Abstract: This invention relates to a method for producing geothermal power using geothermal brines while producing a reduced silica and iron brine having improved injectivity. The resulting compositions include a composition with reduced silica, iron, and lithium having reduced quantity of total suspended solids.

Abstract: The present disclosure relates to techniques for extracting heat energy from geothermal briny fluid. A briny fluid can be extracted from a geothermal production well and delivered to a heat exchanger. The heat exchanger can receive the briny fluid and transfer heat energy from the briny fluid to a molten salt. The molten salt can be pumped to a molten salt storage tank that can serve as energy storage. The briny fluid can be returned to a geothermal source via the production well. The briny fluid can remain in a closed-loop system, apart from the molten salt, from extraction through return to the geothermal production well.

Abstract: The present disclosure relates to methods of treating water to remove contaminants, including harmful metal ions, and water treatment plants for practicing such methods. In an embodiment, the process includes adding a sulfur-containing, metal-decreasing agent; an iron (III)-containing, metalloid-decreasing agent; forming a solid precipitate from the contaminated water, wherein the solid precipitate includes a solid metal sulfide, a solid iron metalloid, a solid calcium metalloid, or a combination thereof; and separating the contaminated water from the solid precipitate to form purified water.

Abstract: A method of extracting metals from polymetallic sulphide ores or concentrates comprising at least Cu, Zn, Pb and Ag, comprising a first step of atmospheric leaching in sulphate medium in the presence of recycled silver for extracting Cu and Zn and a second step of atmospheric leaching in chloride medium for extracting Pb and Ag.

Abstract: A method of producing a kesterite material of CZTS, CZTSe or CZTSSe type, including the steps of: a) preparing an acidic solution by dissolving copper and zinc salts in water in desired molar ratio, b) preparing a basic solution by dissolving an alkali metal stannate together with an alkali metal carbonate or an alkali metal hydrogen carbonate or an alkali metal hydroxide or a combination thereof, and optionally with an alkali metal selenate or an alkali metal selenite or a mixture thereof, c) carrying out a precipitation reaction by mixing the acidic and the basic solution, d) drying the precipitate thereby providing a precursor for the kesterite material, and e) sulfurizing the precursor of step d to provide the kesterite material. Also, a precursor for a kesterite material of CZTS, CZTSe or CZTSSe type.

Abstract: A method of recovering iron from a zinc sulfate solution according to an embodiment of the present disclosure is associated with recovering iron from a zinc sulfate solution produced by a leaching process in which zinc ore is dissolved in sulfuric acid. The method comprises a conditioning process including a step of reducing a conditioning process input solution, which is the zinc sulfate solution, and an iron precipitation process for recovering iron as hematite, including a step of pressurizing and oxidizing an iron precipitation process input solution discharged from the conditioning process. The iron precipitation process is performed at a temperature ranging from 135° C. to 150° C. and a pressure ranging from 5 barg to 10 barg.

Abstract: A method of improving leach kinetics and recovery during atmospheric or above-atmospheric leaching of a metal sulfide is disclosed. A system for practicing the aforementioned method is also disclosed. Apparatus for practicing the aforementioned method is also disclosed. A new composition of matter which is formed by the aforementioned method, and which may be utilized in the system and apparatus is further disclosed. The new composition of matter may exhibit improved leach kinetics, and may have some utility in the semi-conductor arts, including uses within photovoltaic materials.

Abstract: A methyl iodide adsorber, comprising a zeolite containing at least one iodide-adsorbing metal or a compound thereof, wherein the zeolite is a hydrophobic zeolite. Also, a use of the adsorber and a method for the adsorption of methyl iodide.

Abstract: There is provided a method for capturing a line after an elapse of a predetermined time, in a case where the line has been disconnected caused by an occurrence of a specific event in which a heavy load signal is input to an input side connecting the line. The control method for controlling a communication apparatus configured to perform a data communication via a line, includes detecting a signal on the line, disconnecting the line based on a level of the detected signal, and capturing the line based on an elapse of a predetermined time after the line has been disconnected.

