Abstract: Modified and insoluble starches are utilized for eliminating natural organic substances/contaminants from liquids and in particular from liquids used for food applications, such as drinking water, beverages, fruit juices or syrups, as well as natural water, industrial process water, or wastewater.

Abstract: Water contaminated with anions of heavy metals, e.g., arsenic values, is purified by contacting same with a composition containing at least one polysaccharide, such as starches or vegetable gums.

Abstract: Unwanted natural and synthetic organic impurities are removed from liquid media contaminated therewith, e.g., liquids and beverages intended for human consumption, or industrial/wastewaters, by introducing into such media a thus effective amount of an optionally modified/insoluble cationic vegetable gum containing one or more cationic or cationizable substituents, maintaining the cationic vegetable gum in such liquid medium until the organic impurities are sorbed thereon, and thence recovering the vegetable gum/sorbed impurities therefrom, whereby purifying the liquid medium.

Abstract: Modified and insoluble starches are utilized for eliminating natural organic substances/contaminants from liquids and in particular from liquids used for food applications, such as drinking water, beverages, fruit juices or syrups, as well as natural water, industrial process water, or wastewater.

Abstract: The invention concerns an agent for eliminating heavy metals contained in an aqueous effluent comprising: an alkaline metal silicate, an alkaline metal carbonate; a phosphate compound, for example a sodium orthophosphate: and optionally a carrier, in particular a clay. Said agent may further contain a sulphur compound. Said agent can constitute an agent stabilizing said metals, and can be used for eliminating or stabilizing heavy metals, in particular cadmium, nickel and lead, contained in industrial aqueous effluents.

Abstract: An agent for recovering heavy metal cations from an aqueous effluent, including a silicate or aluminosilicate type compound, e.g. an alkali metal silicate or aluminosilicate, and a carbonate type compound, e.g. an alkali metal carbonate, and preferably a carrier such as a lay. The agent may also form a cation stabilizer. Said agent is useful for removing or stabilizing heavy metal cations in the water used for cleaning flue gases from waste incineration, particularly household refuse and industrial waste incineration.

Abstract: The invention relates to a process of treatment for the recovery of the precious metals, such as platinum, rhodium and palladium, contained in various compositions including a layer of oxide(s) which is deposited on a metal support, in particular worn or spent motor vehicle postcombustion catalysts, in which the layer of oxide(s) containing the precious metals is separated from the metal support by an electrochemical route, the composition to be treated forming one of the electrodes employed or being in direct contact with one of the electrodes employed.

Abstract: Rare earth values are recovered from gypsum starting material by (i) dissolving such gypsum in water and separating therefrom the water-insoluble fractions which contain the rare earth elements (ii) treating such insoluble fractions with a solution of carbonate ions, (iii) next digesting the insoluble fractions thus treated with a mineral acid and converting at least the rear earth values into water-soluble salts thereof, and (iv) recovering such rear earth values from the medium of digestion.

Abstract: Rare earth values are nonpollutingly recovered from a rare earth mineral/ore, especially one containing but minor amounts of the rare earths, by (a) leaching/decomposing such rare earth mineral/ore with a solution of nitric acid to solubilize the rare earth values contained therein, (b) optionally separating insoluble residue from the resulting leach solution, (c) separating the rare earth values from the leach solution, (d) treating the leach solution thus stripped of rare earth values with a hydroxide of a metallic cation M to precipitate solubilized impurities and separating the thus precipitated impurities therefrom, (e) treating the resulting purified solution with sulfuric acid to precipitate metal sulphates and separating the thus precipitated sulfates therefrom to regenerate the above nitric acid solution, and (f) optionally recycling such regenerated solution of nitric acid to the leaching/decomposition step (a).