SYSTEM AND PROCESS FOR PROGRESSIVE REFRACTORY ORE TRANSFORMATION

Abstract

A hydrometallurgical system for processing metal ore includes a dynamic oxidative step in which the ore is irrigated with specific reactive liquid mixtures to progressively transform the ore and maintain conditions for enhanced recovery of metal from the ore by solvent-extraction. In embodiments, the systems described herein may be used for obtaining metal from refractory ores of copper, silver, cobalt, nickel, gold, rhenium, molybdenum, tungsten, and zirconium.

Claims

1. A method for recovering metal from metal ore, comprising: forming a heap of a metal ore; irrigating the heap with a first reactive liquid mixture comprising nitrate ions, sulfuric acid, an oxidizing agent and at least one of ferrous and ferric ions; irrigating the heap with a second reactive liquid mixture comprising sulfuric acid, nitrate ions, at least one of ferrous and ferric ions, an oxidizing agent, and a metal-containing solution; and subjecting the heap to leaching with a leaching solution to obtain a metal-rich pregnant liquor solution (PLS).

2. The method according to claim 1, further comprising, prior to forming the heap, activating crushed metal ore with an agglomerating solution comprising nitrate ions, sulfuric acid, an oxidizing agent, and at least one of ferric ions and ferrous ions.

3. The method according to claim 1, wherein flow rate of irrigating the heap with the first and the second reactive liquid mixtures is in a range of about 0.5-5 L/h.Math.m.sup.2.

4. The method according to claim 1, wherein the metal ore comprises at least one of copper, silver, cobalt, nickel, gold, rhenium, molybdenum, tungsten, zirconium, or combination thereof.

5. The method according to claim 1, wherein the metal ore is copper ore comprising chalcopyrite.

6. The method according to claim 5, comprising irrigating the heap at a flow rate of about 0.5-5 L/h.Math.m.sup.2 with the first reactive liquid mixture until a molar ratio of dissolved copper to chalcopyrite in the heap reaches between about 0.1:1 to 0.3:1.

7. The method according to claim 5, comprising irrigating the heap at a flow rate of about 0.5-5 L/h.Math.m.sup.2 with the second reactive liquid mixture until a molar ratio of dissolved copper to chalcopyrite in the heap reaches between about 0.3:1 to 0.6:1.

8. The method according to claim 1, wherein the oxidizing agent is selected from the group consisting of aqueous hydrogen peroxide, gaseous ozone in micro and nano bubbles, gaseous oxygen in micro and nano bubbles, air in micro and nano bubbles, and a mixture thereof.

9. The method according to claim 1, wherein the first reactive liquid mixture and/or the second reactive liquid mixture comprises nitrate ions at a concentration in a range of about 0.02 M to 0.4 M, sulfuric acid at a concentration in a range of about 0.05 M to 1 M, at least one of ferrous and ferric ions at a concentration in a range of about 0.02 M to 0.3 M, and hydrogen peroxide at a concentration in a range of about 0.03 M to 0.3 M.

10. The method according to claim 1, wherein the metal-containing solution comprises an aqueous stream obtained from the bottom of the heap after the irrigation with the first reactive liquid mixture and/or the second reactive liquid mixture.

11. The method according to claim 10, wherein the leaching solution comprises nitrate ions, sulfuric acid, and at least one of ferric and ferrous ions.

12. The method according to claim 1, wherein the leaching solution further comprises hydrogen peroxide.

13. The method according to claim 1, wherein the leaching solution comprises nitrate ions at a concentration in a range of about 1 mM to 160 mM, sulfuric acid at a concentration in a range of about 0.05 M to 1 M, ferric and/or ferrous ions at a concentration in a range of about 1 mM to 180 mM, and hydrogen peroxide at a concentration in a range of about 0.01-0.3 M.

14. The method according to claim 1, wherein the leaching step is conducted at an irrigation rate of about 5-12 L/h.Math.m.sup.2.

15. The method according to claim 1, further comprising after forming the heap and prior to irrigating the heap with the first reactive liquid mixture, irrigating the heap with a third reactive liquid mixture, wherein the third reactive liquid mixture comprises nitrate ions at a concentration in a range of about 0.4 M to 3.2 M, sulfuric acid at a concentration in a range of about 0.2 M to 3 M, ferric and ferrous ions at a concentration in a total amount of about 0.03 M to 0.18 M, and hydrogen peroxide at a concentration in a range of about 3 mM to 150 mM.

16. The method according to claim 5, wherein irrigating the heap with the third reactive liquid mixture is conducted at an irrigation rate of about 0.5-5 L/h.Math.m.sup.2.

17. The method according to claim 1, wherein the first reactive liquid mixture and the second reactive liquid mixture, each has a redox potential higher than about 770 mV (vs SHE).

18. The method according to claim 1, further comprising subjecting the PLS to solvent extraction to obtain a metal-rich electrolyte stream.

19. The method according to claim 18, further comprising subjecting the metal-rich electrolyte stream to electrowinning to obtain metal cathodes.

20. The method according to claim 1, further comprising allowing the heap to rest in between irrigation for about 5 to 15 days without irrigation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] 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.

[0053] FIG. 1 schematically depicts an overview of the dynamic oxidative process according to embodiments of the invention.

[0054] FIG. 1A is a detail of FIG. 1 depicting details of the dynamic oxidative process.

[0055] FIG. 2 schematically depicts an overview of the dynamic oxidative process, according to other embodiments of the invention.

[0056] FIG. 2A is a detail of FIG. 2 depicting details of the dynamic oxidative process.

[0057] FIG. 3 shows copper recovery achieved according to embodiments of the invention, with comparative examples.

[0058] FIG. 4 shows copper recovery achieved according to embodiments of the invention.

[0059] FIG. 5 schematically depicts a detail of process island according to embodiments of the invention.

[0060] 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

[0061] 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.

[0062] Dynamic oxidation is a process of irrigating a copper heap with one or more oxidative solution(s) at a lower flow rate than is used during a subsequent leaching stage to affect oxidation-reduction potential in the heap and/or to promote chemical activity in the heap, such as (without limitation) a metathesis related mechanism for Cpy dissolution.

[0063] Embodiments described herein relate to one or more dynamic oxidative processes (DOPs) conducted on a heap of copper ore, which increase copper recovery. Broadly speaking, dynamic oxidation process also include a treatment stage referred to herein as dynamic boost, performed after activating and prior to leaching, alone or in combination with other dynamic oxidative processes. The term activation or activating, as used herein, may refer to modifications to conventional agglomeration, such as by addition of nitrate and other reagents. The term oxidative boost may refer to the combination of agglomeration/activation and dynamic boost stages. All of these terms are understood to be aspects of a dynamic oxidative process.

[0064] The overall process achieves its technical effect through irrigation treatments on the ore using specific reactive mixtures, sequences and irrigation rates. Different copper and/or non-copper ores and mineralogical species may be treated and leached according to different embodiments of the invention, as will be apparent from the following description. The DOP stages have been shown to be effective for copper sulfide mineralogical species, including copper sulfides rich in chalcopyrite, and may be used for other species and mixtures, such as chalcocite (Cu.sub.2S), covellite (CuS), enargite (Cu.sub.3AsS.sub.4), bornite (Cu.sub.5FeS.sub.4) and digenite (Cu.sub.9S.sub.5). In some embodiments, the copper sulfide ore contains pyrite (FeS.sub.2) and other iron containing mineralogical species. In some embodiments, the metal ion is copper, converted from Cut to Cu.sup.2+, the metal ion is Fe.sup.2+ converted to Fe.sup.3+. In some embodiments, the oxidation state of the sulfur is 6+, 4+, 2+, 0, 2. The DOP stages are intended to be used with different subsequent leaching systems. Embodiments of the invention may relate to ores other than copper ores. For example, in some aspects, the method may be applied to recover metals from refractory ores of silver, cobalt, nickel, gold, rhenium, molybdenum, tungsten, zirconium and combinations thereof.

