A method for simultaneously recovering metallic copper from leaching residue of copper oxide concentrate and roasted residue of copper sulfide concentrate.

Abstract

This invention belongs to the field of non-ferrous metal smelting technology and discloses a method for simultaneously recovering metallic copper from leaching residue of copper oxide concentrate and roasted leaching residue of copper sulfide concentrate. The method includes: performing acid flotation on the copper oxide concentrate leaching residue to obtain a copper concentrate with a Cu grade of 6-10%; mixing the obtained copper concentrate and roasted leaching residue of copper sulfide concentrate to obtain a mixed ore; stirring and mixing the obtained mixed ore with a leaching agent to obtain a slurry; leaching the obtained slurry at 80-90℃, and obtaining leaching residue and leachate after solid-liquid separation; washing the obtained leaching residue to obtain washing residue and washing solution; extracting the obtained leachate to obtain a loaded organic phase and raffinate; and back-extracting and electrowinning the obtained loaded organic phase to obtain metallic copper. This invention achieves effective synergistic leaching of copper concentrate and roasted leaching residue of copper sulfide concentrate, with a leaching rate of over 82%, enabling comprehensive recovery of copper resources from smelting waste.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, and in particular, to a method for simultaneously recovering metallic copper from copper oxide concentrate leaching residue and copper sulfide concentrate roasted sand leaching residue. Background Technology

[0002] Continuously optimizing, improving, innovating, and elevating traditional metallurgical processes, optimizing process flows, developing new metallurgical processes, and adopting refined treatment methods to transform industrial pollution into value during enterprise production are important research topics for improving the resource integration of non-ferrous metal production enterprises from point to line to surface.

[0003] According to the "China Mineral Resources Report" released by the Ministry of Natural Resources of the People's Republic of China in 2022, as of the end of 2021, the country's proven copper reserves (metal content) were 34.9479 million tons, copper concentrate production was 1.855 million tons, and refined copper production was 10.487 million tons. However, the copper in most copper-bearing belts in my country is a mixed ore formed by complex copper sulfide and oxide ores with multiple associated elements. Currently, copper ores in Africa, particularly in the Democratic Republic of Congo, are primarily mixtures of sulfide and oxide ores. Due to the extremely complex physicochemical properties of these mixtures, most processing involves a first-sulfur-then-oxygen flotation to produce copper oxide and copper sulfide concentrates. The copper oxide concentrate then enters the hydrometallurgical system, while the copper sulfide concentrate undergoes roasting to produce roasted sand, which is also then fed into the hydrometallurgical system. During the first-sulfur-then-oxygen flotation, the fine or uneven particle size of the minerals leads to intergrowth and inclusion of copper oxide and copper sulfide minerals. The copper oxide concentrate contains sulfide minerals that cannot be leached using conventional hydrometallurgical methods; simultaneously, the roasted sand from the copper sulfide concentrate contains unoxidized sulfide copper minerals. Consequently, the hydrometallurgical leaching residues from both concentrates contain a large amount of unrecovered copper metal.

[0004] The copper grade in the leaching residue of low-grade copper oxide concentrate is generally 1%-3%. This residue is obtained after leaching copper oxide concentrate products produced from complex mixed ores using a process of first flotating copper sulfide and then copper oxide. The copper grade in the leaching residue of roasted copper sulfide concentrate is generally 4%-8%. This residue is obtained after two-stage leaching of roasted sand obtained from roasting high-grade copper sulfide concentrate. Currently, the individual processing of these low-grade leaching residues is quite difficult, and most of the leaching residues are piled up in slag heaps, causing environmental pollution and wasting a large amount of copper resources. However, copper resources are non-renewable resources, and with continuous human mining and consumption, reserves are gradually decreasing. Existing processes are increasingly problematic in processing "poor, fine, and complex" ores. Therefore, how to recover copper metal from complex low-grade leaching residues has become a challenge and an important area for development in the industry.

[0005] Currently, hydrometallurgical processes for treating complex, low-grade copper oxide leaching slag and copper sulfide concentrate roasted leaching slag are mainly focused on pressure leaching, chloride leaching, ammonia leaching, and bioleaching. However, pressure leaching requires large investments, consumes a lot of energy, and demands high-performance equipment. Chloride leaching can only process copper minerals with a Cu content of 25% or higher. The process involves large solid-liquid separation, and the chloride ions introduced into the system during treatment can affect the quality of cathode copper and accelerate equipment corrosion, requiring high corrosion resistance. Ammonia leaching is harmful to human health and causes serious environmental pollution, requiring significant environmental protection investment. Bioleaching, or biometallurgy, is a product of the cross-application of microbiology and hydrometallurgical technology. However, microorganisms must first undergo domestication or mutagenesis breeding to effectively leach, and due to the difficulty in cultivating microbial communities, the long cycle, and low leaching rate, it is constrained by multiple factors such as geographical conditions, natural environment, and ore properties, making large-scale application in my country difficult. Given the multiple limitations of the above-mentioned copper extraction processes, and the fact that there is still no good processing technology for the leaching residue of low-grade copper oxide concentrate and copper sulfide concentrate roasted sand, which have complex structures and contain multiple elements, large quantities of copper oxide concentrate leaching residue and copper sulfide concentrate roasted sand leaching residue are stockpiled or abandoned because it is difficult to recover copper metal. This results in the waste of copper resources and brings great environmental pressure. Summary of the Invention

[0006] This invention provides a method for simultaneously recovering metallic copper from copper oxide concentrate leaching residue and copper sulfide concentrate roasted leaching residue, in order to solve the technical problem of tailings accumulation and waste caused by the difficulty in recovering metallic copper from low-grade complex copper oxide concentrate leaching residue and copper sulfide concentrate roasted leaching residue in existing processes, which in turn leads to copper resource waste and environmental pollution.

