Abstract: A process is disclosed for the recovery and assay of gold, silver (PMs) and the 6 platinum group elements (PGEs) from playa-evaporite sediments. Fine sediments are subjected to a primary leach with a highly caustic sodium thiosulfate leach liquor to produce a metal-pregnant solution. After filtration the pregnant solution is subjected to a two-stage precipitation of gold, silver and PGE values. In a first stage precious metals and some PGE elements are precipitated by lead acetate or sodium borohydride reagents. The precipitate may be subjected further to desulfurization and metallic footing to produce a lead-precious metal sponge. The sponge is de-leaded by firing and cupelling, selective cementation or electrolysis and reduction to dore is best effected by a carburizing distillation. The final recovery of the metal values is produced by controlled acid parting into individual precious metals and cupellation to the metallic state.

Abstract: A method of removal of valuable minerals of oil sand tailings including continuous operation of mixing said tailings with acid, curing the agglomeration and leaching of the cured agglomeration for removal of valuable minerals.

Abstract: A process for recovering at least one precious metal from an ore containing carbonaceous material is disclosed. The process involves the use of certain plant derived ortho-quinone containing components, in particular, certain lignin and/or tannin derived components containing ortho-quinone functionality.Preferred compositions comprise at least one ligno sulfonate component containing ortho-quinone functionality. In the process, the use of at least one additional oxidant capable of maintaining the ortho-quinone containing functionality in the desired oxidation state provides for integrated process synergy.

Abstract: A hydrometallurgical process for the recovery of precious metal values from refractory precious metal ore materials containing preg-robbing carbon by leaching with a thiosulfate lixiviant, the process comprisinga. providing a body of particles and/or particulates of an ore material having precious metal values and preg-robbing carbonaceous components;b. contacting the body of particles and/or particulates with a thiosulfate lixiviant solution at conditions conducive to the formation of stable precious metal thiosulfate complexes;c. recovering the thiosulfate lixiviant from the body of particles and/or particulates after a period of contact which is sufficient for the lixiviant solution to become pregnant with precious metal values extracted from the ore material; andd. recovering the precious metal values from the lixiviant solution.In a preferred embodiment, the refractory ore materials are low grade precious metal ore materials.

Abstract: A process and apparatus for recovering metal values from ores is described. Comminuted ores are mixed with a liquid to form a pulp. A plurality of streams of pulp are then projected against one another, thereby causing erosion of ore particles in the pulp. A pair of pulp streams preferably emit through nozzles 68, 70 which are coaxially aligned with each other. The nozzles are located in any impact chamber 66. Gas may be supplied to the impact chamber through a gas inlet 72. The chamber may be kept at an elevated pressure, and the gas may be selected in order to facilitate the reaction of reagents in the pulp with the ore. Pulp from the impact chamber passes into a co-axial vertical tube assembly 78, 80 from where it passes back to a tank 50 for continued treatment.

Abstract: A process for recovering at least one precious metal from an ore containing metal sulfide material is disclosed. The process involves the use of promoting amounts of certain plant derived ortho-quinone containing components, in particular, certain lignin and/or tannin derived components containing ortho-quinone functionality. Preferred compositions comprise at least one ligno sulfonate component containing ortho-quinone functionality. In the process, the use of at least one additional oxidant capable of maintaining the ortho-quinone containing functionality in the desired oxidation state provides for integrated process synergy.

Abstract: An improved process for recovery of precious metals such as gold or silver using novel ion exchange resins having aryl guanidyl functionality from aryl guanidine compounds having a pKa at 25.degree. C. less than 13 and preferably less than 12. The resins have improved elution properties compared to known guanidine reagents using caustic eluant solutions, particularly improved eluant solutions such as a mixture of sodium hydroxide and sodium benzoate. A selective elution of base metals may be carried out before elution of the precious metals from the resins having guanidyl functionality.

Abstract: The invention relates to the extraction of metal values from metal bearing ores. More specifically, the invention comprises, in a process 10 for extracting metal values from metal bearing ores, a method of enhancing metal value recovery from the ore. The method comprises introducing, upstream of a metal recovery section 26, a gaseous agent by means of arrangements 30. The gaseous agent is capable of promoting recovery of metal values from the ore. The gaseous agent introduction is into at least one of the pipelines 20, 24, 28 conveying ore slurry or process water for use in slurry ore or for slurry make-up.