[0065] The term copper ore refers broadly to any material containing copper ore, at any stage in the process, including, for example, native ore that has not been treated, and copper ore that has been agglomerated, previously treated or leached, including mine tailings.

[0066] Likewise, the term heap refers to a heap of ore at any stage in the process, after agglomeration and stacking, after treatment with dynamic oxidation solutions, and during leaching. Generally, a heap is formed from agglomerated copper ore, but a heap may be formed from untreated, native ore. A heap may be, for example, approximately 6-10 m high with a flat top surface area of 0.1-1 km.sup.2, although these dimensions are exemplary only and should not be deemed to limit the invention. A heap may be modelled using one or more columns of copper ore containing material to approximate reaction times and kinetics. Therefore, as used herein, a heap includes such column.

[0067] The term irrigation rate is given in units of L/h.Math.m.sup.2, where the volume refers to a volume applied of reactive solution distributed over a specific area of the heap during a period of time and the area refers to the surface area at the top of the heap, or in the case of a column, an equivalent area.

[0068] Ratio of solution per ton of ore or volume ratio, refers to a volume of reactive solution irrigated onto a ton of ore.

[0069] Embodiments herein may be used in connection with leaching secondary and/or primary copper sulfide ore, including chalcopyrite. As used herein, copper ore is said to be primarily copper sulfide if the copper-containing species in the native ore comprise more than 50% by weight primary and secondary copper sulfide species. Likewise, an ore is primarily chalcopyrite if more than 50% of the copper in the ore is contained in chalcopyrite. It is understood in this context that any native ore contains a large amount of gangue and usually more than one species of copper mineral. An ore is said to consist essentially of chalcopyrite (for example) if other species in the native ore effectively do not contribute to the recovery of copper from the ore.

[0070] The refractory nature of Cpy is explained in terms of two main phenomena: the energy of the lattice of the chalcopyrite and the ore surface passivation formed by elemental sulfur, polysulfides, and iron hydroxy compounds as byproducts of conventional chalcopyrite dissolution. These compounds form a layer hindering the metal dissolution from the ore, impeding free diffusion of reagents and slowing down the kinetics of the copper recoveries from the ore. In biologically assisted leaching, the passivation layer is also generated by the growth of microbial communities on the Cpy surface. Overall, the refractory nature of the Cpy and other copper sulfides under traditional acid leaching is intimately related to interphase phenomena and the crystal structure of these chemical compounds. The inventors have noted a Passivation zone that occurs during leaching of copper sulfide ores, a levelling off in the amount of copper recovery generally achievable by acid leaching, in a copper recovery range of about 25% to 32%, which has been difficult to overcome on a commercial scale on heaps, and which is largely believed to be due to ore surface passivation.

[0071] As disclosed herein, the DOP stages cause a progressive transformation in refractory primary sulfide ores, including chalcopyrite (Cpy), resulting in part from continuous diffusion of ions on the ore surface, particularly, on the double layer of the dynamic liquid phase, enabling Cu.sup.2+ ions and eventually NOx-derived chemical species such as NO.sup.+ to diffuse and enter into the crystal lattice of the Cpy, distorting the CuFeS.sub.2 crystal and generating the electrochemical diode [CuFS.sub.2].sub.x[Cu.sub.(1+x) Fe.sub.(1-y) S.sub.2], which is the starting point of an electrochemical succession of catalytic reactions occurring on the Cpy lattice. In this way, the heap chemistry is optimized to unlock copper from refractory mineral species prior to leaching.

[0072] The heap chemistry and the electrochemical regime within the heap render the ore accessible to leaching, which represents a conceptual departure from conventional hydrometallurgy, wherein the driving consideration has always been to accelerate copper dissolution, so that copper cathodes can be generated through electrowinning. A focus on the electrochemical regime in the heap has resulted in processes with lower water requirement (as a result of a smaller volume of recirculating raffinate needed for enabling different and non-canonical electrochemical regimes); low or even eliminated NOx gas emissions (as a result of the chemical involvement of catalytic nitrate and nitrite species in dynamic oxidation, among other factors); and little or no formation of a passivation layer (because electrochemical regimes prevent crystallization or formation of jarosite-derived precipitates and sulfur-derived species on the ore particle surface).

[0073] In general, the baseline treatment of semiconductor n-type and antiferromagnetic materials like Cpy is strongly influenced by the aqueous and the solid state of the process. Oxidative treatment of Cpy breaks and destabilizes the Cpy lattice to release the metal. The addition of oxidants, potentially the formation of microfractures, and NOx-related physical perturbations, result in alterations to the Cpy surface, either directly or indirectly. These alterations may occur at the surface or interior of the crystalline lattice, leading to a distortion in the CuS and FeS molecular bonds and alterations in the electronic densities of the atoms involved, as compared to the basal crystalline structure of Cpy which enables the continuity of electron flows on the Cpy electrode ultimately leading to its dissolution and high copper recoveries observed. Thus, a progressive ore transformation is deployed to facilitate chemical conversion of the refractory structure of the Cpy (CuFeS.sub.2), to chemical intermediate species such as CuS, Cu.sub.2S, and CuS.sub.2. These intermediate species may then be further dissolved in conventional leaching processes.

[0074] Modifications to conventional initial ore agglomeration as well as activation, the dynamic boost, DOP 1 and DOP 2, and finally, the copper-rich solution for further cathode productionthe entire dynamic oxidative processmay be geared to prevent depletion of the [CuFcS.sub.2].sub.x[Cu.sub.(1+x) Fe.sub.(1-y) S.sub.2] diode to minimize the passivation of the Cpy ore surface, allowing dissolution of copper sulfides by further leaching.

[0075] In embodiments, nitrate ions are used in concentrations and dosages below the amounts dictated by the global stoichiometric relationship with Cpy, typically described in the prior art, as follows:

##STR00001##

[0076] Instead, the treatment of refractory ores according to embodiments of the invention relies on the power of breaking and destabilizing the copper sulfide crystal lattice to release copper. As noted, n-type and antiferromagnetic materials like Cpy are strongly influenced by the aqueous and the solid state of the process.

[0077] The progressive ore transformation, activated under high anodic potentials (e.g., above 700 mV, above 750 mV, above 770 mV, 800 mV and above), occurs at the surface of the Cpy as a semiconductor, which becomes electrically charged and shifts the energy level. Therefore, this behavior enables a non-stoichiometric liberation of iron ions and sulfur from the basal lattice and finally generates a diode of Cpy semiconductor type n and p, deficient in iron with electrons flowing through the diode [CuFeS.sub.2].sub.x[Cu.sub.(1+x) Fe.sub.(1-y) S.sub.2], which enables the continuity of electron flows on the Cpy electrode, ultimately leading to its dissolution and high copper recoveries observed.

##STR00002##

[0078] During the dynamic oxidative process, Cpy particles are embedded into a saturated system due to the limited solution drainage and the low moisture of the system (e.g., 3-12%). Moreover, if generated, NOx emissions will be immersed and get trapped into this triphasic system. Nitrate derived chemical species are generated in the aqueous phase, likely including but not limited to NOx, HNO.sub.2, and other highly reactive oxi nitrogenous reactive species (ONRS). This complex system of chemical reactions, governed by capillary-related forces and several catalytic and electrocatalytic mechanisms, finally allows the refractory nature of Cpy to be overcome and further release copper into solution.

[0079] Elevated ion diffusion at the dynamic boost step, and the successive slow and gradual increase in the reactive mixture flow dynamics within the ore body during DOP 1 and DOP 2 stages result in a reduction in the salt precipitation phenomena in pores or over the surface of the ore. This, in turn, reduces passivation of the surface, reduces uncontrolled gas emissions and accelerates copper movement from the lattice of the ore to the liquid phase. Activation, dynamic boost, and DOP1+DOP2 taken separately or together, allow for a reduction in the refractoriness of copper sulfide species.