[0007] This invention provides a method for simultaneously recovering metallic copper from copper oxide concentrate leaching residue and copper sulfide concentrate roasted leaching residue, wherein the copper oxide concentrate leaching residue has a Cu grade of 1-3%, and the copper sulfide concentrate roasted leaching residue has a Cu grade of 4-8%. The method includes the following steps:

[0008] (1) Acid flotation is performed on the leaching residue of the copper oxide concentrate to obtain copper concentrate with a Cu grade of 6-10% by slag flotation.

[0009] (2) The obtained copper concentrate from slag beneficiation and the leaching residue from roasted copper sulfide concentrate are mixed in a mass ratio of 1:(1~1.2) to obtain a mixed ore;

[0010] (3) The obtained mixed ore is stirred and mixed with a leaching agent to obtain a slurry, wherein the leaching agent is a sulfuric acid solution system leaching agent; the mass concentration of the slurry is 15-17%;

[0011] (4) The slurry obtained by leaching at 80-90℃ is separated into solid and liquid residue and leaching liquid;

[0012] (5) The obtained leaching residue is washed to obtain washing residue and washing liquid; the obtained leaching liquid is extracted to obtain a loaded organic phase and raffinate, wherein the obtained washing liquid is used in the extraction step, and the obtained washing residue is discharged as a tailings treatment; the raffinate obtained from the extraction is used to prepare the leaching agent of the sulfuric acid solution system.

[0013] (6) The obtained loaded organic phase is back-extracted and electrowinning to obtain metallic copper.

[0014] Further, the acid flotation of the copper oxide concentrate leaching residue in step (1) includes the following steps:

[0015] (a) The copper oxide concentrate leaching residue is mixed with water to obtain a slurry, wherein the slurry has a mass percentage concentration of 15-25%;

[0016] (b) Add collectors and frothers to the obtained slurry for roughing to obtain rough concentrate and roughing tailings;

[0017] (c) The obtained rough concentrate is subjected to a first and a second fine cleaning to obtain copper concentrate from slag beneficiation; the obtained rough tailings are subjected to scavenging to obtain copper scavenged ore and tailings, wherein the copper scavenged ore enters the first fine cleaning step and the tailings are discharged.

[0018] Further, the collector mentioned in step (b) is sodium dithiocarbonate-O-butyl ester, and the addition amount is 100-300 grams per ton of copper oxide concentrate leaching residue.

[0019] Furthermore, the foaming agent mentioned in step (b) is pine oil, and the addition amount is 30-50 grams per ton of copper oxide concentrate leaching residue.

[0020] Further, in step (c), the first refining process produces copper middlings and copper concentrate, the copper middlings are returned to the roughing step, and the copper concentrate is entered into the second refining process.

[0021] Further, the second refining process in step (c) produces copper middlings and copper concentrate from slag beneficiation. The copper middlings are returned to the first refining step, and the copper concentrate from slag beneficiation is copper concentrate from slag beneficiation with a Cu grade of 6-10%.

[0022] Furthermore, in step (3), particles with a diameter less than 0.074 mm account for 70-80% of the total particle weight in the slurry.

[0023] Furthermore, the leaching time of the slurry obtained by leaching at 80-90°C in step (4) is more than 6 hours.

[0024] Furthermore, step (4) includes concentrating the leached slurry before solid-liquid separation.

[0025] Furthermore, the washing of the obtained leaching residue in step (5) includes stirring and washing the obtained leaching residue with clean water with a pH of 6.5-7.5 under natural conditions.

[0026] The present invention has the following beneficial effects:

[0027] This invention utilizes acid flotation on copper oxide concentrate leaching residue to initially enrich easily floatable copper sulfide minerals in the residue. The enriched copper concentrate and copper sulfide concentrate roasted leaching residue are then subjected to processes such as ore blending, slurry preparation, and heated leaching to effectively synergistically leach copper sulfide and copper ferrite, which are difficult to process individually. The final synergistic leaching rate of the copper concentrate and copper sulfide concentrate roasted leaching residue reaches over 82%.

[0028] The essence of the co-processing method proposed in this invention is to first enrich the copper oxide concentrate leaching residue, and then directly leach the solid raw materials of the enriched copper concentrate from slag beneficiation and the roasted copper sulfide concentrate leaching residue. The leaching system consists of copper sulfide concentrate from slag beneficiation, roasted copper sulfide concentrate leaching residue, sulfuric acid, and an aqueous phase. At a temperature of 80-90℃, valuable metals such as Cu, which are difficult to leach, are continuously converted into soluble sulfates, allowing them to enter the solution in ionic form for recovery. This co-processing technology is highly practical for low-grade copper oxide concentrate leaching residue and roasted copper sulfide concentrate leaching residue with complex structures and variable properties. It effectively achieves the co-processing of both, and the leaching agent is only a sulfuric acid solution system, resulting in low leaching costs and simple and mature subsequent processing technology. By performing the above-mentioned treatment on the complex low-grade copper oxide concentrate leaching residue and roasted copper sulfide concentrate leaching residue, the copper content in the final leaching residue is significantly reduced, avoiding the large-scale stockpiling and waste of leaching tailings generated during copper mining and processing.

[0029] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0030] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0031] Figure 1 This is a schematic diagram of the processing flow of low-grade copper-cobalt mixed ore according to a preferred embodiment of the present invention;

[0032] Figure 2This is a schematic diagram of the process flow for preparing copper concentrate from copper oxide concentrate leaching residue according to a preferred embodiment of the present invention.

