Abstract: Processes are provided for the kinetically efficient reduction of selenate species to selenide species using chromous ions in acidic solution. This reduction may advantageously be carried out in the presence of sulphate species, with selective selenate reduction in preference to the reduction of sulfate. The reduced selenate may be removed from the chromous-treated solution, for example by precipitation of a copper-selenide solid. The chromic ions formed by reaction of chromous ions in the reduction of selenate may also be removed from solution, for example by addition of a base to form an insoluble chromic hydroxide solid. The chromic hydroxide may be recycled to regenerate chromous ions, for example by electrolysis. In this way, systems are provided for continuously removing dissolved selenium from wastewater streams.

Abstract: These disclosures relate to preparing nickel metal (Ni(0)) suited for use in catalyst systems, such as nickel complexes with phosphorus-containing ligands, useful to catalyze the hydrocyanation of ethylenically unsaturated compounds. The methods described herein can include use of steam during reduction of nickel.

Abstract: Provided is a method for producing a high-purity tungsten powder having a phosphorus content of less than 1 wtppm; wherein an ammonium tungstate solution containing 1 wtppm or more of phosphorus as an impurity in terms of the inclusion in tungsten is used as a starting material, this solution is neutralized with hydrochloric acid at a temperature of 50° C. or less to adjust the pH at 4 or more and less than 7 so as to precipitate ammonium paratungstate undecahydrate crystals, the resulting solution is heated to 70 to 90° C. and filtered in a high-temperature state so as to obtain ammonium paratungstate pentahydrate crystals, the obtained crystals are calcined so as to form a tungsten oxide, and the tungsten oxide is subject to hydrogen reduction so as to obtain a high-purity tungsten powder. Additionally provided is a method for producing a high-purity tungsten powder having a phosphorus content of 0.

Abstract: These disclosures relate to preparing nickel metal (Ni(0)) suited for use in catalyst systems, such as nickel complexes with phosphorus-containing ligands, useful to catalyze the hydrocyanation of ethylenically unsaturated compounds. The methods described herein can include use of steam during reduction of nickel.

Abstract: Each of the metal nano-particles present in a dispersion, which comprises at least one metal selected from the group consisting of precious metals and transition metals or an alloy of at least two metals selected from the foregoing metals, comprises a metal particle in which an organic metal compound of a fatty acid and/or an amine-metal complex is adhered to the periphery of the metal particle. This organic metal compound and the amine-metal complex are admixed together in a solvent and then the resulting mixture is subjected to a reducing treatment to thus form a dispersion containing metal nano-particles in a concentration of not less than 5% by mass and not more than 90% by mass. The resulting dispersion is applied onto the surface of a base material, followed by drying the applied layer of the dispersion and then firing the dried layer of the dispersion at a low temperature to thus form a thin metallic wire or a metal film having conductivity.

Abstract: The present invention is directed to methods for making metal oxide compositions, specifically, metal oxide compositions having high surface area, high metal/metal oxide content, and/or thermal stability with inexpensive and easy to handle materials. In one embodiment, the present invention is directed to methods of making metal and/or metal oxide compositions, such as supported or unsupported catalysts. The method includes combining a metal precursor with an organic acid to form a mixture and calcining the mixture for a period of time sufficient to form a metal oxide material.

Abstract: A method for separating metals from metal-containing materials by extraction without generating large quantities of liquid waste is disclosed. Also disclosed is an extractant composition for use with this method. The method comprises exposing a metal-containing material to a solvent, such as supercritical carbon dioxide, an acid-base complex, and a chelating agent that is not a component of the acid-base complex. The metal is released into the solvent by a combination of oxidation by an oxidizing agent in the acid-base complex and chelation by the chelating agent. The oxidizing agent in the acid-base complex is solubilized by a solubilizing agent. The disclosed method and composition have many applications and are particularly well suited for the extraction of transition metals, including, but not limited to, platinum group metals, nom a metals and coinage metals. Applications include the recovery of metals from scrap materials and the planarization of semiconductor structures.