[0080] The following equations (together with equations (1) and (2)) describe redox reduction of nitrous and nitric acid in the chemical environment of DOP. Nitrate derived species (reactions 4, 5, 6) may react with the semiconductive Cpy to finally oxidize the copper sulfide (reactions 7, 8, 9, 10, 11).

##STR00003##

[0081] A progressive ore transformation is deployed to facilitate the chemical conversion of the refractory structure of the Cpy, to chemical intermediate species such as CuS, Cu.sub.2S, and CuS.sub.2. Thereby, Cu.sup.2+ is released from the Cpy lattice, increasing the molar ratio of copper based on Chalcopyrite [Cu.sup.2+ in solution]/[Cpy]. During DOP, this molar ratio will fluctuate between 0.1-0.3 (in DOP1) and between 0.3 to 0.6 in the DOP2. Metathesis reactions (see below (12)-(15)) may be mediating this process, by means of Cpy transformation into other copper sulfide intermediate species:

##STR00004##

[0082] Furthermore, NOx gases which result from the reaction of nitrate ions with the CuFeS.sub.2 at low pH and in aqueous solution 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 unreacted Cpy, thereby facilitating the conversion of elemental sulfur and polysulfides in sulfuric acid (H.sub.2SO.sub.4) and ultimately, increasing the copper dissolution kinetics of the leaching process. This phenomenon thus contributes to a reduction in NOx emission embedded in the interface gas-liquid and solid, thereby preventing the escape of gases from the heap.

[0083] Thus, dynamic oxidation leverages: a) the electrochemical potential first applied to the system (e.g., above 770 mV, and in embodiments between 770-1000 mV vs SHE); b) on the fast dissolution of the Cpy outer layer forming a conductive layer formed by non-stoichiometric copper and iron sulfides ([CuFS.sub.2].sub.x[Cu.sub.(1+x) Fe.sub.(1-x) S.sub.2]); c) the Cu.sup.2+ ion diffusion; and d) NO.sub.3 derived aqueous species, such as Radical Nitrogen Oxygen Species (NO.sup.+ radical ion generated during the anodic dissolution of Cpy). Overall this multivariable and complex system diminishes the refractoriness of the Cpy crystal, avoiding the depletion of the diode [CuFeS.sub.2].sub.x[Cu.sub.(1+x) Fe.sub.(1-x) S.sub.2], enabling the process to reach a high efficiency within a temperature range of 30-45 C., which is a normal temperature within a copper sulfide heap. In further embodiments, the heap is sheltered with a thermo blanket to keep the temperature at that range.

[0084] The system is designed to integrate fluid dynamics and bespoke solutions, which are dependent on the transformation stage of the treated ore. Moreover, a circulation of various solutions is employed. This integration of precise control and monitoring the triphasic environment system allows for the deployment of the entire refractory ore and at the same time capitalize on the established idle capacity of existing copper mines.

[0085] In FIG. 1, DOP stages according to embodiments of the invention are shown schematically within the lower dashed line box 110. These stages are integrated with elements of a copper recovery system in the process island shown within the upper dashed line box 120.

[0086] Crushed ore is provided by crusher 51 to an agglomeration/activation stage 101 (shown in the detail of FIG. 5). In embodiments, ore may be crushed in a High-Pressure Grinding Roll (HPGR) or equivalent apparatus to generate microfractures into the ore. Without limitation, the crusher may be adapted to prepare ore particles of P100 or P80 size (in a range of about 0.5 to 1 inch, depending on the mineralogical composition of the ore). In some embodiments, prior to the first irrigation, a crushed ore is alternatively treated with NOx derived gases, to generate physical perturbations or microfractures into the ore.

[0087] In the activating step 101, crushed copper ore obtained from crusher 51 may be agglomerated in an agglomeration device 52, such as a drum, with an agglomeration solution provided from an agglomeration solution supply 121.

[0088] In embodiments, activating solution comprises at least nitrate ions, sulfuric acid, at least one of ferric ions and ferrous ions, an oxidizing agent, and water. The crushed particles 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 agglomerates.

[0089] In embodiments, after activating the ore with an agglomerating solution and prior to the first irrigation with the first reactive liquid mixture, the ore is further stabilized. For example, stabilization may comprise but is not limited to: treating the agglomerated ore in a reactor comprising stabilizing reagents selected from the group consisting of gypsum, calcium carbonate, calcium chloride, polyacrylamide or a mixture thereof and mixing the ore with the stabilizing reagents to form improved mechanical agglomerates.

[0090] The reactive mixtures described herein are aqueous. In some embodiments, water for such water-based streams is supplied as raffinate, industrial water, sea water, or a mixture thereof.

[0091] Nitrate may be provided to supply 121 and activating stage 101 in the form of HNO.sub.3 (aq.), and may be provided to the agglomeration solution via agglomeration solution supply pond 121. In embodiments, the concentration of nitrate ion in the activating stage is in a range of about 0.4 M to 3.2 M. Sulfuric acid may be present in a range of about 0.2 M to 3 M. Ferric ions may be present in an amount of about 0.03 M to 0.18 M, provided for example as aqueous ferric sulfate. In embodiments, the oxidation-reduction potential (ORP) versus standard hydrogen electrode (SHE) in the activation stage is greater than or equal to 700 mV. In other embodiments the ORP is greater than 770 mV in the activating stage.

[0092] In some embodiments, the source of nitrate is ammonium nitrate salt, sodium nitrate salt, nitrite salt, nitric acid, nitrous acid, caliche, or a mixture thereof. In some embodiments, the nitrate source contains sulfates, chlorides, magnesium, calcium, potassium, FeAlMgNa silicates, clays, alite, quarts, thenardite, iodine derived salts or a mixture thereof. In some embodiments, the nitrate source is in crystal, granules or refined salt. In some embodiments, the source of nitrate is natural or synthetic. In further embodiments, the nitrate 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-blend.

[0093] In some embodiments, the nitrate source is nitrogen gas converted into nitric acid, nitrous acid or a mixture thereof. In some embodiments, the source of nitrate comprises nitrate sources externally supplied, nitrate sources generated in situ, or a mixture thereof. In further embodiments, the nitrate source is directly injected into the systems from the source. In some embodiments, the nitrate source is added to the system as salt and is mixed within the tank system to form an homogenous solution before being conducted to the ore. In some embodiments, the nitrate source is in the raffinate generated after processing nitrate-containing PLS by solvent extraction. The nitrate source is an ammonia subproduct of industrial processes such as the hydrolysis of water to form hydrogen. The nitrate source may be ammonia oxidized to form intermediate ammonia derived species which is in situ connected to the system. Any of these sources may be combined generating a nitrate blend.

[0094] In further embodiments, the nitrate derived catalytic species are externally generated in a reactor, and directly conducted to contact the ore. In some embodiments, the catalytic species are in situ generated and directly added to the ore surface. In some embodiments, catalytic nitrate-derived species are selected, but not limited, from the group consisting of: nitrate ions, nitrite ions, NO.sub.3.sup., NO.sub.2(g) NO.sub.2(aq), NO.sub.(g), NO.sub.(aq), HNO.sub.2, NO.sup.+, NO.sup.+, NO, N.sub.2O.sup.4 (g) or a mixture thereof. In some embodiments, catalytic nitrate-derived species are mixed with Fc.sup.2+, Fe.sup.3+, Cu.sup.2+ and other cations, [Fe(NO)].sup.2+, or [Cu(NO)].sup.2+/1+ or a mixture thereof.

[0095] In some embodiments, the catalytic species are externally generated in a reactor or tank, connected to the system of solutions and piping in process island 120. In some embodiments, the catalytic species are generated within the heap. In some embodiments, the catalytic species mixture is generated within the heap and externally, in a mixture thereof. In some embodiments, formation of catalytic species is promoted by heating within process island 120.