[0033] Figure 3 This is a schematic diagram of the co-processing technology of copper concentrate from slag beneficiation and leaching residue from roasted copper sulfide concentrate according to a preferred embodiment of the present invention.

[0034] Figure 4 This is a schematic diagram of a co-processing device for copper concentrate from slag beneficiation and copper sulfide concentrate roasted leaching residue according to a preferred embodiment of the present invention.

[0035] Legend:

[0036] 1-Slurry mixing tank; 2-Feed valve; 3-Feed pump; 4-Agitator; 5-Leaching tank; 6-Digital thermometer; 7-Discharge valve; 8-Discharge pump; 9-Sulfuric acid pipe; 10-Sulfuric acid flow meter; 11-Sulfuric acid valve; 12-Clean water pipe; 13-Flow meter; 14-Control valve; 15-Steam pipe; 16-Steam valve. Detailed Implementation

[0037] To make the inventive objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the embodiments described in this specification are merely illustrative of the invention and are not intended to limit the invention.

[0038] For simplicity, this paper only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an undefined range; and any lower limit can be combined with other lower limits to form an undefined range, just as any upper limit can be combined with any other upper limit to form an undefined range. Furthermore, although not explicitly stated, every point or individual value between the endpoints of a range is included within that range. Therefore, each point or individual value can serve as its own lower or upper limit and be combined with any other point or individual value, or with other lower or upper limits, to form an undefined range.

[0039] In this description, it should be noted that, unless otherwise stated, "above" and "below" include the stated number, "multiple" in "one or more" means two or more, and "more than" in "one or more" means two or more.

[0040] An embodiment of the present invention provides a method for simultaneously recovering metallic copper from copper oxide concentrate leaching residue and copper sulfide concentrate roasted leaching residue, wherein the copper oxide concentrate leaching residue has a Cu grade of 1-3% and the copper sulfide concentrate roasted leaching residue has a Cu grade of 4-8%, and the method includes the following steps:

[0041] (1) Acid flotation is performed on the leaching residue of the copper oxide concentrate to obtain copper concentrate with a Cu grade of 6-10% by slag flotation.

[0042] (2) The obtained copper concentrate from slag beneficiation and the leaching residue from roasted copper sulfide concentrate are mixed in a mass ratio of 1:(1~1.2) to obtain a mixed ore;

[0043] (3) The obtained mixed ore is stirred and mixed with a leaching agent to obtain a slurry, wherein the leaching agent is a sulfuric acid solution system leaching agent; the mass concentration of the slurry is 15-17%;

[0044] (4) The slurry obtained by leaching at 80-90℃ is separated into solid and liquid residue and leaching liquid;

[0045] (5) The obtained leaching residue is washed to obtain washing residue and washing liquid; the obtained leaching liquid is extracted to obtain a loaded organic phase and raffinate, wherein the obtained washing liquid is used in the extraction step, and the obtained washing residue is discharged as a tailings treatment; the raffinate obtained from the extraction is used to prepare the leaching agent of the sulfuric acid solution system.

[0046] (6) The obtained loaded organic phase is back-extracted and electrowinning to obtain metallic copper.

[0047] In the embodiments of this application, the "copper sulfide concentrate roasted leaching residue" is obtained by first flotating copper sulfide and then copper oxide from a copper-cobalt mixed ore with a grade of 2-4%, resulting in a copper sulfide concentrate with a copper grade of 60-70%. The copper sulfide concentrate is then subjected to oxidative roasting and partial acid roasting to obtain roasted sand with a grade of 50-60%. The roasted sand is then subjected to a sulfuric acid leaching process to obtain the final copper sulfide concentrate roasted leaching residue, in which the copper grade is 4-8%.

[0048] In the embodiments of this application, the "copper oxide concentrate leaching residue" is a copper oxide concentrate with a copper grade of 15-25% obtained by first flotating copper sulfide and then flotating copper oxide from a copper-cobalt mixed ore with a grade of 2-4%. The copper oxide concentrate is then subjected to a sulfuric acid leaching process to obtain the final copper oxide concentrate leaching residue, wherein the copper grade in the copper oxide concentrate leaching residue is about 1-3%.

[0049] In the embodiments of this application, the "copper concentrate from slag" referred to in this invention refers to the intermediate product obtained by acid flotation of "copper oxide concentrate leaching residue" with a Cu grade of 1-3%, wherein the copper grade is about 6-10%.

[0050] According to a typical embodiment of the present invention, the method for generating the copper sulfide concentrate roasted leaching residue and the copper oxide concentrate leaching residue is as follows: Figure 1 As shown. Figure 1 The simplified process of generating copper sulfide concentrate roasted leaching residue and copper oxide concentrate leaching residue is shown.

[0051] In the embodiments of this application, the acid flotation of the copper oxide concentrate leaching residue in step (1) includes the following steps:

[0052] (a) The copper oxide concentrate leaching residue is mixed with water to obtain a slurry, wherein the slurry has a mass percentage concentration of 15-25%;

[0053] (b) Add collectors and frothers to the obtained slurry for roughing to obtain rough concentrate and roughing tailings;

[0054] (c) The obtained rough concentrate is subjected to a first and a second fine cleaning to obtain copper concentrate from slag beneficiation; the obtained rough tailings are subjected to scavenging to obtain copper scavenged ore and tailings, wherein the copper scavenged ore enters the first fine cleaning step and the tailings are discharged.

[0055] According to a typical embodiment of the present invention, the method for treating the copper oxide concentrate leaching residue is as follows: Figure 2 As shown. Figure 2 A schematic diagram of the process flow for preparing copper concentrate from copper oxide concentrate leaching residue is shown. This method includes pulp preparation and flotation steps. Pulp preparation refers to mixing copper oxide concentrate leaching residue with water to form a pulp, where particles smaller than 0.074 mm account for 70-80% of the total particle weight. The flotation process sequentially includes roughing and cleaning.