Abstract: At the beginning of a dezincification plant used in a dezincification step in a hydrometallurgical method for nickel, a decrease throughout the dezincification plant is controlled to prevent a decrease in production volume and a cake layer is formed on a filter cloth provided to a filter device inside the dezincification plant. At the beginning of dezincification plant, a slurry containing a formed zinc sulfide is supplied to a filter for filtration and separation, an adjustment is performed in which the flow rate of the slurry is increased to reach a target flow rate in a time T2 which satisfies the following relational expression 3×T1?T2?5×T1, where T1 represents the time between starting a slurry supply and attaining the target flow rate in the case of transferring the slurry at the maximum liquid transfer capacity of a pump configured to transfer the slurry.

Abstract: The present invention relates to a method for preparing basic zinc chloride, comprising the following steps: A: preparing raw materials: preparing zinc chloride solution, ammonia water and an induction system; B: performing synthesis: adding the zinc chloride solution and the ammonia water into the induction system in a parallel flow manner, and controlling the temperature to be 60.0-90.0° C.; after the feeding is finished, continuing to react for 20.0-40.0 minutes; and C: performing filtration, washing and drying: after filtering and washing the synthesized basic zinc chloride, drying the basic zinc chloride for 4.0-8.0 hours at 80-105° C. to obtain the basic zinc chloride product. Compared with the prior art, the method for preparing basic zinc chloride has such advantages as simple process, low impurity content, easy-to-control product quality, and suitability for industrialization.

Abstract: A method of precipitating a zinc containing solid from an acidic solution containing dissolved zinc and magnesium comprising contacting the solution with a calcium containing neutralizing agent to raise the pH of the solution to 4.5 to 7.5 at a temperature of from 70 to 95° C. to thereby precipitate a solid zinc containing material and gypsum without causing substantial precipitation of magnesium, and separating the zinc containing material from the gypsum.

Abstract: Zinc and lead are usually concomitantly present in Zn—Pb ores and tailings. A novel non-polluting hydrometallurgical process for selectively leaching and recovering zinc (Zn) from a composite lead (Pb) and zinc sulphide containing mineral, crushed untreated rock or unconsolidated mineral particles, mill tailings and/or agglomerated or unagglomerated sulphidic zinc containing waste material without necessitating smelting and refining operation has been developed. A combination of selected oxidant and alkali metal hydroxide has been found effective. A leachant consisting of e.g. a mixture of sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) is employed to selectively dissolve zinc sulphide at high pH at standard temperature and pressure (STP). The kinetics of leaching along with the effect of varying concentration (preferably of sodium hydroxide and sodium hypochlorite) were systematically investigated. Feed ore containing diverse set of minerals e.g.

Abstract: Various embodiments provide a process roasting a metal bearing material under oxidizing conditions to produce an oxidized metal bearing material, roasting the oxidized metal bearing material under reducing conditions to produce a roasted metal bearing material, leaching the roasted metal hearing material in a basic medium to yield a pregnant leach solution, conditioning the pregnant leach solution to thrill a preprocessed metal bearing material; and leaching the preprocessed metal bearing material in acid medium.

Abstract: High purity MnO and zinc oxide may be efficiently recovered from alkaline and/or carbon zinc batteries using a process involving the treatment of the crushed batteries with an alkali hydroxide to produce insoluble manganese oxides and an alkali zincate solution. Zinc oxide is obtained by reacting the zinc solution with carbon dioxide or an acid such as a mineral acid and furnacing. The manganese oxides are converted to MnO by furnacing under an inert atmosphere.

Abstract: In an embodiment, the present invention relates to an apparatus and a process for producing a concentrated form of basic zinc sulphate from a, typically dilute, acidic zinc sulphate-bearing solution. The process embodiment comprises the steps of precipitating the zinc, preferably primarily as basic zinc sulphate, from the acidic zinc sulphate solution, preferably using calcium oxide, in such a way as to promote the formation of separate gypsum crystals and basic zinc sulphate particles, and upgrading the zinc content in the precipitates by separating the basic zinc sulphate from the gypsum using size separation techniques.

Abstract: A method for separating nickel, cobalt and a rare earth element from a material containing positive and negative electrode active materials of a nickel-metal hydride battery includes mixing a material containing positive and negative electrode active materials with a sulfuric acid solution and dissolving therein, and then separating a leachate from a residue; adding an alkali metal sulfate to the leachate to obtain a mixed precipitate of double sulfate of rare earth elements, and a rare-earth-element-free solution; and adding a sulfurizing agent to the rare-earth-element-free solution to separate a nickel and cobalt sulfide raw material and a residual solution.

