an appreciable quantity of metal ions, such as Ca, Mg, Cr, V, Co, Zn and Pb, and further serves to concentrate the initial solution. In the second stage, the remaining ions, such as Al, Na and particularly Fe.sup.+++ are eliminated by a two-phase extraction with an organic extractant, preferably a C.sub.4 to C.sub.10 alcohol or a quaternary ammonium chloride.

Purification of solutions of gallium values by serial ion

Highly pure (&gt;99.99%) aqueous solutions of gallium chloride are obtained by (i) liquid/liquid extracting an aqueous hydrochloric acid solution of gallium values with an organic phase which comprises a quaternary ammonium chloride extractant, (ii) separating the organic phase from the aqueous phase, (iii) selectively washing said organic phase by intimately contacting same with an aqueous solution of hydrochloric acid to remove any remaining impurities, whereby purified gallium values are transferred from said organic phase into an aqueous solution thereof, and (iv) then separating said organic phase from said resulting aqueous phase, whereby said aqueous phase comprises pure gallium chloride.

Purification of solutions of gallium values by liquid/liquid extraction

Highly pure (&gt;99.99%) aqueous solutions of gallium chloride are obtained by (i) liquid/liquid extracting an aqueous hydrochloric acid solution of gallium values with an organic phase which comprises an alcohol extractant, (ii) separating the organic phase from the aqueous phase, (iii) selectively washing said organic phase by intimately contacting same with water or with an aqueous solution of hydrochloric acid, (iv) next transferring the purified gallium values from said organic phase into an aqueous solution thereof, and (v) thence separating said organic phase from said resulting aqueous phase, whereby said aqueous phase comprises pure gallium chloride.

A process is provided for separating, by solvent extraction, metal compounds contained in aqueous solutions. The aqueous solution is contacted with an organic phase containing at least one substituted hydroquinoline. The process of the invention is particularly applicable to the separation of at least one element selected from among the group consisting of the rare earths and yttrium from an aqueous solution containing it.

Process for the separating of rare earths

Gallium values are recovered from basic aqueous solutions thereof, especially from sodium/aluminum liquors of Bayer process origin, by liquid/liquid extraction with a water immiscible organic phase comprising an organic solvent and, dissolved therein, an organic-solvent-soluble substituted hydroxyquinoline and an organic carboxylic acid compound.

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Paris, France

Alain Leveque