[0096] In embodiments, the system comprises, within the process island, at least one solid-liquid mixer, at least one stirred tank, and at least one valve in order to mix the nitrate ions, the sulfuric acid, the water, and other compounds fed from each conduit, and prepare the agglomeration solution, the reactive liquid mixture, and the leaching solution. In embodiments, process island 120 is configured to supply specified amounts of the agglomeration solution, the reactive liquid mixtures and the leaching solution according to an amount of copper ore to be treated.

[0097] In some embodiments 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. In further embodiments, the refining process for the acidified solution may be selected from the group consisting of ion exchange, electrochemical separation and solvent extraction. In further embodiments, the ion exchange process for the refining process for the acidified solution comprises treating the acidified solution with any resin absorbing sulfuric acid. In other embodiments, the sulfuric acid is generated in situ by pyrite containing ores and further injected into the system. In other embodiments, 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 other embodiments, the sulfuric acid is recycled from SX process, generating an acid containing raffinate. In other 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.

[0098] In other embodiments, the iron source is a ferric containing raffinate, a ferrous containing raffinate, ferric sulfate, ferrous sulfate, or a mixture thereof. In other embodiments, the ferric source is obtained by externally oxidizing ferrous iron by iron oxidizer bacteria such as Acidithiobacillus ferrooxidans. In further embodiments, the ferric iron is reduced to ferrous iron externally by iron-reducing bacteria such as Shewanella spp.

[0099] The lixiviant may be added to the heap 54 via a typically equi-spaced network of plastic pipes laid on top of the heap. Such conduits are sized with suitable pumping according to the flow rates described above.

[0100] In some embodiments of the invention, PLS, copper-rich triggering solution A and copper-rich triggering solution B may be collected on a sloped impermeable liner or pad 56 at the base of the heap and directed to a respective storage pond. In some embodiments, the Cu.sup.2+ rich stream source is locally generated by a downstream process (such as SX/EW) or is externally generated by a refinery process. In further embodiments, the copper rich stream is a mixture of in situ and ex situ copper rich generated solutions.

[0101] Activation prepares the copper from refractory ores, such as chalcopyrite, to be more available for extraction in the later stages. The wetting process may be performed while the material is being agglomerated, in an agglomeration drum, or using other wetting systems. For example, activating may be conducted in one or more drums until a moisture content in a range of 3-12 percent is reached. In embodiments, gasses produced in the agglomerating step may be treated in a gas scrubber to remove or recover chemical species such as NOx, but the generation of such species is minimized according to the principles of the process described herein.

[0102] In embodiments, the agglomerating solution further comprises hydrogen peroxide, or other oxidizing reagents to increase the ORP. In embodiments, the agglomeration solution further comprises raffinate 202 from SX/EW 130 with water. Water replenishment may be required in process island 120 to replace evaporative and ore hold-up losses.

[0103] Following activation, the ore is stacked in a heap and allowed to rest. In embodiments, when using the DOP stages described herein, relatively short rest times, no more than 15 days, for example 5 to 15 days, may be effective to promote copper recovery, even more effective than longer rest times practiced in the prior art. Longer resting times as practiced in the art may lead to passivated ore surface. This resting time allows the oxidative power of the agglomeration solution to achieve transformation of the material, making copper from refractory ores available for extraction in the later stages. In embodiments, the copper ore may be wetted during the stacking process, for example on conveyor belts on which the ore is transported.

[0104] In FIG. 1 DOP 1 Treatment 102 depicts a first stage of dynamic oxidation performed on the stacked heap. This stage is characterized by relatively low irrigation rates and volume ratios compared to later leaching stage(s) and compared to leaching stages practiced in the prior art. In embodiments, DOP 1 Treatment 102 includes irrigation with a first reactive liquid mixture, comprising at least nitrate ions, sulfuric acid, iron ions, and an oxidizing reagent (for ORP adjustment of the reactive mixture) in an aqueous mixture. In embodiments, nitrate ion is present at a concentration up to about 0.4 M, for example in a range of 0.02 M to 0.4 M. Sulfuric acid may be present in a range of about 0.05 M to about 1 M, iron ions (present as both ferric ions and ferrous ions) may be present in a combined amount of about 0.02 M to 0.3 M. hydrogen peroxide may be provided in an amount less than 0.3 M, for example in a range of about 0.03 M to 0.3 M, which may serve to control the ferric/ferrous conversion in addition to adjusting electrochemical conditions of the reactive mixture such as increasing the oxidative potential of the reactive mixture. Copper ions may be present in the first reactive liquid mixture in a concentration less than 2 mM. The first reactive liquid mixture may be irrigated onto the heap at an irrigation rate of less than 5 L/h.Math.m.sup.2, for example in a range of about 0.5-5 L/h.Math.m.sup.2 and in embodiments 1-3 L/h.Math.m.sup.2. The concentration of nitrate ions, sulfuric acid, iron ions, and hydrogen peroxide maintains an oxidative environment. In embodiments, said DOP 1 irrigation treatment may be conducted until reaching a volume ratio of about 0.1-0.5 m.sup.3 of said first reactive liquid mixture per ton of copper ore. In embodiments first reactive liquid mixture for the first irrigation may be substantially free of copper ions. Substantially free of copper ions in this context means that an amount of copper ions present (e.g., from recirculated raffinate or from another source) does not affect the oxidation potential of the mixture or otherwise impact the kinetics of the first irrigation 102 (DOP 1). Thus, generally the concentration of copper ions in the reactive liquid mixture used in the first irrigation is less than 2 mM.

[0105] An oxidizing solution, triggering solution A may be obtained from the bottom of the heap after the first irrigation treatment, retained in pond 111, and recirculated to process island 120 for use as a copper-containing solution in subsequent steps. Oxidizing solution A has an increased copper concentration compared to the first reactive liquid mixture. Triggering solution A is not used as a product stream for copper recovery except for small amounts forwarded to Main PLS pond 112 for combination.

[0106] In embodiments, the first reactive liquid mixture further comprises, gaseous ozone in micro and nano bubbles, gaseous oxygen in micro and nano bubbles, air in micro and nano bubbles, or a mixture thereof. These oxidizing reagents also impact the ferric/ferrous rate, enhancing the oxidative properties of the mixture. In embodiments, the first reactive liquid solution may further comprise raffinate 202 with water. Water replenishment in process island 120 may be required to replace evaporative and ore hold-up losses.

[0107] DOP 2 irrigation treatment 103 with a second reactive liquid mixture follows DOP 1 treatment 102. The second reactive liquid mixture, supplied from supply area 123, comprises at least nitrate ion, sulfuric acid, iron ions, hydrogen peroxide, and further contains copper-containing solution. In embodiments, the copper-containing solution comprises Intermediate Liquor Solution (ILS), e.g. leachate prior to full copper extraction from the heap, and/or copper-rich triggering solution A from the first irrigation stage (DOP 1), which is held in pond 111. Copper containing solution may further contain copper rich triggering solution, from the second irrigation stage (DOP 2) which is likewise held in pond 111 and recirculated to process island 120.

[0108] In embodiments, nitrate ion is present in second reactive liquid mixture (also called Reactive Mixture B in some embodiments) in an amount up to about 0.4 M, for example in a range of 0.02 M to 0.4 M. Sulfuric acid may be present in a range of 0.05 to 1.0 M. Iron ions, which may be present as ferric ion and ferrous ion, may be present in a range of 0.02 M to 0.3 M. Hydrogen peroxide may be present in an amount up to 0.3 M, for example in a range of 0.03 M to 0.3 M. Hydrogen peroxide is used to adjust electrochemical conditions of the reactive mixture. Copper ions may be present in second reactive liquid mixture in a range of 2 mM to 100 mM, which may provided from triggering solution A in pond 111, from Intermediate Liquor Solution (ILS) in pond 113, and from Pregnant Liquor Solution (PLS) in pond 112, or a combination thereof, constituted in process island 120 in pond 123.

