Abstract: The present invention is directed to a system for recovering metal values from metal-bearing materials. During a reactive process, a seeding agent is introduced to provide a nucleation site for the crystallization and/or growth of solid species which otherwise tend to passivate the reactive process or otherwise encapsulate the metal value, thereby reducing the amount of desired metal values partially or completely encapsulated by such material. The seeding agent may be generated in a number of ways, including the recycling of residue or the introduction of foreign substances. Systems embodying aspects of the present invention may be beneficial for recovering a variety of metals such as copper, gold, silver, nickel, cobalt, molybdenum, zinc, rhenium, uranium, rare earth metals, and platinum group metals from any metal-bearing material, such as ores and concentrates.

Abstract: A method of leaching sulphide mineral concentrates wherein heat generated by bioleaching of sulphide mineral concentrates in at least one reactor is transferred into a heap in which bio-assisted leaching takes place.

Abstract: Methods for detecting gold and quantitating gold in ore samples utilizing a gold-specific protein are provided, including methods for multiple sample handling. Also provided are methods for extracting gold from mineral suspensions utilizing a magnetic mineral binding reagent and gold-specific protein, or hydrophobic reagent and gold-specific protein in conjunction with a flotation reagent.

Abstract: Methodology for the extraction of metallic elements from solid and liquid metal-contaminated starting material such as mineral ores, recyclable wastes, contaminated soils, engraving solutions, metal finishing solutions, battery manufacturing solutions, toxic wastes such as dusts producing through steelmaking processes by effectuating preferably prolonged contacting of such starting material with liquor compositions to cause the underlying structure of the starting material to be broken down. The contaminated starting materials are more susceptible to metal separation because the released metallic element are readily solubilized in the contacting liquor. Compositions of the contacting liquor comprise caustic silicate solutions containing essentially saturating levels of silica.

Abstract: A method of leaching zinc from a zinc concentrate comprising leaching a zinc concentrate in an aqueous solution containing free sulfuric acid and ferric ions, whereby elemental sulfur is deposited on the zinc concentrate, and grinding the zinc concentrate under atmospheric pressure in the aqueous solution to provide particles of the zinc concentrate having surfaces, wherein the elemental sulfur and other by-products which form on the surfaces of the particles of the zinc concentrate are stripped by the grinding.

Abstract: A method of processing a mineral composition comprising a refractory material the method comprising milling the composition to a particle size of P80 of less than 25 microns and leaching said composition with a solution comprising lime and/or limestone in the presence of an oxygen containing gas.

Abstract: The present invention is directed to a method for recovering a precious metal from a precious metal-containing material using a leaching agent and one or more oxidants. The leaching agent is preferably thiosulfate and the oxidants one or more of chlorite (ClO2−), chlorate (ClO3−), bromate (BrO3−), iodate (IO3−), ferric oxide (Fe2O3), chromate (CrO42−) and manganese dioxide (MnO2). The invention is particularly suitable for in situ mining or leaching of precious metal deposits.

Abstract: A process for the selective removal of a least a portion of at least one precious metal in the form of a metal-cyanide complex from an ion-exchange resin to which the precious metal and at least one base metal-cyanide complex are bound, wherein the at least one precious metal is eluted from the resing by contacting the resin with an eluent comprising at least one counter-ion contained in a solvent selected from an organic solvent or a combination of an organic solvent and an aqueous solvent.

Abstract: A method for recovering catalytic metals from compositions containing catalytic metal colloids. Compositions such as rinse solutions or dragout baths containing catalytic metal colloids are passed through a filter that entraps catalytic metal colloids from the solutions. The catalytic metal colloid has a high affinity for the filter in contrast to other components of the solutions. The other components of the solution pass through the filter concentrating the catalytic colloid on the filter. The filter containing the catalytic metal colloid is rinsed with an acid solution to remove the catalytic metal from the filter. The catalytic metal is collected in a suitable container or on an adsorbent such as a resin. The method is economically efficient and environmentally friendly.

Abstract: A method for recovering catalytic metals from fluids containing catalytic metal colloids. Fluid compositions such as rinse solutions or dragout baths containing catalytic metal colloids are passed through a filter that entraps catalytic metal colloids on the filter. The catalytic metal colloids have a high affinity for the filter in contrast to other components of the fluids. The other components of the fluids pass through the filter while the catalytic colloids concentrate on the filter. The filter containing the catalytic metal colloids is burned, and the catalytic metal is retrieved. The method is economically efficient and environmentally friendly.

