Methods and systems for activation of metal in metal ore for metal leaching

Abstract

Provided herein are sequential methods to activate metal in a metal ore for leaching by treatment with a first activation solution comprising nitrate ions, nitrite ions, or combination thereof and forming aggregates; and irrigating the aggregates with a second activation solution comprising one or more concentrated acids and causing volumetric expansion in the metal ore to form agglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases. Also provided herein are systems comprising multi-chamber agglomeration device configured to sequentially activate the metal in the metal ore and capture and process the NOx gases.

Description

METHODS AND SYSTEMS FOR ACTIVATION OF METAL IN METAL ORE FOR METAL LEACHINGRELATED APPLICATION DATA

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 733,514 filed December 13, 2024, entitled “Methods and systems for activation of metal in metal ore for metal leaching”, which is incorporated herein by reference.FIELD OF THE INVENTION

[0002] The present invention relates to a hydrometallurgical process and system for activation of metal in a metal ore for enhancement in leaching of the metal from the metal ore.BACKGROUND OF THE INVENTION

[0003] Leaching, followed by solvent-extraction and electrowinning, may be the primary hydrometallurgical process for recovering desired metals from metal-containing ores. The process may entail crushing the ore to a uniform particle size, agglomerating the crushed ore, and subsequently stacking the agglomerated ore on large leach pads where the ore may be subjected to leaching. However, due to ore composition, leaching processes may face significant challenges in achieving efficient metal extraction from the ores.

[0004] For example, conventional copper leaching comprises extraction of copper from oxide ores and certain sulfide ores composed of a mixture of secondary sulfides and oxides ores. However, most copper oxide ore deposits have now been depleted and there has been a concurrent increase in the discovery of low-grade copper deposits, such as chalcopyrite (Cpy). Cpy may be one of the most abundant copper ore worldwide, accounting for about 70% of the world’s total copper reserves, but it is a refractory mineral that is highly stable in acid systems resulting in slow dissolution rates and low levels of copper extraction by traditional hydrometallurgical processes. Thus, Cpy at present is typically processed using pyro- metallurgical techniques to extract copper from its concentrates. The process requires large inputs of water and energy. In recent decades, new projects for building concentrators have been challenged due to negative environmental impact and high capital requirements.

[0005] Several strategies have been proposed to address the refractory nature of metal sulfide ores. Some of those strategies are focused on the pretreatment of these ores in anagglomeration step, while others leverage the incorporation of nitrate and / or nitrite ions as, either at the agglomeration stage or during leaching .

[0006] US. Patent No. 10,544,480 describes an agglomeration device and its method of operation, mainly suited for chloride leaching processes, which are known for being corrosive and requiring significant CAPEX investments.

[0007] International Patent Publication No. WO2021186374 discloses a multi-stage method whose agglomeration step relies on the effect of combining acid, nitrate or nitrite, and chloride. The use of high levels of chloride puts forward several challenges, such as corrosion and others.

[0008] US. Patent Publication No. 20230086259 describes a method and system for recovering metal whose agglomeration step relies on hydrogen peroxide, which presents significant handling risks, particularly at the concentration necessary to generate the required heat during its reaction with the mineral.

[0009] International Patent Publication No. WO2024057216 discloses a leaching process which may lead to the release of NOx, which can be harmful to the environment if the system is unable to fully capture it.

[0010] Hernandez et al. (2019) examines the impact which an agglomeration step performed under an acid-nitrate-chloride medium has on copper recovery through leaching. In the pretreatment assayed, nitrate and chloride are added in solid form. Implementing the addition of solids in the agglomeration stage presents significant challenges for industrial-scale operations.

[0011] Chilean patent No. 61 ,719 outlines a hydrometallurgical process for leaching copper minerals and other related materials, using a reactive mixture composed of nitrate ions, iron ions, sulfuric acid and oxidizing chlorine-base salts.

[0012] Provided herein are effective environmentally friendly and less capital-intensive methods and systems for activating the metals in the metal ores that facilitate efficient leaching of the metals from the metal ores. A unique sequential addition of the reagents employed in the methods and systems herein facilitates enhanced activation and conditioning of the metal ore for subsequent processing.SUMMARY OF THE INVENTION

[0013] In one aspect, there is provided a sequential method to activate metal in a metal ore for leaching, comprising treating a metal ore with a first activation solution comprising nitrate ions, nitrite ions, or combination thereof and forming aggregates, wherein theaggregates comprise metal ore and nitrate ions, nitrite ions, or combination thereof; and irrigating the aggregates with a second activation solution comprising one or more concentrated acids and causing a volumetric expansion in the metal ore to form agglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases, thereby sequentially activating the metal in the metal ore.

[0014] In some embodiments of the aforementioned aspect, the method comprises evenly distributing or embedding the first activation solution in the metal ore to form the aggregates. In some embodiments of the aforementioned aspect and embodiments, the even distribution or the embedding of the first activation solution results in an effective distribution of the volumetric expansion in the metal ore to activate the metal in the agglomerates. In some embodiments of the aforementioned aspect and embodiments, the volumetric expansion in the metal ore activates the metal and facilitates leaching of the metal from the metal ore. In some embodiments of the aforementioned aspect and embodiments, the method comprises causing gas release in the metal ore and the volumetric expansion after the irrigation of the aggregates with the second activation solution.

[0015] In some embodiments of the aforementioned aspect and embodiments, the method comprises causing effective impregnation or permeability from the surface of the metal ore to its inside by the volumetric expansion by the sequential treating and the irrigating steps.

[0016] In some embodiments of the aforementioned aspect and embodiments, the sequential treating and the irrigating steps enhances hydraulic conductivity by between about 2-20% compared to a non-sequential method.

[0017] In some embodiments of the aforementioned aspect and embodiments, the sequential method increases the leaching of the metal from the metal ore by between about 2-20% compared to a non-sequential method.

[0018] In some embodiments of the aforementioned aspect and embodiments, the first activation solution comprises nitrate ions, nitrite ions, or combination thereof at a concentration above about 50 g / L and below about 300 g / L. In some embodiments of the aforementioned aspect and embodiments, dose of the nitrate and / or the nitrite ions from the first activation solution onto the metal ore is in a range of between about 0.5 kg / ton ore - 30 kg / ton ore.

[0019] In some embodiments of the aforementioned aspect and embodiments, the first activation solution further comprises a redox modulating agent. In some embodiments ofthe aforementioned aspect and embodiments, the redox modulating agent is selected from the group consisting of an oxidant gas, highly oxidant reagent, iron-oxidizing microorganism, sulfur-oxidizing microorganism, ozone, oxygen, hydrogen peroxide, air, and a mixture thereof.

[0020] In some embodiments of the aforementioned aspect and embodiments, the second activation solution comprises one or more concentrated acids in a concentration above about 70 g / L. In some embodiments of the aforementioned aspect and embodiments, the dose of the one or more concentrated acids from the second activation solution onto the mineral ore is in a range of between about 1 kg / ton ore - 50 kg / ton ore.

[0021] In some embodiments of the aforementioned aspect and embodiments, the one or more concentrated acids are selected from the group consisting of sulfuric acid, nitric acid, and mixture thereof.

[0022] In some embodiments of the aforementioned aspect and embodiments, the concentration of the first activation solution and the second activation solution is in a ratio of between about 1 :1 to 1 :50.

[0023] In some embodiments of the aforementioned aspect and embodiments, the method further comprises capturing and separating the NOx gases from the agglomerates.

[0024] In some embodiments of the aforementioned aspect and embodiments, the first activation solution and / or the second activation solution further comprises chloride salt. In some embodiments of the aforementioned aspect and embodiments, the concentration of the chloride salts in the first and / or the second activation solutions is up to about 25 g / L. In some embodiments, the concentration of the chloride salt in the first and / or the second activation solution is up to about 20 g / L, or up to about 15 g / L, or up to about 10 g / L, or up to about 5 g / L. In some embodiments, the first and / or the second activation solution are substantially free of chloride salts.

[0025] In some embodiments of the aforementioned aspect and embodiments, the sequential method shortens the time for recovery of the metal from the metal ore and avoids significant NOx emissions from the metal ore heap during leaching.

[0026] In some embodiments of the aforementioned aspect and embodiments, the method further comprises conditioning the agglomerates with one or more conditioning agents selected from the group consisting of stabilizer, surfactant, sorbent, oxidizer, and mixtures thereof. In some embodiments of the aforementioned aspect and embodiments, the stabilizer is selected from the group consisting of calcium chloride, calcium carbonate, gypsum, polyacrylamide, polyaluminum chloride (PAC), sodium alginate, sodiumaluminate, aluminum sulfate, ferric chloride, starch, carboxymethyl cellulose, and mixtures thereof. In some embodiments of the aforementioned aspect and embodiments, the surfactant is selected from the group consisting of cetyltrimethylammonium bromide (CTAB), dodecyl trimethyl ammonium bromide (DTAB), sodium dodecyl sulfate (SDS), sodium oleate, oleic acid, polyethylene oxide 4000 (PEG), bio-surfactant, triethylene glycol (TEG), and mixtures thereof. In some embodiments of the aforementioned aspect and embodiments, the sorbent is zeolite, activated alumina, activated charcoal, silica gel, calcium chloride, charcoal sulfate, clay, carbon nanotubes, biochar, carbon fibers, graphene oxide, perlite, or mixture thereof. In some embodiments of the aforementioned aspect and embodiments, the oxidizer is one or more of an oxidant gas, highly oxidant reagent, iron-oxidizing microorganism, sulfur-oxidizing microorganism, or mixture thereof.

[0027] In some embodiments of the aforementioned aspect and embodiments, the sequential method further comprises, after the irrigating step and / or after the conditioning step, applying a nitrate / nitrite recovering solution to recover unreacted nitrate, nitrite, or mixture thereof. In some embodiments of the aforementioned aspect and embodiments, the method further comprises adding sea water during the activation and / or during the recovery step. In some embodiments of the aforementioned aspect and embodiments, the nitrate / nitrite recovering solution comprises iron ions. In some embodiments of the aforementioned aspect and embodiments, the nitrate / nitrite recovering solution comprise ferrous ions, ferric ions, or combination thereof. In some embodiments of the aforementioned aspect and embodiments, the nitrate / nitrite recovering solution comprises iron-containing raffinate and / or ferrous sulfate. In some embodiments of the aforementioned aspect and embodiments, concentration of the iron ions, e.g., ferrous ions in the nitrate / nitrite recovering solution is between about 5 g / L and 50 g / L.

[0028] In some embodiments of the aforementioned aspect and embodiments, the first activation solution, the second activating solution and the nitrate / nitrite recovering solution are irrigated or applied at a temperature of up to about 80°C.

[0029] In some embodiments of the aforementioned aspect and embodiments, the method further comprises subjecting the metal ore to shockwaves during, before, and / or after any of the steps.

[0030] In some embodiments of the aforementioned aspect and embodiments, the metal ore is of metal selected from the group consisting of gold, silver, platinum, copper, nickel, molybdenum, rhenium, tungsten, zirconium, and cobalt. In some embodiments of the aforementioned aspect and embodiments, the metal ore comprises copper ore. In someembodiments of the aforementioned aspect and embodiments, the metal ore comprises chalcopyrite.

[0031] In one aspect, there is provided a system to activate metal in a metal ore for leaching, comprising: a multi-chamber agglomeration device comprising a first chamber operably connected to an input for metal ore and a feeding inlet for a first activation solution comprising nitrate ions, nitrite ions, or combination thereof, and configured to embed the metal ore with the first activation solution to form aggregates, wherein the aggregates comprise metal ore and nitrate ions, nitrite ions, or combination thereof; and a second chamber operably connected to the first chamber and a feeding inlet for a second activation solution comprising one or more concentrated acids, and configured to mix the aggregates with the second activation solution and cause volumetric expansion in the aggregates to form agglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases.

[0032] In some embodiments of the aforementioned aspect, the multi-chamber agglomeration device is a drum, a tank, a large conduit, a column, or the like.

[0033] In some embodiments of the aforementioned aspect and embodiments, the first chamber and the second chamber are partially or fully separated from each other by a partition. In some embodiments of the aforementioned aspect and embodiments, the partition is a retractable door between the first chamber and the second chamber.

[0034] In some embodiments of the aforementioned aspect and embodiments, the multichamber agglomeration device further comprises a third chamber operably connected to the second chamber and a feeding inlet to feed one or more conditioning agents selected from the group consisting of stabilizer, surfactant, sorbent, oxidizer, or mixtures thereof, and configured to mix the agglomerates with the conditioning agent.

[0035] In some embodiments of the aforementioned aspect and embodiments, the multichamber agglomeration device further comprises an extraction pipe operably connected to the second chamber and optionally the third chamber and configured to capture and extract the NOx gases from the chamber.

[0036] In some embodiments of the aforementioned aspect and embodiments, the multichamber agglomeration device is operably connected to a gas processing unit comprising a gas scrubber wherein the gas scrubber is operably connected to the extraction pipe and configured to process the NOx gases.

[0037] In some embodiments of the aforementioned aspect and embodiments, the second chamber and / or the third chamber further comprise a feeding inlet for a nitrate / nitrite recovering solution configured to apply the nitrate / nitrite recovering solution onto the agglomerates to recover any unreacted nitrate / nitrite ions. In some embodiments of the aforementioned aspect and embodiments, the nitrate / nitrite recovering solution comprises iron ions. In some embodiments of the aforementioned aspect and embodiments, the nitrate / nitrite recovering solution comprises ferrous sulfate, iron-containing raffinate, or a mixture thereof.

