Abstract: A hydrometallurgical process for treating copper feed materials containing gold and/or silver by simultaneously leaching copper, gold and/or silver into an aqueous cyanide solution, recovering copper in metallic form by electrowinning and regenerating cyanide ions is provided, wherein high current efficiencies are achieved at high current densities and at low copper concentrations.

Abstract: A membrane and electrode structure is formed by surface hydrolyzing an ion exchange membrane and then applying electrode ink of catalytically active particles on the surface of the membrane. The membrane and electrode structure of the present invention is particularly useful in fuel cells and batteries. The inventive process prevents the membrane from swelling or distorting following application of the electrode ink and also improves adhesion between the electrode ink layer and the surface of the membrane.

Abstract: A sealant composition comprises a dispersion of a fluorocarbon polymer with particles no larger than 25 micrometers in a low volatility liquid and up to 50 percent of a higher volatility liquid. Also covered is an applicator for applying the sealant to the gasket of an electrochemical cell.

Abstract: A sealant composition comprises a dispersion of a fluorocarbon polymer with particles no larger than 25 micrometers in a low volatility liquid and up to 50 percent of a higher volatility liquid. Also covered is an applicator for applying the sealant to the gasket of an electrochemical cell.

Abstract: A membrane and electrode structure is formed by applying ink of catalytically active particles on the surface of the membrane. The electrode ink comprises:(a) catalytically active particles;(b) a hydrocarbon having at least one ether, epoxy or ketone linkage and an alcohol group, preferably 1 methoxy 2 propanol; and(c) optionally, perfluorinated sulfonyl fluoride polymer or perfluorinated sulfonic acid polymer.

Abstract: A hydrometallurgical process for treating copper ores or concentrates containing gold by simultaneously leaching both copper and gold into an aqueous cyanide solution, recovering copper and gold in metallic form by electrowinning or cementation and regenerating cyanide ions is provided.

Abstract: The electrode layer of a ion exchange membrane is formed by printing a ink of catalytically active particles on the surface of the membrane. The inventive electrode ink comprises:(a) catalytically active particles;(b) a hydrocarbon having at least one ether, epoxy or ketone linkage and an alcohol group, preferably 1-methoxy 2-propanol; and(c) optionally a binder, preferably perfluorinated sulfonyl fluoride polymer or perfluorinated sulfonic acid polymer.

Abstract: A process is provided for hydrolysis of fluorinated ion exchange membranes. The membrane is contacted with an aqueous solution containing a hydrocarbon having ether, epoxy or ketone linkages and an alcohol group, preferably 1-methoxy 2-propanol, for a period of time sufficient to perform the hydrolysis of the precursor groups. The membrane is useful in a fuel cell or in an electrolytic cell, particularly a chloralkali cell.

Abstract: The invention is a process for the nonaqueous polymerization of tetrafluoroethylene with functional fluorinated comonomers. The process uses low TFE to comonomer ratios to form copolymers with high molecular weight and low melt flow. The copolymers are useful as membranes in electrolytic cells or fuel cells.

Abstract: An applicator for applying a sealant to the ribbed gasket of an electrochemical cell is covered. The applicator controls the flow of sealant through an orifice in the applicator head and advantageously controls the amount of sealant near to center of the gasket.

Abstract: A device and process are disclosed for continuously removing cations from an aqueous solution by means of two compartment ion exchanger wherein one compartment cation exchange membrane material serves to separate the compartments and particulate cation exchange material serves as a cation absorber in the compartment opposite the cations to be removed.

Abstract: Fluorinated ion exchange polymers which have pendant side chains which contain --OCF.sub.2 COOR groups, or which have both pendant side chains containing carboxylic groups and pendant side chains which contain sulfonyl groups, when used in the form of membranes to separate the anode and cathode compartments of an electrolysis cell, permit operation at high current efficiency. Those containing both carboxylic and sulfonyl groups can be made by oxidation of fluorinated polymers which have pendant side chains containing sulfinic groups, or both sulfinic and sulfonyl groups. The fluorinated polymers which have pendant side chains containing sulfinic groups, or both sulfinic and sulfonyl groups, are in turn made from fluorinated polymers which have pendant side chains containing sulfonyl halide groups by reduction with, for example, hydrazine. Those polymers which have only pendant side chains which contain --OCF.sub.

Abstract: A protective garment fabricated at least in part from a composite fabric which contains a layer of a highly fluorinated ion exchange polymer having sulfonic acid functional groups, all the components of said composite fabric being hydrophilic.

Abstract: A protective garment fabricated at least in part from a fabric which contains a layer of a highly fluorinated ion exchange polymer having functionality of the sulfonic and/or carboxylic type in the form of an alkali metal, ammonium or amine salt.

Abstract: A process is provided for making a liquid composition of a perfluorinated polymer having sulfonic acid or sulfonate groups in a liquid medium by contacting the polymer with a mixture of 25 to 100% by weight of water and 0 to 75% by weight of a second liquid component such as a lower alcohol, e.g., propanol or methanol, at a temperature of at least 180.degree. C. (at least 240.degree. C. when about 90% to 100% water is used), in a closed system. The liquid composition made by this process, or modified liquid products prepared therefrom, are used in coating various substrates, in casting films, and in repairing perfluorinated ion exchange films and membranes. The process is also useful in recovering perfluorinated polymer having sulfonic acid or sulfonate groups from scraps and used articles made of such polymer or containing such polymer as a component part thereof.

Abstract: A process is provided for making a liquid composition of a perfluorinated polymer having sulfonic acid or sulfonate groups in a liquid medium by contacting the polymer with a mixture of 25 to 100% by weight of water and 0 to 75% by weight of a second liquid component such as a lower alcohol, e.g., propanol or methanol, at a temperature of at least 180.degree. C. (at least 240.degree. C. when about 90% to 100% water is used), in a closed system. The liquid composition made by this process, or modified liquid products prepared therefrom, are used in coating various substrates, in casting films, and in repairing perfluorinated ion exchange films and membranes. The process is also useful in recovering perfluorinated polymer having sulfonic acid or sulfonate groups from scrap and used articles made of such polymer or containing such polymer as a component part thereof.

Abstract: A process for preparing a fluorinated polymer having carboxylic ester groups from a corresponding polymer having carboxylic acid groups is disclosed, wherein the polymer having carboxylic acid groups is treated with a selected ortho ester, acetal, ketal, borate ester or sulfite ester. The process is useful for assuring that all of the carboxylate groups of a polymer are in the ester form before an extrusion or lamination procedure, both of which are performed with heat and pressure, so as to preclude decarboxylation of free carboxylic acid groups during such procedure.

Abstract: Fluorinated ion exchange polymers which have pendant side chains which contain --OCF.sub.2 COOR groups, or which have both pendant side chains containing carboxylic groups and pendant side chains which contain sulfonyl groups, when used in the form of membranes to separate the anode and cathode compartments of an electrolysis cell, permit operation at high current efficiency. Those containing both carboxylic and sulfonyl groups can be made by oxidation of fluorinated polymers which have pendant side chains containing sulfinic groups, or both sulfinic and sulfonyl groups. The fluorinated polymers which have pendant side chains containing sulfinic groups, or both sulfinic and sulfonyl groups, are in turn made from fluorinated polymers which have pendant side chains containing sulfonyl halide groups by reduction with, for example, hydrazine. Those polymers which have only pendant side chains which contain --OCF.sub.