Abstract: A process is provided for the recovery of a metallic nickel product in a solvent extraction process which includes the steps of forming a nickel ammine complex by stripping nickel from a nickel loaded organic phase with a high strength ammonia solution and then reducing the nickel ammine complex with hydrogen from the high strength ammonia solution to produce a metallic nickel product. By virtue of the present process, a reductive precipitation of nickel by hydrogen is obtained so as to recover a metallic nickel product, and the process is advantageous in that it will allow for commercial processes wherein nickel may be recovered by hydrogen reduction based on high strength ammonia solutions.

Abstract: A method for producing dispersed metal particles on a substrate and the compositions produced is disclosed. A method for producing the particles comprises exposing an organometallic and a particulate substrate to supercritical or near supercritical fluid under conditions to form a mixture of the fluid and the organometallic, allowing the mixture to remain in contact with the substrate for a time sufficient to deposit dispersed organometallic onto the substrate, venting the mixture, thereby adsorbing the organometallic onto the substrate, and reducing the dispersed organometallic to dispersed metal particles with a reducing agent.

Abstract: A sieve tray column for stripping or recovering metal values from a metal value bearing material includes an elongate column body having an upper end and a lower end and a chamber defined therein. A plurality of spaced apart sieve trays are located within the chamber at intervals between the upper and lower ends. A first inlet is located intermediate the upper and lower ends of the column for introducing a value bearing material, such as a solution or slurry thereof, into the chamber, which value bearing material is arranged to flow in an upwards direction through successive trays towards the upper end. A second inlet is located at or adjacent the upper end of the column for introducing a resin into the chamber, which resin is fluidised by the upwardly moving value bearing material and caused to flow from one sieve tray to another successive sieve tray towards the lower end of the column.

Abstract: A process for producing cobalt metal powder from nickel-cobalt sulphides wherein said nickel-cobalt sulphides are leached in an ammoniacal ammonium sulphate solution under an elevated pressure of an oxygen bearing gas, at a temperature of at least 80° C., with an effective ammonia to metals mole ratio in the range of 5:1 to 6.5:1 to oxidize the nickel and cobalt sulphides to sulphates, and to produce an ammoniacal leach liquor in which dissolved cobalt is predominantly in the (III) oxidation state, and an ammoniacal ammonium sulphate leach residue containing a cobalt (III) hexammine sulphate-calcium sulphate double salt.

Abstract: A method for dissociating metal-ligand complexes in a supercritical fluid by treating the metal-ligand complex with heat and/or reducing or oxidizing agents is described. Once the metal-ligand complex is dissociated, the resulting metal and/or metal oxide form fine particles of substantially uniform size. In preferred embodiments, the solvent is supercritical carbon dioxide and the ligand is a .beta.-diketone such as hexafluoroacetylacetone or dibutyldiacetate. In other preferred embodiments, the metals in the metal-ligand complex are copper, silver, gold, tungsten, titanium, tantalum, tin, or mixtures thereof. In preferred embodiments, the reducing agent is hydrogen. The method provides an efficient process for dissociating metal-ligand complexes and produces easily-collected metal particles free from hydrocarbon solvent impurities. The ligand and the supercritical fluid can be regenerated to provide an economic, efficient process.

Abstract: The present invention relates to the extraction and separation of low concentrations of precious group metals from acid chloride solutions, which are obtained by leaching catalytic converters, by utilizing a 8-hydroxyquinoline containing resin and a thiourea stripping process. The said process eliminates the phase separation problems and reagent losses which are normally associated with prior art methods. In addition to being used as a catalytic converter recycler, the present invention can be also employed by waste water treatment plants.

Abstract: A process for precipitating solid hydrates of cupric tetrammine sulfate from a solution, wherein the solution contains at least 40 grams per liter of free ammonia, at least 50 grams per liter of ammonium sulfate and wherein the temperature of the solution is less than 21.degree. C. The hydrates of cupric tetrammine sulfate can be converted to additional useful copper compounds.

Abstract: The invention relates to a method for producing metal powders, where the employed raw materials are metal ions in a liquid phase. According to the invention, at a preliminary stage of the method the liquid phase containing metal ions is reduced with hydrogen at an increased pressure and raised temperature in order to produce porous, sponge-like metal powder. The obtained porous, sponge-like metal powder is further processed at a high temperature, for instance by means of plasma, in order to improve the qualities of the metal powder.

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.