[0038] In one aspect, there is provided a system to activate metal in a metal ore for leaching, comprising: a multi-chamber agglomeration device comprising a first chamber operably connected to an input for metal ore and a feeding inlet for a first activation solution comprising nitrate ions, nitrite ions, or combination thereof, and configured to embed the metal ore with the first activation solution to form aggregates, wherein the aggregates comprise metal ore and nitrate ions, nitrite ions, or combination thereof; a second chamber operably connected to the first chamber and a feeding inlet for a second activation solution comprising one or more concentrated acids, and configured to mix the aggregates with the second activation solution and cause volumetric expansion in the aggregates to form agglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases; and an extraction pipe operably connected to the second chamber and optionally the first chamber and configured to capture and extract the NOx gases from the chamber.

[0039] In one aspect, there is provided a system to activate metal in a metal ore for leaching, comprising: a multi-chamber agglomeration device comprising a first chamber operably connected to an input for metal ore and a feeding inlet for a first activation solution comprising nitrate ions, nitrite ions, or combination thereof, and configured to embed the metal ore with the first activation solution to form aggregates, wherein the aggregates comprise metal ore and nitrate ions, nitrite ions, or combination thereof; a second chamber operably connected to the first chamber and a feeding inlet for a second activation solution comprising one or more concentrated acids, and configured to mix the aggregates with the second activation solution and cause volumetric expansion inthe aggregates to form agglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases; and a third chamber operably connected to the second chamber and a feeding inlet to feed one or more conditioning agents selected from the group consisting of stabilizer, surfactant, sorbent, oxidizer, or mixtures thereof, and configured to mix the agglomerates with the conditioning agent.

[0040] In one aspect, there is provided a system to activate metal in a metal ore for leaching, comprising: a multi-chamber agglomeration device comprising a first chamber operably connected to an input for metal ore and a feeding inlet for a first activation solution comprising nitrate ions, nitrite ions, or combination thereof, and configured to embed the metal ore with the first activation solution to form aggregates, wherein the aggregates comprise metal ore and nitrate ions, nitrite ions, or combination thereof; a second chamber operably connected to the first chamber and a feeding inlet for a second activation solution comprising one or more concentrated acids, and configured to mix the aggregates with the second activation solution and cause volumetric expansion in the aggregates to form agglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases; a third chamber operably connected to the second chamber and a feeding inlet to feed one or more conditioning agents selected from the group consisting of stabilizer, surfactant, sorbent, oxidizer, or mixtures thereof, and configured to mix the agglomerates with the conditioning agent; and an extraction pipe operably connected to the second chamber and optionally the first and / or a third chamber and configured to capture and extract the NOx gases from the chamber.

[0041] In one aspect, there is provided a system to activate metal in a metal ore for leaching, comprising: a multi-chamber agglomeration device comprising a first chamber operably connected to an input for metal ore and a feeding inlet for a first activation solution comprising nitrate ions, nitrite ions, or combination thereof, and configured to embed the metal ore with the first activation solution to form aggregates, wherein the aggregates comprise metal ore and nitrate ions, nitrite ions, or combination thereof;a second chamber operably connected to the first chamber and a feeding inlet for a second activation solution comprising one or more concentrated acids, and configured to mix the aggregates with the second activation solution and cause volumetric expansion in the aggregates to form agglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases; and an extraction pipe operably connected to the second chamber and optionally the first chamber and configured to capture and extract the NOx gases from the chamber; and a gas processing unit operably connected to the multi-chamber agglomeration device comprising a gas scrubber wherein the gas scrubber is operably connected to the extraction pipe and configured to process the NOx gases.

[0042] In some embodiments of the aforementioned aspects and embodiments, the multichamber agglomeration device further comprises a third chamber operably connected to the second chamber and a feeding inlet to feed one or more conditioning agents selected from the group consisting of stabilizer, surfactant, sorbent, oxidizer, or mixtures thereof, and configured to mix the agglomerates with the conditioning agent.

[0043] In some embodiments of the aforementioned aspects and embodiments, the extraction pipe is retractable pipe that moves back and forth between the second and the third chamber.BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Non-limiting examples of embodiments of the disclosure are described below with reference to figures attached hereto. The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, can be understood by reference to the following detailed description when read with the accompanied drawings. Embodiments of the invention are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like reference numerals indicate corresponding, analogous or similar elements.

[0045] Fig. 1A illustrates some embodiments of the methods provided herein for the activation of the metal in the metal ore for enhancing the yield in the leaching process.

[0046] Fig. 1 B depicts some detailed embodiments of Fig. 1 illustrating some embodiments for the activation of the metal in the metal ore for enhancing the yield in the leaching process.

[0047] Fig. 1 C illustrates some embodiments of the methods provided herein for sequentially activating the metal in the metal ore.

[0048] Fig. 2 illustrates an overall schematic for some embodiments of the methods for the activation of the metal in the metal ore for enhancing the yield in the leaching process.

[0049] Fig. 3 illustrates some embodiments of the systems comprising the multi-chamber agglomeration device for the activation of the metal in the metal ore.

[0050] Fig. 4 depicts the effect of the sequential method of metal activation A on copper recovery as compared to the negative control with one step method B.

[0051] Fig. 5 depicts the impact of the sequential activation on reduced reagent consumption with high copper recovery in comparison to the negative control corresponding to a one-step agglomeration.

[0052] Fig. 6 illustrates the impact of the sequential activation on reduced NOx emissions during activation / agglomeration and leaching in comparison to a one-step regular agglomeration.

[0053] Fig. 7 shows the impact of the sequential activation on the structure of the ore (A), in comparison to a one-step regular agglomeration (B).

[0054] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn accurately or to scale. For example, the dimensions of some of the elements can be exaggerated relative to other elements for clarity, or several physical components can be included in one functional block or element.DETAILED DESCRIPTION

[0055] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, modules, units and / or circuits have not been described in detail so as not to obscure the invention.

[0056] Provided herein are methods and systems for sequentially and effectively activating the metal in the metal ore and facilitating efficient and enhanced leaching of the metal from the metal ore. Applicants unexpectedly and surprisingly found that a highly effective activation of the metal in the metal ore to facilitate its leaching, can be achieved by sequentially adding a series of activation solutions that cause effective volumetric expansion in the metal ore and make the metal available for leaching or provide a biggermetal agglomerate-leaching reagent contact surface for leaching. This sequential addition of the activation solutions enhances the permeability of the metal ore (measured by, for example only, through hydraulic conductivity (HC) or through tomography) which otherwise may not be achieved by adding a mix of the activation solutions together to the metal ore (one-step) and / or by adding the activation solutions in a different sequence. Without being limited by any theory, it is contemplated that the sequential addition of the activation solutions to the metal ore (which enhances the permeability of the metal ore) causes controlled release of the NOx gases in the metal ore lattice, causing volumetric expansion by enabling, unlocking and / or expanding veins, micro-veins, channels and / or microchannels in the interior of the metal ore, and activate or expose the metal so that it can then be stacked and efficiently leached. This activation of the metal in the metal ore as provided herein increases the extractive yield of the leaching process thereby reducing the downstream processing cost for the leaching. Applicants also unexpectedly and surprisingly found that the emission of NOx gases and the consumption of the reagents during the sequential methods and systems provided herein are substantially reduced as compared to the one-step method of adding the reagents together to the ore (or compared to standard agglomeration methods).

[0057] Also provided herein are methods and systems to manage the high levels of NOx emissions during the leaching process using a uniquely designed multi-chamber agglomeration device or a drum that carries out the agglomeration process in a contained atmosphere to limit the uncontrollable NOx emissions as well as to capture and sequester the emissions to a gas processing unit.

[0058] Typically, at an industrial scale for the metal leaching process, high levels of NOx emissions through the chemical reactions may be produced. The methods and systems provided herein enhance metal recovery in a subsequent leaching stage by activating the metal ore through the means of volumetric expansion by expanding, for example only, the veins, micro-veins, channels and / or micro-channels in the ore before heap formation. These methods and systems also control the NOx gases expelled from the ore by concentrating them in the agglomeration stage within the agglomeration device of the invention as well as capture and sequester the emissions using the uniquely designed multi-chamber agglomeration device or the drum. In some embodiments, the capture / scrubbing / recirculation of the NOx gases prevents the release of the harmful gases to the environment.

[0059] In one aspect, there is provided the sequential method to activate the metal in the metal ore for leaching, comprising: treating the metal ore with the first activation solution comprising, consisting essentially of, or consisting of nitrate ions, nitrite ions, or combination thereof and forming aggregates, wherein the aggregates comprise metal ore and nitrate ions, nitrite ions, or combination thereof; and irrigating the aggregates with the second activation solution comprising, consisting essentially of, or consisting of one or more concentrated acids and causing volumetric expansion in the metal ore to form agglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases, thereby sequentially activating the metal in the metal ore.

[0060] The “activate” or its grammatical equivalents as used herein, includes making or exposing the metal in the metal ore available for processing such as leaching. The activation includes mechanical and / or chemical activation. For example, the sequential addition of the activation solutions and the volumetric expansion in the metal ore, as described herein, may expose or activate the metal typically occluded in the metal ore or provide a bigger metal agglomerate-leaching reagent contact surface for further process of leaching.

[0061] The “activated metal” or its grammatical equivalents as used herein, includes metal that is exposed or is readily available in the metal ore for processing such as leaching.

[0062] The “volumetric expansion” or the “expansion” or its grammatical equivalents as used herein, includes the enablement, unlocking and / or expansion of the veins, microveins, channels and / or micro-channels in the metal ore aggregates to activate the metal and form the agglomerates. The volumetric expansion may depend on the intensity of the gases released when the first activation solution comes into contact with the second activation solution, and / or on the nature of the ore matrix and corresponding gangue. In some embodiments, the volumetric expansion in the metal ore aggregate facilitates and / or accelerates exposure of the metal for its movement from the lattice of the metal ore to the liquid phase (or provide a bigger metal agglomerate-leaching reagent contact surface) for the leaching.

[0063] The metal ore may be of any metal known in the art that may be treated in accordance with the methods and systems provided herein. The metal ore includes native and un-treated ore, or the ore obtained from various stages of the mining and leaching process, such as, but not limited to, previously agglomerated ore, previously leached ore,or gangue or tailings. In some embodiments, the metal ore is a metal selected from the group consisting of gold, silver, platinum, copper, nickel, molybdenum, rhenium, tungsten, zirconium, and cobalt. For example, in some embodiments, the methods and systems may be applied to recover metals from refractory ores of gold, silver, platinum, copper, nickel, molybdenum, rhenium, tungsten, zirconium, and cobalt. In some embodiments, the metal ore comprises copper ore. In some embodiments, the copper ore comprises primarily copper sulfide species. In some embodiments, the copper ore comprises primarily chalcopyrite. Exemplary copper ores include, without limitation, sulfide minerals, including chalcopyrite (CuFeS2; primary ore mineral) in sulfide deposits, or porphyry copper deposits; covellite (CuS); chalcocite (Cu2S; secondary with other sulfide minerals) with native copper and cuprite deposits and bornite (Cu5FeS4; secondary with other sulfide minerals); enargite (CU3ASS4); digenite (CU9S5); oxidized minerals, including malachite (CU2CO3(OH)2) in the oxidized zone of copper deposits; cuprite (Cu2O; secondary mineral); and azurite (Cu3(CO3)2(OH)2; secondary). In some embodiments, the copper sulfide ore may contain pyrite (FeS2) and other iron containing mineralogical species. In some embodiments, exemplary copper ores further comprise, without limitation, black copper comprising copper wad, copper pitch, chrysocolla, atacamite and other species.

[0064] An illustration of some of the aforementioned aspects and embodiments is as shown in Fig. 1A. Some embodiments of the sequential method to activate the metal in the metal ore are shown in Fig. 1A, Fig. 1 B, Fig. 1 C, and Fig. 2 where the first activation solution is added to the metal ore in step I to form the aggregates. In some embodiments, the metal ore may be crushed ore or may be used as is. In some embodiments, the crushed particles of the ore may be wetted during agglomeration to increase porosity and to achieve adhesion of the fine particle fraction to larger particles resulting from the crushing process to yield hydraulically and mechanically stable material.

[0065] In some embodiments, the first activation solution comprises nitrate ions, nitrite ions, combination thereof, or the like. The solutions described herein are aqueous. In some embodiments, water for such water-based solutions is supplied as regular water, raffinate, industrial water, or a mixture thereof. In some embodiments, the first activation solution may be combined with a raffinate solution and / or a dilute acid. The raffinate solution is the solution or the water remaining after the metal is extracted from the metal ore. In some embodiments, the raffinate or a raffinate solution is a water-based metal- depleted and acid-rich solution which may be obtained from an acidic aqueous phasereceived after metal extraction or retrieval, for example using solvent extraction / electrowinning (SX / EW) and / or additional or alternative procedures.

[0066] In some embodiments, the metal ore may optionally be rested after the treatment with the first activation solution for at least a few minutes. For example only, the metal ore may be rested after the treatment with the first activation solution for about 5 min to about 30 min, or about 15 min, or about an hour. In some embodiments, the treatment of the metal ore with the first activation solution comprises evenly distributing or embedding the first activation solution in the metal ore to form the aggregates wherein the aggregates comprise metal ore and nitrate ions, nitrite ions, or combination thereof.

[0067] The “even distribution” or “embedding” or its grammatical equivalents, as used herein includes spreading of the activation solution over the surface of the metal ore and in between the rocks and / or the particles of the metal ore; and / or impregnation of the ore intratissue with the activation solution.

[0068] The sequential addition of the first activation solution, as provided herein, facilitates enhanced humectation of the metal ore through the interaction of the nitrate and / or the nitrite ions with the metal ore. The treatment of the metal ore with the first activation solution may allow for more effective permeation facilitating homogenization of the reagents across the surface and in between the metal ore. As described further, this even distribution or the embedding of the metal ore with the first activation solution, results in an efficient activation of the metal in the metal ore.