Abstract: A process for treating a mixed sulphidic material containing lead sulphide and at least one other metal sulphide. The process includes the steps of subjecting the mixed sulphidic material to selective oxidation such that lead sulphide in the material is oxidised to form an oxidised lead compound while substantial oxidation of the at least one other metal sulphide is avoided, and separating the oxidized lead compound from the at least one other metal sulphide. The oxidized lead compound may be separated by flotation wherein the oxidized lead compound reports to the tailings and the at least one other metal sulphide reports to the concentrate (froth).

Abstract: A process for recovering zinc from a zinc containing material, the process including the steps of: leaching the zinc containing material with an alkaline lixiviant comprising an aqueous mixture of NH3 and NH4Cl, or ionic equivalent, having a NH4Cl concentration of between about 10 g/L and about 150 g/L H2O and a NH3 concentration of between 20 g/l H2O and 250 g/L H2O, to produce a zinc containing leachate; stripping ammonia from the leachate to produce a stripped liquor which includes a zinc containing precipitate, the stripped liquor having a NH3 concentration of between 7 and 30 g/L H2O; and recovering the zinc from the stripped liquor.

Abstract: Zinc, nickel and iron can be recovered from spent brines and produced water using a method that includes admixing an aqueous fluid with hydrazine to form a hydrazine complex and then filtering or otherwise removing the hydrazine complex from the aqueous fluid. Once treated, the aqueous fluid can then be recycled or at be the subject to an easier disposal. The isolated metal hydrazine complex may be recycled or discarded.

Abstract: A method for selectively processing a polymetallic oxide solution containing a plurality of base metals comprising at least one of: Cu, Co, Ni, Zn associated with iron, comprising acid leaching the solution; recovering a filtered leachate; oxidizing the leachate; and adjusting the pH of the leachate in presence of a complexing agent; wherein the acidic solution is one of: i) a hydrochloric acid solution and ii) a sulfuric acid solution at a pH lower than about 1.5, and the complexing agent is one of: i) ammonium chloride and ii) ammonium sulfate, the step of adjusting the pH comprising raising the pH to a range between about 2.5 and about 3.5.

Abstract: A method of precipitating a zinc containing solid from an acidic solution containing dissolved zinc and magnesium comprising contacting the solution with a calcium containing neutralising agent to raise the pH of the solution to 4.5 to 7.5 at a temperature of from 70 to 95° C. to thereby precipitate a solid zinc containing material and gypsum without causing substantial precipitation of magnesium, and separating the zinc containing material from the gypsum.

Abstract: A method of production of activated carbon for removal of mercury gas which provides activated carbon impregnated with both sulfur and iodine which gives a higher mercury gas adsorption performance compared with a conventional activated carbon adsorbent and also enables the prime cost of manufacture to be kept down, that is, a method of production provided with a sulfur impregnation step which adds sulfur to activated carbon and heats the mixture to obtain sulfur-impregnated activated carbon comprised of activated carbon to 100 parts by weight of which sulfur is impregnated in 5 to 20 parts by weight and, after the sulfur impregnation step, an iodine substance impregnation step which adds an aqueous solution containing iodine and an iodine salt to the sulfur-impregnated activated carbon.

Abstract: A topical formulation for application to exposed body tissue, the formulation comprising a silver(II) oxide and zinc oxide, intimately dispersed within a carrier medium.

Abstract: Method of separating recoverable material from products containing mercury. The method including crushing products to form crushed material, mixing crushed material with a liquid which has an oxidizing agent which has been chosen from a group which sodium hypochlorite, hydrogen peroxide and chlorates, oxidizing at least a portion of metallic mercury in the products for forming mercury oxide under influence of oxidizing agent. The method further includes separating a sludge, which sludge having formed mercury oxide, from at least a portion of the liquid.

Abstract: A process for separating zinc from a feedstock containing a mixture of metals and metal compounds. The process includes leaching a zinc-containing feedstock with a concentrated basic solution, optionally diluting the slurry with an amount of water sufficient to reduce the viscosity of the slurry thereby facilitating separation of a pregnant liquor containing dissolved zinc from insoluble materials, separating the insoluble materials from the pregnant liquor, and precipitating zinc oxide from the pregnant liquor by adding an anti-solvent to the pregnant liquor. The described process also provides for recycling of the basic solution and the anti-solvent.