[0056] According to a preferred embodiment of the present invention, the pulp concentration is 15-25%, and the pH is 3-5. Copper oxide concentrate is acid-leached to obtain copper oxide concentrate leaching residue, which is in a solid-liquid coexistence state. The copper oxide concentrate leaching residue is mixed with water and then subjected to pulp conditioning and flotation. The present invention preferably feeds the pulp into the flotation cell when the mass percentage concentration is controlled at 15-25% because the recovery rate of the copper concentrate from the slag must be considered in subsequent processing. Flotation within this pulp concentration range ensures the copper recovery rate in the copper concentrate from the slag; flotation with a pulp concentration below 15% or above 25% is not conducive to improving the Cu recovery rate in the copper concentrate from the slag. The pH of the pulp system is 3-5, which is the natural pH of the copper oxide concentrate leaching residue after adjustment with aqueous solution. Flotation within this pH range has no impact on the copper recovery rate in the copper oxide concentrate leaching residue.

[0057] According to a preferred embodiment of the present invention, the flotation process includes a roughing step and a cleaning step. The roughing step includes adding a collector and a frother to the slurry and stirring and separating to obtain a rough concentrate and roughing tailings. The cleaning step includes stirring and separating the rough concentrate twice, with the first stirring and separation time being 8-10 minutes and the second stirring and separation time being 16-20 minutes.

[0058] According to the embodiments of this application, the main purpose of roughing is to recover copper minerals from the leaching residue of copper oxide concentrate. One roughing operation is sufficient to float 50-80% of the copper minerals. Specifically, a slurry of a certain concentration is fed into the flotation cell, and collectors and frothers are added to the slurry system while stirring. The collector is added to float copper sulfide in the slurry. The collector works by interacting with the surface of the copper minerals to form chemical adsorption, increasing the hydrophobicity of the copper minerals and allowing them to adhere to the froth and float together. The frother is added to increase the amount and viscosity of the froth during the frothing process, which is beneficial for the copper minerals to adhere to the surface of the froth. Stirring is to ensure that the flotation reagents, such as the collector and frother, are more thoroughly mixed with the slurry. The stirring time is generally 31 minutes, which is sufficient to ensure thorough mixing of the copper minerals and flotation reagents.

[0059] In the embodiments of this application, in step (b), the collector in the roughing stage is sodium dithiocarbonate-O-butyl ester, added at a rate of 100-300 g / ton of copper oxide concentrate leaching residue. The frother is pine oil, added at a rate of 30-50 g / ton of copper oxide concentrate leaching residue.

[0060] In the embodiments of this application, the tailings after roughing are fed into the next froth tank for scavenging. The froth product obtained from scavenging and the froth product obtained from roughing are fed together into the next froth tank for further cleaning. The flotation reagents in the scavenging stage may include the collector sodium dithiocarbonate-O-butyl dithiocarbonate and the frother pine oil. In the copper scavenging step, the amount of sodium dithiocarbonate-O-butyl dithiocarbonate added is 30 g / ton of copper oxide concentrate leaching residue; the amount of pine oil added is 5-10 g / ton of copper oxide concentrate leaching residue; the scavenging time can be 5-10 minutes.

[0061] In the embodiments of this application, in step (c), the obtained rough concentrate is subjected to a first cleaning and a second cleaning. The first cleaning produces copper middlings and copper concentrate. The copper middlings are returned to the roughing step. The copper concentrate is then subjected to the second cleaning.

[0062] In the embodiments of this application, the second refining in step (c) produces copper middlings and copper concentrate from slag beneficiation. The copper middlings are returned to the first refining step, and the copper concentrate from slag beneficiation is copper concentrate from slag beneficiation with a Cu grade of 6-10%.

[0063] According to embodiments of this application, the rough concentrate obtained in the roughing step and the scavenging concentrate obtained in the scavenging step are further refined. The concentration of the pulp entering the refining step is reduced by approximately 10-15% compared to the pulp concentration in the roughing step. Flotation reagents can be added and stirred during the refining step. Alternatively, blank refining can be used. "Blank refining" here refers to refining without adding any flotation reagents, only through stirring. Because the mineral particles in the pulp have flotation reagents adsorbed on their surface during the roughing process, these adsorbed flotation reagents can float copper sulfide from the pulp during stirring, so blank refining can be performed directly without adding further flotation reagents.

[0064] The specific selection process is as follows: Figure 2 As shown, the refining process of this invention is a continuous two-stage blank refining process, with each blank refining yielding copper middlings and copper tailings. Specifically, the first-stage blank refining step yields copper concentrate and copper tailings, with copper concentrate entering the second-stage blank refining and copper tailings returning to the previous stage's roughing step. The second-stage blank refining step yields copper concentrate and copper tailings, with copper tailings returning to the first-stage blank refining. The refined concentrate is the final slag-refined copper concentrate.

[0065] In the embodiments of this application, such as Figure 3-4 As shown, in step (2), copper concentrate from slag beneficiation and copper sulfide concentrate roasted leaching residue with a particle size of -0.074mm accounting for 70-80% and similar grades are mixed in a ratio of 1:1 to 1:1.2. The resulting mixed ore is then fed into the slurry preparation tank 1, and the prepared leaching agent is added and stirred evenly for slurry preparation. The leaching agent is a sulfuric acid solution system, which is fed through sulfuric acid pipe 9. The amount of sulfuric acid used is controlled by sulfuric acid flow meter 10 and sulfuric acid valve 11. The sulfuric acid concentration is 2-3.5 mol / L at the beginning of leaching.