Abstract: A process is disclosed for refining silver bullion, i.e. raw silver containing generally more than 90% silver besides Se, Pb, Au, Cu and platinum group metals (PGM) as main impurities. The process comprises: optionally removing Se as gaseous SeO2 from the molten metallic phase by injecting air, which is preferably O2 enriched, into the metallic phase at a preferred bath temperature of 1000-1100° C.; optionally slagging off the Pb by contacting the molten metallic phase with a silica and borax based flux at a preferred bath temperature of 1000-1150° C.; granulating the molten metallic phase in water, thereby forming Ag rich granules; leaching the Ag rich granules with HNO3 at a temperature above 50° C., preferably in an O2 enriched atmosphere, followed by filtration, thereby separating an Au bearing residue from an Ag rich liquor; heating the Ag rich liquor, thereby evaporating H2O and forming an AgNO3 bearing melt; maintaining the AgNO3 bearing melt at a temperature of 220-350° C.

Abstract: A method for recovering catalytic metals from fluid compositions containing catalytic metal colloids. Fluid compositions such as aqueous rinse solutions or dragout baths containing catalytic metal colloids are passed through a porous metal filter that entraps the catalytic metal colloids. The catalytic metal colloids have a high affinity for the porous metal filter in contrast to other components of the fluids. The other components of the fluids pass through the porous metal filter while the catalytic metal colloids concentrate on the porous metal filter. The catalytic metal colloids that are captured on the porous metal filter are removed from the filter by backwashing the filter with a gas and/or a liquid. The backwashing forces the catalytic metal colloids off of the porous metal filter and through a solids discharge valve and into a solids collection container. The method is economically efficient with high catalytic metal recovery and is environmentally friendly.

Abstract: A hydrometallurgical process for extracting copper and any one or more than one of zinc, silver and gold from a sulphide ore or concentrate is disclosed. The process includes a range of mineral species that contain copper and one or more than one of zinc, silver and gold, which process includes two or more than two leach steps using each liquors of different composition, each leach step selectively leaching one or more than one metal from the minerals. The process also includes separating a solid residue and an exit leach liquor after each leach step, leaching the solid residue produced in each leach step in a successive leach step, and recovering metal from the exit leach liquor produced in each leach step.

Abstract: The present invention is directed to a system for recovering metal values from metal-bearing materials. During a reactive process, a seeding agent is introduced to provide a nucleation site for the crystallization and/or growth of solid species which otherwise tend to passivate the reactive process or otherwise encapsulate the metal value, thereby reducing the amount of desired metal values partially or completely encapsulated by such material. The seeding agent may be generated in a number of ways, including the recycling of residue or the introduction of foreign substances. Systems embodying aspects of the present invention may be beneficial for recovering a variety of metals such as copper, gold, silver, nickel, cobalt, molybdenum, zinc, rhenium, uranium, rare earth metals, and platinum group metals from any metal-bearing material, such as ores and concentrates.

Abstract: Processes are provided for recovering precious metals from refractory materials using thiosulfate lixiviants. The processes can employ lixiviants that include at most only small amounts of copper and/or ammonia and operate at a relatively low pH, reduction of polythionates, inert atmospheres to control polythionate production, and electrolytic solutions which provide relatively high rates of precious metal recovery.

Abstract: A system and process for recovering copper from a copper-containing ore, concentrate, or other copper-bearing material to produce high quality cathode copper from a leach solution without the use of copper solvent extraction techniques or apparatus. A process for recovering copper from a copper-containing ore generally includes the steps of providing a feed stream containing comminuted copper-containing ore, concentrate, or other copper-bearing material, leaching the feed stream to yield a copper-containing solution, conditioning the copper-containing solution through one or more physical or chemical conditioning steps, and electrowinning copper directly from the copper-containing solution, without subjecting the copper-containing solution to solvent extraction.

Abstract: Processes are provided for recovering precious metals from refractory materials using thiosulfate lixiviants. The processes can employ lixiviants that include at most only small amounts of copper and/or ammonia and operate at a relatively low pH, reduction of polythionates, inert atmospheres to control polythionate production, and electrolytic solutions which provide relatively high rates of precious metal recovery.