[0109] The second reactive liquid mixture used for the second irrigation may be provided to the heap at a rate in a range of up to about 5 L/h.Math.m.sup.2, for example 1-5 L/h.Math.m.sup.2, and in embodiments 1-3 L/h.Math.m.sup.2. In the stated concentrations, in conjunction with the low irrigation rate, the oxidative environment (greater than 700 mV SHE) achieved in DOP 1 is maintained in DOP 2.

[0110] In embodiments, the DOP 2 irrigation treatment may be conducted until reaching a volume ratio of about 0.1-0.5 m.sup.3 of the combined reactive mixtures in a ton of copper ore. In embodiments, Triggering Solution B obtained from the heap subjected to DOP 2 irrigation treatment may be added to pond 111 or pond 112.

[0111] In embodiments, the oxidizing agent in the Reactive Mixture B used in the second irrigation stage is selected from the group consisting of aqueous hydrogen peroxide, gaseous ozone in micro and nano bubbles, gaseous oxygen in micro and nano bubbles, air in micro and nano bubbles. These oxidative reagents also interact with the ferric/ferrous rate, enhancing the oxidative properties of the solution. In embodiments, the nitrate source on the raffinate comes as a nitrate-derived chemical species that requires oxidation by oxidizing reagents. In some embodiments an advance oxidation process is incorporated to the oxidizing tank for adjusting redox conditions of the reactive mixtures. In embodiments, the Reactive Mixture B further comprises raffinate with water replenishment. Water make-up may be required to replace evaporative and ore hold-up losses.

[0112] Referring again to FIG. 1, leaching may be performed on the heap after the DOP 2 irrigation in leaching stage 104, characterized by a higher irrigation rate of about 5-10 L/h.Math.m.sup.2 and increased copper extraction. Applying dynamic oxidation steps to the heap (DOP 1 and DOP 2) will prepare the ore for leaching whatever leach system is used, including chloride-based leaching systems. However, in embodiments, leaching solution comprises at least nitrate ions present in an amount up to about 160 mM, for example 1 Mm to 160 mM; sulfuric acid in a range of 0.05 M to 1 M; and iron ions (present as ferrous and ferric ions) in a range of 1 mM to 180 mM. Each of these reagents enhances the electrochemical properties of the reactive mixture for further leaching of copper from the ore. In embodiments, the leaching solution further comprises raffinate with water replenishment. Water make-up in process island 120 may be required to replace evaporative and ore hold-up losses.

[0113] In embodiments, as shown in FIG. 2, a further treatment of the heap may be added prior to the first irrigation treatment, or substituted for the first and second irrigation treatments, to achieve dynamic oxidation. This treatment step 105, referred to as a dynamic boost may be conducted with a third reactive liquid mixture (Reactive Mixture C) after the heap has been left to stand, for example for 5 to 15 days. In this stage, the heap is treated with an aqueous third reactive liquid mixture comprising nitrate ion, sulfuric acid, ferric ions, and hydrogen peroxide or other oxidizing agent, at a low flow rate and without withdrawing leachate from the bottom of the heap. In embodiments, the concentration of nitrate ion, sulfuric acid, ferric ions and hydrogen peroxide in the third reactive liquid mixture may be in a range of about 0.4 M to 3.2 M, about 0.2 M to 3 M, about 0.03 M to 0.18 M, and up to about 150 mM, respectively. The third reactive liquid mixture may be used in the dynamic boost irrigation step at a rate of about 1-5 L/h.Math.m.sup.2, for example 1-3 L/h.Math.m.sup.2. In embodiments, the dynamic boost step is conducted until the heap reaches a state having an amount of solution retained therein before solution is able to be drained from the bottom of the heap. The third reactive liquid mixture composition, in conjunction with the irrigation rate, and the state of dynamic moisture, enhances the oxidative environment achieved by the activating and curing step, especially on stable, refractory copper ores. In embodiments, gasses produced in the dynamic boost step may be treated in a gas scrubber to remove or recycle gaseous chemical emissions. In embodiments, the third reactive liquid mixture further comprises raffinate with water make-up. Water make-up may be required to replace evaporative and ore hold-up losses.

[0114] In embodiments, using the reagents described, each of the agglomeration solution, the first, second and third reactive liquid mixtures and the leaching solution comprise a redox potential higher than 700 mV (vs NHE) and a pH less than 2. In embodiments, the heap is maintained at a temperature in a range of about 30-45 C. as a result of exothermic chemical activity in the heap during each of the dynamic boost step, DOP 1 DOP 2 and leaching stages. In embodiments, the temperature of the heap may be controlled by heating or cooling first reactive liquid mixture, second reactive liquid mixture, third reactive liquid mixture, and the leaching solution, prior to irrigation onto the heap, not limited by the heat exchanging devices.

[0115] Processing systems such as, e.g., ponds, tanks and inlet systems used in different embodiments of the invention may include heating systems for controlling the temperature, e.g., in accordance with the different protocols and procedures described hereinas well as filters which may be used for cleaning of processes streams and/or mixtures, where, e.g., triggering solution(s), PLSs, ILSs and/or raffinate solutions may be treated to remove undesired byproducts, precipitants, contaminant metals and solids, and the like.

[0116] As shown in FIG. 2, a method for dynamic oxidation of copper ore may comprise providing copper ore-containing material, crushing and performing an activating step 101 wherein the ore is agglomerated and cured with an agglomeration solution, to form agglomerated copper ore-containing material. The ore is stacked to form a heap and allowed to stand. A dynamic boost irrigation step 105 is performed on the heap with a third reactive liquid mixture from pond 125 to reach a state of dynamic moisture in the heap (e.g., to a point where copper rich solution cannot yet be withdrawn from the bottom of the heap). Thereafter a dynamic oxidation DOP 1 irrigation treatment 102 is performed on the heap with first reactive liquid solution from pond 122. Copper rich Triggering Solution A resulting from the DOP 1 irrigation 102 may be withdrawn from the bottom of the heap, stored in pond 111 and circulated to process island 120 for use in second reactive liquid mixture and potentially in the leaching solution. A second irrigation treatment on the heap with a second reactive liquid mixture may yield Triggering Solution B from the bottom of the heap, which may be combined in pond 111 and/or forwarded to main PLS pond 112. Finally, leaching is performed on the heap with a leaching solution to obtain copper-rich PLS, collected in PLS pond 112. PLS is advanced to solvent-extraction electrowinning for copper recovery. In embodiments, rinsing 201 is performed on the heap after leaching to recover residual leaching solution.

[0117] As schematically depicted in FIG. 2, the solution from copper-rich Triggering Solution A in Oxidative PLS pond 111 may be advanced to a main PLS pond. In embodiments, PLS from the main PLS pond 112 may further be advanced to a copper recovery stage 130.

[0118] In embodiments, the copper recovery stage may be a solvent extraction and electrowinning process to produce copper cathodes. In embodiments, the PLS enters the solvent extraction process for copper separation and reagents recovery. In SX/EW process 130, two streams are produced: a copper-rich electrolyte solution advanced to the electrowinning process 131 to produce copper cathodes, and a raffinate solution which may be recirculated to any of the agglomerating solution, first reactive liquid mixture, second reactive liquid mixture, third reactive liquid mixture, and/or leaching solution in a respective pond in the process island 120.

[0119] In embodiments, the raffinate PLS and ILS included in the reactive liquid mixtures is treated prior to the corresponding irrigations to obtain an aqueous solution with a ORP higher than 800 mV/ENH.

[0120] In some embodiments, the raffinate produced in the solvent extraction and electrowinning process (SX/EW) may be purged. In 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 for metal abatement produced by exopolysaccharide-containing bacteria or other microorganisms. In some embodiments, the raffinate is purged by physical filters. In some embodiments, the raffinate is purged by chemical methods. In further embodiments, the purged raffinate treatment comprises acid-base neutralization methods, heavy metals precipitation, solid-liquid separations or a combination thereof.