[0069] In some embodiments, the first activation solution comprises nitrate ions, nitrite ions, or combination thereof at a concentration which may range from about 50 g / L to about 300 g / L. In some embodiments, the concentration of the nitrate ions, nitrite ions, or combination thereof in the first activation solution ranges from between about 50 g / L-300 g / L; or between about 50 g / L-200 g / L; or between about 50 g / L-150 g / L; or between about 50 g / L-100 g / L; or between about 50 g / L-75 g / L. In some embodiments, the nitrate ions are provided in the form of nitric acid. In some embodiments, the concentration of the nitrate and / or nitrite ions in the first activation solution is in a range of between about 0.8M to 5M; or between about 0.8M to 3.2M; or between about 0.8M to 2.5M; or between about 0.8M to 1.5M; or between about 0.8M to 1.3M; or between about 1.3M to 5M; or between about 1 ,3M to 3.2M; or between about 1 ,3M to 2.5M; or between about 1 ,3M to 1 ,5M; or between about 1.5M to 5M; or between about 1.5M to 3.2M; or between about 1.5M to 2.5M; or between about 2.5M to 5M; or between about 2.5M to 3.2M; or between about 3.2M to 5M.

[0070] In some embodiments, the dose of the nitrate and / or the nitrite ions onto the metal ore is in a range of about 0.5 kg / ton ore to about 30 kg / ton ore. In some embodiments, the dose of the nitrate and / or the nitrite ions onto the metal ore is in a range of between about 0.5 to 15 kg / ton ore; or between about 0.5 to 10 kg / ton ore; or between about 0.5 to 7.5 kg / ton ore; or between about 0.5 to 5 kg / ton ore; or between about 5 to 30 kg / ton ore; or between about 5 to 15 kg / ton ore; or between about 5 to 10 kg / ton ore; or between about 5 to 7.5 kg / ton ore; or between about 7.5 to 30 kg / ton ore; or between about 7.5 to 15 kg / ton ore kg / ton ore; or between about 7.5 to 10 kg / ton ore; or between about 10 to 30 kg / ton ore; or between about 10 to 15 kg / ton ore.

[0071] In some embodiments, the source of nitrate or nitrite ions is, without limitation, ammonium nitrate salt, sodium nitrate salt, potassium nitrate salt, nitrite salt, nitric acid, nitrous acid, caliche, or a mixture thereof. In some embodiments, the nitrate or nitrite source contains sulphates, magnesium, calcium, potassium, Fe-AI-Mg-Na silicates, clays, alite, quarts, thenardite, iodine derived salts or a mixture thereof. In some embodiments, the nitrate or nitrite source is in crystal, granules or refined salt. In some embodiments, the source of nitrate or nitrite is natural or synthetic. In further embodiments, the nitrate or nitrite source is of high grade or contains impurities. In some embodiments of the aforementioned aspect and embodiments, any of these sources are combined generating a nitrate and / or a nitrite blend.

[0072] In some embodiments, the source of nitrate or nitrite comprises sources externally supplied, sources generated in situ, or a mixture thereof. In some embodiments, the nitrate or nitrite source is directly injected into the systems from the source. In some embodiments, the nitrate and / or the nitrite source is added to the system as salt and is mixed within the system to form a homogenous solution before being treated with the ore. In some embodiments, the nitrate and / or the nitrite source is in the raffinate generated after processing nitrate and / or the nitrite containing pregnant liquor solution (PLS) by solvent extraction. In some embodiments, the nitrate and / or the nitrite source may be ammonia oxidized to form NO2 / NO gases that are absorbed in a solution to form a solution that has nitrate / nitrite ions. In some embodiments, the source of the ammonia is the Haber-Bosch process which combines hydrogen with nitrogen. In some embodiments the source of hydrogen is an hydrolysis process using water. In some embodiments the water sources is selected from the waters of this group: purified water, sea water, hard water, etc.

[0073] In some embodiments, the nitrate and / or the nitrite ions are derived catalytic species externally generated in a reactor and directly conducted to treat the ore. In some embodiments, the catalytic species are in situ generated and directly added to the ore surface. In some embodiments, the catalytic nitrate derived species are selected from, without limitation, nitrate ions, nitrite ions, NO2<g), NO2(aq), NO(g), NO(aq), HNO3, HNO2, NO+, NO+, NO , N2O4(g) or a mixture thereof.

[0074] In some embodiments, the first activation solution further comprises a redox modulating agent. In some embodiments, the metal ore that has been previously leached may contain a passivated surface which can be activated by using the redox modulating agent. The “redox modulating agent” as used herein includes a substance, a chemical species, or a biomolecule, that can alter the redox status of the metal ore. For example, in some embodiments, it enhances the leaching ore susceptibility thereby facilitating the leaching process.

[0075] In some embodiments, the redox modulating agent is an oxidizing agent. In some embodiments, the oxidizing agent is a substance, a chemical species, or a biomolecule that undergoes or favors chemical reactions in which it gains one or more electrons. Examples of the oxidizing agent include, without limitation, an oxidant gas, a highly oxidant reagent, iron-oxidizing microorganims, sulfur-oxidizing microorganism, ozone, oxygen, hydrogen peroxide, air, or a mixture thereof. Various redox modulating agents may be present, for example only, in an amount up to about 1 M, for example in a range of between about 0.03 M to 0.6 M.

[0076] In some embodiments, the redox modulating agent is selected from the group consisting of an oxidant gas, highly oxidant reagent, iron-oxidizing microorganism, sulfur- oxidizing microorganism, ozone, oxygen, hydrogen peroxide, air, and a mixture thereof.

[0077] As illustrated in Fig. 1A, Fig. 1 B, Fig. 1 C, and Fig. 2 step I of the treatment with the first activation solution is followed by step II of the irrigation of the aggregates of the metal ore with the second activation solution to form the agglomerates. In some embodiments, the second activation solution comprises one or more concentrated acids. The concentrated acid may be any acid known in the art. For example only, the one or more concentrated acids include, without limitation, sulfuric acid, nitric acid, combination thereof, or the like. The step II illustrated in Fig. 1A, Fig. 1 B, Fig. 1 C, and Fig. 2 shows irrigation of the aggregates with the second activation solution comprising one or more concentrated acids and causing volumetric expansion by e.g., the enablement, and / or the expansion of the veins, micro-veins, channels and / or micro-channels in the metal ore to formagglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases.

[0078] Without being limited by any mechanism or theory, an exemplary reaction between the reagents of the first activation solution with that of the second activation solution and the copper ore, chalcopyrite, can be shown as follows:

[0079] The amount of the nitrate ions and the protons in the above noted reaction would be dependent on the stoichiometric relationship with the chalcopyrite.

[0080] In some embodiments, the aggregates may optionally be rested after the treatment with the second activation solution for a few minutes to hours. For example only, the aggregates may be rested after the treatment with the second activation solution for about 5 min to about 30 min, or about 15 min, or about an hour. In some embodiments, the irrigation of the aggregates of the metal ore with the second activation solution with optional resting, may result in enhanced penetration of the second activation solution in the aggregates where the first activation solution comes into contact with the second activation solution in the aggregates. In some embodiments, this contact, e.g., of the nitrate and / or nitrite ions with the concentrated acids, within the aggregates of the metal ore, results in gas release allowing the volumetric expansion of the veins, micro-veins, channels and / or micro-channels in the metal ore aggregates and activate the metal in the metal ore. In some embodiments, the even distribution or the embedding of the first activation solution results in an effective distribution of the expansion of the metal ore to activate the metal in the agglomerates.

[0081] In some embodiments, the irrigation of the aggregates with a second activation solution causes the expansion of between about 5-95% of the metal ore; or between about 5-75% of the metal ore; or between about 5-50% of the metal ore; or between about 5- 25% of the metal ore; or between about 5-10% of the metal ore; or between about 25-20% of the metal ore, via hydraulic conductivity measurement.

[0082] As described, the sequential treatment and the irrigation steps provided herein cause the effective activation of the metal by the volumetric expansion, e.g., expansion of the veins, micro-veins, channels and / or microchannels in the metal ore. In some embodiments, the activation of the metal in the aggregates of the metal ore affected by the NOx gas release, improves access to the leaching solutions in subsequent steps. This is in sharp contrast to a hypothetical one-step treatment with both the activation solutions (both the activation solutions added at the same time) that would result in a differentoutcome, with the principal reaction occurring between concentrated acid and nitrate as an instantaneous reaction, without any significant effect on the metal ore.

[0083] The sequential methods and systems provided herein are also in sharp contrast to a hypothetical scenario where the sequence of the first activation solution and the second activation solution may be reversed, namely, treating the metal ore with the second activation solution and then irrigating it with the first activation solution. In the methods provided herein the treatment of the metal ore with the first activation solution comprising nitrate ions, nitrite ions, or combination thereof, may not result in any significant reaction between the first activation solution and the metal ore which may assist in the even distribution or the embedding of the first activation solution in the metal ore (and the subsequent volumetric expansion). However, the irrigation of the metal ore with the second activation solution comprising one or more concentrated acids, if done first, may result in a significant reaction between the concentrated acids and the metal ore thereby reducing or preventing the even distribution of the activation solution. In some embodiments, the irrigation of the aggregates with the second activation solution causes an increase in the recovery of the desired metal in a subsequent leaching step of between about 5-95% as compared to a leaching step following a one-step treatment.

[0084] The volumetric expansion after step II in Fig. 1A, Fig. 1 B, Fig. 1C, and Fig. 2 is evident by the release of large amounts of NOx gases which are captured and treated. In some embodiments, the volumetric expansion is induced by the NOx gases where the diffusion of the NOx gases or the NOx-derived chemical species within the channels, micro-channels, veins and / or micro-veins and into the crystal lattice of the metal ore may take place, further activating the metal in the metal ore. The volumetric expansion in the agglomerates of the metal ore along with the physical turbulence caused by the NOx emissions may together activate the metal in the metal ore structure and expose it for dissolution and leaching. Further, the sequential methods provided herein direct the chemical reactions thereby controlling the NOx emissions by sequentially introducing the activating solutions instead of mixing the activating solutions together and irrigating the metal ores with a highly reactive mixture. Furthermore, the NOx gases may facilitate formation of reactive oxy-nitrogen (RONS) species within the aqueous solution. Without wishing to be bound by any particular mechanism or theory, the RONS species may also activate metal in the metal ore, thereby increasing the metal dissolution kinetics of the leaching process.

[0085] In some embodiments, the sequential treating and the irrigating steps enhance permeability or hydraulic conductivity of the metal ore (in the aggregate and / or the agglomerate form) by between about 2-20% compared to a non-sequential method or a one-step method. In some embodiments, the sequential treating and the irrigating steps enhance permeability or hydraulic conductivity of the metal ore by between about 2-20%; or by between about 2-15%; or by between about 2-10%; or by between about 2-8%; or by between about 2-5%; or by between about 5-20%; or by between about 5-15%; or by between about 5-10%; or by between about 5-8%; or by between about 8-20%; or by between about 8-15%; or by between about 8-10%; or by between about 15-20%; or by about 8-8.5 or 9%; compared to a non-sequential method or a one-step method.

[0086] In some embodiments, the second activation solution comprises one or more concentrated acids in a concentration between about 70 g / L and below about 1800 g / L. In some embodiments, the concentration of concentrated acids in the second activation solution ranges between about 70 g / L-1800 g / L: or between about 70 g / L-1700 g / L; or between about 70 g / L-1600 g / L; or between about 70 g / L-1500 g / L; or between about 70 g / L-1400 g / L; or between about 70 g / L-1300 g / L; or between about 70-1200 g / L; or between about 70 g / L-1200 g / L; or between about 70 g / L-1100 g / L; or between about 70 g / L-1000 g / L; or between about 70 g / L-900 g / L; or between about 70 g / L-800 g / L; or between about 70 g / L-700 g / L, or between about 70 g / L-600 g / L; or between about 70 g / L- 500 g / L; or between about 70 g / L-400 g / L; or between about 70 g / L-300 g / L, or between about 70 g / L-200 g / L; or between about 70 g / L-150 g / L; or between about 70 g / L-100 g / L. It is to be understood that the concentration of the second activation solution may be adjusted depending upon the metal ore’s head and gangue. In some embodiments, the concentration of the concentrated acid (e.g., sulfuric acid or nitric acid) in the second activation solution is in a range of between about 0.7 M and below about 19 M. In some embodiments, the concentration of concentrated acid in the second activation solution ranges between about 0.7 M to 19 M; or between about 0.7 M to 17 M; or between about 0.7 M to 16 M; or between about 0.7 M to 15 M; or between about 0.7 M to 14 M; or between about 0.7 M to 13 M; or between about 0.7 M to 12 M; or between about 0.7 M to 11 M; or between about 0.7 M to 10 M; or between about 0.7 M to 9 M; or between about 0.7 M to 8 M; or between about 0.7 M to 7 M; or between about 0.7 M to 6 M; or between about 0.7 M to 5 M; or between about 0.7 M to 4 M; or between about 0.7 M to 3 M; or between about 0.7 M to 2 M; or between about 0.7 M to 1 M.

[0087] In some embodiments, the dose of the one or more concentrated acids onto the mineral ore, or the one or more concentrated acids contained in the second solution which is applied onto the mineral ore, is in a range of between about 1 kg / ton ore to 50 kg / ton ore. In some embodiments, the dose of the one or more concentrated acids can be adjusted according to the mineralogical characteristics of the ore, such as acid consumption of the ore, type of gangue, degree of association and liberation. In some embodiments, the dose of the one or more concentrated acids onto the mineral ore is in a range of between about 1 to 50 kg / ton ore; or between 1 to 40 kg / ton ore; or between 1 to 30 kg / ton ore; or between 1 to 20 kg / ton ore; or between 1 to 10 kg / ton ore; or between 10 to 50 kg / ton ore; or between 10 to 40 kg / ton ore; or between 10 to 30 kg / ton ore; or between 10 to 20 kg / ton ore; or between 20 to 50 kg / ton ore; or between 20 to 40 kg / ton ore; or between 20 to 30 kg / ton ore; or between 30 to 50 kg / ton ore; or between 30 to 40 kg / ton ore; or between 40 to 50 kg / ton ore.