[0066] The prepared slurry is then transported to the leaching tank 5 for leaching via the feed valve 2 and feed pump 3 (a discharge valve 7 is installed at the bottom of the leaching tank 5, which is connected to and used in conjunction with the discharge pump 8 for discharging the slurry after leaching). The solid-liquid ratio during leaching is 1:5. Steam valve 16 is opened, and steam enters through steam pipe 15, causing the temperature inside the leaching tank 5 to rise. A digital thermometer 6 displays the temperature inside the leaching tank 5. The temperature inside the leaching tank 5 is controlled to 80-90℃, preferably 85℃, via steam valve 16, and leaching is performed by stirring with a stirrer 4. Specifically, the heating method can utilize the waste heat boiler steam from the roasting furnace.

[0067] Figure 4The co-processing device also includes a clean water pipe 12, which is connected to the slurry preparation tank 1 via a control valve 14 and to the leaching tank 5 via a flow meter 13. One or more leaching tanks 5 may be provided.

[0068] Under the above conditions, the valuable metallic copper mainly present in minerals such as malachite, copper sulfate, copper ferroate, copper ferrite, covellite, and bornite in the mixed ore reacts with other substances in quartz, gypsum, magnetite, kaolinite, muscovite, chlorite, and rutile, entering the solution in ionic form and transforming into soluble sulfates. The main reactions occurring in the synergistic leaching process are as follows:

[0069] The Cu₂O·Fe₂O₃ and CuFe₂O₄ in the ore undergo the following reaction in an aqueous solution of sulfuric acid:

[0070] 2Cu2O·Fe2O3+4H2SO4+O2=4CuSO4+2Fe2O3+4H2O (1)

[0071] CuO·Fe2O3+H2SO4=CuSO4+Fe2O3+H2O (2)

[0072] CuFe2O4+H2SO4+2H2O=CuSO4+2Fe(OH)3 (3)

[0073] CuFe2O4+H2SO4=CuSO4+Fe2O3+H2O (4)

[0074] Sulfides such as CuS in the ore are reacted with sulfuric acid to produce Fe. 3+ Oxidation, regenerating S o Cu 2+ Fe 3+ It is reduced to Fe 2+ The overall reactions occurring during the leaching process are as follows:

[0075] 2CuS+2H2SO4+O2=2CuSO4+2S+2H2O (5)

[0076] The specific reaction process of CuS in the leaching residue of copper oxide concentrate in solution is as follows:

[0077] CuS exists in ionization equilibrium in solution:

[0078] CuS=Cu 2+ +S 2－ (6)

[0079] ionized S 2－ The ions are converted from sulfuric acid in the system to hydrosulfuric acid:

[0080] S 2－ +2H + =H2S (7)

[0081] Because hydrosulfuric acid is a weak acid, S0 in acidic solution 2－ It exists almost entirely in the form of hydrosulfuric acid. Simultaneously, the hydrosulfuric acid is reacted with Fe in the solution. 3+ Oxidized elemental sulfur:

[0082] H2S + 2Fe 3+ →2H + +S↓+2Fe 2+ (8)

[0083] The generated elemental sulfur readily appears in colloidal form, because sulfur colloids can adsorb hydrogen sulfide ions (HS-H ions) in the solution. － The negative charge, combined with the adsorption effect of the micelles themselves, causes a considerable amount of Fe to be adsorbed on the surface of the sulfur micelles. 2+ ions, Fe 2+ It reacts with oxygen dissolved in the solution during stirring to produce Fe. 3+ :

[0084] 4Fe 2+ +4H + +O2→4Fe 3+ +2H2O (9)

[0085] The generated Fe 3+ Continue oxidizing elemental S to HSO 3－ H2SO3 and a small amount of SO3 2－ :

[0086] S+4Fe 3+ +3H₂O→H₂SO₃+4Fe 2+ +4H + (10)

[0087] H2SO3 reacts with dissolved O2 in the solution to produce SO4. 2－ :

[0088] 2H₂SO₃ + O₂ → 2SO₄ 2－ +4H + (11)

[0089] Other substances in the leaching residue of copper oxide concentrate and the leaching residue of roasted copper sulfide concentrate undergo the following reactions in the reaction system:

[0090] MgO + H₂SO₄ = MgSO₄ + H₂O (12)

[0091] CaO + H₂SO₄ = CaSO₄ + H₂O (13)

[0092] Al2O3+H2SO4=Al2(SO4)3+3H2O (14)

[0093] CuFeS2 + O2 + H + → Cu 2+ +So / -+S + Fe2O3·H2O+ H2O (15)

[0094] Ferric ions hydrolyze to form hematite according to the following formula:

[0095] Fe2(SO4)3+ 3H2O = Fe2O3 + 3H2SO4 (16)

[0096] Copper sulfides and copper ferrite react slowly with sulfuric acid at room temperature and pressure. In leaching tank 5, the leaching agent is mainly an aqueous solution of sulfuric acid. In addition to the aqueous phase, some O2 from the steam heating also plays a good oxidizing role. The leaching agent and materials are simultaneously placed in leaching tank 5 and stirred. Through the intensification of heating, the copper oxide concentrate leaching residue and the copper sulfide concentrate roasted sand leaching residue are leached together. Sulfur is produced as elemental sulfur and sulfate ions. The leaching process completely eliminates the emission of SO2, H2S, and NOx vapors, and also improves the leaching rate of Cu metal in both.

