Abstract: A process for recovering nickel and copper from a concentrate which includes the steps of subjecting the concentrate to a treatment phase to produce a first leach solution which contains predominantly copper and a second leach solution which contains predominantly nickel, subjecting the first leach solution to a process for copper recovery which includes a solvent extraction step to produce a raffinate which is high in sulphuric acid, recycling at least a portion of the raffinate to the aforementioned treatment phase and subjecting the second leach solution to a process for nickel.

Abstract: A process for the recovery of copper from an aqueous phase containing nitrate ions, in which the aqueous phase is contacted with a solution of an oxime extractant in a water-immiscible organic solvent, which comprises using at least one of the following process variants:

Abstract: The invention relates to a method for processing residues containing at least one non-ferrous metal, preferably chosen from the group comprising zinc, lead, nickel, copper and cadmium and/or compounds thereof. According to this method, the non-ferrous metal is extracted from the residues by an extracting agent containing a carboxylic acid and/or a substituted carboxylic acid and/or its alkali salts and/or ammonium salts and/or mixtures thereof.

Abstract: Polymer-stabilized metal colloid solutions, process for preparing them and their use as catalysts for fuel cells. Process for preparing metal colloid solutions by reacting a platinum compound and, if desired, one or more compounds of Rh, Ru, Ir or Pd with a reducing agent. At least one cation-exchange polymer is used for stabilizing the metal colloid solution.

Abstract: A process for the recovery of copper from an aqueous phase containing nitrate ions, in which the aqueous phase is contacted with a solution of an oxime extractant in a water-immiscible organic solvent, which comprises using at least one of the following process variants: I) reducing the acidity of the aqueous phase prior to contact with the organic solution; and II) reducing the electromotive force in the aqueous phase prior to contact with the organic solution.

Abstract: An organic acid salt is deposited on the surface of a solder powder containing Sn and Zn. Alternatively, 0.5 to 10 wt. % of a nonionic surfactant is added to a flux. By a method comprising such a procedure, provided are a lead-free solder powder and solder paste having good soldering characteristics wherein the reaction of an activating component with an alloy component in a flux is suppressed.

Abstract: A process for the extraction of metals from an aqueous solution of metals in the form of their metal ions. The preparation and use of an efficient organic extractant and also the recovery from the organic extractant of the metal ions. A process for preparing an extractant solution where the extractant solution is a solution of a calcium ion or magnesium ion loaded extractant in a water-immiscible organic solvent, and where the extractant solution is suitable for extracting metal ions from an aqueous solution containing the metal ions, including mixing an aqueous solution of calcium ions or magnesium ions with a basic calcium salt or a basic magnesium salt and with a solution of an organic extractant in a water-immiscible organic solvent to form the extractant solution, and then separating the extractant solution from the aqueous solution.

Abstract: There are provided a treatment solution for reducing a copper oxide formed on the surface of copper to copper, wherein dimethylamine borane is contained in an amount of 0.3 to 2.0 g/L and the relationship y≧0.232x−0.185 holds between the concentration y (g/L) of dimethylamine borane and an area x (dm2/L) to be treated per unit solution amount, and a treatment method for reducing a copper oxide formed on the surface of a copper material to copper by dipping the copper material in the treatment solution as described above, wherein the addition of dimethylamine borane to water is carried out within 10 minutes before the dipping of the copper material or after the dipping of the copper material.

Abstract: A method for preparing ultra-pure silver from a crude silver mixture containing metallic and/or non-metallic impurities, said method comprising; dissolving the crude silver mixture in nitric acid to form a crude silver nitrate solution; adding a first selective reducing agent to the crude silver nitrate solution to precipitate a silver/contaminant matrix and form a partially purified silver nitrate solution; separating the partially purified silver nitrate solution from the precipitated silver/contaminant matrix; adding a second selective reducing agent to the partially purified silver nitrate solution to precipitate silver powder; and isolating the silver powder.

Abstract: A system for recovery of metals from solutions containing dissolved metals. The system includes an apparatus and method for placing supercritical carbon dioxide that contains an extractant in contact with the solution and agitating the two resulting phases. Once the metals are extracted by the extractant, they can be removed from the carbon dioxide phase by depressurization or by reduction by exposure to hydrogen. The extractant preferably comprises a metal binding group, a spacer group and a C02-philic group.