[0088] In some embodiments, the sulfuric acid may be generated in situ by providing a sulfur rich solid residue source, aerating the sulfur rich solid residues and irrigating them with a solution comprising sulfur-oxidizing bacteria, such as Acidithiobacillus thiooxidans, and acidified water, recovering an acidified solution from the bottom of the sulfur rich source to be refined and reinserted into the system.

[0089] In some embodiments, the nitric acid may be generated in situ by reacting added nitrate with sulfuric acid as shown in the following equation:H2S04+ 2NO2-► HN03+ SO ~

[0090] The generation of the nitric acid may enhance the recovery due to the dissolution of gangue (i.e. biotite, chlorite, etc.) that could encapsulate the copper minerals.

[0091] In some embodiments, the sulfuric acid is generated in situ by pyrite containing ores and further injected into the system. In some embodiments, a part of the acid required is generated within the heap, due to the presence of pyrite or other related chemical species in the ore. In some embodiments, the sulfuric acid is a byproduct of refinery process. In some embodiments, any of these generated solutions are recirculated to the system and readjusted to be further reused in the method. In some embodiments, the acid source is a mixture of the generated solutions described above.

[0092] In some embodiments, the first activation solution and / or the second activation solution further comprise a minimal amount of metal ions that are being activated in the metal ore. For example, the first activation solution and / or the second activation solution may comprise copper ions when the copper is being activated in the copper ore. Theminimal amount of the copper ions in this context includes an amount of copper ions that (e.g., from recirculated raffinate or from another source) would enhance the kinetics of the treatment and / or the irrigation. Thus, the concentration of the metal ions, e.g., copper ions, in the first activation solution and / or the second activation solution is between about 0.1 -30 mM.

[0093] In some embodiments, the concentration of the first activation solution and the second activation solution is in a ratio of between about 1 :1 to about 1 :50; or between about 1 :2 to about 1 :40; or between about 1 :2 to about 1 :30; or between about 1 :2 to about 1 :25; or between about 1 :1.5 to about 1 :10; or between about 5:7 to about 1 :25.

[0094] In some embodiments of the methods and systems provided herein, the first activation solution and / or the second activation solution further comprises a minimal amount of chlorides. This contribution may be due to the use of industrial water that is commonly found in mining sites. In some embodiments, the concentration of the chloride salts in the first and / or the second activation solutions is between about 0 g / L to 25 g / L. In some embodiments, the concentration of the chloride salt in the first and / or the second activation solution is between about 0 g / L to about 20 g / L; or between about 0 g / L to 15 g / L; or between about 0 g / L to about 10 g / L; or between about 0 g / L: to about 15 g / L. In some embodiments, the concentration of the chloride salt in the first and / or the second activation solution is between about 5 g / L to about 25 g / L; or between about 5 g / L to about 20 g / L; or between about 5 g / L to about 15 g / L; or between about 5 g / L to about 10 g / L. In some embodiments, the first and second activation solution are substantially free of chloride salts.

[0095] In some embodiments of the methods and systems provided herein, the treating and the irrigating methods and systems do not utilize chloride salts.

[0096] The NOx gases typically include nitric oxide (NO) and nitrous oxide (N2O). It may also include, without limitation, dinitrogen dioxide (N2O2), dinitrogen trioxide (N2O3), nitrogen dioxide (NO2), dinitrogen tetraoxide (N2O4), and dinitrogen pentoxide (N2O5). The NOx gases are high air pollutants where NO2is not only an important air pollutant by itself, but also reacts in the atmosphere to form ozone (O3) and acid rain. NO2may react in the presence of air and ultraviolet light (UV) in sunlight to form ozone and nitric oxide (NO). The NO may react with free radicals in the atmosphere, which may also be created by the UV acting on volatile organic compounds (VOC). The free radicals then may recycle NO to NO2. In this way, each molecule of NO can produce ozone multiple times. There is an obvious need to reduce NOx emissions and Applicants have devised an innovative closedsystem (described further herein) to carry out the methods provided herein and capture and process the NOx gases.

[0097] In some embodiments, the methods provided herein further comprise capturing and extracting the NOx gases from the agglomerates. In embodiments when the first activation solution, such as the nitrate and / or the nitrite ions come into contact with the second activation solution, such as, the concentrated sulfuric acid, large amounts of NOx gases are released both during and after the agglomeration process including, but not limited to, conditioning, curing, stacking and heap leaching stage. The NOx gases released (as shown in Fig. 1A, Fig. 1 B, Fig. 1 C, and Fig. 2), during and / or after the volumetric expansion, are then captured and further processed. This embodiment is described in detail further.

[0098] In some embodiments of the aspects and embodiments provided herein, the sequential method optionally further comprises conditioning the agglomerates with one or more conditioning agents. As illustrated in Fig. 1A, Fig. 1 B, and Fig. 2, step II of the irrigation of the aggregates of the metal ore with the second activation solution to form the agglomerates is followed by step III of conditioning the agglomerates with one or more conditioning agents. In some embodiments, the one or more conditioning agents include, but are not limited to, stabilizer, surfactant, sorbent, oxidizer, or mixtures thereof. These conditioning agents may be used separately or in conjunction depending upon the requirement. In some embodiments, the conditioning of the agglomerates prepares it for stacking on a heap for metal leaching.

[0099] In some embodiments of the methods and systems provided herein, after the irrigating step II (before the conditioning step) and / or after the conditioning step III, a nitrate / nitrite recovery step is provided. In some embodiments, the method further comprises applying a nitrate / nitrite recovering solution to the agglomerates to recover unreacted nitrate, nitrite, or mixture thereof. The unreacted nitrate, nitrite, or mixture thereof may not have reacted with the one or more concentrated acids in the second activation solution after step II and may need to be recovered to prevent or reduce the NOx emissions during the heap leaching stage. For example, in some embodiments, the nitrate reacts with the nitrate / nitrite recovering solution comprising ferrous ions to form NO which is recovered in the gas scrubber along with the other NOx gases.

[0100] This step has been illustrated in detail on Fig. 1 B. As shown in Fig. 1 B, the nitrate / nitrite recovery step lib is shown by two pathways a and b inside a dashed box.The steps I, II, and III in Fig. 1 B are same as the steps I, II, and III in Fig. 1A and Fig. 2 except that in Fig. 1 B is shown an additional nitrate / nitrite recovery step lib which occurs after step II and before step III, and / or after step III. The pathway a illustrates the nitrate / nitrite recovery step lib by application of the nitrate / nitrite recovery solution after the step III of the conditioning. The pathway b illustrates the nitrate / nitrite recovery step lib by application of the nitrate / nitrite recovery solution after the step II and before the step III of the conditioning. In some embodiments, sea water is added during the nitrate / nitrite recovery step.

[0101] In some embodiments, and without limitation, the nitrate / nitrite recovering solution comprises iron ions. In some embodiments, the nitrate / nitrite recovering solution comprises ferrous sulfate, iron-containing raffinate, or a mixture thereof. In some embodiments, the nitrate / nitrite recovering solution comprises ferric containing raffinate, ferrous containing raffinate, ferric sulfate, ferrous sulfate, or a mixture thereof. In some embodiments, the source of ferrous may be ferric irons that are reduced to ferrous irons externally by iron-reducing bacteria such as Shewanella spp. In some embodiments, the concentration of the ions, such as, e.g., ferrous ions in the nitrate / nitrite recovering solution is between about 5 g / L and about 50 g / L. In some embodiments, the concentration of the ions, such as, e.g., ferrous ions in the nitrate / nitrite recovering solution is in the range of between about 5 g / L-50 g / L; or between about 5 g / L-40 g / L; or between about 5 g / L-30 g / L; or between about 5 g / L-20 g / L; or between about 5 g / L-10 g / L. In some embodiments, the concentration of the ions, such as, e.g., ferrous ions in the nitrate / nitrite recovering solution is up to about 0.9M, or in the range of between about 0.09M-0.9M; or between about 0.09M-0.7M; or between about 0.09M-0.5M; or between about 0.09M-0.4M; or between about 0.09M-0.2M.

[0102] In some embodiments, the first activation solution, the second activating solution and the nitrate / nitrite recovering solution are irrigated or applied at a temperature up to about 80° C.

[0103] In some embodiments of the aspects and embodiments provided herein, the sequential method comprises conditioning the agglomerates with conditioning agent comprising stabilizer in step III. For example only, in some embodiments, the irrigation with the one or more concentrated acids in the second activation solution may potentially compromise the structural integrity of the metal ore’s agglomerate structures. In some embodiments, the conditioning of the agglomerates with the stabilizer may stabilize the agglomerate for stacking. In some embodiments, the stabilizer includes, but not limited to,one or more calcium chloride, calcium carbonate, gypsum, polyacrylamide, polyaluminum chloride (PAC), sodium alginate, sodium aluminate, aluminum sulfate, ferric chloride, starch, carboxymethyl cellulose, and the like. These chemicals are commercially available and may be procured as such. In some embodiments, the stabilization process is carried out by the irrigation of the agglomerates with the dissolved form of the stabilizer. Once this stage is complete, the stabilized and activated agglomerates are ready for stacking and further leaching treatments.

[0104] In some embodiments of the aspects and embodiments provided herein, the sequential method comprises conditioning the agglomerates with the conditioning agent comprising surfactant in step III. For example only, in some embodiments, the permeability of the agglomerates may be enhanced through the addition of one or more surfactants. In some embodiments, the surfactants may facilitate a reduction in surface tension within a liquid solution, thereby increasing its spreading and wetting properties. In some embodiments, the surfactants may also facilitate the leaching solution to penetrate the agglomerate or the metal ore body through the volumetric expansion generated during the process described herein. In some embodiments, the conditioning of the agglomerates with the surfactants may facilitate an increase in the wetting of further leaching solutions over the treated metal ore. In some embodiments, the examples of the surfactant include, but not limited to, cetyl trimethylammonium bromide (CTAB), dodecyl trimethyl ammonium bromide (DTAB), sodium dodecyl sulfate (SDS), sodium oleate, oleic acid, polyethylene oxide 4000 (PEG), bio-surfactant, triethylene glycol (TEG), or mixtures thereof. These chemicals are commercially available and may be procured as such.

[0105] In some embodiments of the aspects and embodiments provided herein, the sequential method comprises conditioning the agglomerates with the conditioning agent comprising sorbent in step III. In some embodiments, the addition of the sorbent to the agglomerates may facilitate capture of toxic gases while the agglomerate of the metal ore is being stacked or is resting in the heap for the metal leaching. In some embodiments, the examples of the sorbent include, but not limited to, zeolite, activated alumina, activated charcoal, silica gel, calcium chloride, charcoal sulfate, clay, carbon nanotubes, biochar, carbon fibers, graphene oxide, perlite, or mixture thereof. These chemicals are commercially available and may be procured as such.

[0106] In some embodiments of the aspects and embodiments provided herein, the sequential method comprises conditioning the agglomerates with the conditioning agent comprising oxidizer in step III. In some embodiments, the oxidation potential of theagglomerates of the metal ore may be augmented for the metal to be leached prior to the leaching process. In some embodiments, an advance oxidation process is incorporated by using the oxidizer for adjusting redox conditions of the reactive mixtures. In this step, the agglomerate can be treated with oxidizer selected from one or more of an oxidant gas, highly oxidant reagents, iron or sulfur-oxidizing microorganisms, or mixtures thereof. Various examples of the oxidizer include, without limitation, aqueous hydrogen peroxide, gaseous ozone in micro and nano bubbles, gaseous oxygen in micro and nano bubbles, air in micro and nano bubbles, and mixtures thereof. Various oxidizers may be present, for example only, in an amount up to 0.3 M, for example in a range of 0.03 M to 0.3 M.

[0107] These conditioning agents may be used either in conjunction or separately, depending on the specific requirements in each situation. As such, Table I below shows various permutations and combinations in which these conditioning agents may be combined in various compositions, where the presence of the conditioning agent is marked as X .Table I: Conditioning agent combinations

[0108] Table II below shows some examples of the combinations in which these conditioning agents may be combined.Table II: Conditioning agent combinations

[0109] In some embodiments of the methods provided herein, the methods further comprise subjecting the metal ore to shockwaves during, before, or after step I and during or before step II. The shockwaves may include physical mixing or stirring or based on electrical pulses.

[0110] After step III of the methods and systems provided herein, the agglomerates may be stacked and heaped IV for the leaching process, as shown in Fig. 1A, Fig. 1 B, Fig. 1 C, and Fig. 2. The sequential methods to activate the metal in the metal ore and the multichamber agglomeration device provided herein result in uniform, stable, and poorly degradable agglomerates that have a high agglomerate-reagent contact surface or agglomerate-leaching solution contact surface.

[0111] It is to be understood that although the figures show the metal ore as individual pieces of rock or sediment in I, II, and III stages, it is purely for illustration purposes only and the metal ore may be obtained from any form including, but not limited to, heap or column form.

[0112] Fig. 2 illustrates an overall process of metal leaching from the metal ore including the activation of the metal as provided herein. As shown in Fig. 2 and including aforementioned aspects and embodiments regarding Fig. 1A, Fig. 1 B and Fig. 1 C, the metal ore or the crushed metal ore is treated with the first activation solution in step I.