Abstract: Zinc and lead are usually concomitantly present in Zn—Pb ores and tailings. A novel non-polluting hydrometallurgical process for selectively leaching and recovering zinc (Zn) from a composite lead (Pb) and zinc sulphide containing mineral, crushed untreated rock or unconsolidated mineral particles, mill tailings and/or agglomerated or unagglomerated sulphidic zinc containing waste material without necessitating smelting and refining operation has been developed. A combination of selected oxidant and alkali metal hydroxide has been found effective. A leachant consisting of e.g. a mixture of sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) is employed to selectively dissolve zinc sulphide at high pH at standard temperature and pressure (STP). The kinetics of leaching along with the effect of varying concentration (preferably of sodium hydroxide and sodium hypochlorite) were systematically investigated. Feed ore containing diverse set of minerals e.g.

Abstract: A process for separating zinc from a feedstock containing a mixture of metals and metal compounds. The process includes leaching a zinc-containing feedstock with a concentrated basic solution, optionally diluting the slurry with an amount of water sufficient to reduce the viscosity of the slurry thereby facilitating separation of a pregnant liquor containing dissolved zinc from insoluble materials, separating the insoluble materials from the pregnant liquor, and precipitating zinc oxide from the pregnant liquor by adding an anti-solvent to the pregnant liquor. The described process also provides for recycling of the basic solution and the anti-solvent.

Abstract: A hydrometallurgical process for a nickel oxide ore comprising obtaining an aqueous solution of crude nickel sulfate by high pressure acid leaching of a nickel oxide ore; obtaining a zinc free final solution by sulfurization of the solution; obtaining a waste solution; and scrubbing hydrogen sulfide gas from an exhaust gas. The process is characterized by at least one of the following operations: Adjusting the total volume (m3) of a sulfurization reactor to a ratio of 0.2-0.9 (m3/kg/h) relative to the input mass (kg/h) of the nickel to be introduced to the reactor; and/or subjecting the waste solution and the exhaust gas to countercurrent contact, then introducing the exhaust gas back to the scrubber and charging the waste solution from the scrubber into the sulfurization reactor.

Abstract: A method for recovering a metal, capable of recovering a metal easily without requiring the use of an organic medium, is provided. A complex between a chelating agent and a metal present in a sample is formed in a mixture prepared by mixing the chelating agent and the sample under pH conditions where the chelating agent can be insoluble in an aqueous medium. Then, the complex is recovered from the mixture, and further, the metal is recovered by dissolving the recovered complex in an aqueous medium under pH conditions that are different from the pH conditions where the chelating agent can be insoluble in an aqueous medium. By this method, a metal can be recovered easily without requiring the use of the use of an organic medium.

Abstract: A method for recovering a metal, capable of recovering a metal easily without requiring the use of an organic medium, is provided. A first complex between a first chelating agent and a metal present in a sample is formed in a first mixture prepared by mixing the first chelating agent and the sample. Then, the first complex is recovered from the first mixture, and a second complex between the metal derived from the first complex and a second chelating agent is formed in a second mixture prepared by mixing the first complex and an aqueous solution of the second chelating agent. The aqueous solution is under the pH conditions where the first chelating agent can be insoluble in the aqueous solution. Then, a liquid fraction containing the second complex is recovered from the second mixture. Thus, the metal can be recovered.

Abstract: A simple, room-temperature method of producing zinc oxide nanoparticles was established by reacting zinc nitrate hexahydrate and cyclohexylamine (CHA) in either aqueous or EtOHic medium. Particles of polyhedra morphology were obtained for zinc oxide, prepared in EtOH (ZnOE), while an irregular spherical morphology, mixed with some chunky particles forzinc oxide prepared in water (ZnOW). The results indicate that there are significant morphological differences between ZnOE and ZnOW. ZnOE showed a regular polyhedral shape, while spherical and chunky particles were observed for ZnOW. The morphology was crucial in enhancing the cyanide ion photocatalytic degradation efficiency of ZnOE by a factor of 1.5 in comparison to the efficiency of ZnOW at equivalent loading of 0.02 ZnO nanoparticles wt %. Increasing the loading wt % of ZnOE from 0.01 to 0.07 led to an increase in the photocatalytic degradation efficiency from 67% to 90% after 45 minutes and a doubling of the first-order rate constant (k).

