Method for recovering copper in micro-fine particle copper leaching residues through combination of precipitation and shear flocculation

Abstract

The invention relates to a method for recovering copper in micro-fine particle copper leaching residues through combination of precipitation and shear flocculation, which comprises the following steps: carrying out solid-liquid separation on the micro-fine particle copper leaching residues to obtain copper-ion-containing liquid and leaching residues without the copper-ion-containing liquid; carrying out iron removal and copper deposition on the copper-containing ionic liquid to obtain copper sulfide precipitate and copper-deposited liquid; and after size mixing is conducted on the leaching residues with the copper-containing ionic liquid removed, chemicals including a vulcanizing agent and a collecting agent are added, strong stirring is conducted, and leaching residue concentrate and flotation tailings are obtained through flotation. According to the method, agglomeration is induced through the combined action of the agent and strong stirring, the apparent particle size of the target mineral is remarkably increased, and the leaching residue concentrate rich in copper sulfide is obtained through flotation; and the technological process is simple, the operation requirement is low, the copper recovery rate is high, and efficient recovery of the micro-fine particle copper leaching residues is achieved.

Description

Technical Field

[0001] This invention relates to the resource recovery of leaching residue from hydrometallurgical processes, specifically to a method for the combined recovery of fine-particle copper leaching residue through precipitation and shear flocculation. Background Technology

[0002] The Democratic Republic of Congo (DRC) is a globally important region rich in copper and cobalt resources. Its non-copper-cobalt metallogenic belt, particularly in the southeastern Katanga province, boasts enormous known copper reserves, accounting for approximately 15% of global reserves, and cobalt reserves that reach as high as 50% of the global total, making it the world's largest cobalt producer. The region's copper resources primarily exist as copper oxide and copper sulfide minerals, while cobalt is mostly found as a by-product. Currently, although various beneficiation and metallurgical processes exist for the development and utilization of copper-cobalt resources in this region, the copper-cobalt ore in this region is mainly a sulfur-oxygen mixture. The mainstream flotation process is "sulfur first, then oxygen." The copper oxide concentrate produced is sent to a hydrometallurgical plant to produce cathode copper using leaching, extraction, and electrowinning processes. At the same time, it produces fine-grained copper leaching residue containing 3wt% to 6wt% copper, with a fine particle size (90wt% below 20μm). The ore has complex properties and contains residual soluble copper ions, resulting in poor flotation performance. Conventional flotation processes cannot effectively recover soluble copper ions and copper minerals in the leaching residue, leading to long-term stockpiling of fine-grained copper leaching residue that cannot be recycled. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a method for recovering copper from fine copper leaching residue by a combination of precipitation and shear flocculation with high copper recovery rate.

[0004] The technical solution adopted by the present invention to solve its technical problem is as follows: a method for recovering copper from fine copper leaching residue by precipitation and shear flocculation, wherein the fine copper leaching residue is subjected to solid-liquid separation to obtain a liquid containing copper ions and a leaching residue from which the liquid containing copper ions is removed; The copper-containing ionic liquid contains 0.9 g / L to 2.0 g / L of copper, 3.5 g / L to 4.7 g / L of iron, and has a pH value below 2.5; The pH value of the copper-containing ionic liquid is adjusted to 4.0~4.5 to remove iron. After solid-liquid separation, iron-removed liquid and iron slag are obtained. The pH value of the iron-removed liquid is adjusted to 5.5~7.0 and mixed with sulfiding agent A to precipitate copper. After solid-liquid separation, copper sulfide precipitate and copper-precipitated liquid are obtained. The copper grade in the leaching residue for removing copper-containing liquid is 2.80wt%~4.10wt%, and the copper contained in the copper blue accounts for 55wt%~70wt% of its total copper content; the particle size of the leaching residue for removing copper-containing liquid is 90wt% below 20μm. The leaching residue from the copper-containing liquid is slurryed to a pulp concentration of 25wt%~38wt% and a pH value of 6.0~7.0; reagents including sulfiding agent B and collector are added, and the mixture is strongly stirred at a speed of 2100r / min~2800r / min, and then flotation is carried out to obtain leaching residue concentrate and flotation tailings. Copper is enriched in the copper sulfide precipitate and leaching residue concentrate.