[0113] The aggregates formed in step I are then irrigated with the second activation solution in step II to form the agglomerates with activated metal. The agglomerates are conditioned in step III optionally including the nitrate / nitrite recovery step lib, after which the agglomerates are stacked and heaped IV for further process of leaching.

[0114] The overall process achieves its technical effect through irrigation treatments on the metal ore using specific concentrations, sequences, and optionally irrigation rates.

[0115] The first and / or the second activation solution may be irrigated onto the metal ore at an irrigation rate of less than about 35 m3 / h, for example in a range of about 0.1-25 m3 / h and in some embodiments 2-15 m3 / h. The irrigation rate is given in units of m3 / h, where it refers to a volume applied of the solution during a period of time. In some embodiments, the first and / or the second activation solution may be irrigated until reaching a volume ratio of about 0.01-0.5 m3of the first and / or the second activation solution per ton of the metal ore. The volume ratio is given in units of m3 / ton ore, where it refers to a volume of solution applied to a given amount of mineral ore that is being treated.

[0116] In some embodiments, a pregnant liquor solution (PLS) rich in metal partially extracted from the metal ore may be collected after step I, step II and / or step III of the irrigation and / or the conditioning respectively, where the reaction between the first and the second activation solution causes activation of the metal and some of the metal extracts and leaches out in the solution. This PLS may be collected and directed to a storage pond or PLS pond.

[0117] Once the metal ore is stacked in a heap in step IV, the heap may be allowed to rest. In some embodiments, relatively short rest times of no more than 15 days, for example 5 to 15 days, or less than 5 days may be effective to promote metal recovery, e.g., even more effective than longer rest times typically practiced which leads to undesirable passivated ore surface. The shorter rest times are achieved due to the activation of the metal by the sequential addition of the activation solutions.

[0118] The heap may be subjected to leaching through irrigation with any leaching solution as described in the art, e.g., nitrate and / or nitrite ions; acid; and optionally iron ions. In some embodiments, the leaching solution comprises, for example only, nitrate ions present in an amount up to about 160mM, for example about 1 mM to about 160mM; sulfuric acid in a range of about 0.05M to about 0.2M; and iron ions (present as ferrous and / or ferric ions) in a range of about 1 mM to about 180mM. Each of these reagents may enhance the electrochemical properties of the ore for further leaching of the metal from the ore. In some embodiments, the leaching solution further comprises raffinate with waterreplenishment. Water make-up may be required to replace evaporative and ore hold-up losses. The leaching solution may be irrigated on the heap with an irrigation rate of about 5-10 L / h m2and increased metal extraction.

[0119] After the leaching is performed on the heap with a leaching solution to obtain metal-rich PLS, the PLS is collected in the PLS pond. The PLS is advanced to solventextraction electrowinning for metal recovery. In some embodiments, rinsing is performed on the heap after leaching to recover residual leaching solution.

[0120] In some embodiments, the metal recovery stage includes a solvent extraction and electrowinning (SX / EW) process to produce metal cathodes, such as, e.g., copper cathodes. In some embodiments, the PLS enters the solvent extraction process for metal separation and reagents recovery. Two streams may be produced: a metal-rich electrolyte solution advanced to the electrowinning process to produce metal cathodes, and a raffinate solution which may be sent to a process island and / or recirculated to any of the first activation solution, the second activation solution, the conditioning solution, and / or the leaching solution. In some embodiments, the raffinate produced in the SX / EW may be purged. In some embodiments, the purged raffinate is advanced to a purge pond, wherein the purged raffinate is treated before disposal. In some embodiments, the raffinate is purged by physical filters. In some embodiments, the raffinate is purged by chemical methods. In some embodiments, the purged raffinate treatment comprises acid-base neutralization methods, heavy metals precipitation, solid-liquid separations or a combination thereof.

[0121] The sequential methods provided herein may be carried out using any of the systems conventionally known, related to the field of the metal leaching from the metal ore. In some embodiments, the sequential methods of the invention may be carried out using any one or more of the systems provided herein.

[0122] In one aspect, there is provided a system to activate metal in a metal ore for leaching, comprising: a multi-chamber agglomeration device comprising a first chamber operably connected to an input for metal ore and a feeding inlet for a first activation solution comprising nitrate ions, nitrite ions, or combination thereof, and configured to embed the metal ore with the first activation solution to form aggregates, wherein the aggregates comprise metal ore and nitrate ions, nitrite ions, or combination thereof; anda second chamber operably connected to the first chamber and a feeding inlet for a second activation solution comprising one or more concentrated acids, and configured to mix the aggregates with the second activation solution and cause volumetric expansion in the aggregates to form agglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases.

[0123] Fig. 3 illustrates some embodiments of the aforementioned system aspect for carrying out the sequential methods described herein. The system 100 shown in Fig. 3 comprises a multi-chamber agglomeration device 101 operably connected to various inlets for feeding the metal ore and the solutions; a gas processing unit; and an outlet for dispensing the treated ore. It is to be understood that the structure of the multi-chamber agglomeration device, the inlet for the metal ore, and the outlet for the metal ore etc. shown in Fig. 3 are for illustration purposes only and as such are not limited by the architecture as shown. Any component that can be used as an inlet and outlet in accordance with the spirit of the invention can be used in the system design provided herein.

[0124] The multi-chamber agglomeration device may be a drum, a tank, a large conduit, a column, a cylinder, or the like. Without deviating from the spirit of the invention, any means that can be divided into chambers that can handle metal ores can be used in the systems provided herein. In some embodiments, the multi-chamber agglomeration device / drum comprises a hollow cylinder or any such shape made of thick rolled steel. In some embodiments, the device may be supported by a supporting structure or a harness (not shown in Fig. 3) over which the device rests and optionally rotates during the agglomeration process. The shape of the multi-chamber agglomeration device or the drum can be any geometric shape, including but not limited to, circular, hexagonal, or elliptical, or the like.

[0125] In some embodiments, the multi-chamber agglomeration device is inclined at an angle which can be adjusted manually, automatically, or digitally such that the first chamber of the device is at a greater height than the second and the third chamber of the device. The inclination may allow for the movement of the metal ore from one chamber to the other chamber by the force of gravity. In some embodiments, the inclination can be adjusted to achieve a desired residence time of the metal ore in each chamber. In some embodiments, the multi-chamber agglomeration device / drum is configured to rotate on an axis using a manually, automatically, or digitally controlled driving system. In some embodiments, the rotation of the multi-chamber agglomeration device / drum allows thecirculation or the movement of the metal ore inside the chambers of the drum to facilitate mixing or the homogenization of the activation solutions with the metal ore to coat the surface of the metal ore. It is to be understood that in the configurations where the multichamber agglomeration device is rotating, the inlets and outlets are configured in such a way that a continuous transfer of the material continues while the main device / drum is rotating. Such configuration includes rotational connection between the inlets or the outlets with the drum which are preferably airtight so that no significant escape of the NOx gases takes place. In some embodiments, the multi-chamber agglomeration device / drum includes air knife blowers, which are located between the first and second chambers, and / or between the second and third chambers. These air knives can serve the dual purpose of acting as air barriers and containing the produced NOx gases inside the main device / drum, while simultaneously allowing the ore to move between these first and second chambers, and between the second and third chambers.

[0126] In some embodiments, the metal ore or the crushed metal ore is provided by crusher to the inlet for the metal ore 102. In some embodiments, the ore may be crushed in a High-Pressure Grinding Roll (HPGR) or equivalent apparatus to crush the ore. Without limitation, for example only, the crusher may be adapted to prepare ore particles of P100 or P80 size (in a range of about 0.5-1 inch, depending on the mineralogical composition of the ore). In some embodiments, prior to the treatment with the first activation solution, the ore or the crushed ore is treated with NOx derived gases (recirculated from the gas processing unit), to generate physical perturbations or mixing into the ore. In some embodiments, prior to or during the treatment with the first activation solution, with the second activation solution, or with the conditioning solution, the metal ore may be wetted using wetting systems until a desirable moisture content is reached, for example only, in a range of 3-12 percent. In some embodiments, the first activation solution, the second activation solution, and the conditioning solution serve the additional function of a wetting solution, enabling the desired moisture content in the metal ore to be reached when they are applied.

[0127] In some embodiments, the inlet for the metal ore 102 is configured to deposit the metal ore into the first chamber 104 of the multi-chamber agglomeration device 101 , which first chamber is operably connected to the feeding inlet 103a for the first activation solution comprising nitrate ions, nitrite ions, or combination thereof. In some embodiments, the metal ore is deposited from inlet 102 into the first chamber 104 via a conveyer belt.

[0128] The inlets in Fig. 3 are sized with suitable pumping according to the desired flow rates and / or irrigation rates. In some embodiments, the inlets for feeding the solutions into the chambers of the multi-chamber agglomeration device are individually connected to a mixer (not shown in the figure) which may be a continuous stirred tank reactor (CSTR) or other engineering unit capable of maintaining an aqueous solution of the desired composition and optionally the raffinate from the solvent extraction (SX) process at a predetermined concentration of the reagents. In some embodiments, the mixer may further comprise one or more inlet conduits to provide one or more of pregnant liquor solution (PLS) from the second chamber, the third chamber, and / or the heap leaching of the metal recovery to provide a desired level of dissolved metal ions in the solutions. Replenishment water, raffinate and make-up reagents may be provided to the mixer.

[0129] The first chamber 104 is configured to treat the metal ore with the first activation solution supplied by the inlet 103a where the first activation solution is embedded or evenly distributed into the metal ore to form the aggregates comprising metal ore and nitrate ions, nitrite ions, or combination thereof. Details of the first activation solution, and the embedding of the first activation solution into the metal ore have been described herein. In some embodiments, the first chamber 104 is optionally connected to an outlet 103b to collect any runoff solution from the first chamber which may be recirculated back to inlet 103a for the first chamber (the recirculation not shown in the figures).

[0130] As shown in Fig. 3, the first chamber 104 in the multi-chamber agglomeration device 101 is operably connected to the second chamber 106, which second chamber is operably connected to an inlet for the second activation solution 105a and optionally the nitrate / nitrite recovery solution. The aggregates produced in the first chamber are transferred to the second chamber using any means to transfer the ore, such as, but not limited to, conveyer belt operating between the two chambers, physical rolling of the aggregates from the first chamber to the second chamber, retraction of the partition (explained further herein); and / or the use of the gravity pulling the aggregates from the first chamber to the second chamber. Not all means are shown in the figure and any one or more of these means can be employed depending on the ore and the convenience. The second chamber 106 is configured to irrigate the aggregates of the metal ore with the second activation solution comprising one or more concentrated acids supplied by the inlet 105a and cause volumetric expansion in the aggregates to form the agglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases. In some embodiments, the second chamber106 is also configured to apply the nitrate / nitrite recovering solution supplied by the inlet 105a or an additional inlet (not shown in Fig. 3) to the aggregates of the metal ore to recover any unreacted nitrate ions, nitrite ions, or combination thereof. Details of the second activation solution, the nitrate / nitrite recovering solution, the volumetric expansion in the aggregates, and the activated metal in the agglomerates have all been described herein.

[0131] In some embodiments, the second chamber of the multi-chamber agglomeration device is configured to withstand and control the gas release (and volumetric expansion in the aggregates) caused by the contact of the first activation solution with the second activation solution that results in the formation of high amounts of NOx gases. The innovative design of the multi-chamber agglomeration device not just contains the emission of the harmful NOx gases but also sequesters and captures the NOx gases for further processing (described further herein). Accordingly, the material for the chamber and / or the entire multi-chamber agglomeration device comprises an explosion and corrosion resistant material such as, but not limited to, stainless steel, titanium, steel with special coating, high density polymer, or any other material that withstands abrasion and / or corrosion, and the like.

[0132] In some embodiments, the second chamber is configured with components such as, but not limited to one or more valves, probes such as temperature, pressure, etc. in order to irrigate and mix the second activation solution with the aggregates. In some embodiments, the second chamber 106 is optionally connected to an outlet 105b to collect any PLS solution from the second chamber which may be transferred to the PLS pond 113.

[0133] As shown in Fig. 3, the second chamber 106 in the multi-chamber agglomeration device 101 is optionally operably connected to the third chamber 110, which third chamber is operably connected to an inlet for the conditioning solution 109a. The agglomerates produced in the second chamber 106 are transferred to the third chamber 110 using any means to transfer the ore, such as, but not limited to, conveyer belt operating between the two chambers, physical rolling of the agglomerates from the second chamber to the third chamber, retraction of the partition (explained further herein); and / or the use of the gravity pulling the agglomerates from the second chamber to the third chamber. All of such means are not shown in the figure and any one or more of these means can be employed depending on the ore and the convenience. The third chamber 110 is configured to irrigate the agglomerates of the metal ore with the solution of the conditioning agentselected from the group consisting of stabilizer, surfactant, sorbent, oxidizer, or mixtures thereof, supplied by the inlet 109a. In some embodiments, the third chamber 110 is also configured to apply the nitrate / nitrite recovering solution supplied by the inlet 109a or an additional inlet (not shown in Fig. 3) to the agglomerates of the metal ore to recover any unreacted nitrate ions, nitrite ions, or combination thereof. Details of the conditioning agent / solution and the nitrate / nitrite recovering solution have been described herein.

[0134] In some embodiments, the third chamber is configured with components such as, but not limited to one or more valves, probes such as temperature, pressure, etc. in order to irrigate and mix the conditioning solution with the agglomerates. In some embodiments, the third chamber 110 is optionally connected to an outlet 109b to collect the PLS solution from the third chamber which may be transferred to the PLS pond 113. In some embodiments, one or more of the outlets 103b, 105b, and 109b are operably connected to a conduit or a pipe 116 to collect the solution exiting the chambers and direct it to the PLS pond 113. In some embodiments, the outlets connect to the conduit or the pipe or in some embodiments, the outlets connect directly and individually to the PLS pond. All of such embodiments are well within the scope of the invention. It is to be understood that the conduit or the pipe 116 as well as the outlets are optional features to the design of the multi-chamber agglomeration device.