Abstract: Gold and silver are extracted from their elemental state or from complex ores and alloys by leaching them with a solution containing ammonia, ammonium salts and one or more oxidants. The process is particularly effective for refractory gold ores including sulfide and carbonaceous ores.

Abstract: This invention relates to the extraction of metal values from metal bearing ores. More particularly, in a process for recovering metal values from metal bearing ore, the invention provides the step of enhancing metal value recovery by introducing into the thickener overflow water 32, a gaseous agent capable of promoting recovery of the metal values from the ore. The gaseous agent may be oxygen or oxygen enriched gas, and can be injected by means of injection means 50.

Abstract: Geothermal brine and other platinum-containing solutions are passed through a carbon-containing zone to recover platinum from the aqueous medium.

Abstract: This invention relates to the extraction of metal values from metal bearing ores. More specifically, according to the invention, in a process for extracting metal values from metal bearing ores, there is provided a method of enhancing metal value recovery from the ore. The method comprises introducing, upstream of a metal recovery section 26, a gaseous or liquid agent capable of promoting recovery of the metal values from the ore, into the gland service water from at least one of the pumps 30. The introduction of the gaseous or liquid agent is by means of an arrangement 35. The agent may be oxygen.

Abstract: A process for recovering at least one precious metal from an ore containing carbonaceous material is disclosed. The process involves the use of promoting amounts of certain metal redox couples and/or metal components, in particular, certain metal complexes with ligands.Preferred metal compositions comprise at least one of (1) redox cyclable vanadium (5+) ligand complex, (2) redox cyclable iron (3+) ligand complex, and (3) redox cyclable manganese (3+) ligand complex. In the process, the use of at least one regenerable component capable of maintaining the complexed metal in the desired oxidation state provides for integrated process synergy.

Abstract: A process for recovering at least one precious metal from an ore containing carbonaceous material is disclosed. The process involves the use of promoting amounts of certain metal redox couples and/or metal components, in particular, certain metal complexes with ligands.Preferred metal compositions comprise at least one of (1) redox cyclable vanadium (5+) ligand complex, (2) redox cyclable iron (3+) ligand complex, and (3) redox cyclable manganese (3+) ligand complex. In the process, the use of at least one regenerable component capable of maintaining the complexed metal in the desired oxidation state provides for integrated process synergy.

Abstract: Refractory sulfidic silver ore which is not amenable to cyanide leaching is formed into an aqueous slurry and oxidized at elevated temperature, usually about 150.degree. to 250.degree. C., in the presence of an oxidizing agent, usually oxygen, and in the presence of about 30 to about 160 g/L zinc. Zinc present in the above range results in increased extractability of silver from the oxidized residue by cyanide leaching.

Abstract: Disclosed is a process for recovering precious metals using a combination of smelting and an effective utilization of molten salt chlorination. More specifically, disclosed is a process including the steps of (i) contacting, for example, a matte with a chloride salt containing at least one of potassium, cesium or rubidium, but not sodium or lithium to form a matte/salt solids mixture, (ii) introducing the solids mixture into a chloride melt having a temperature ranging from 300.degree. C. to 650.degree. C., said melt containing at least one of potassium, cesium, rubidium, sodium or lithium, (iii) introducing a chlorine containing gas into the melt, and (iv) maintaining the salt ratio in the matte/salt mixture at a stoichiometrically equivalent amount with the precious metals and base metals contained in the matte.

Abstract: A hydrometallurgical process is described for recovery of a precious metals from ores refractory to treatment by lixiviating agents by crushing the ore to no finer than a nominal 1/4 inch size, acidifying the ore with a mineral acid, treating the ore to a preliminary oxidation with nitric acid, optionally adding a binder to the oxidized ore, heap treating the ore with nitric acid to complete oxidation of the ore, water washing the heaped ore, optionally increasing the alkalinity of the heaped ore, heap treating the ore with a lixiviating solution and recovering precious metals from the lixiviating solution. The process recovers NO.sub.x gases generated during the preliminary oxidation and binder addition stage for conversion into nitric acid which is recycled for treating ore. Chemical treatments in the process can be carried out at ambient temperatures and atmospheric pressures.