[0005] Preferably, the pH value of the copper-containing liquid is adjusted by adding lime milk.

[0006] Preferably, the pH value of the solution after iron removal is adjusted by adding lime milk.

[0007] Preferably, the vulcanizing agent A includes at least one of sodium hydrosulfide and sodium sulfide.

[0008] Preferably, the amount of vulcanizing agent A is 2.1 g / L to 2.55 g / L.

[0009] Preferably, the copper plating process takes less than 0.5 hours.

[0010] Preferably, the vigorous stirring is performed after the addition of vulcanizing agent B and collector.

[0011] Preferably, the strong stirring time is 10 min to 20 min.

[0012] Preferably, after adding vulcanizing agent B and collector, a foaming agent is also added.

[0013] Preferably, the strong stirring is performed after adding the vulcanizing agent B and the collector, and before adding the foaming agent.

[0014] Preferably, the foaming agent comprises 2 # At least one of oil and BK204.

[0015] Preferably, the amount of foaming agent used is 10g / t to 20g / t.

[0016] Preferably, a dispersant is added before adding the vulcanizing agent B and the collector.

[0017] Preferably, the dispersant comprises sodium hexametaphosphate.

[0018] Preferably, the amount of the dispersant is 200g / t to 300g / t.

[0019] Preferably, the sulfiding agent B includes at least one of sodium sulfide, sodium hydrosulfide, and ammonium sulfide.

[0020] Preferably, the collector includes at least one of butyl xanthate, BK404B, and ZH-1147.

[0021] Preferably, the amount of vulcanizing agent B is 100g / t to 200g / t.

[0022] Preferably, the amount of the collector is 300g / t to 400g / t.

[0023] Preferably, the flotation includes one or more stages, the concentrate obtained from each stage of flotation is leaching residue concentrate; the tailings obtained from each stage of flotation except the last stage enter the next stage of flotation; the tailings obtained from the last stage of flotation are flotation tailings.

[0024] The present invention has the following beneficial effects: The present invention separates fine-particle copper leaching residue into copper-containing liquid and leaching residue after removing the copper-containing liquid. The copper-containing liquid is subjected to iron removal and copper precipitation to obtain copper-enriched copper sulfide precipitate. The leaching residue after removing the copper-containing liquid is re-slurryed and induced to agglomerate through the combined action of reagents and strong stirring, which significantly increases the apparent particle size of the target mineral. The leaching residue concentrate rich in copper sulfide is obtained by flotation. The process is simple, the operation requirements are low, and the copper recovery rate is high, realizing the efficient recovery of fine-particle copper leaching residue.

[0025] 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 accompanying drawings. Attached Figure Description

[0026] 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 undue limitation of the invention. In the drawings: Figure 1 This is a process flow diagram of the method for recovering copper from fine copper leaching residue by combined precipitation and shear flocculation in Embodiment 1 of the present invention. Detailed Implementation

[0027] To make the objectives, solutions, and beneficial technologies of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. It should be noted that the embodiments described in this specification are merely illustrative of the invention and are not intended to limit the invention.

[0028] 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.

[0029] 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.

[0030] In the various embodiments and comparative examples, BK404B is a modified thiocyanate collector produced by Beikuang Chemical Technology (Cangzhou) Co., Ltd., BK204 is a mixed fatty alcohol foaming agent produced by Beikuang Chemical Technology (Cangzhou) Co., Ltd., and ZH-1147 is a modified thiocyanate collector produced by Hunan Nonferrous Metals Research Institute.