Abstract: The method of the invention is based on the unique electron-carrying function of a photocatalytic unit such as the photosynthesis system I (PSI) reaction center of the protein-chlorophyll complex isolated from chloroplasts. The method employs a photo-biomolecular metal deposition technique for precisely controlled nucleation and growth of metallic clusters/particles, e.g., platinum, palladium, and their alloys, etc., as well as for thin-film formation above the surface of a solid substrate. The photochemically mediated technique offers numerous advantages over traditional deposition methods including quantitative atom deposition control, high energy efficiency, and mild operating condition requirements.

Abstract: An agent for treating metal ions in an aqueous solution, which comprises an anthrahydroquinone compound and a metal supported on a carbonaceous carrier.

Abstract: The present invention relates to a process for obtaining an iron powder, which may incorporate nickel and/or cobalt, by organic liquid phase precipitation. This process comprises a stage of introducing metal precursors into a basic polyol or optionally simple alcohol solution, a stage of heating said reaction medium to obtain a metal precipitate and a stage of recovering and treating said precipitate to obtain the desired powder.

Abstract: A powerful reducing agent such as hydrazine monohydrate is added to the standard eluent solutions such as NsOH-NaCN with or without alcohol. The kinetics of elution of gold or of silver are thus markedly enhanced.

Abstract: There is provided a process for converting a silver-mercapto-s-triazine precipitate to a solid containing silver and a solution containing mercapto-s-triazine by contacting the silver-mercapto-s-triazine precipitate with one or more reducing agents. In preferred embodiments, at least one of the reducing agents has a redox potential more negative than about -0.9 V vs. Normal Hydrogen Electrode, NHE.

Abstract: An improved process for dissolving gold metal in ligand and oxidant lixiviation systems, wherein the solubility of gold is enhanced by the addition of heterocyclic aromatic compounds containing nitrogen or sulfur in the ring.

Abstract: An agent for treating metal ions in an aqueous solution, comprising a solid porous carrier and, supported thereon, an organic reagent (hereinafter referred to as a "redox reagent") which is capable of converting metal ions (inclusive of metal complex ions) contained in an aqueous solution to zero valent metal or monovalent metal ions by a redox reaction and which is capable of carrying out oxidation-reduction reversibly.

Abstract: Carbonaceous pyropolymers possessing recurring units containing at least carbon and hydrogen atoms on their surface are effective in removing from solution metal cations having a standard reduction potential to their zerovalent state of greater than -0.2 volts. Their mode of action appears to be via reduction of the metal to the zerovalent state which then is deposited on the pyropolymer surface.

Abstract: The present invention is directed to a process for reducing the oxidation state of a metal by contacting an acidic solution of the metal with an electroactive polymer, and accumulating and recovering the metal. More particularly, the invention is directed to a method for recovering precious metals like gold, platinum, palladium, and gold-platinum alloys from acidic solution by contacting the solution with an electroactive polymer like polyaniline or polypyrrole.

Abstract: A method for the preparation of finely divided, dense packing, spherical shaped silver particles comprising the sequential steps of:(1) reacting an aqueous mixture of a silver salt with an alkanolamine to form a homogeneous aqueous solution of a dissolved silver alkanolamine complex;(2) preparing an aqueous solution of a reducing agent and, optionally, an alkanolamine; and(3) mixing together the silver alkanolamine complex solution and the reducing agent alkanolamine solution at a buffered pH and a temperature of 10.degree. C. to 100.degree. C. to form finely divided spherical silver particles.

Abstract: The treatment of solutions of metal ions with redox polymers under conditions to reduce the ions to a lower valence. The resulting solutions of the lower valence ions are separated from the polymers, and the polymers are regenerated for further use in such treatment. The method of the invention is employed to convert high valence, toxic metal ions to lower valence ions of reduced toxicity. Preferably, the electronically conductive polymer is mounted on a suitable support, and a solution of the toxic metal ion is brought into contact with the polymer. A variety of redox polymers, in particular, electronically conductive polymers, may be used in the practice of the invention, and individual such polymers may be structurally altered to suit particular metal ions. Polymers especially contemplated for use in the invention are polypyrroles, polyanilines and polythiophenes. All of these polymers are characterized as redox polymers with a positive charge on their backbones.

Abstract: A novel zerovalent zinc species and an organozinc reagent are disclosed. The zerovalent zinc species is directly produced by reaction of a reducing agent on a zinc salt, preferably Zn(CN).sub.2. The organozinc reagent results from the reaction of the zerovalent zinc species and an organic compound having one or more stable anionic leaving groups. These organozinc reagents include a wide spectrum of functional groups in the organic radical, and are useful in a variety of reactions schemes.