Abstract: A process for separating precious metals from an MnO.sub.2, sulfidic or carbonaceous refractory ore or refractory feed such as tailings is provided. The process includes the step of leaching a feed with a leach liquor that includes an acid selected from the group of HCl and H.sub.2 SO.sub.4 in the presence of MnO.sub.2 and a reductant. A source of chloride ion is added to the leach sufficient to dissolve at least about 50% of the precious metals present in the ore. A portion of the leach is removed and precious metals are recovered from the removed portion. A portion of the chloride carrier is recycled to the leach to carry chloride values to the leach. In one embodiment, HCl is regenerated by pyrohydrolysis, which minimizes harmful waste products. The present process can advantageously avoid the use of noxious reagents.

Abstract: In the recovery of noble metals, including gold, silver and members of the platinum group, the ores or tailings are subjected to the action of various leaching agents, namely, sodium cyanide, thiourea, chlorine and aqua regia and optionally a leaching aid, such as chloride ions. The resulting slurry is then diluted to an optimum pulp density of 0.1 to 10.0% and allowed to stand in a holding tank for periods up to 30 minutes, preferably 15 minutes, with the optional addition of a dispersant, such as sodium silicate, sodium carbonate, trisodium polyphosphate or sodium hexametaphosphate. The pulp is then centrifuged to remove solids if necessary and is then passed at a pH <9 through a column containing activated carbon or ion exchange resin/fibre to adsorb any precious metal in solution in the liquor. This is followed by desorption and the cycle repeated as often as warranted by the economics of the process.

Abstract: The invention relates to a method of extracting gold from a gold-containing material. The invention provides a process of extracting precious metals from a precious metal-containing material comprising mixing the material in a finely-divided state with an alkaline cyanide solution to form a mixture and recovering the metal from solution by known methods characterized in that said process is carried out in the presence of peroxymonosulfuric acid or salt thereof and, where necessary, adding oxygen or a source thereof to said mixture to provide a dissolved oxygen level of at least about 6 ppm.In a preferred embodiment the process is used in conjunction with a carbon-in-pulp plant. In the preferred process ore slurry 2 is passed through a valve means 3a to a wood screen 5 via line 4a. The slurry is separated from waste wood splinters 5a under gravity to a reservoir 6 where it is combined with an alkaline cyanide solution 7 introduced via line 4b and metering pump 8a.

Abstract: Rhodium is recovered from an aqueous precious metal solution by first contacting the solution with stannous chloride at a Sn:Rh molar ratio of at least 2:1 to produce activated Rh solution; solvent extracting rhodium from the activated solution with an organic extractant to produce an organic phase containing Rh; the Rh can be recovered from the organic phases by burning-off the organic, precipitating Rh by reduction or stripping with a stripping agent and recovering Rh from an Rh-loaded stripping agent; the method produces high yields of Rh in short periods as compared with time consuming prior procedures.

Abstract: An improved process for recovery of precious metals such as gold or silver using novel ion exchange resins having aryl guanidyl functionality from aryl guanidine compounds having a pKa at 25.degree. C. less than 13 and preferably less than 12. The resins have improved elution properties compared to known guanidine reagents using caustic eluant solutions, particularly improved eluant solutions such as a mixture of sodium hydroxide and sodium benzoate.

Abstract: A variety of processes for recovering gold from gold ore are disclosed. Briefly, the methods include culturing at least one microorganism species capable of producing cyanide ion under conditions wherein the microorganism produces cyanide ion, thus forming a cyanide ion-containing culture; contacting the cyanide ion-containing culture with gold ore, causing production of gold ion-cyanide ion complexes and biosorption of said complexes to said cultures; and recovering gold from the culture. The invention may be practiced with a variety of microorganisms, including Chromobacterium violaceum and Chlorella vulgaris.