[0097] This invention uses copper oxide concentrate leaching residue and copper sulfide concentrate roasted sand leaching residue as co-leaching raw materials, fundamentally solving the problem of high cost and high input associated with processing copper oxide concentrate leaching residue and copper sulfide concentrate roasted sand leaching residue alone. Leaching is carried out at a temperature of 80-90℃. Compared with high-temperature roasting, oxygen pressure leaching, and ammonia leaching processes, this method saves energy and environmental protection investment while significantly improving operational safety.

[0098] The leaching time is generally 6 hours. When the leaching time reaches 6 hours, the operation is stopped, and the leached mixed slurry is fed into a thickener for concentration and liquid-solid separation using a slurry pump.

[0099] The leaching residue contains iron, manganese, calcium, silicon, etc. Under natural conditions, it is washed with water at a pH of 6.5-7.5. After washing, the slurry is fed back into a filter press for filtration. The washing liquid is mixed with the leachate and fed into the next process, while the leaching residue is sent to a slag yard for stockpiling.

[0100] This invention discloses a method for the co-processing and recovery of valuable copper from copper oxide concentrate leaching residue and copper sulfide concentrate roasted leaching residue. This method is applicable to the processing of low-grade copper oxide concentrate leaching residue and copper sulfide concentrate roasted leaching residue. After flotation enrichment, the low-grade copper oxide concentrate leaching residue yields a copper concentrate containing copper-containing substances such as copper ferroate, copper ferrite, chalcopyrite, chalcopyrite, and trace amounts of copper vitriol, bornite, chalcopyrite, chalcopyrite, and arsenic sulfide. Co-leaching of the copper concentrate and copper sulfide concentrate roasted leaching residue achieves a good copper recovery rate. High levels of impurities such as calcium, iron, cadmium, manganese, and phosphorus do not affect the leaching of Cu metal during the co-leaching process, with the main metal leaching rate reaching over 82%. Therefore, comprehensive recovery of copper resources from copper sulfide concentrate roasted leaching residue and copper oxide concentrate leaching residue can be achieved.

[0101] The synergistic processing method proposed in this invention has very broad application prospects in the field of hydrometallurgy, and it has characteristics that traditional processes do not possess:

[0102] (1) The leaching residue of low-grade copper oxide concentrate can be directly fed into flotation without grinding and pH adjustment. The flotation process is simple, the technology is simple, and the equipment investment is small. The grade of copper concentrate after flotation is required to be 6-10%. The actual processing does not require a large investment.

[0103] (2) The synergistic leaching material is composed of copper concentrate leaching residue obtained after flotation of copper oxide concentrate leaching residue and roasted copper sulfide concentrate leaching residue. The material is easy to obtain and consists of two single difficult-to-process materials. Both can be leached simultaneously in an aqueous sulfuric acid system.

[0104] (3) The leaching process involves a simple material composition, requiring no other additives or oxidants. During steam heating, the high-temperature oxygen-rich ions carried in the steam can play a good oxidizing role. The gas-liquid-solid three phases are uniformly mixed in leaching tank 5, utilizing the main oxide Fe in the leaching residue of copper sulfide concentrate roasted sand. 3+ In the process of removing Cu from copper concentrate by oxidation leaching residue, the main metallic copper in both oxidant and acid is leached out simultaneously while reducing the consumption of oxidant and acid.

[0105] (4) The co-leaching process is carried out in a closed container at a moderate temperature and with moderate stirring, which is conducive to improving the mass transfer rate and production control.

[0106] (5) The co-leaching process does not cause environmental pollution problems due to the discharge of S, SO2 and H2S, and the process is simple and clean.

[0107] Example

[0108] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0109] Example 1

[0110] Raw materials: copper concentrate (containing 9.53% copper) obtained by flotation enrichment of copper oxide concentrate leaching residue (containing 3.14% copper) from a mining company in the Democratic Republic of Congo; copper sulfide concentrate roasted leaching residue (containing 4.42% copper).

[0111] The leaching residue of copper oxide concentrate containing 3.14% copper was enriched by flotation to obtain copper concentrate containing 9.53% copper and leaching residue of roasted copper sulfide concentrate containing 4.42% copper. The mixture was prepared in a 1:1 ratio and added to a 3*3.5m stirring tank with an effective volume of 21m3. A sulfuric acid aqueous solution with a concentration of 2.55mol / L was added to adjust the mass percentage concentration of the slurry to 15.19%. The slurry was then fed into leaching tank 5, and steam was introduced to raise the temperature while stirring. Once the temperature reached 85℃, the temperature of leaching tank 5 was kept constant and the leaching time was started for 6 hours.

[0112] After leaching, the mixed liquid is pumped through discharge pump 8 into the next process for subsequent treatment, including concentration and filtration. The subsequent treatment includes: using a thickener to concentrate and separate the leached mixed liquid into leachate and leaching residue; washing the leaching residue to obtain washing liquid and washing residue; the washing residue is discharged as tailings; the washing liquid and leachate are mixed and then fed into the extraction-back-extraction process for electrodeposition to prepare cathode copper; the raffinate from the extraction process is filtered to obtain iron-removed filtrate; the iron-removed filtrate is then filtered to obtain copper-removed filtrate; and the copper-removed filtrate is then processed to prepare crude cobalt hydroxide. The total copper content in the washing residue after leaching is determined using atomic absorption spectrometry, and the co-leaching rate of copper in the leaching residue of the flotation-enriched copper concentrate and the roasted copper sulfide concentrate is calculated to be 82.96%.

[0113] Example 2

[0114] Raw materials: copper concentrate (containing 6.93% copper) obtained by flotation enrichment of copper oxide concentrate leaching residue (containing 1.46% copper) from a mining company in the Democratic Republic of Congo; and roasted copper sulfide concentrate leaching residue (containing 5.73% copper).