Abstract: Disclosed is an efficient biological process for recovering silver and manganese from refractory manganiferous silver ore. The process utilizes manganese reducing Bacillus sp. Specifically exemplified is a novel microbe designated Bacillus MBX 69, or mutants thereol Further, gene(s) encoding the enzyme(s) obtainable from the said bacteria can be used by placing such gene(s) on a suitable vector and transforming a competent host. The transformed host then can be used to recover silver and manganese from refractory manganiferous silver ore.

Abstract: Method for recognition of noble metals otherwise not recognizable in base material clusters includes using an electron beam furnace in which base material clusters are vaporized by means of an electron beam gun, and the vaporized materials are condensed as free atoms or are alloyed with other components of the base materials, and are able to be recovered by conventional recovery techniques once they are recognized. The base material includes the products of smelting processes, pellets of compacted raw material, like anode-mud or waste material, and the base materials are remelted utilizing the heat from electron beam guns for the remelting.

Abstract: Aqueous solutions containing metal cations, that may include cations of both desired metal and impurity or secondary metal, are treated with an organic liquid extractant suitable for the extraction of cations of the desired metal, cations of at least one secondary metal being co-extracted. After phase disengagement, the loaded organic phase containing cations of either a desired metal or desired metal together with at least one secondary metal is contacted with a solid metal or solid metal alloy capable of reducing in the organic phase cations of either a desired metal or a secondary metal from a higher to a lower state of oxidation. Depending on the extracted metal(s) and the added solid metal or alloy, cations of the at least one extracted metal are reduced to the lower state of oxidation and either are deposited (cemented) in the metallic state onto the solid metal or alloy, or are partially reduced in the organic phase to a lower oxidation state with the solid metal or alloy being oxidized in part.

Abstract: Heavy metal ions react with ferrous dithionite in acidic aqueous solution. They are reduced to metallic particles that are suitable for recycling and reuse when recovered from the acidic water. When chelating agents are present, they are deactivated by bonding to the ferrous ions. Ferrous dithionite, (FeS.sub.2 O.sub.4) is either generated in-situ or ferrous ions and dithionite ions can be provided by other methods.

Abstract: A process for recovering copper from cupric ion containing aqueous solutions which comprises adding to the aqueous solution containing cupric ions an amount of reducing agent which corresponds from 0.1 to 10 moles of reducing agent per mole cupric ion, and heating the reaction mixture in the absence of oxygen in a closed vessel to a temperature of from 170.degree. to 240.degree. C., said reducing agent being one or more members of the group consisting of:(a) organic aldehydes RCHO (R=H, C.sub.1 to C.sub.5 alkyl)(b) carboxylic acids R COOH (R=H, linear or branched C.sub.1 to C.sub.5 alkyl)(c) hydroxycarboxylic acids R.sub.1 COOH (R.sub.1 =HO(CH.sub.2).sub.n, CH.sub.3 CH(OH)--, CH.sub.3 (CH.sub.2).sub.n, CH(OH)-- with n=1 to 3)(d) dicarboxylic acids R.sub.2 COOH (R.sub.2 =HOOC(CH.sub.2).sub.n with n=1 to 3)(e) amino acids R.sub.3 COOH (R.sub.3 =CH.sub.3 (CH.sub.m CH(NH.sub.2)-- (CH.sub.3).sub.2 (CH).sub.m CH(NH.sub.2 -- with m=1 to 3, CH.sub.3.CH(OH)(NH.sub.2), HOO C.CH(NH.sub.2).(CH.sub.2).sub.

Abstract: A method of treating a gold-bearing ore to render the gold component of the ore more amenable to standard cyanidation treatment in a reduced amount of time is disclosed. An aqueous slurry of the gold-bearing ore is introduced into at least one vessel. An oxidizing agent, such as chlorine gas, an alkali metal hypochlorite and an alkaline earth metal hypochlorite, is rapidly introduced into the vessel so that it intimately contacts the aqueous slurry. While the oxidizing agent is being introduced into the vessel, the slurry is agitated with agitating means including a plurality of impeller blades that provide high shear agitation and a large interfacial surface area between the oxidizing agent and the liquid phase of the slurry to enhance the mass transfer of the oxidizing agent so that it becomes substantially completely adsorbed by the aqueous slurry in about 5 to about 15 minutes.