Abstract: A method for recovering platinum group metals from a catalyst material comprises leaching the material with a cyanide solution at a temperature greater than about 100.degree. C. to form soluble platinum group metal-cyanide complexes in solution. Solids are removed from the resulting pregnant leach solution, and the pregnant leach solution is then heated to a temperature sufficient to decompose the platinum group metal-cyanide complexes and precipitate the platinum group metals.

Abstract: A variety of processes for recovering gold from gold ore are disclosed. Briefly, the methods include culturing at least one microorganism species capable of producing cyanide ion under conditions wherein the microorganism produces cyanide ion, thus forming a cyanide ion-containing culture; contacting the cyanide ion-containing culture with gold ore, causing production of gold ion-cyanide ion complexes and biosorption of said complexes to said cultures; and recovering gold from the culture. The invention may be practiced with a variety of microorganisms, including Chromobacterium violcaceum and Chlorella vulgaris.

Abstract: Geothermal brine is passed through a zone containing a packing metal so as to reduce its tendency to deposit iron/silica scale, reduce corrosivity of the brine, and/or remove and recover metals from the brine. The method polished the geothermal brine by contacting the brine with a packing metal higher in the electromotive series than silver for a time sufficient for a precious metals to precipitate onto the packing at brine temperature and pH conditions which inhibit iron-rich silica scale. Most preferably, the contacting is accomplished near an injection well at the end of a heat extraction process and the packing comprises coiled zinc-galvanized steel chicken wire mesh packed in a sufficient density to also act as a filter for suspended particles. Alternatively, contacting is also accomplished near the production well. Dissolving the packing in a suitable acid leaves a precious metal-rich residue behind for subsequent recovery.

Abstract: A cylindrical tank (12) is formed from stainless steel plates. Proximate an open top end (17) of the tank (12) are four evenly spaced mixing assemblies (20). An intake pipe (22) is positioned with an open end (38) below the surface of a biological conversion medium (16) to allow a pump (28) to draw the medium (16) into a receiving box (24). A downcomer (26) merges with the receiving box (24) in order to allow the medium (16) to be injected with a biological conversion component such as air through an inlet pipe (34). The medium (16) and the injected component then pass through a static in-line mixer (30) which thoroughly mixes the medium (16) with the component and creates a multitude of finely-divided air bubbles for circulation and feeding of the medium (16) throughout the tank (12).

Abstract: Aqueous iodine-iodide etching solutions are employed in the recovery of precious metals. Elemental iodine is precipitated from spent etching solutions and used to supply both the iodine and iodide of new etching solutions. Prior to extraction of the elemental iodine, used solutions, if not substantially contaminated, may be oxidized and recycled for further precious metal recovery. Aqueous etching solutions of hydriodic acid and iodine, or of ammonium iodide and iodine may be employed. Etching in such solutions, as well as in solutions of iodine and an alkali metal iodide, such as potassium iodide, may be accelerated by the use of small amounts of hydrogen peroxide (or equivalents) during etching.

Abstract: Gold and silver are extracted from their elemental state or from complex ores and alloys by leaching them with a solution containing ammonia, ammonium salts and one or more oxidants. The process is particularly effective for refractory gold ores including sulfide and carbonaceous ores.

Abstract: Agglomerating agent and method for use in heap leaching of mineral bearing ores. A moderate to high molecular weight anionic polymer in combination with lime provides a highly effective agglomerating agent. The anionic polymer is preferably a copolymer of acrylamide and acrylic acid. The polymer preferably has a molecular weight of from about 1 to 8 million or higher.

Abstract: Agglomerating agent and method for use in heap leaching of mineral bearing ores. A moderate to high molecular weight anionic polymer either alone or in combination with cement provides a highly effective agglomerating agent. The anionic polymer is preferably a copolymer of acrylamide and acrylic acid. The polymer preferably has a molecular weight of from about 1 to 8 million or higher.

Abstract: Agglomerating agent and method for use in heap leaching of mineral bearing ores. A moderate to high molecular weight anionic polymer either alone or in combination with cement provides a highly effective agglomerating agent. The anionic polymer is preferably a copolymer of acrylamide and acrylic acid. The polymer preferably has a molecular weight of from about 1 to 8 million or higher.