[0031] Embodiments of the present invention provide a method for recovering copper from fine copper leaching residue by a combination of precipitation and shear flocculation. The fine copper leaching residue is subjected to solid-liquid separation to obtain a liquid containing copper ions and a leaching residue from which the liquid containing copper ions has been removed. The copper-containing ionic liquid contains 0.9 g / L to 2.0 g / L of copper, 3.5 g / L to 4.7 g / L of iron, and has a pH value below 2.5; The pH value of the copper-containing ionic liquid is adjusted to 4.0~4.5 to remove iron. After solid-liquid separation, iron-removed liquid and iron slag are obtained. The pH value of the iron-removed liquid is adjusted to 5.5~7.0 and mixed with sulfiding agent A to precipitate copper. After solid-liquid separation, copper sulfide precipitate and copper-precipitated liquid are obtained. The copper grade in the leaching residue for removing copper-containing liquid is 2.80wt%~4.10wt%, and the copper contained in the copper blue accounts for 55wt%~70wt% of its total copper content; the particle size of the leaching residue for removing copper-containing liquid is 90wt% below 20μm. The leaching residue from the copper-containing liquid is slurryed to a pulp concentration of 25wt%~38wt% and a pH value of 6.0~7.0; reagents including sulfiding agent B and collector are added, and the mixture is strongly stirred at a speed of 2100r / min~2800r / min, and then flotation is carried out to obtain leaching residue concentrate and flotation tailings. Copper is enriched in the copper sulfide precipitate and leaching residue concentrate.

[0032] The leaching residue concentrate is rich in copper sulfide and partially sulfided copper oxide. The resulting copper sulfide precipitate and leaching residue concentrate product can be roasted and leached to obtain copper-rich solution, which can then be used to manufacture cathode copper products via electrowinning.

[0033] Fine-grained copper leaching residue is a product of leaching and pressure filtration in a hydrometallurgical system, containing residual soluble copper from the acid leaching process. Originally designed to be pumped to a mineral processing system for flotation recovery after slurry preparation, the fine particles in this residue exhibit characteristics such as small mass, large specific surface area, high surface energy, high surface charge, and low unsaturated bond compensation. These particles are easily mechanically carried into the tailings by the water flow. Furthermore, surface oxidation increases hydrophilicity, further deteriorating the flotation effect, resulting in poor flotation performance and ineffective recovery of residual soluble copper from the leaching residue. The Fe in the fine-grained copper leaching residue... 2＋ It readily reacts to produce Fe 3+ : 4Fe 2＋ + 4H ＋ + O2→ 4Fe 3＋ + 2H2O And Fe 3+ The adsorption of Fe(OH)3 onto the surface of fine-grained copper oxide ore weakens the effective sulfidation of the copper ore, thereby reducing the hydrophobicity of the mineral surface and preventing the formation of hydrophobic aggregates. This further leads to lower copper ore flotation recovery and flotation speed. A high iron content in the pulp also negatively impacts the sulfur-induced agglomeration flotation of valuable copper sulfide minerals.

[0034] The inventors of this invention discovered through research that by separating the fine-particle copper leaching residue into solid and liquid phases and then re-adjusting the slurry, soluble copper ions and other impurity ions that affect flotation can be effectively separated from the leaching residue solids. By adopting targeted methods for recovery, the recovery effect can be significantly improved.

[0035] In this invention, the leaching residue is subjected to solid-liquid separation, separating it into a copper-ion-containing liquid and a leaching residue from which the copper-ion-containing liquid has been removed, which are then processed separately; a portion of Fe 3+ Upon entering the copper-containing ionic liquid, according to the Langevin Chemical Handbook: K sp (CuS) = 6.3 × 10 -36 K sp (Cu₂S) = 2.5 × 10⁻⁶ -48 ; K sp (αCoS) = 4 × 10 -21 K sp (βCoS) = 2 × 10 -25 ; K sp (MnS) = 2.5 × 10 -13 ; K sp (FeS) = 6.3 × 10 -18 ; K sp (Al2S3)=2×10 -7; From the K of the corresponding sulfide sp The order in which sulfide precipitates form is as follows: Cu 2+ >Co 2+ >Fe 2+ >Mn 2+ >Al 3+ However, this order does not mean that Co and Fe will not precipitate when Cu is not completely precipitated. In reality, small amounts of Co and Fe still precipitate even when copper is not completely precipitated; preferentially precipitating Fe reduces the amount of Fe entering the smelting process and also reduces the amount of sulfiding agent used. Furthermore, sulfiding agents react readily with H₂ in low pH environments. + The reaction produces toxic gas H2S and also reduces the utilization rate of the vulcanizing agent.

[0036] After iron removal, the iron ion content in the liquid is 0.02 g / L to 0.05 g / L, with an iron removal rate of over 99%. After precipitation with sulfiding agent A, copper can be recovered, and cobalt can also be recovered simultaneously (if available). Sulfur is selective for Cu and Co, and can preferentially precipitate Cu and Co in copper-containing liquid as CuS and CoS, while other impurity elements are basically not precipitated, resulting in copper-enriched copper sulfide precipitate.