[0115] The leaching residue of copper oxide concentrate containing 1.46% copper was enriched by flotation to obtain copper concentrate containing 6.93% copper and roasted copper sulfide concentrate containing 5.76% copper. The mixture was prepared into a 1:1 ratio and added to a 3*3.5m stirring tank with an effective volume of 21m3. A sulfuric acid aqueous solution with a concentration of 2.04mol / L was added to adjust the mass percentage concentration of the slurry to 15.49%. The slurry was then fed into leaching tank 5, and steam was introduced to raise the temperature while stirring. Once the temperature reached 85℃, the temperature of leaching tank 5 was kept constant and the leaching time was started for 6 hours.

[0116] After leaching, the mixed liquid is fed into the next process via discharge pump 8 for subsequent treatment such as concentration and filtration, which is the same as in Example 1. The total copper content in the washing residue after leaching is determined by atomic absorption spectrometry, and the co-leaching rate of copper in the copper concentrate from flotation enrichment and the roasted copper concentrate leaching residue is calculated to be 82.78%.

[0117] Example 3

[0118] Raw materials: copper concentrate (containing 7.02% copper) obtained by flotation enrichment of copper oxide concentrate leaching residue (containing 2.06% copper) from a mining company in the Democratic Republic of Congo; and roasted copper sulfide concentrate leaching residue (containing 8.00% copper).

[0119] The leaching residue of copper oxide concentrate containing 2.06% copper was enriched by flotation to obtain copper concentrate containing 7.02% copper and roasted copper sulfide concentrate containing 8.00% copper. The mixture was prepared into a 1:1 ratio and added to a 3*3.5m stirring tank with an effective volume of 21m3. A sulfuric acid aqueous solution with a concentration of 2.11mol / L was added to adjust the mass percentage concentration of the slurry to 16.67%. The slurry was then fed into leaching tank 5, and steam was introduced to raise the temperature while stirring. Once the temperature reached 85℃, the temperature of leaching tank 5 was kept constant and the leaching time was started for 6 hours.

[0120] After leaching, the mixed liquid is fed into the next process via discharge pump 8 for subsequent treatment such as concentration and filtration, which is the same as in Example 1. The total copper content in the washing residue after leaching is determined by atomic absorption spectrometry, and the co-leaching rate of copper in the copper concentrate from flotation enrichment and the roasted copper concentrate leaching residue is calculated to be 83.02%.

[0121] Example 4

[0122] Raw materials: copper oxide concentrate leaching residue (containing 2.14% copper) obtained by flotation enrichment from copper oxide concentrate leaching residue (containing 7.08% copper) from a mining company in the Democratic Republic of Congo; roasted copper sulfide concentrate leaching residue (containing 7.59% copper).

[0123] The leaching residue of copper oxide concentrate containing 2.14% copper was enriched by flotation to obtain copper concentrate containing 7.08% copper and roasted copper concentrate containing 7.59% copper. The leaching residue was mixed with the copper oxide concentrate in a 1:1 ratio and added to a 3*3.5m stirring tank with an effective volume of 21m3. A sulfuric acid aqueous solution with a concentration of 2.08mol / L was added to adjust the mass percentage concentration of the slurry to 16.01%. The slurry was fed into leaching tank 5 and heated by steam while stirring. After the temperature reached 85℃, the temperature of leaching tank 5 was kept constant and the leaching time was started for 6 hours.

[0124] After leaching, the mixed liquid is fed into the next process via discharge pump 8 for subsequent treatment such as concentration and filtration, which is the same as in Example 1. The total copper content in the washing residue after leaching is determined by atomic absorption spectrometry, and the co-leaching rate of copper in the copper concentrate from flotation enrichment and the roasted copper concentrate leaching residue is calculated to be 82.99%.

[0125] Comparative Example 1

[0126] Raw materials: The copper oxide concentrate leaching residue (containing 3.14% copper) and copper sulfide concentrate roasted sand leaching residue (containing 4.42% copper) from a mining company in the Democratic Republic of Congo, as described in Example 1.

[0127] Take copper oxide concentrate leaching residue containing 2.75% copper, without flotation enrichment, and copper sulfide concentrate roasted sand leaching residue containing 4.42% copper, mix them in a 1:1 ratio to form a mixed ore, and add it to a 3*3.5m stirring tank with an effective volume of 21m3. Add sulfuric acid aqueous solution with a concentration of 2.55mol / L to adjust the mass percentage concentration of the slurry to 15.19%. Send the slurry into leaching tank 5, and heat it by passing steam while stirring. After the temperature reaches 85℃, keep the temperature of leaching tank 5 constant and start timing. The leaching time is 6 hours.

[0128] After leaching, the mixed liquid is fed into the next process via discharge pump 8 for subsequent treatment such as concentration and filtration, which is the same as in Example 1. The total copper content in the washing residue after leaching is determined by atomic absorption spectrometry, and the co-leaching rate of copper in the copper oxide concentrate leaching residue and the copper sulfide concentrate roasted sand leaching residue is calculated to be 71.54%.

[0129] Comparative Example 2

[0130] Raw materials: The copper concentrate (containing 9.53% copper) obtained by flotation enrichment of the leaching residue (containing 3.14% copper) of copper oxide concentrate from a mining company in the Democratic Republic of Congo, as described in Example 1.

[0131] The leaching residue of copper oxide concentrate containing 3.14% copper was enriched by flotation to obtain copper concentrate containing 9.53% copper. The leaching residue of roasted copper sulfide concentrate was not added and was added to a 3*3.5m stirring tank with an effective volume of 21m3. A sulfuric acid aqueous solution with a concentration of 2.18mol / L was added to adjust the mass percentage concentration of the slurry to 16.01%. The slurry was sent to leaching tank 5 and heated by steam while stirring. After the temperature reached 85℃, the temperature of leaching tank 5 was kept constant and the leaching time was started. The leaching time was 6 hours.