[0121] In other aspect, the invention is a method for the recovery of metal values from at least two different Pregnant Liquor Solution (PLS) streams obtained from at least two different sources of metal ore-containing material, comprising: providing at least two different Pregnant Liquor Solution (PLS) streams from at least two different previously leached metal ore-containing materials, wherein at least two of said previously leached metal ore-containing materials comprise a different combination of types of metal ore-containing material, and/or have been previously subjected to different leaching processes and/or have been previously leached using reactive liquid mixtures; performing at least two separated solvent extraction processes of the different PLS streams and obtaining at least two compatible metal rich electrolyte streams; Collecting at least two compatible metal rich electrolyte streams in at least two different tanks; Combining at least two compatible metal rich electrolyte streams; Subjecting the compatible metal rich electrolyte streams to a single electrowinning process; Recovering at least one of the metal-depleted raffinate streams from the electrowinning process; Recycling at least one of the metal-depleted raffinate streams and; Obtaining the metal lean electrolyte stream and a metal product. In further embodiments, the metal ore-containing material is a hydrometallurgy module comprising a heap, a dump, a tailing, a slag, a run-of-mine and/or stockpiled metal ore-containing material; wherein such a metal ore-containing material comprises copper, gold, nickel, zinc, molybdenum, cobalt, silver, and a mixture thereof. In some embodiments, the metal ore-containing materials comprise metal oxide, metal sulfides or a mixture thereof. In further embodiments, the metal ore-containing material previously leached comprise chalcopyrite. In further embodiments, the process to transform the metal value rich electrolyte is selected from the group of electrowinning, salt precipitation and crystallization. In further embodiments, the depleted metal value electrolyte is recirculated onto the heap.

[0122] FIG. 5 depicts a schematic detail of process island 120 in which supply pond 122 for first reactive liquid mixture may be provided with a mixer 616, an oxidation tank 618, and dispensing tank 620 to formulate and dispense the first reactive liquid mixture. Mixer 616 may be a continuously stirred tank reactor (CSTR) or other engineering unit capable of maintaining an aqueous solution of dissolved nitrate anion, sulfuric acid and raffinate in a uniform aqueous solution at a predetermined concentration of the reagents. Inlets 640 to the mixer may include an inlet for water make-up, an inlet for dissolved nitrate anion, an inlet for acid replenishment and an inlet for a portion of raffinate recirculated from the SX process.

[0123] Flow rates of the first reactive liquid mixture contacting the heap are lower than used for leaching, and mixer 616 and associated piping may be sized accordingly. For example, a mixing tank and associated piping may accommodate a flow rate of reactive solution less than 5 L/h.Math.m.sup.2 and in embodiments in a range of 1-3 L/h.Math.m.sup.2. Moreover, the amount of recirculated raffinate and water replenishment is significantly less than in a leaching context.

[0124] Oxidizing tank 618 may be designed to mix an oxidizing reagent into the mixture from mixer 616 and one or more inlet(s) 650 may be provided for the purpose. The oxidizing reagent may be any one of ferrous sulfate, ferric sulfate, aqueous hydrogen peroxide, gaseous ozone in micro and nano bubbles, gaseous oxygen in micro and nano bubbles, air in micro and nano bubbles, or a mixture of two or more of them, and the structure of tank 618 and inlet(s) 650 may be dictated by the required amount and nature of the oxidizing reagent to reach a required ORP, for example greater than 650 mv (vs. NHE), equal to or greater than 700 mv (vs NHE) or greater than 770 mv (vs. NHE). For example, a gaseous oxidizing reagent may be bubbled through the mixture via a perforated tube using gas supplied under pressure. A liquid reagent may be piped and an opening above the liquid level in the tank may be provided as an inlet for solid reagent.

[0125] To oxidize the compounds in the agglomerating solution and in the reactive liquid mixtures to a higher oxidation state, an electrochemical reactor can be used. The reactor may replace at least one of the oxidizing tanks in the agglomerating solution supply and in the first and second reactive liquid mixtures supplies.

[0126] Dispenser tank 620 is connected to piping adapted to distribute the mixed and oxidized reagent onto heap 54.

[0127] Second supply 123 may be one or more tanks or containers and provided with mixer 622, oxidation tank 624, and dispensing pond 626 similar in configuration to the supply pond for the first reactive liquid mixture to formulate and dispense the second reactive liquid mixture. Mixer 622 may be a continuously stirred tank reactor (CSTR) or other engineering unit capable of maintaining an aqueous solution of dissolved nitrate anion, sulfuric acid and raffinate in a uniform aqueous solution at a predetermined concentration of the reagents and may also be provided with plurality of inlet conduits to provide water replenishment, dissolved nitrate anion, a portion of raffinate solution from the copper solvent extraction process, and a copper-containing solution obtained from the irrigation of the heap with the first reactive liquid mixture maintained in the separate oxidizing triggering solution pond. Mixer 622 may further comprise one or more inlet conduit 690 to provide one or more of pregnant liquor solution (PLS) and intermediate liquor solution (ILS) from the heap leaching of the copper recovery process to provide a desired level of dissolved copper ions in the second reactive liquid mixture. Replenishment water, raffinate and make-up nitrate and acid may be provided to second reactive liquid solution supply 123 from the same source 640 that serves the first reactive liquid mixture supply 122.

[0128] A third supply pond may be provided to formulate an activation solution and/or an agglomeration solution which may be provided to one or more activation and/or agglomeration devices. Mixer tank 610, oxidation tank 612 and dispenser tank 614 may have a similar construction and configuration as the like elements in the first reactive solution pond.

[0129] Solvent extraction loop or system 130, processes a copper rich electrolyte stream to produce copper depleted raffinate solution 202, and metal cathodes after electrowinning 175. Various SX/EW components that may be included in some embodiments of the invention, e.g.: an SX/EW loop including at least one Solvent Extraction process units for the treatment of at least one PLS stream. Separate SX process units which may accept a copper lean electrolyte stream as input and produce corresponding copper-depleted raffinate streams as output; an EW unit providing a copper lean electrolyte stream as output; a Rich Electrolyte Tank (RET) system, which may receive a copper rich electrolyte stream as input, and may produce a copper rich electrolyte stream as output (which may, e.g., be fed into an EW unit); a Lean Electrolyte Tank (LET) system, which may receive a copper lean electrolyte stream as input (e.g., from an EW unit) and may produce copper lean electrolyte streams as output (e.g., to feed one or more corresponding SX units).

[0130] In some embodiments of the invention and as further discussed herein, a recirculating intermediate liquor solution (ILS) and corresponding ILS system (which may include for example a dedicated ILS pond such as for example described herein)may be employed or used, e.g., for managing or regulating the copper concentration of a PLS, for example prior to being fed forward to SX recovery. In some embodiments, ILS may be or may comprise the acidic aqueous phase of the heap leaching process prior to metal reduction or extraction and may have a copper concentration in a range of 0.5 and 1.5 g/L, although additional or alternative concentrations and/or ingredients or reagents may be used in different embodiments.

[0131] Raffinate or a raffinate solution as used herein may refer to a water-based copper-depleted and acid-rich solution which may be, or may be obtained from an acidic aqueous phase received subsequent to metal extraction or retrieval, for example using SX/EW and/or additional or alternative procedures known in the art.

[0132] Different ponds and/or processing systems described herein may include inlet conduits to transfer or provide, e.g., ingredients and/or reagents including, but not limited to water make-up, dissolved nitrate ion, a portion of a raffinate solution from the copper solvent extraction process, aqueous ferrous sulfate, aqueous ferric sulfate, 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.

Examples

[0133] FIGS. 3 and 4 depict copper recovery according to various embodiments of the invention with comparative examples.

