Rhone-Poulenc Chimie

Kemrhone France

Yvette Pescher

Sylvain Danda

Magnus Kvant

Jean-Louis Sabot

Pierre Macaudiere

Bernard Castelas

Jean-Paul Raes

Jean Bonfill

Jose Morales

Francedillaois Rabatel

Process for the purification of a medium containing organic waste

The present invention concerns a process for the preparation of a rare-earth sulphide characterized in that a rare-earth halide is brought into the presence of an alkaline or aluminum halide and heated in the presence of hydrogen sulphide at a temperature which is sufficient to volatilize the halides. More particularly, the halide is a chloride, the rare-earth is cerium and the alkali is sodium.

Process for the preparation of rare-earth sulphides from halides

Coagulant compositions, advantageously solvent (water) solution thereof, well suited for the treatment/purification of impure aqueous media, e.g., surface waters, wastewaters, effluents, etc., via sedimentation technique, comprise (i) at least one basic aluminum polychloride or polychlorosulfate, (ii) at least one iron(II) and/or iron(III) compound, and (iii) at least one alkali metal and/or alkaline earth metal halide.

Coagulants containing basic aluminum polychloride or polychlorosulfatean

Purification of aqueous media using aluminum polychloride/iron

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

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Bagneux, France

Yvette Pescher