Rhone-poulenc Chimie

Rhone-poulenc Specialites Chimiques

Rhone-poulenc S.a.

Rhone-poulenc Chimie De Base

Rhone-poulenc Specialties Chimiques

Jean-Louis Sabot

Thierry Delloye

Alain Leveque

Alain Rollat

Richard Fitoussi

Patrick Fourre

Denise Bauer

Jean-Yves Chane-Ching

Jean-Yves Dumousseau

Yvette Pescher

Francinet Cailly

Michel Burgard

Gerard Hustache

Hubert Lauvray

Marie-Christine Bitar

Jean-Charles Maurice

Paul Aviron-Viollet

A process for the treatment of a glass to reduce or remove its wettability by gallium is provided, wherein the glass is treated with a silyling agent. Also is provided an apparatus comprising at least one hollow element containing a gallium or gallium based alloy or in which a gallium or gallium based alloy can circulate, wherein the glass forming the hollow element has been treated using the process. The apparatus may be thermometer, barometer or electric switch.

Process for the treatment of a glass to reduce its wettability by

Gaseous effluents containing oxygen and no greater than 2% by volume of sulfur dioxide, SO.sub.2, for example those emanating from facilities for the industrial-scale production of sulfuric acid, are converted into useful solutions of ammonium or of alkali or alkaline earth metal bisulfites, by first absorbing such gaseous effluent in a solution of ammonium or of an alkali or alkaline earth metal sulfite and bisulfite, at a pH ranging from 5 to 7, and, secondly, contacting the solution thus produced with an acidic reagent, advantageously a gaseous feedstream containing oxygen and greater than 2% by volume of sulfur dioxide, the O.sub.2 / SO.sub.2 ratio by volume thereof being less than 5.

Conversion of SO.sub.2 gaseous effluents into solutions of ammonium or

Yttrium is selectively separated from other rare earth values by contacting a mixed aqueous solution thereof that contains nitrate ions with a water-immiscible organic phase which includes a selective extractant for such other rare earth values, whereby such other rare earth values are selectively liquid/liquid extracted into this organic phase, the selective extractant comprising:

Selective liquid/liquid extraction of yttrium from other rare earths

Gallium values are recovered from basic aqueous solutions thereof, e.g., Bayer liquors, by (i) contacting such basic aqueous solution (A) with a medium (I) containing a gallium extractant, whereby the gallium values are transferred to the medium (I), (ii) contacting such gallium-enriched medium (I) with a basic aqueous solution (B) and back-extracting the gallium values into the basic aqueous solution (B), (iii) contacting such gallium-enriched basic aqueous solution (B) with a second medium (II) containing a gallium extractant, whereby the gallium values are transferred to the medium (II), and (iv) contacting such gallium-enriched medium (II) with an aqueous solution (C), which may be acidic or basic, and back-extracting the gallium values into the aqueous solution (C); such gallium-enriched aqueous solution (C) may, for example, be directly electrolyzed to produce gallium metal.

Recovery of gallium values from basic aqueous solutions thereof

The rare earth values contained in an aqueous solution of the nitrates of at least two rare earth elements are conveniently separated by first liquid/liquid extracting such aqueous nitrate solution with a liquid organic phase containing at least two P(O)R.sub.1 R.sub.2 R.sub.3 /P(O)R.sub.4 R.sub.5 R.sub.6 organophosphorus extractants.

Separation of rare earth values by liquid/liquid extraction

The rare earth values contained in an aqueous solution of the nitrates of at least two rare earth elements are conveniently separated by first liquid/liquid extracting such aqueous nitrate solution with a liquid organic phase containing a P(O)R.sub.1 R.sub.2 R.sub.3 organophosphorus extractant.

Desired amino acids, e.g., phenylalanine, arginine, leucine, isoleucine, valine and/or histidine, are selectively countercurrently extracted from more complex, essentially cystine-free solutions of a plurality of amino acids, utilizing an organic phosphorus acid extractant, advantageously in solution in at least one alcohol, ether, ketone and/or aliphatic hydrocarbon.

Selective extraction of amino acids

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

Highly pure europium (II) values are produced in high yields by electrolytically reducing an aqueous solution of europium (III) values circulating in the cathode compartment of an electrolytic cell, the electrolytic cell including a graphite cathode and an anode compartment separated from the cathode compartment by a cationic exchange membrane, recovering a solution of europium (II) values from the cathode compartment, and advantageously liquid/liquid extracting the europium (II) values thereform, e.g., with an organic solution of an organophosphorus extractant.

Recovery of europium (II) values by electrolysis

Gallium values are separated and recovered from strongly basic aqueous solutions thereof, e.g., Bayer process aluminate liquors, by (i) contacting such basic solution with an organic phase comprising an organic extractant and an organic solvent and liquid/liquid extracting gallium values therefrom, and permitting phase separation into an aqueous phase and an organic phase containing said extracted gallium values; (ii) contacting said organic phase with a solution of an acid halide in part comprising acidic phase recycled from the below stage (iv), after the selective extraction thereof, and liquid/liquid extracting gallium values therefrom, and permitting phase separation into a second organic phase and an acid phase containing said extracted gallium values; (iii) adjusting the halide ion concentration of the acidic gallium phase; (iv) selectively extracting gallium values from said acidic gallium phase; and (v) recovering such selectively extracted gallium values.

Liquid/liquid extraction of gallium values

Purified barium salts essentially devoid of strontium impurities, e.g., highly pure barium carbonate, are produced by liquid/liquid extracting an aqueous solution of impure barium values with an organic solvent medium which comprises at least one water-insoluble carboxylic acid, phosphonic acid monoester, or substituted 8-hydroxyquinoline extractant. The mixture of extraction is separated into a purified aqueous phase containing the desired barium salt values and an organic phase containing the impurity values sought to be removed.

Purification of barium values

Barium compounds containing contaminating amounts of strontium, e.g., barium salts, are effectively purified, notably into barium values suitable for conversion into specialty grade barium carbonate and titanate, by intimately contacting and liquid/liquid extracting aqueous solutions thereof with an organic solvent phase comprising at least one essentially water insoluble --CH.sub.2 --R' substituted 8-hydroxy-quinoline extractant.

Purified, strontium-free barium values

Aqueous nitric solutions of salts of at least one rare earth, and containing contaminating amounts of at least one alkaline earth cation, e.g., calcium, barium and/or radium, are conveniently purified by liquid/liquid extracting same with an organic phase which comprises a polyether extractant for said at least one alkaline earth cation, e.g., a crown ether, and whereby said at least one alkaline earth cation is selectively transferred into said organic phase.

Liquid/liquid extraction/purification of impure solutions of rare earth

At least one rare earth value is selectively separated from at least one other rare earth value, by selectively liquid/liquid extracting an aqueous phase comprising the nitrates of said rare earth values with an organic phase which comprises an organic extractant, said organic extractant comprising at least one organophosphinic compound having one of the formulae (I) or (I'): ##STR1## wherein R.sub.1 and R.sub.2, which may be identical or different, are each substituted or unsubstituted alkyl, cycloalkyl, alkoxyalkyl or alkylcycloalkyl radicals, and X is either hydrogen or a cation.

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Maisons Laffitte, France

Jean-Louis Sabot