[0134] FIG. 3 depicts the effects of DOP on copper recovery versus operational time. For this experiment, leaching columns were prepared with crushed primary copper sulfide ore (about 84-95% 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). The ore size of the crushed material is 80% under ( inch). The crushed material was first subjected to a treatment designated as Dynamic Oxidative Process setting 0 (DOP setting 0), consisting of an activating step, followed by a resting step of 5 days, a first irrigation with a first reactive liquid mixture, a second irrigation with a second reactive liquid mixture, and finally a leaching step. The composition, pH and redox potential of each reactive liquid mixture used in this example are shown in Table 1 below. The internal temperature of the leaching columns in each of the experiments was maintained at 30-45 C. The height of the columns employed was one meter.

TABLE-US-00001 TABLE 1 Electrochemical and operational conditions DOP1 DOP2 Activating irrigation irrigation step treatment treatment Leaching Reagent Agglomeration First reactive Second reactive Leaching used solution liquid mixture liquid mixture solution NO.sub.3.sup. 1.4M 0.20M 0.16M 0.16M H.sub.2SO.sub.4 0.8M 0.15M 0.15M 0.15M Fe.sub.total 0.08M 0.10M 0.10M 0.10M H.sub.2O.sub.2 0.07M 0.07M 0.07M 0.07M Cu.sup.2+ 0.006M Ph <1 1.1-1.3 1.1-1.3 1.1-1.3 ORP[mV >770 >770 >770 >770 SHE] Irrigation 1.5-2.9 1.5-2.5 5.0-5.6 rate L/m.sup.2 * h L/m.sup.2 * h L/m.sup.2 * h Ratio of 0.30 0.40 solution m.sup.3/ton m3/ton per ton of ore used in each step

[0135] An additional leaching column labelled Leaching 1 or Acid leaching was used as a comparative example. This column underwent agglomeration and a resting step for 5 days, followed by slow acid leaching (5-5.6 L/h.Math.m.sup.2). This flow rate is on the low end of what would be considered feasible for conventional leaching. In this way the kinetic curves produced according to the inventive examples and according to this comparative example would be comparable. The agglomeration step for Leaching 1 was practiced using an agglomeration solution composed of 1.4 M H.sub.2SO.sub.4, 0.08 M Fe.sub.total, a pH less than 1, and ORP of >770 mV vs SHE. This was followed by a leaching step with a leaching solution composed of 0.15 M of H.sub.2SO.sub.4, 0.1 M of Fe.sub.total, a pH of 1.1-1.3, an ORP of >770 mV vs SHE, with an irrigation rate at 5.0-5.6 L/h.Math.m.sup.2.

[0136] As a reference, a further additional leaching column labelled Leaching 2 or Leaching supplemented with nitrate, underwent agglomeration and resting for 5 days, followed by a slow leaching stage. The agglomeration for Leaching 2 was practiced using the agglomeration solution described in Table 1 above and the leaching step was practiced using the leaching solution described in Table 1. Again, a low flow rate was selected for Leaching 2 to make a better comparison of the kinetic curve of the course of leaching. Consequently, the nitrate concentration used in the agglomeration, resting, and leaching steps is comparable to that of the Dynamic Oxidative Process. However, the DOP1 and DOP2 treatments, were only utilized in the aforementioned DOP leaching column (DOP setting 0).

[0137] In FIG. 3, ore subjected to the DOP setting 0 achieved higher copper recoveries compared to acid and nitrate leaching and, significantly, surpassed the Passivation zone. Both references, Leaching 1 and Leaching 2, remained trapped in the Passivation zone, showing a weaker performance in copper extraction of copper sulfides rich in Cpy. As seen in FIG. 3, the DOP treatment effectively unlocked the sulfide copper ore and avoided surface passivation. The kinetic curves obtained for the acid leaching (Leaching 1) and nitrate leaching (Leaching 2) were predictable based on known models. In contrast, the example according to the invention produced a novel kinetic curve.

[0138] FIG. 4 depicts the effect of various electrochemical regimes employed in the Dynamic Oxidative Process with leaching columns adapted for treating copper sulfide ores. Again, the ore used in this experiment was crushed primary copper sulfide ore (about 84-95% 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). The ore size of the crushed material is 80% under ( inch). The height of the columns employed was one meter.

[0139] The column labelled DOP setting 1 was subjected to an activating step, followed by a resting step of 5 days, followed by first and second irrigation treatment stages, wherein copper-containing solution was introduced in the second irrigation stage (DOP 2). These steps were followed by a leaching step with the reactive solutions shown in the Table 2 below.

[0140] The column labelled DOP setting 2 differed from the electrochemical regime of DOP setting 1 in the reduction of nitrate source. The nitrate concentration in the first reactive liquid mixture (from the DOP 1 irrigation treatment), the second reactive liquid mixture (from the DOP 2 irrigation treatment), and the leaching solution (from the leaching step) were adjusted to one-third of the nitrate concentration corresponding to each solution shown in Table 2 below.

[0141] The column depicted as DOP setting 3 was subjected to the same treatments and the corresponding reagent solution as the DOP treatment 1, but a stronger oxidative boost was applied by means of a longer activating step (a rest period three times longer than DOP setting 1, and a dynamic boost (DB) stage followed the first and second irrigation treatment stages. The DB stage was practiced using a third reactive liquid mixture, composed of 1.6 M NO.sub.3.sup., 0.8 M H.sub.2SO.sub.4, 0.08 M Fe.sub.total, 0.06 M H.sub.2O.sub.2, a pH less than 1, and ORP of >770 mV vs SHE, with an irrigation rate of 1.5-2.9 L/m.sup.2.Math.h. The volume ratio used was 0.05 m.sup.3/ton.

[0142] The column depicted as DOP setting 4 was subjected to the same treatments and the corresponding solutions as the DOP setting 1, but with a different electrochemical regime due to an adjustment of nitrate source and copper ions. The nitrate concentration in the second reactive liquid mixture (from the DOP 2 irrigation treatment) were adjusted to twice the nitrate concentration of the corresponding solution shown in Table 2 below. Conversely, the copper concentration in the second reactive liquid mixture was adjusted to eight times the copper concentration of the corresponding solution shown in Table 2 below.

[0143] The composition, pH and redox potential of each reactive liquid mixture used in DOP setting 1, DOP setting 2, DOP setting 3 and DOP setting 4, and the leaching stage, together with the operational conditions, are shown in Tables 2-5 below.

TABLE-US-00002 TABLE 2 Electrochemical and operational conditions of Agglomeration/Activation. ACTIVATING STEP (Agglomeration solution) NO.sub.3.sub. H.sub.2SO.sub.4 Fe.sub.(t) H.sub.2O.sub.2 ORP Condition (M) (M) (M) (M) pH (mV SHE) DOP setting 1 1.4 0.8 0.09 0.06 <1 >770 DOP setting 2 1.4 0.8 0.09 0.06 <1 >770 DOP setting 3 1.4 0.8 0.09 0.06 <1 >770 DOP setting 4 1.4 0.9 0.05 0.03 <1 >770

TABLE-US-00003 TABLE 3 Electrochemical and operational conditions of DOP 1 treatment. DOP1 IRRIGATION TREATMENT (First reactive liquid mixture) NO.sub.3.sub. H.sub.2SO.sub.4 Fe.sub.(t) H.sub.2O.sub.2 Cu2+ ORP Volume ratio Condition (M) (M) (M) (M) (mM) pH (mV SHE) (m.sup.3/ton) DOP setting 1 0.12 0.15 0.09 0.06 <1.6 1.1-1.3 >770 0.25 DOP setting 2 0.04 0.15 0.09 0.06 <1.6 1.1-1.3 >770 0.22 DOP setting 3 0.12 0.15 0.09 0.06 <1.6 1.1-1.3 >770 0.35 DOP setting 4 0.12 0.08 0.05 0.03 <1.6 1.1-1.3 >770 0.28