Abstract: A method of recovering precious metal values from refractory sulfide ores is provided. The method includes the steps of separating clays and fines from a crushed refractory sulfide ore, forming a heap from the refractory sulfide ore, producing a concentrate of refractory sulfide minerals from the separated fines and adding the concentrate to the heap, bioleaching the heap to thereby oxidize iron sulfides contained therein, and hydrometallurgically treating the bioleached ore to recover precious metal values contained therein.

Abstract: A method for the treatment of sulfide ores containing silver by pressure oxidation. The method includes the addition of a sulfate-binding material to reduce the formation of jarosite species during pressure oxidation. Silver can then be recovered from the solids portion of the discharge slurry. A jarosite reduction step, such as by a lime boil, that is typically required to recover silver after pressure oxidation can advantageously be eliminated.

Abstract: A Process for the treatment or removal of impurities, such as arsenic, antimony or bismuth, generated as by-products during smelting and refining of copper concentrates, comprises subjecting the by-products to pressure oxidation along with a copper concentrate in a hydrometallurgical copper extraction process or the treatment of impurities when present in a concentrate by subjecting the concentrate to a hydrometallurgical extraction process.

Abstract: The present invention is directed to a process for recovering metal values from metal-bearing materials. During a reactive process, a seeding agent is introduced to provide a nucleation site for the crystallization and/or growth of solid species which otherwise tend to passivate the reactive process or otherwise encapsulate the metal value, thereby reducing the amount of desired metal values partially or completely encapsulated by such material. The seeding agent may be generated in a number of ways, including the recycling of residue or the introduction of foreign substances. Processes embodying aspects of the present invention may be beneficial for recovering a variety of metals such as copper, gold, silver, nickel, cobalt, molybdenum, zinc, rhenium, uranium, rare earth metals, and platinum group metals from any metal-bearing material, such as ores and concentrates.

Abstract: A process for leaching precious metals from material containing precious metals, such as oxidic and sulfidic gold-bearing ores, is disclosed. The process includes the steps of: (i) leaching the precious metal with a leach solution containing a thiosulfate-based lixiviant; (ii) treating the material by oxidising precious metal in the material into a form that is leachable in a subsequent leaching step; and thereafter as a separate step.

Abstract: An improvement in the solvent extraction process for recovering metal values, i.e. copper, from acidic aqueous solutions containing copper and iron which may also include chloride, and more particularly to an improvement which provides for increased copper to iron ratios in the loaded organic extractant phase. The improvement comprises washing the loaded organic extractant phase prior to stripping of the copper values therefrom with an aqueous acidic wash solution containing at least a portion of electrolyte solution, wherein the wash solution or the electrolyte solution has been previously contacted with copper metal.

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: 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 system and method are disclosed after chemical processing involving agitation and/or mixing of components. In one embodiment, the chemical processing involves pressure oxidation and in another embodiment involves pressure leaching. Agitation during chemical processing is aided by an agitator pump disposed in each compartment or stage of a reactor to draw components into a cavity of the agitator pump. In another embodiment, feed to a multi-stage reactor is split between different compartments of reactor.

Abstract: A process for the recovery of gold and the platinum group metals from sources that contain relatively low amounts of the metals is described. The process is environmentally acceptable and uses no expensive and potentially dangerous organic solvents.

Abstract: The invention relates to a biological process for the preparation of nano-sized colloidal metal particles by treating wet fungus or fungus extract with a metal ion solution of the desired metal and separating the biomass to obtain the nano-sized colloidal metal particles.

Abstract: In one aspect, the present invention provides a method for recovering precious metal, and particularly gold, from a particulate substrate loaded with a precious metal-containing coating, in which a portion, but less than substantially all, of the particulate substrate is dissolved away to physically release precious metal-containing coating from the particulate substrate. The particulate substrate loaded with a precious metal-containing coating may be prepared during precious metal recovery operations by cementation of precious metal on a base metal particulate substrate from a pregnant leach solution, such as a leach solution including a thiosulfate lixiviant for the precious metal.