Abstract: Method of separating recoverable material from products containing mercury. The method including crushing products to form crushed material, mixing crushed material with a liquid which has an oxidizing agent which has been chosen from a group which sodium hypochlorite, hydrogen peroxide and chlorates, oxidizing at least a portion of metallic mercury in the products for forming mercury oxide under influence of oxidizing agent. The method further includes separating a sludge, which sludge having formed mercury oxide, from at least a portion of the liquid.

Abstract: A ZnO varistor powder can be obtained with high operating voltage and excellent current-voltage nonlinear resistance characteristics. In the ZnO varistor powder, the main ingredient is zinc oxide (ZnO); and at least bismuth (Bi), cobalt (Co), manganese (Mn), antimony (Sb), nickel (Ni), and aluminum (Al), calculated as Bi2O3, CO2O3, MnO, Sb2O3, NiO, and Al3+, are contained as accessory ingredients in amounts of 0.3 to 1.5 mol % Bi2O3, 0.3 to 2.0 mol % Co2O3, 0.3 to 3 mol % MnO, 0.5 to 4 mol % Sb2O3, 0.5 to 4 mol % NiO, and 0.0005 to 0.02 mol % Al3+. ZnO content is greater than or equal to 90 mol %; the bulk density is greater than or equal to 2.5 g/cc; the powder is a spherical powder in which the 50% particle diameter in the particle size distribution is 20 ?m to 120 ?m.

Abstract: Uses for a composition comprising a polymer derived from at least two monomers: acrylic-x and an alkylamine, wherein said polymer is modified to contain a functional group capable of scavenging one or more compositions containing one or more metals are disclosed. These polymers have many uses in various mediums, including wastewater systems.

Abstract: Disclosed is a process for removing metals from waste, particularly electronic waste (or “e-waste”). The process generally includes the steps of dissolving at least some of the metals from the waste with nitric acid reagent and then causing at least some of the metals to precipitate as metal oxides and/or metal nitrates. NOx gases produced as by-product by the nitric acid dissolution of metallic components in the electronic waste are reused, in particular for generating permanganate when one of the metallic components comprises manganese.

Abstract: Cd-112 isotope is recycled from a Cd-112 chemical separated solution or a remainder of an electroplating solution having a Cd-112 target. The present invention recycles Cd-112 isotope with a low cost, a high purity and a high recycle rate. The recycled Cd-112 isotope can be easily stored. And, the Cd-112 isotope can be used as an imaging agent in nuclear medicine.

Abstract: A method for selective removal of cadmium from a feed solution also containing other metals such as nickel (Ni) and/or cobalt (Co), utilizing a thiourea based ion exchange resin, and a method for eluting cadmium adsorbed on the thiourea based resin.

Abstract: The separation method for zinc sulfide, in the hydrometallurgical process by a High Pressure Acid Leach for nickel oxide ore comprising leaching and solid/liquid separation step, neutralization step, zinc removal step, and nickel recovery step, which can inhibit clogging of a filter cloth and reduce a frequency of washing operation and replacement operation of a filter cloth by improving filtration performance of zinc sulfide, and inhibit decrease of nickel recovery ratio, in the zinc removal step in which zinc sulfide is formed by adding a sulfurizing agent to the neutralization final liquid containing zinc as well as nickel and cobalt and zinc sulfide is separated to obtain a mother liquid for nickel recovery containing nickel and cobalt. The separation method for zinc sulfide of the present invention is characterized in that in the above-described neutralization step, the leach residue is added to the leach liquor, and pH of the neutralization final liquid is adjusted so as to fall to the range from 3.

Abstract: A process for the recovery of a metal sulfide from a metal ion containing solution, including the steps of: a) providing a slurry containing seed panicles of said metal sulfide; h) adding a sulfide ion containing solution to said slurry to form an activated seed slurry; c) mixing said activated seed slurry with said metal ion containing solution to thereby form a metal sulfide precipitate; and d) recovering said metal sulfide precipitate.

Abstract: Method for producing hydrometallurgical zinc oxide powder having characteristics equivalent to that derived from a French process, comprising formation of an aqueous pulp from a starting zinc oxide having particles of nodular structure, wet milling of this aqueous pulp, separation in this milled pulp between a liquid phase and a solid phase containing the zinc oxide, and drying of said solid phase, coupled with a mechanical deagglomeration of the particles during drying, to obtain a dry zinc oxide powder with particles of nodular structure having a particle size distribution where the particles have an average size (d50) between 0.02 and 20 ?m.