[0135] In embodiments where the conditioning agent is a gas, e.g., the gaseous oxidizing agent may be bubbled through the agglomerates of the metal ore via a perforated tube using gas supplied under pressure. In some embodiments, the liquid reagent may be piped and an opening above the liquid level in the tank may be provided as an inlet for solid reagent.

[0136] In some embodiments, the PLS or the metal-rich solution, such as e.g., copper rich solution from the outlets 103b, 105b and / or 109b or the pipe 116 may be collected on a sloped impermeable liner or pad before being directed to the PLS storage pond 113. The PLS solution from the PLS pond may be subjected to solvent extraction and metal recovery.

[0137] In some embodiments, the first chamber and the second chamber and / or the second chamber and the third chamber are partially or fully separated from each other by a partition 107. In some embodiments, partition 107 may be any means to separate the ingredients of the first chamber from the second chamber and / or the ingredients of the second chamber from the third chamber such as, but not limited to, a retractable door, an air knife blower or a mesh. In some embodiments, the partition may be manually,mechanically, or automatedly retracted to transfer the metal ore from one chamber to the other. While Fig. 3 shows the partition 107 separating the first chamber from the second chamber and separating the second chamber from the third chamber, it is to be understood that no partition may be needed for the multi-chamber agglomeration device. In some embodiments, the metal ore may be transferred from one chamber to the other chamber through means such as, e.g., conveyer belt where the metal ore is irrigated with appropriate solutions in each chamber. As such, all such embodiments are well within the scope of the invention.

[0138] As described earlier, when the first activation solution, such as the nitrate and / or the nitrite ions comes into contact with the second activation solution, such as, the concentrated sulfuric acid in the second chamber of the multi-chamber agglomeration device, large amounts of NOx gases are released both during and after the agglomeration process including, but not limited to, conditioning, curing, stacking and heap leaching stage. The NOx gases (as shown in the figures) are then captured and further processed. The uniquely designed multi-chamber agglomeration device of the invention not just contains the harmful NOx gases in an enclosed environment but also extracts and scrubs the gases to prevent them from harming the environment. Furthermore, these gases may be analyzed in real time using an appropriate device, such as, e.g., a gas analyzer.

[0139] In some embodiments of the system aspects and embodiments provided herein, the multi-chamber agglomeration device further comprises an extraction pipe operably connected to the second chamber and optionally the third chamber and is configured to capture and extract the NOx gases from the chamber. This embodiment is illustrated in Fig. 3 where the extraction pipe 108 is located inside the second chamber 106 where the NOx gases are extracted. In some embodiments, the extraction pipe 108 may also extend to the third chamber 110 (shown by dashed lines) where the NOx gases are further removed. In some embodiments, the extraction pipe is fixed inside the second chamber and optionally the third chamber or is retractable where the pipe is moved back and forth between the chambers. In some embodiments, the extraction pipe is configured to extract NOx gases via perforations on the pipe. In some embodiments, the extraction pipe is operably connected to a pump or a vacuum or a fan or an exhaust fan (not shown in figures) to suck the NOx gases and extract the gases from the chamber. In some embodiments, the extraction pipe is configured with fan-like structure with blades to extract the gases from the chamber and drive them towards the gas processing unit. While Fig. 3 illustrates the configuration where the extraction pipe is exiting the first chamber and isconnecting to the gas processing unit; in another configuration the extraction pipe may exit from the other end, i.e. , the third chamber and connect to the gas processing unit; in yet another configuration, the extraction pipe goes vertically through the second chamber without going through the first or the third chamber. All of such configurations are well within the scope of the invention and one or more of the aforementioned embodiments may be combined to design the multi-chamber agglomeration device of the invention.

[0140] In some embodiments, the multi-chamber agglomeration device is operably connected to a gas processing unit 111 comprising a gas scrubber where the gas scrubber is operably connected to the extraction pipe and is configured to scrub and process the NOx gases. In some embodiments, the NOx gases may be subjected to an oxidation process previous to their recovery. In some embodiments, the gas scrubber is a wet scrubber (or absorber) which uses either alkali in water, water alone, or hydrogen peroxide as the liquid that captures the NOx. In some embodiments, the wet scrubber may operate by liquid flowing downward by gravity through a packing medium, opposed by an upward flow of NOx gases. Scrubbers may operate on the interchange of substances between gas and liquid. The height of the absorber, type of packing, liquid flow, liquid properties, gas properties, and gas flow may collectively cause a scrubber to have the desired control efficiency.

[0141] In some embodiments, the gas processing unit comprises filters that can be an electrostatic precipitator, a membrane filter, or any other type of filter, which is installed before the fan, before the gas scrubber, and / or in the extraction pipe 108, which allows retaining the particles of the NOx gases preventing their re-entering in the chamber along with the gases.

[0142] In some embodiments, after the conditioning of the agglomerates in chamber 110, the multi-chamber agglomeration device 101 is configured to transfer the treated agglomerates to a tank or container or the like 115 through an outlet or a conduit or a pipe or the like 114. The agglomerates are further sent for stacking and heap leaching. Processing systems such as, e.g., ponds, tanks and inlet systems used in different embodiments herein may include heating systems for controlling the temperature as well as filters which may be used for cleaning of processes streams and / or mixtures to remove undesired byproducts, precipitants, contaminant metals and solids, and the like.

[0143] In further embodiments, the multi-chamber agglomeration device includes an electric resistance heater placed on its mantle. In further embodiments, the multi-chamberagglomeration devices include thermal insulation to reduce heat loss and improve energy efficiency.

[0144] Various solvent extraction / electrowinning (SX / EW) components (not shown in Fig. 3) that may be included in the system embodiments, e.g., an SX / EW loop including at least one Solvent Extraction process unit for the treatment of at least one PLS stream. Examples of some of the SX process units include, units which may accept a metal lean electrolyte stream as input and produce corresponding metal-depleted raffinate stream as output; an EW unit providing a metal lean electrolyte stream as output; a rich electrolyte tank system, which may receive a metal rich electrolyte stream as input, and may produce a metal rich electrolyte stream as output (which may, e.g., be fed into an EW unit); a lean electrolyte tank system, which may receive a metal lean electrolyte stream as input (e.g., from an EW unit) and may produce metal lean electrolyte streams as output (e.g., to feed one or more corresponding SX units).

[0145] The methods and systems provided herein may also include one or more detectors configured for monitoring the source of water, the source of the reagents, the source of the metal ore, and / or the activation and conditioning agents / solutions (not illustrated in figures). Monitoring may include, but is not limited to, collecting data about the pressure, temperature and composition of the solutions, the reagents, and / or the NOx gases. The detectors may be any convenient device configured to monitor, for example, pressure sensors (e.g., electromagnetic pressure sensors, potentiometric pressure sensors, etc.), temperature sensors (resistance temperature detectors, thermocouples, gas thermometers, thermistors, pyrometers, infrared radiation sensors, etc.), volume sensors (e.g., geophysical diffraction tomography, X-ray tomography, hydroacoustic surveyors, etc.), moisture sensor (e.g., infrared sensors), and devices for determining chemical makeup of the solutions (e.g. IR spectrometer, NMR spectrometer, UV-vis spectrophotometer, high performance liquid chromatographs, inductively coupled plasma emission spectrometers, inductively coupled plasma mass spectrometers, ion chromatographs, X-ray diffractometers, gas chromatographs, gas chromatography-mass spectrometers, flow-injection analysis, scintillation counters, acidimetric titration, and flame emission spectrometers, etc.).

[0146] In some embodiments, the detector may be a monitoring device such that it can collect real-time data (e.g., internal pressure, temperature, moisture, etc.). In other embodiments, the detector may be one or more detectors configured to determine the parameters at regular intervals, e.g., determining the composition every 1 minute, every 5minutes, every 10 minutes, every 30 minutes, every 60 minutes, every day, every few days, or some other interval.

[0147] In some embodiments, the systems may include a control station, configured to control the concentrations and / or the amount and / or the irrigation rates of the activation and the conditioning solutions; the amount of the metal ore; etc. A control station may include a set of valves or multi-valve systems which are manually, mechanically or digitally controlled, or may employ any other convenient flow regulator protocol. In some instances, the control station may include a computer interface, (where regulation is computer-assisted or is entirely controlled by computer) configured to provide a user with input and output parameters to control the amount, as described above.

[0148] In some embodiments, the detectors may also include a computer interface which is configured to provide a user with the collected data about the activation solutions, the conditioning solutions, the concentrations, the irrigation rates, the flow rates, the gas emissions, the pressure, the temperature, etc. In some embodiments, the summary may be stored as a computer readable data file or may be printed out as a user readable document.

[0149] Throughout the description, where compositions or solutions are described as having, including, or comprising specific components, or where systems and methods are described as having, including, or comprising specific steps, it is contemplated that, additionally, there are compositions or solutions of the present invention that consist essentially of, or consist of, the recited components, and that there are systems and methods according to the present invention that consist essentially of, or consist of, the recited processing steps.

[0150] In the application, where an element or component is said to be included in and / or selected from a list of recited elements or components, it should be understood that the element or component can be any one of the recited elements or components, or the element or component can be selected from a group consisting of two or more of the recited elements or components.

[0151] Further, it should be understood that elements and / or features of a composition or a method or system described herein can be combined in a variety of ways without departing from the spirit and scope of the present invention, whether explicit or implicit herein. For example, where reference is made to a particular solution, that solution can be used in various embodiments of solutions of the present invention and / or in methods of the present invention, unless otherwise understood from the context. In other words, withinthis application, embodiments have been described and depicted in a way that enables a clear and concise application to be written and drawn, but it is intended and will be appreciated that embodiments may be variously combined or separated without parting from the present teachings and invention(s). For example, it will be appreciated that all features described and depicted herein can be applicable to all aspects of the invention(s) described and depicted herein.

[0152] Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.

[0153] The use of the term “include,” “includes,” “including,” “have,” “has,” “having,” “contain,” “contains,” or “containing,” including grammatical equivalents thereof, should be understood generally as open-ended and non-limiting, for example, not excluding additional unrecited elements or steps, unless otherwise specifically stated or understood from the context.

[0154] The use of any and all examples, or exemplary language herein, for example, “such as” or “including,” is intended merely to illustrate better the present invention and does not pose a limitation on the scope of the invention unless claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the present invention.

[0155] Certain ranges are presented herein with numerical values being preceded by the term "about." The term "about" is used herein to provide literal support for the exact number that it precedes, as well as a number that is near to or approximately the number that the term precedes. As used herein, the term “about” refers to a ±10% variation from the nominal value unless otherwise indicated or inferred.

[0156] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the invention, representative illustrative methods and materials are described herein.

[0157] All publications, patents, and patent applications cited in this specification are incorporated herein by reference to the same extent as if each individual publication, patent, or patent application were specifically and individually indicated to be incorporated by reference. Furthermore, each cited publication, patent, or patent application is incorporated herein by reference to disclose and describe the subject matter in connection with which the publications are cited. The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the invention described herein is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates, which may need to be independently confirmed.

[0158] It should be understood that the expression “at least one of” includes individually each of the recited objects after the expression and the various combinations of two or more of the recited objects unless otherwise understood from the context and use. The expression “and / or” in connection with three or more recited objects should be understood to have the same meaning unless otherwise understood from the context.

[0159] It is noted that, as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation.

[0160] As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the invention. Any recited method can be carried out in the order of events recited or in any other order, which is logically possible. It should be understood that the order of steps or order for performing certain actions is immaterial so long as the present invention remains operable. Moreover, two or more steps or actions may be conducted simultaneously.

[0161] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the invention and are not intended to limit the scope of what the inventors regard as their invention nor are they intended to represent that the experiments below are all or the only experiments performed. Efforts have been made to ensure accuracy with respect to numbers used(e.g. amounts, temperature, etc.) but some experimental errors and deviations should be accounted for.

[0162] In the examples and elsewhere, abbreviations have the following meanings:EXAMPLESExample 1Effect of the sequential activation of copper in copper recovery from copper ore compared to one step treatment

[0163] In the sequential addition experiment, 50 kg of crushed copper sulfide ore (e.g., about 80-95% of the contained copper as chalcopyrite, and to a lesser extent, secondary copper sulfide ore (up to 10% of the contained copper as covellite; and up to 10% of the contained copper as chalcocite / digenite); ore size of the crushed material is 80% under 3 / 4" (3 / 4 inch)) is introduced into an agglomeration drum, which operates at 10 RPM. In the first step, the first activation solution comprising a solution of nitrate ions dissolved in diluted acid (e.g., sulfuric acid) is added to the rolling ore until a moisture content of 3-5% is reached. Subsequently, the second activation solution comprising a concentrated acid solution is added to the rolling ore, until a moisture content of 7-11% is reached. Then, the copper ore is loaded into a leaching column with a height of one meter, where the treated material is left to rest for about 5-15 days. Finally, the leaching column is subjected to a leaching step, after which the obtained PLS is analyzed to determine the copper extraction. At each stage of the process, NOx emissions are monitored.

[0164] As a negative control, the same amount of crushed ore described above is subjected to a one step process, wherein the nitrate dissolved in the concentrated sulfuric acid is added into the rolling ore in a unique solution. This irrigation reaches the same nitrate dose, acid dose, and moisture content as found in the experiment described above, for about 10-45 minutes but in only one step. The subsequent steps, including column loading, resting, and leaching remain consistent.