Abstract: A method of recovering precious metal values from refractory sulfide ores is provided. The method includes the steps of separating clays and fines from a crushed refractory sulfide ore, forming a heap from the refractory sulfide ore, producing a concentrate of refractory sulfide minerals from the separated fines and adding the concentrate to the heap, bioleaching the heap to thereby oxidize iron sulfides contained therein, and hydrometallurgically treating the bioleached ore to recover precious metalvalues contained therein.

Abstract: The present invention relates generally to a process for the production of sulfuric acid and liberation of precious metal values from materials containing sulfur through pressure leaching operations. In accordance with various aspects of the present invention, the sulfur-bearing materials may comprise residues from pressure leaching operations, such as those carried out at medium temperatures. The process of the present invention can be advantageously used to convert such sulfur-bearing materials to sulfuric acid by means of pressure leaching. The sulfuric acid so produced can be used beneficially in other mineral processing operations, for example those at the site where it is produced. Metals, such as precious metals, that are contained within the sulfur-bearing materials advantageously may be recovered from processing products by established precious metals recovery technology.

Abstract: A wear-resistant flash tank pressure let down nozzle for use in passing an ore slurry into an ore slurry flash tank to release steam from the slurry and reduce the pressure of the slurry. The nozzle has an expansion cone flaring toward the discharge end of the nozzle. The cross-sectional area of a choke section of the nozzle and the exit diameter of the expansion cone are selected to establish a relationship between pressure upstream of the nozzle and pressure in the flash tank so that underflashing, overflashing, and shock waves inside the flash tank are minimized.

Abstract: Disclosed and claimed are efficient methods for leaching minerals from ores using an acidic solution such as sulfuric acid. Additional factors which can improve mineral recovery include the use of an alkali metal halide, grinding the ore, addition of a carbon source, and/or, adjustment of the temperature at which the process is carried out. Minerals such as titanium, iron, nickel, cobalt, silver and gold may be recovered by the methods of the present invention.

Abstract: The present invention is directed to a process for recovering metal values from metal-bearing materials. During a reactive process, a seeding agent is introduced to provide a nucleation site for the crystallization and/or growth of solid species which otherwise tend to passivate the reactive process or otherwise encapsulate the metal value, thereby reducing the amount of desired metal values partially or completely encapsulated by such material. The seeding agent may be generated in a number of ways, including the recycling of residue or the introduction of foreign substances. Processes embodying aspects of the present invention may be beneficial for recovering a variety of metals such as copper, gold, silver, nickel, cobalt, molybdenum, zinc, rhenium, uranium, rare earth metals, and platinum group metals from any metal-bearing material, such as ores and concentrates.

Abstract: A system and process for recovering copper from a copper-containing ore, concentrate, or other copper-bearing material to produce high quality cathode copper from a leach solution without the use of copper solvent extraction techniques or apparatus. A process for recovering copper from a copper-containing ore generally includes the steps of providing a feed stream containing communicated copper-containing ore, concentrate, or other copper-bearing material, leaching the feed stream to yield a copper-containing solution, conditioning the copper-containing solution through one or more physical or chemical conditional steps, and electowinning copper directly from the copper-containing solution, without subjecting the copper-containing solution to solvent extraction.

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: The invention is concerned with techniques and apparatus suitable for extraction of at least one valuable metal such as one or more of: gold, platinum, silver, cobalt, nickel, molybdenum, and manganese from a starting material which, by way of example, could be freshly mined mixed ore containing both oxidic and refractory (sulphide) ores.

Abstract: Processes are provided for recovering precious metals from refractory materials using thiosulfate lixiviants. The processes can employ lixiviants that include at most only small amounts of copper and/or ammonia and operate at a relatively low pH, reduction of polythionates, inert atmospheres to control polythionate production, and electrolytic solutions which provide relatively high rates of precious metal recovery.

Abstract: A method of increasing the leaching yield of gold in the cyanide treatment of refractory ores or concentrates of such ores, while delivering air in an alkaline environment at atmospheric pressure, wherein gold present in said ores or concentrates is bound as tellurides. The method is characterised by carrying out the cyanide treatment at a temperature above room temperature, up to a temperature immediately beneath the boiling point of the leaching liquid. The treatment is suitably carried out at a temperature of 60-80° C., and at a pH between 10 and 12.