TABLE-US-00004 TABLE 4 Electrochemical and operational conditions of DOP 2 treatment. DOP2 IRRIGATION TREATMENT (Second reactive liquid mixture) NO.sub.3.sub. H.sub.2SO.sub.4 Fe.sub.(t) H.sub.2O.sub.2 Cu.sup.2+ ORP Volume ratio Condition (M) (M) (M) (M) (mM) pH (mV SHE) (m.sup.3/ton) DOP setting 1 0.2 0.25 0.09 0.06 5 1.1-1.3 >770 0.41 DOP setting 2 0.06 0.25 0.09 0.06 5 1.1-1.3 >770 0.39 DOP setting 3 0.2 0.10 0.09 0.06 5 1.1-1.3 >770 0.44 DOP setting 4 0.4 0.10 0.09 0.06 40 1.1-1.3 >770 0.39

TABLE-US-00005 TABLE 5 Electrochemical and operational conditions of Leaching stage. LEACHING STAGE (Leaching solution) NO.sub.3.sub. H.sub.2SO.sub.4 Fe.sub.(t) H.sub.2O.sub.2 ORP Condition (M) (M) (M) (M) pH (mV SHE) DOP setting 1 0.13 0.15 0.09 0.06 1.1-1.3 >770 DOP setting 2 0.04 0.25 0.09 0.06 1.1-1.3 >770 DOP setting 3 0.13 0.15 0.09 0.06 1.1-1.3 >770 DOP setting 4 0.13 0.1 0.05 0.03 1.1-1.3 >770

[0144] In FIG. 4. ores subjected to the dynamic oxidative process with different electrochemical regimes were able to surpass the passivation zone of copper recovery. Specifically, the copper recovery in DOP setting 1, 2 and 3 were similar around day 70. demonstrating that a range of nitrate concentration in the first and second reactive liquid mixture, as well as different volume ratio (or ratio of solution per ton of ore used) in these steps, and the application of a stronger oxidative boost with the dynamic boost stage, impacts the solubilization of the copper from chalcopyrite. The DOP setting 4 demonstrates that the presence of copper ions in the second reactive liquid mixture impacts the copper solubilization from chalcopyrite via metathesis effect.

[0145] Table 7 depicts water consumption using the DOP protocols compared to Leaching 1 and Leaching 2. Samples were prepared with the same ore type as in the above trials, consisting of primary sulfide ore (84-95% of 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). The crushed copper ore was first subjected to an activation treatment designed Dynamic oxidative process (DOP). consisting of an activating step followed by a rest period, a first irrigation with a first reactive mixture, a second irrigation with a second reactive mixture and finally a leaching step. The composition, pH and redox potential of each reactive mixture used in this example are shown in Table 6.

TABLE-US-00006 TABLE 6 Electrochemical and Operational Conditions DOP1 DOP2 Activating irrigation irrigation Leaching step treatment treatment step Reagent Agglomeration First reactive Second reactive Leaching used solution liquid mixture liquid mixture solution NO.sub.3.sup. 1.5M 0.14M 0.40M 0.15M H.sub.2SO.sub.4 1.0M 0.08M 0.07M 0.10M Fe.sub.total 0.03M 0.05M 0.08M 0.05M H.sub.2O.sub.2 0.02M 0.03M 0.06M 0.04M Cu.sup.2+ 0.04M pH <1 1.1-1.3 1.1-1.3 1.1-1.3 ORP >770 >770 >770 >770 [mV SHE] Irrigation 1.5-2.9 1.5-2.5 5.0-5.6 rate L/m.sup.2 .Math. h L/m.sup.2 .Math. h L/m.sup.2 .Math. h Ratio of 0.30 0.40 solution m.sup.3/ton m.sup.3/ton per ton of ore used in each step

[0146] The column labelled Leaching 1 underwent agglomeration, a rest step of 5 days, followed by slow acid leaching (5-5.6 L/h/m.sup.2), which is considered slow compared to the conventional irrigation rates for leaching which fluctuate between 8-12 L/h m.sup.2). The agglomeration step for Leaching 1 was practiced using an agglomeration solution composed of 1.4 M H.sub.2SO.sub.4. 0.08 M Fe.sub.total. a pH of less than 1, and an ORP of >770 mV vs SHE. This was followed by a leaching step with a leaching solution composed of 0.15 M of H.sub.2SO.sub.4, 0.1 M of Fe.sub.total, a pH of 1.1-1.3, and ORP of >770 mV vs SHE.

[0147] The column labelled Leaching 2 underwent agglomeration and a rest period of 5 days followed by a slow leaching stage. The agglomeration step was practiced using the agglomeration solution described in Table 1 and the composition of the solution for the leaching step is also described as in Table 1. Consequently, the nitrate concentration used in the agglomeration, resting and leaching steps is in the range of the Dynamic Oxidative Process. Leaching 2 lacks DOP1 and DOP2 treatments, which were only utilized in the aforementioned Dynamic Oxidative Process leaching column.

[0148] The referred DOP in Table 7 is capable of unlocking chalcopyrite with approximately 50% less water than a slow acid leach process (5 L/h m.sup.2). Evaporation of water and absorption of the solution by the ore are the primary factors contributing to the water requirements in a heap leach operation.

TABLE-US-00007 TABLE 7 Water consumption during the DOP compared to the acid conventional leaching and nitrate leaching of sulfide ore Water ratio: Absorbance of water-based Evaporation water on heap Irrigation rate solution makeup; water tailings- Total water make- Condition (L/h .Math. m.sup.2) m.sup.3/per lbCu m.sup.3/lbCu m.sup.3/lbCu up heap-m.sup.3/lbCu DOP 2 0.27 0.016 0.033 0.049 Leaching 1 5 0.54 0.033 0.065 0.098 Leaching 2 5 0.47 0.028 0.056 0.084

[0149] The calculation for evaporative make-up is based on an estimated 6% loss due to evaporation, which is based on the average annual water makeup requirements commonly used in the industry.

[0150] The calculation for water makeup on heap tailings, 12% of the absorbance of water on heap tailings, is based on an average water loss observed in the industry.

[0151] For comparison, the amount of water required to process copper sulfide ore through a conventional crush-grind-flotation-concentrate circuit can range from 1.5 up to 3 cubic meters (m.sup.3) per ton of ore, or more, with an average of 0.4 m.sup.3 of water per pound of copper (lb Cu). Results indicate that DOP significantly reduced the water required for extracting copper from copper sulfides.

[0152] Some components used in different embodiments of the invention, such as heating and/or process control systems, may include or may be coupled to appropriate power inputs which may be or may include in some examples a photovoltaic panel or a plurality of panelsalthough different power inputs and/or sources may be used in different embodiments. In some embodiments of the invention, the energy is delivered controlled to get the desired temperature for the electrochemical regimes.

[0153] Some embodiments of the invention may include process control units such as for example an Industrial Control System (ICS) or systems in different steps and/or protocols and procedure such as. e.g., described herein, which may include for example appropriate sensors (including, but not limited to, thermometers, pH sensors, Oxidation-Reduction Potential (ORP) sensors, ion-selective electrodes (ISEs), and flowmeters), transmission or communication paths or channels (which may be wireless or hard-wired) and actuators (which may include control valves and/or relays)as known in the art.

[0154] Different embodiments are disclosed herein. Features of certain embodiments may be combined with features of other embodiments; thus, certain embodiments may be combinations of features of multiple embodiments. Likewise, in the following claims a feature expressed in a dependent claim may be combined with a different independent claim and/or with the features of other dependent claims. The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. It should be appreciated by persons skilled in the art that many modifications, variations, substitutions, changes, and equivalents are possible in light of the above teaching. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

[0155] While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes and equivalents will now occur to those of ordinary skill in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

[0156] Unless explicitly stated, different process or method steps described herein with regard to different embodiments of the invention may not be constrained to a particular order or sequence. Additionally, some of the described method embodiments or elements thereof can occur or be performed simultaneously, at the same point in time, or concurrently.