[0132] After leaching, the mixed liquid is fed into the next process via discharge pump 8 for subsequent treatment such as concentration and filtration, which is the same as in Example 1. The total copper content in the washing residue after leaching is determined by atomic absorption spectrometry, and the single leaching rate of the copper concentrate from the slag is calculated to be 55.76%.

[0133] Comparative Example 3

[0134] Raw material: Leaching residue from roasted copper sulfide concentrate of a mining company in the Democratic Republic of Congo (containing 4.42% copper).

[0135] Take the leaching residue of roasted copper sulfide concentrate containing 4.42% copper, without adding the copper concentrate enriched by flotation, and add it to a 3*3.5m stirring tank with an effective volume of 21m3. Add sulfuric acid aqueous solution with a concentration of 2.18mol / L to adjust the mass percentage concentration of the slurry to 16.01%. Send the slurry into leaching tank 5, and heat it by passing steam while stirring. After the temperature reaches 85℃, keep the temperature of leaching tank 5 constant and start timing. The leaching time is 6 hours.

[0136] After leaching, the mixed liquid is pumped through discharge pump 8 into the next process for subsequent treatment such as concentration and filtration, which is the same as in Example 1. The total copper content in the washing residue after leaching is determined by atomic absorption spectrometry, and the single leaching rate of the copper sulfide concentrate roasted sand leaching residue is calculated to be 40.72%.

[0137] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for simultaneously recovering metallic copper from leaching residue of copper oxide concentrate and leaching residue of roasted copper sulfide concentrate, characterized in that, The Cu grade of the copper oxide concentrate leaching residue is 1-3%, and the Cu grade of the copper sulfide concentrate roasted sand leaching residue is 4-8%. The method includes the following steps: (1) Acid flotation is performed on the leaching residue of the copper oxide concentrate to obtain copper concentrate with a Cu grade of 6-10%; (2) The obtained copper concentrate from slag beneficiation and the leaching residue from roasted copper sulfide concentrate are mixed in a mass ratio of 1:(1~1.2) to obtain a mixed ore; (3) The obtained mixed ore is stirred and mixed with a leaching agent to obtain a slurry, wherein the leaching agent is a sulfuric acid solution system leaching agent; the mass concentration of the slurry is 15-17%; (4) The slurry obtained by leaching at 80~90℃ is separated into solid and liquid residue and leachate; (5) The obtained leaching residue is washed to obtain washing residue and washing liquid; the obtained leaching liquid is extracted to obtain a loaded organic phase and raffinate, wherein the obtained washing liquid is used in the extraction step, and the obtained washing residue is discharged as a tailings treatment; the raffinate obtained from the extraction is used to prepare the leaching agent of the sulfuric acid solution system. (6) The obtained supported organic phase is back-extracted and electrodeposited to obtain metallic copper; The acid flotation of the copper oxide concentrate leaching residue in step (1) includes the following steps: (a) The copper oxide concentrate leaching residue is mixed with water to obtain a slurry, wherein the slurry has a mass percentage concentration of 15-25%; (b) Add collectors and frothers to the obtained slurry for roughing to obtain rough concentrate and roughing tailings; (c) The obtained rough concentrate is subjected to a first and a second cleaning process to obtain copper concentrate from slag beneficiation; the obtained rough tailings are subjected to scavenging to obtain copper scavenged ore and tailings, wherein the copper scavenged ore enters the first cleaning step and the tailings are discharged. The collector mentioned in step (b) is sodium dithiocarbonate-O-butyl ester, and the addition amount is 100-300 grams per ton of copper oxide concentrate leaching residue; The foaming agent mentioned in step (b) is pine oil, and the addition amount is 30-50 grams per ton of copper oxide concentrate leaching residue.

2. The method for simultaneously recovering metallic copper from copper oxide concentrate leaching residue and copper sulfide concentrate roasted sand leaching residue according to claim 1, characterized in that, The first refining process in step (c) produces copper middlings and copper concentrate. The copper middlings are returned to the roughing process; the copper concentrate is then processed in the second refining process.

3. The method for simultaneously recovering metallic copper from copper oxide concentrate leaching residue and copper sulfide concentrate roasted sand leaching residue according to claim 1, characterized in that, The second refining process in step (c) produces copper middlings and copper concentrate from slag beneficiation. The copper middlings are returned to the first refining step, and the copper concentrate from slag beneficiation is copper concentrate from slag beneficiation with a Cu grade of 6-10%.

4. The method for simultaneously recovering metallic copper from copper oxide concentrate leaching residue and copper sulfide concentrate roasted sand leaching residue according to claim 1, characterized in that, In step (3), particles with a diameter of less than 0.074 mm account for 70-80% of the total particle weight in the slurry.

5. The method for simultaneously recovering metallic copper from copper oxide concentrate leaching residue and copper sulfide concentrate roasted sand leaching residue according to claim 1, characterized in that, The leaching time of the slurry obtained by leaching at 80~90℃ in step (4) is more than 6 hours.

6. The method for simultaneously recovering metallic copper from copper oxide concentrate leaching residue and copper sulfide concentrate roasted sand leaching residue according to claim 1, characterized in that, Step (4) includes concentrating the leached slurry before solid-liquid separation.

7. The method for simultaneously recovering metallic copper from copper oxide concentrate leaching residue and copper sulfide concentrate roasted sand leaching residue according to claim 1, characterized in that, The washing of the obtained leaching residue in step (5) includes stirring and washing the obtained leaching residue with clean water with a pH of 6.5-7.5 under natural conditions.

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