Abstract: The present invention is directed to an improvement in a process for the recovery of gold from refractory sulfidic auriferous ores which comprises oxidizing a slurry of ore with oxygen gas under pressure in the presence of sulfuric acid, neutralizing the oxidized slurry, cyanidizing the neutralized slurry to leach gold therefrom, and recovering gold from the resultant leachate. In accordance with the improved process, the oxidation of the ore slurry is carried out in a manner whereby, after a startup phase during which oxidation is initiated, the amount of sulfuric acid added to the ore slurry is sufficient to insure the oxidation of that portion of the sulfide sulfur in the ore which will allow recovery, by cyanide leaching, of at least about 80% of the gold in the ore. The oxidized slurry can be neutralized without a washing operation.

Abstract: A method for recovering silver from a refractory manganese dioxide-silver ore. The ore is contacted with an effective amount of a culture of direct manganese-reducing Bacillus polymyxa bacteria. The ore-bacteria mixture is maintained at an approximately neutral pH until a sufficient amount of the manganese dioxide in the ore is reduced from Mn(IV) to Mn(II). The silver present in the ore is then recovered by conventional methods such as cyanide leaching.

Abstract: There is disclosed a process for recovering gold and silver values from ore using activated carbon for adsorbing the values, wherein the activated carbon is treated with a suitable oxidant having an oxidation potential higher than that of oxygen. A preferred oxidant is potassium permanganate. Activated carbon so treated has an enhanced affinity for adsorbing silver, even under conditions which traditionally have favored loading of carbon with gold.

Abstract: There is disclosed an activated carbon for use in the process of recovery of gold which comprises adsorbing aurocyanide complexes thereon, desorbing the complexews therefrom and separating the activated carbon with a screen, the activated carbon being spherical and having a diameter of more than the opening of the screen but of not more than 2 mm; an iodine number of not less than 950 mg/g as determined by JIS K 1474-1975; and a hardness of not less than 99% as determined by JIS K 1474-1975.Also disclosed is an improved, high efficient process of the recovery of gold which uses such a spherical activated carbon.

Abstract: A process for recovering gold from a refractory sulfidic ore which has been suspended in an aqueous slurry and oxidized using nitric acid so that substantially all of the gold in the ore is made available for recovery and at least a portion of the sulfidic components present during the oxidation are oxidized to elemental sulfur, comprises bubbling air as a discontinuous phase upwardly through the oxidized slurry, thereby creating a froth containing elemental gold and sulfur. The froth is separated from the slurry to provide a concentrate, and the gold is recovered from the concentrate.

Abstract: Precious metal values, particularly gold and silver, are liberated from refractory, carbonate ores by adjusting the molar ratio of sulfide to total acid consumers to between about 1.2 and about 3.2 in the ore feed to a pressure oxidation process. The ore is contacted with oxygen to oxidize sulfide in the ore with at least about 65 percent of the sulfide oxidation occurring in a first oxidation zone at a temperature above about 360.degree. F. The oxidation of sulfide forms at least about 5 grams of free sulfuric acid in the first oxidation zone. The oxidation process is continued in subsequent oxidation zones. A gas stream is removed from the oxidation zones and oxygen is separated from carbon dioxide and other inerts in the gas stream and the purified oxygen is recycled to the oxidation zones.

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.

Abstract: Noble metals, particularly gold, are recovered from ores by a leaching process in which a slurry of ground ore containing an oxidant and a lixiviant for dissolving the noble metal is subjected to an alternating electric field which accelerates and promotes the dissolution of the noble metal.

Abstract: Carbonaceous ore containing a precious metal (gold) is treated with an aqueous solution of chlorine dioxide to enhance the recovery of the precious metal.

Abstract: The present invention involves the isolation or leaching of noble metals from materials containing noble metals, e.g. ores, by treating the noble metal- containing materials with a cyclic thiourea derivative under acid pH conditions. Removal is effected by adsorption onto charcoal or by an ion exchanger, for example. Preferred cyclic thioureas are N,N'-ethylenethiourea and N,N'-propylenethiourea and the acid pH conditions may be achieved by sulfuric acid or hydrochloric acid solutions containing 0.01 to 2.0% by weight of the cyclic thiourea.