[0165] In Table III, the composition and the operational parameters of the sequential addition experiment for the activation of copper in the copper ore are shown.Table III: Operational parameters in the activation step

[0166] Enhanced recovery of the metal may be defined as an increase in metal recovery above the maximum recovery achieved by a standard leaching process. Fig. 4 depicts the effect of the sequential method of addition on copper recovery as compared to the negative control with one step method where both the activation solutions are added at the same time. As shown in Fig. 4, an enhanced copper recovery / extraction is achieved when the copper ore is subjected to the sequential method of activation A, compared to the negative control B. This enhanced copper recovery is obtained due to the effect of the sequential addition of nitrate and the concentrated sulfuric acid, where the nitrate applied in the first activation step embeds the crushed ore but may not fully react with it. When the concentrated sulfuric acid is then added, the nitrate begins to react strongly, causing volumetric expansion and gas release within the copper ore and activating copper metal for the subsequent leaching step. The multi-chamber agglomeration device provided herein concentrates the NOx emissions inside the agglomeration chamber and reduces its production outside the agglomeration drum.Example 2Effect of the sequential activation of copper in copper ore on hydraulic properties

[0167] In this experiment, the same conditions are applied as in Example 1 for the sequential addition experiment and the negative control. However, after the copper ore is treated with the first activation solution and the second activation solution, the ore is dried in an oven at 50°C for 24 hours. Then, the permeability of the dried material is measured with a permeameter. In Table III above, the operational parameters of this experiment are shown.

[0168] It is observed that the invention works more effectively when employed as the sequential addition of the first activating solution and the second activating solution,whereby the permeability of the treated ore is enhanced. The sequential addition allows for more effective permeability, whereby the first step of the addition of the nitrate solution facilitates the homogenization of the reagent across the surface of the ore. Subsequently, the second step of the addition of the concentrated sulfuric acid represents the primary step of the reaction, occurring in contact with the concentrated sulfuric acid within the homogeneous solution of the nitrate over the surface of the ore. This reaction results in the ore being affected by expansion of the channels, micro-channels, veins and microveins in the ore, thereby improving access to leaching solutions in subsequent steps due to its enhanced permeability. In contrast, the negative control results in a different outcome, with the principal reaction occurring between concentrated sulfuric acid and nitrate as an instantaneous reaction, without any mechanochemical effect on the copper ore.Example 3Nitrate recovery

[0169] In this experiment, the same conditions apply as in Example 1 for the sequential addition experiment. However, after treating the copper ore with the first activation solution and the second activation solution, a solution comprising ferrous ions in a concentration between 5 to 30 g / L is applied to the ore, which corresponds to the nitrate recovery step. As a negative control, acidified water lacking ferrous ions is added in this step. The application of the solution comprising ferrous ions produces the emission of NOx gases and allows for the recovery of said gases on the ore through a gas scrubber, by 95% when compared to the negative control.Example 4Multi-chamber agglomeration device

[0170] Crushed copper ore is continuously fed into the first chamber of the agglomeration device / drum. In the first chamber of the device, the first activation solution comprising a solution of 200 g / L nitrate ions dissolved in raffinate is irrigated onto the rolling ore. It is estimated that the residence time of the ore in this first chamber is approximately 5-15 minutes, until it reaches the end of the edge of this chamber. Subsequently, the ore is transferred to the second chamber, where the second activation solution comprising a solution of concentrated acid (500 g / L sulfuric acid or around 27 %) is applied to the rolling ore. It is estimated that the residence time of the ore in this second stage is approximately 30 min, until it reaches the end of this chamber. Afterward, the treated ore is transferred to the third chamber, where a conditioning solution containing 1-2% activated charcoal, 0.25-0.5% SDS and 0.4-3 g / L poly aluminum chloride solution is applied onto it. It is estimated that the residence time of the ore in this third stage is approximately 15 minutes, until the conditioned ore reaches the edge of the agglomeration drum. At this point, the ore is transferred to the conveyor belt and loaded into a leaching column with a height of one meter, where the treated material is left to rest for up to 10 days. Finally, the leaching column is subjected to a leaching step, after which the obtained PLS is analyzed to determine the copper extraction. As a parallel assay, part of the treated material that is leaving the agglomeration drum is collected and dried at 60°C for 24 h, with a subsequent permeability measurement with a permeameter. While the crushed copper ore is undergoing treatment inside the agglomeration drum, the gas pipe extractor for capturing the NOx gases is moved along the three chambers inside the drum, and the NOx gas emissions are measured in each of them.

[0171] The maximum production of the NOx emissions happens in the second chamber as the nitrate ions react with sulfuric acid. The third chamber also shows low gas detection compared to the second chamber. Also, the enhancement in the copper extraction is due to the treatment of the ore in three steps rather than one step agglomeration. Finally, enhanced permeability is observed in the treated copper ore as a result of the expansion produced by the aforementioned treatment. This further improves the effectiveness of the leaching process.Example 5Reduced reagents consumption through the employment of the sequential activation compared to one step treatment

[0172] This example illustrates that the sequential activation may reduce reagent consumption and enhance copper extraction during the later leaching step, when compared to a regular one-step agglomeration.

[0173] In this experiment, 38 kg of primary copper sulfide ore (about 80-98 % of the contained copper as chalcopyrite), and to a lesser extent, secondary copper sulfide ore (up to 10% of the contained copper as covellite; and up to 10% of the contained copper as chalcocite / digenite), was crushed to produce a crushed material with an ore size of 80% under 3 / 4" (3 / 4 inch). The crushed material was then divided into three different samples of the same weight. The samples obtained were then individually introduced into the agglomeration drum, which was operated at 10 RPM and treated with different activation / agglomeration regimes, as depicted in Table IV. Particularly, sequential agglomeration was tested and compared to conventional one-step agglomeration with bothlow and high levels of acid and nitrate. Following the activation / agglomeration step, each sample was loaded into leaching columns (with a height of one meter) and left to rest for approximately 5 days. Thereafter, each column was subjected to a 40-day leaching step using a leaching solution comprising sulfuric acid and nitrate at concentrations of 10-20 g / L and 7.5 g / L, respectively, with a pH below 2. The columns were irrigated at 5 L / h.m2The PLS obtained from each column was then analyzed to determine the copper extraction.Table IV: Operational parameters of each column

[0174] Fig. 5 depicts the percentage of copper extraction from the three columns previously subjected to different activation / agglomeration regimes. As demonstrated in the results, columns 3, which was treated with the sequential activation, achieved a higher copper recovery compared to columns 1 and 2, which were treated with a standard one- step agglomeration.

[0175] Furthermore, referring to the dose of acid and nitrate used in each column, Fig. 5 depicts that, for the standard one-step agglomeration, a higher dose of nitrate and acid (column 2) leads to an increase in copper recovery compared to a column with lower doses of both reagents (column 1 ). Surprisingly, even applying a lower dose of acid and nitrate during sequential agglomeration led to significantly higher copper recovery. Specifically, this condition achieved about 18% more copper than one-step agglomeration using the same nitrate and acid levels (column 1 ), and around 13% more than one-step agglomeration with increased nitrate and acid amounts (column 2).

[0176] These findings demonstrate the efficacy of employing the sequential activation process on crushed ore, in terms of copper recovery during the subsequent leaching step. In the sequential activation, the application of the first activation solution to the crushed ore results in the ore being completely embedded in nitrate ions, thereby establishing the basis of the activation process. Then, the application of the second activation solution to the embedded ore results in a vigorous reaction between the distributed nitrate and the acid. This leads to a volumetric expansion and gas release within the ore, activating the ore for the subsequent leaching step with high copper recovery rates.

[0177] Further, these results also demonstrate a surprising and unexpected result that acid and nitrate doses are not necessary for achieving a higher copper recovery. Any person having ordinary skill in the art would normally assert that, only when higher doses of acid and nitrate are applied to a crushed ore, a better agglomeration may be produced, leading to a higher copper recovery from the ore during the leaching step. Nevertheless, using a sequential activation even with low levels of nitrate and acid boosts the copper extraction from the ore. In one-step, the application of nitrate and acid to the crushed ore may result in a higher and abrupt reaction between those reagents upon the crushed ore failing to activate the copper ore in the ore matrix efficiently. On the contrary, the sequential reaction between the acid solution and the mineral impregnated with the reactive solution rich in nitrate and ferric causes an increase in corrosion of the mineral on the surface as well as the interior, improving access to copper in the following leaching step. As demonstrated, this behavior leads to a reduction in the acid and nitrate dosing, where less acid and nitrate is required to achieve a higher copper extraction.Example 6Reduced NOx emissions through the employment of the sequential activation compared to one step treatment

[0178] This example illustrates the effect of the sequential activation on reducing NOx emissions from the activated ore.

[0179] In this experiment, 25 kg of primary copper sulfide ore (about 80-98 % of the contained copper as chalcopyrite), and to a lesser extent, secondary copper sulfide ore (up to 10% of the contained copper as covellite; and up to 10% of the contained copper as chalcocite / digenite), was crushed to produce a crushed material with an ore size of 80% under 3 / 4" (3 / 4 inch). The crushed material was then divided into two different samples of the same weight. One sample was introduced into an agglomeration drum, which was operated at 10 RPM. In the first step of the sequential activation, a first activation solution comprising a solution of nitrate ions dissolved in diluted acid (e.g., sulfuric acid) was added to the rolling ore until a moisture content of 3-5% was reached. Following this, a second activation solution comprising a concentrated acid solution was added to the rolling ore, until a moisture content of 6-8% in the ore was reached. Then, the copper ore was loaded into a leaching column with a height of one meter. The treated, loaded material was left to rest for approximately 5 days, after which it was subjected to a 15-day leaching step with a leaching solution comprising sulfuric acid and nitrate at a concentration of 10-20 g / L and 7.5 g / L, respectively. Here, the columns were irrigated at 5 L / h.m2During this period, NOx emissions were monitored every 5 days.

[0180] As a negative control, the other sample of crushed ore was subjected to a regular, one-step agglomeration. In this process, the nitrate dissolved in the concentrated sulfuric acid was added to the rolling ore in a unique solution.

[0181] In Table V, the composition and the operational parameters of the sequential activation and the regular one-step agglomeration are shown.Table V: Operational parameters

[0182] The reduction in NOx emissions resulting from the sequential activation may be clearly demonstrated by comparing the levels of NOx emissions observed during theresting and leaching steps, when using the sequential activation process as opposed to the regular, one step agglomeration.

[0183] Fig. 6 depicts the impact of the sequential activation on NOx emissions compared to the application of the negative control (regular one-step agglomeration). These NOx emissions were measured at the beginning and at the end of the resting step (day 0 and 5), as well as the leaching step (from day 5 to 20). As shown in Fig. 6, an average increase in NOx gas emissions can be observed from the column subjected to a regular agglomeration process during the resting and leaching stages, in contrast to the column subjected to the sequential activation. The only day where a higher NOx gas emission from the sequential activation was observed was at the beginning of the resting stage, with an emission of 2 mg / Nm3In the following days, the NOx emissions of this column were found to be lower than those of the column with a regular agglomeration, with levels of less than 10 mg / Nm3being achieved. In contrast, the column with a regular agglomeration achieved NOx emissions in a range of 11 to 37 mg / Nm3, in the leaching step. As a reference, it is important to note that Chilean law stipulates a maximum NOx emission limit of 50 mg / Nm3, when gaseous fuels are used in the industry.

[0184] The application of the sequential activation to a copper sulfide ore, as demonstrated in this experiment, results in enhanced NOx emission control following ore stacking, resting and leaching. The implementation of this technology results in the generation of NOx emissions during the activation step in the agglomeration drum. This forced NOx production can also be observed at the beginning of the resting step (which also corresponds to the end of the activation step), which ultimately leads to a reduction of these emissions on the consecutive stages. In contrast, an ore treated with regular agglomeration retains a significant amount of unreacted nitrate. This nitrate reacts with the leaching solution during the leaching stage, which results in NOx emission for an extended period of time.Example 7Structural modifications in the copper ore

[0185] This example shows that the sequential activation may increase copper accessibility in copper ore by enabling cracks, channels, micro-channels, veins and microveins within the ore, as well as by improving the interconnection between them. These structural modifications improve the permeability of solutions, such as those used for leaching, through these newly enabled pathways on both the surface and in the matrix of the activated ore. Consequently, this approach facilitates an enhancement in copperextraction during subsequent leaching steps compared to a regular one-step agglomeration.

[0186] In this experiment, 25 kg of primary copper sulfide ore (about 80-98 % of the contained copper as chalcopyrite), and to a lesser extent, secondary copper sulfide ore (up to 10% of the contained copper as covellite; and up to 10% of the contained copper as chalcocite / digenite), was crushed to produce a crushed material with an ore size of 80% under 3 / 4" (3 / 4 inch). The crushed material was then divided into two different samples of the same weight. The samples obtained were then individually introduced into the agglomeration drum, which was operated at 10 RPM and treated with different activation / agglomeration regimes, as depicted in Table VI below. After the activation / agglomeration process, each sample was left to rest for 5 days. After the resting period, the mineral was washed with water and then dried until the total moisture content was less than 1%.Table VI: Operational parameters for each column

[0187] Structural and morphometric features for each sample were determined using a Bruker SkyScan 1273 X-ray microtomography analyzer. These features include surface image, along with the Euler characteristic parameter, the connectivity density and the anisotropy of each sample. A pixel size of 8 pm and 700 layers were the setup parameters for each analysis. The resulting data was processed using Bruker 3D. Suite software (CTVox v3.0, DataViewer, and CTAn v1 .20.8.0) for ore image reconstruction and parameter quantification.

[0188] The increase in copper exposure resulting from the sequential activation may be clearly demonstrated by comparing the structural and morphometric features that were determined in a copper ore subjected to this process, with those determined in copper ore processes through a regular one step agglomeration.