Abstract: A cadmium sulfide nanocrystal, wherein the cadmium sulfide nanocrystal shows maximum luminescence peaks at two or more wavelengths and most of the atoms constituting the nanocrystal are present at the surface of the nanocrystal to form defects.

Abstract: A semiconductor nanocrystal, wherein the semiconductor nanocrystal shows maximum luminescence peaks at two or more wavelengths and most of the atoms constituting the nanocrystal are present at the surface of the nanocrystal to form defects.

Abstract: The invention relates to a highly reactive zinc form, to a method for the production thereof, and to the use of said highly reactive zinc form in synthetic chemistry.

Abstract: The present invention is a method of recovering valuable metals from a quantity of furnace dust consisting the following steps. A first leaching step wherein the furnace dust is leached at atmospheric pressure in a first leaching solution to produce a first leach liquor and a first leach residue, the first leaching solution consisting of an aqueous mineral acid solution. The first leach liquor is then separated from the first leach residue. A second leaching step is then performed wherein the first leach residue is atmospherically leached in a second leaching solution to form a second leach liquor and a second leach residue, the second leaching solution comprising a solution of aqueous HCl with a reductant. The second leach liquor is then separated from the second leach residue.

Abstract: The separation method for zinc sulfide, in the hydrometallurgical process by a High Pressure Acid Leach for nickel oxide ore comprising leaching and solid/liquid separation step, neutralization step, zinc removal step, and nickel recovery step, which can inhibit clogging of a filter cloth and reduce a frequency of washing operation and replacement operation of a filter cloth by improving filtration performance of zinc sulfide, and inhibit decrease of nickel recovery ratio, in the zinc removal step in which zinc sulfide is formed by adding a sulfurizing agent to the neutralization final liquid containing zinc as well as nickel and cobalt and zinc sulfide is separated to obtain a mother liquid for nickel recovery containing nickel and cobalt. The separation method for zinc sulfide of the present invention is characterized in that in the above-described neutralization step, the leach residue is added to the leach liquor, and pH of the neutralization final liquid is adjusted so as to fall to the range from 3.

Abstract: A cadmium sulfide nanocrystal, wherein the cadmium sulfide nanocrystal shows maximum luminescence peaks at two or more wavelengths and most of the atoms constituting the nanocrystal are present at the surface of the nanocrystal to form defects.

Abstract: A process for reclaiming spent selenium filter mass containing an inert material. The spent mass is treated with a hydrogen peroxide solution for leaching out selenium content from unspent active substance present in the filter mass to form selenious acid. The filter mass is treated with aqua regia solution to dissolve mercury selenide present in the mass. The aqua regia solution is separated from the mass and isolated. Suitably, the filter mass, which now contains inert carrier material, is transferred with the isolated selenious acid, to production of new selenium filter mass. After partial neutralization of the aqua regia solution, mercury is precipitated out for disposal. Before this, elemental selenium can be separated from the aqua regia solution by adjusting the pH level and used advantageously for production of new filter mass. Thusly, reclaimed selenium content and inert carrier material can be advantageously used for production of new selenium filters.

Abstract: Process for the stabilization of mercury metal by reaction of the mercury metal with sulphur in the solid state, in which the mercury and the sulphur are brought into contact, at an Hg/S molar ratio of 1/1 to 1/3, in a reactor integral with a hollow pipe in fluid communication with the interior space of the said reactor, the said hollow pipe comprising a first end connected to the wall of the said reactor and a second end distant from the said reactor; the said hollow pipe and the said reactor being hermetically sealed, the said hollow pipe being provided with rotating means external to the said pipe and to the said reactor for rotating the said reactor and the said pipe around the axis of the said pipe, and the said hollow pipe being provided, at its end distant from the reactor, with means for introducing the sulphur and the mercury inside the reactor and discharging the reaction products.

Abstract: A method for treating a polymetallic sulfide ore containing gold and/or silver, and further containing base metals selected from the group consisting of iron, aluminum, chromium, titanium, copper, zinc, lead, nickel, cobalt, mercury, tin, and mixtures thereof, is disclosed. The method comprises the steps of grinding the polymetallic sulfide ore to produce granules, oxidizing the granules to produce oxidized granules, and chloride leaching the granules using a brine solution including dissolved halogens, as well as chloride and bromide salts.