Abstract: A method of biotreating a solid material to remove an undesired compound using a nonstirred surface bioreactor is provided. According to the method the surface of a plurality of coarse substrates is coated with a solid material to be biotreated to form a plurality of coated coarse substrates. The coarse substrates have a particle size greater than about 0.3 cm and the solid material to be biotreated has a particle size less than about 250 &mgr;m. A nonstirred surface reactor is then formed by stacking the plurality of coated coarse substrates into a heap or placing the plurality of coated coarse substrates into a tank so that the void volume of the reactor is greater than or equal to about 25%. The reactor is inoculated with a microorganism capable of degrading the undesired compound in the solid material, and the solid material is then biotreated in the surface bioreactor until the undesired compound in the solid material is degraded to a desired concentration.

Abstract: Use of a mixture of a C9 alkylsalicylaldoxime and a ketoxime as an extractant in a water-immiscible organic solvent solution in a metal extraction circuit to enhance the transfer of iron values to a dilute acid wash solution when the metal loaded organic solvent/extractant solution is washed with the dilute acid wash solution.

Abstract: A system and method for recovering gold using pressure oxidation is disclosed. In one embodiment, a feed slurry is introduced into multiple compartments or stages of a multi-stage autoclave. In another embodiment, an agitator pump is disposed in each compartment or stage of an autoclave to draw the feed slurry and oxygen into a pump cavity for intimate mixing. Preferably these embodiments are used in combination, and each is believed to contribute to enhanced utilization of the oxygen within the autoclave.

Abstract: A method of recovering precious metal values from refractory sulfide ores is provided. The method includes the steps of separating clays and fines from a crushed refractory sulfide ore, forming a heap from the refractory sulfide ore, producing a concentrate of refractory sulfide minerals from the separated fines and adding the concentrate to the heap, bioleaching the heap to thereby oxidize iron sulfides contained therein, and hydrometallurgically treating the bioleached ore to recover precious metal values contained therein.

Abstract: A hydrochloric acid solution containing platinum group metals has its acidity adjusted to 5.5 to 6.5M HCl and its redox potential adjusted to at least 500 mV, before being treated by chromatography. Particularly clean separation of at least Pt and Pd can be obtained, and recovered Pt and Pd of at least 99.99% purity may be obtained by following conventional precipitation processes.

Abstract: A method for separating gold and/or silver from copper or other contaminant metals is provided in which a suitable filter membrane (64), particularly a nanofilter, is used to form a retentate (134) containing most of the multivalent metal cyanide complexes and a permeate (135) containing most of the precious metal cyanide complexes. The process is particularly applicable to the recovery of gold and/or silver from ores containing these metals and one or more contaminant metals. The precious metal can thereafter be recovered from the permeate (135) and the metal in the multivalent metal cyanide complex from the retentate (134).

Abstract: A process for treating zinc mine tailings wherein a series of wave tables and cone separators are utilized to remove various components from the zinc mine tailings, such as carbon, zinc, lead, copper and precious metals. The recovered carbon is then transferred to a cogeneration plant where it is utilized as fuel.

Abstract: A method for recovering a precious metal from a host material, comprises the steps of subjecting the host material to an oxidative pressure leach process, in the presence of a halide ion constituent which is reactive with the precious metal, and at a temperature sufficient to cause at least a portion of the precious metal to be extracted by a leach solution; and recovering the precious metal from the leach solution.

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 method for preparing ultra-pure silver from a crude silver halide matrix containing metallic and/or non-metallic impurities, said method comprising; roasting the crude silver halide matrix to substantially remove carbonaceous material; treating the roasted crude silver halide matrix with ammonium hydroxide to dissolve the silver halides and form an ammonium hydroxide reaction mixture; adding an initial reducing agent to the ammonium hydroxide reaction mixture to precipitate a crude silver powder mixture; separating the crude silver powder mixture from the ammonium hydroxide reaction mixture dissolving the crude silver powder 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

Abstract: A process for recovering a base metal from a material, the base metal being selected from cobalt, copper, nickel and zinc, the process comprising the steps of reacting the host material with a ferric ion species in a leach solution, at conditions sufficient to cause at least a portion of the base metal to be oxidized by the ferric ion species, thereby causing the ferric ion species to be converted to a ferrous ion species, and oxidizing the ferrous ion species with an oxidation mixture of SO2 and oxygen to form the ferric ion species for subsequent reaction with the material.