[0189] Fig. 7 depicts the surfaces of copper ore subjected to sequential activation and regular one step agglomeration, respectively. Examination revealed that copper oretreated with the sequential activation (A) exhibited greater definition in the veins and channels, along with a more extensively connected porous structure within the ore matrix. Conversely, copper ore treated through regular agglomeration (B) exhibited poor sharpness in the veins and channels, with minimal connectivity in the porous structure of the ore matrix.Table VII: Results of X-ray micro tomography

[0190] Table VII presents the structural and morphometric features determined in each of the previously described samples. The data indicates that the sequential activation significantly enhances the connectivity density of the ore, leading to an order-of-magnitude increase compared to the regular agglomeration. Furthermore, the Euler characteristic, a measure of structural connectivity (negative values for high connectivity in a structure, positive values for poorly connected structures), indicates that the sequential activation promotes structural changes in the ore, improving its internal connectivity. Finally, the degree of anisotropy, which reflects the variation of a material property with respect to direction, that helps to reveal organized patterns (value of 1 for complete isotropy) from randomness (infinite value for complete anisotropy), demonstrates that the sequential activation produces treated sample with consistent distribution of veins, channels and porous structures, resulting in an ore that exhibits uniform permeation characteristics.

[0191] The increased connectivity density of the material, the negative value of the Euler characteristic, and the more uniform isotropic behavior of the sample, resulting from the sequential activation, indicates that any liquid solution would permeate the ore more easily and uniformly. This result can be explained by the effect of the sequential application of the two reactive solutions. The first activation solution, which contains a high concentration of nitrate, wets the copper ore. The second activation solution, which contains a high concentration of acid, reacts with the nitrate that is homogeneously present on and inside the surface of the wetted ore. This reaction alters the ore, releasing and enabling the veins, micro-veins, channels, and microchannels (volumetric expansion) that ultimately expose the copper trapped in the ore to the action of any leaching solution used in asubsequent leaching stage. This results in enhanced copper extraction and kinetic extraction. Conversely, when each solution is applied in a single step, the reaction between the ore and the solution is less vigorous and the exothermic synergistic effect between the ore impregnated with ferric and nitrate and the concentrated acid would not occur. Hence, the simultaneous application of these two reagents in a single step, as is typically in a regular agglomeration, would result the two reagents undergo reaction prior to their application to the ore, diminishing their effectiveness in disrupting the ore matrix. As a result, the desired structural modification necessary for enhanced copper recovery during a subsequent leaching process would not be achieved.

[0192] Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it should be readily apparent to those of ordinary skill in the art in light of the teachings of this invention that certain changes and modifications may be made thereto without departing from the spirit or scope of the appended claims. Accordingly, the preceding merely illustrates the principles of the invention. It will be appreciated that those skilled in the art will be able to devise various arrangements, which, although not explicitly described or shown herein, embody the principles of the invention, and are included within its spirit and scope. Furthermore, all examples and conditional language recited herein are principally intended to aid the reader in understanding the principles of the invention and the concepts contributed by the inventors to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents and equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure. The scope of the invention, therefore, is not intended to be limited to the exemplary embodiments shown and described herein. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims

CLAIMS1 . A sequential method to activate metal in a metal ore for leaching, comprising: treating a metal ore with a first activation solution comprising nitrate ions, nitrite ions, or combination thereof and forming aggregates, wherein the aggregates comprise metal ore and nitrate ions, nitrite ions, or combination thereof; and irrigating the aggregates with a second activation solution comprising one or more concentrated acids and causing volumetric expansion in the metal ore to form agglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases, thereby sequentially activating the metal in the metal ore.2 The sequential method of claim 1 , comprising evenly distributing or embedding the first activation solution in the metal ore to form the aggregates.3 The sequential method of claim 2, wherein the even distribution or the embedding of the first activation solution results in an effective distribution of the volumetric expansion in the metal ore to activate the metal in the agglomerates.4 The sequential method of claim 1 , wherein the volumetric expansion in the metal ore activates the metal and facilitates leaching of the metal from the metal ore.5 The sequential method of claim 1 , comprising causing gas release in the metal ore and the volumetric expansion after the irrigation of the aggregates with the second activation solution.6 The sequential method of claim 1 , comprising causing effective permeability from the surface of the metal ore to its inside by the volumetric expansion, by the sequential treating and the irrigating steps.7 The sequential method of claim 1 , wherein the sequential treating and the irrigating steps enhance hydraulic conductivity by between about 2-20% compared to a non-sequential method.8 The sequential method of claim 1 , wherein the sequential method increases the leaching of the metal from the metal ore by between about 2-20% compared to a non-sequential method.9 The sequential method of claim 1 , wherein the first activation solution comprises nitrate ions, nitrite ions, or combination thereof at a concentration above about 50 g / L and below about 300 g / L.

10. The sequential method of claim 1 , wherein dose of the nitrate and / or the nitrite ions from the first activation solution onto the metal ore is in a range of between about 0.5 kg / ton ore - 30 kg / ton ore.

11. The sequential method of claim 1 , wherein the first activation solution further comprises a redox modulating agent.

12. The sequential method of claim 11 , wherein the redox modulating agent is selected from the group consisting of an oxidant gas, highly oxidant reagent, iron-oxidizing microorganism, sulfur-oxidizing microorganism, ozone, oxygen, hydrogen peroxide, air, and a mixture thereof.

13. The sequential method of claim 1 , wherein the second activation solution comprises one or more concentrated acids in a concentration between about 70 g / L and about 1800 g / L.

14. The sequential method of claim 1 , wherein dose of the one or more concentrated acids from the second activation solution onto the mineral ore is in a range of between about 1 kg / ton ore - 50 kg / ton ore.

15. The sequential method of claim 1 , wherein the one or more concentrated acids are selected from the group consisting of sulfuric acid, nitric acid, and mixture thereof.

16. The sequential method of claim 1 , wherein concentration of the first activation solution and the second activation solution is in a ratio of between about 1 :1 to 1 :50.

17. The sequential method of claim 1 , further comprising capturing and separating the NOx gases from the agglomerates.

18. The sequential method of claim 1 , wherein the first and the second activation solution further comprises chloride salts in a concentration between about 0 g / L to about 25 g / L.

19. The sequential method of claim 1 , wherein the sequential method shortens the time for recovery of the metal from the metal ore and avoids significant NOx emissions from the metal ore heap during leaching.

20. The sequential method of claim 1 , further comprising conditioning the agglomerates with one or more conditioning agents selected from the group consisting of stabilizer, surfactant, sorbent, oxidizer, and mixtures thereof.

21. The sequential method of claim 20, wherein the stabilizer is selected from the group consisting of calcium chloride, calcium carbonate, gypsum, polyacrylamide, polyaluminum chloride (PAC), sodium alginate, sodium aluminate, aluminum sulfate, ferric chloride, starch, carboxymethyl cellulose, and mixtures thereof.

22. The sequential method of claim 20, wherein the surfactant is selected from the group consisting of cetyltrimethylammonium bromide (CTAB), dodecyl trimethyl ammoniumbromide (DTAB), sodium dodecyl sulfate (SDS), sodium oleate, oleic acid, polyethylene oxide 4000 (PEG), bio-surfactant, triethylene glycol (TEG), and mixtures thereof.

23. The sequential method of claim 20, wherein the sorbent is zeolite, activated alumina, activated charcoal, silica gel, calcium chloride, charcoal sulfate, clay, carbon nanotubes, biochar, carbon fibers, graphene oxide, perlite, or mixture thereof.

24. The sequential method of claim 20, wherein the oxidizer is one or more of an oxidant gas, highly oxidant reagent, iron-oxidizing microorganism, sulfur-oxidizing microorganism, or mixture thereof.

25. The sequential method of claim 1 , further comprising after the irrigating step, applying a nitrate / nitrite recovering solution to recover unreacted nitrate, nitrite, or mixture thereof.

26. The sequential method of claim 25, further comprising adding sea water during the activation and / or during the recovery step.

27. The sequential method of claim 25, wherein the nitrate / nitrite recovering solution comprises iron ions.

28. The sequential method of claim 25, wherein the nitrate / nitrite recovering solution comprises ferrous sulfate, iron-containing raffinate, or a mixture thereof.

29. The sequential method of claim 28, wherein concentration of the ferrous ions in the nitrate / nitrite recovering solution is between about 5 g / L and about 50 g / L.

30. The sequential method of claim 25, wherein the first activation solution, the second activating solution and the nitrate / nitrite recovering solution are irrigated or applied at a temperature of up to about 80°C.

31. The sequential method of claim 1 , further comprising subjecting the metal ore to shockwaves during, before, and / or after any of the steps.

32. The sequential method of claim 1 , wherein the metal ore is of metal selected from the group consisting of gold, silver, platinum, copper, nickel, molybdenum, rhenium, tungsten, zirconium, and cobalt.

33. The sequential method of claim 1 , wherein the metal ore comprises copper ore.

34. The sequential method of claim 1 , wherein the metal ore comprises chalcopyrite.

35. A system to activate metal in a metal ore for leaching, comprising: a multi-chamber agglomeration device comprising a first chamber operably connected to an input for metal ore and a feeding inlet for a first activation solution comprising nitrate ions, nitrite ions, or combination thereof, and configured to embed the metal ore with the first activation solution to form aggregates, wherein the aggregates comprise metal ore and nitrate ions, nitrite ions, or combination thereof; anda second chamber operably connected to the first chamber and a feeding inlet for a second activation solution comprising one or more concentrated acids, and configured to mix the aggregates with the second activation solution and cause volumetric expansion in the aggregates to form agglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases.

36. The system of claim 35, wherein the multi-chamber agglomeration device is a drum, a tank, a large conduit, a column, or the like.

37. The system of claim 35, wherein the first chamber and the second chamber are partially or fully separated from each other by a partition.

38. The system of claim 37, wherein the partition is a retractable door between the first chamber and the second chamber.

39. The system of claim 35, wherein the multi-chamber agglomeration device further comprises a third chamber operably connected to the second chamber and a feeding inlet to feed one or more conditioning agents selected from the group consisting of stabilizer, surfactant, sorbent, oxidizer, or mixtures thereof, and configured to mix the agglomerates with the conditioning agent.

40. The system of claim 39, wherein the multi-chamber agglomeration device further comprises an extraction pipe operably connected to the second chamber and optionally the third chamber and configured to capture and extract the NOx gases from the chamber.

41. The system of claim 40, wherein the multi-chamber agglomeration device is operably connected to a gas processing unit comprising a gas scrubber wherein the gas scrubber is operably connected to the extraction pipe and configured to process the NOx gases.

42. The system of claim 39, wherein the second chamber and / or the third chamber further comprise a feeding inlet for a nitrate / nitrite recovering solution configured to apply the nitrate / nitrite recovering solution onto the agglomerates to recover any unreacted nitrate / nitrite ions.

43. The system of claim 42, wherein the nitrate / nitrite recovering solution comprises iron ions.

44. The system of claim 42, wherein the nitrate / nitrite recovering solution comprises ferrous sulfate, iron-containing raffinate, or a mixture thereof.

45. A system to activate metal in a metal ore for leaching, comprising: a multi-chamber agglomeration device comprising a first chamber operably connected to an input for metal ore and a feeding inlet for a first activation solution comprising nitrate ions, nitrite ions, or combination thereof, and configured to embed the metal ore with the first activation solution to form aggregates,wherein the aggregates comprise metal ore and nitrate ions, nitrite ions, or combination thereof; a second chamber operably connected to the first chamber and a feeding inlet for a second activation solution comprising one or more concentrated acids, and configured to mix the aggregates with the second activation solution and cause volumetric expansion in the aggregates to form agglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases; and an extraction pipe operably connected to the second chamber and optionally the first chamber and configured to capture and extract the NOx gases from the chamber. A system to activate metal in a metal ore for leaching, comprising: a multi-chamber agglomeration device comprising a first chamber operably connected to an input for metal ore and a feeding inlet for a first activation solution comprising nitrate ions, nitrite ions, or combination thereof, and configured to embed the metal ore with the first activation solution to form aggregates, wherein the aggregates comprise metal ore and nitrate ions, nitrite ions, or combination thereof; a second chamber operably connected to the first chamber and a feeding inlet for a second activation solution comprising one or more concentrated acids, and configured to mix the aggregates with the second activation solution and cause volumetric expansion in the aggregates to form agglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases; and a third chamber operably connected to the second chamber and a feeding inlet to feed one or more conditioning agents selected from the group consisting of stabilizer, surfactant, sorbent, oxidizer, or mixtures thereof, and configured to mix the agglomerates with the conditioning agent. A system to activate metal in a metal ore for leaching, comprising: a multi-chamber agglomeration device comprising a first chamber operably connected to an input for metal ore and a feeding inlet for a first activation solution comprising nitrate ions, nitrite ions, or combination thereof, and configured to embed the metal ore with the first activation solution to form aggregates, wherein the aggregates comprise metal ore and nitrate ions, nitrite ions, or combination thereof; a second chamber operably connected to the first chamber and a feeding inlet for a second activation solution comprising one or more concentrated acids, and configured tomix the aggregates with the second activation solution and cause volumetric expansion in the aggregates to form agglomerates wherein the agglomerates comprise activated metal; metal ore; nitrate ions, nitrite ions, or combination thereof; acid; and NOx gases; a third chamber operably connected to the second chamber and a feeding inlet to feed one or more conditioning agents selected from the group consisting of stabilizer, surfactant, sorbent, oxidizer, or mixtures thereof, and configured to mix the agglomerates with the conditioning agent; and an extraction pipe operably connected to the second chamber and optionally the first and / or a third chamber and configured to capture and extract the NOx gases from the chamber.

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