[0037] The leaching residue from the copper-containing liquid removal process contains copper at a grade of 2.80 wt% to 4.10 wt%. Most of the copper minerals are liberated monomers, with a degree of liberation of approximately 95%. Copper is primarily found in chalcopyrite, accounting for 55 wt% to 70 wt% of the total copper content. The chalcopyrite particles are extremely fine, generally below 5 μm, making recovery difficult. Secondary copper is found in chalcocite, bornite, and chalcanthite, with a distribution rate of 18 wt% to 22 wt%. Some copper is present in copper-containing limonite and copper-iron-silica-alumina compounds via isomorphous inclusions, mechanical mixing, or adsorption, with a distribution rate of 12 wt% to 15 wt%. Copper is less found in pseudomalachite, chrysocolla, malachite, and chalcocite, with a distribution rate of 5 wt% to 8 wt%. The leaching residue from the copper-containing liquid removal process is re-slurryed, and the combined action of reagents and vigorous stirring induces agglomeration, significantly increasing the apparent particle size of the target minerals. In this invention, the occurrence of agglomeration depends on two key conditions: hydrophobicity of the particle surface and hydrodynamic regulation. Specifically, in this scheme, the hydrophobicity of the particle surface is achieved by adding specific sulfiding agents and collectors (such as xanthates and thiocarbamates) to make the surface of the target mineral hydrophobic and reduce the hydration film energy barrier. Hydrodynamic regulation is achieved by controlling the stirring intensity, i.e., the rotation speed is in the range of 2100 r / min to 2800 r / min, to provide a suitable shear field, which promotes the collision and agglomeration of useful mineral particles while avoiding the breakage of agglomerates, i.e., shear flocculation occurs.

[0038] Fine-grained chalcocite, chalcocite, and copper oxide minerals with hydrophobic surfaces after sulfidation pretreatment exhibit negative interparticle interaction energy under the action of collectors, meaning they possess attractive forces. Under appropriate shear force provided by mechanical agitation, this attractive force overcomes the energy barrier between particles, inducing selective hydrophobic agglomeration of mineral particles, forming aggregates with larger apparent particle sizes. This agglomeration effect significantly increases the apparent particle size of the target mineral, thereby greatly improving its collision probability and adhesion efficiency with air bubbles. This leads to efficient recovery of fine-grained copper minerals in the subsequent flotation stage, yielding a copper sulfide-rich leaching concentrate. Compared to traditional fine-sludge flotation processes, the hydrophobic agglomeration principle underlying this invention effectively improves the recovery rate of fine-grained copper minerals and helps reduce the amount of flotation reagents required. The increased aggregate particle size also reduces fine-sludge entrainment, improving concentrate quality.

[0039] In some embodiments of the present invention, the solid-liquid mass ratio of the fine copper leaching residue is 1:1.8~3.

[0040] In some embodiments of the present invention, the copper-containing ionic liquid further contains: Mn: 0.6 g / L~0.8 g / L, Ca: 0.9 g / L~1.2 g / L, Mg: 14.5 g / L~17.7 g / L, and Al: 0.9 g / L~1.3 g / L. The copper-containing ionic liquid contains a relatively large number of metal ion impurities, which may reduce flotation performance if it enters the flotation process.

[0041] In embodiments of the present invention, the pH value of the copper-containing ionic liquid is adjusted by adding lime slurry. Lime slurry is used primarily because of its low cost; however, other pH adjusters without specific reactions are also feasible.

[0042] In embodiments of the present invention, the pH value of the solution after iron removal is adjusted by adding lime slurry. Lime slurry is used primarily because of its low cost; however, other pH adjusters without specific reactions are also feasible.

[0043] In embodiments of the present invention, the sulfiding agent A includes at least one of sodium hydrosulfide and sodium sulfide.

[0044] In the embodiments of the present invention, the amount of vulcanizing agent A is 2.1 g / L to 2.55 g / L.

[0045] In embodiments of the present invention, the copper deposition process takes less than 0.5 hours. Excessive reaction time may cause the generated sulfide precipitate to dissolve back into the solution, resulting in a decrease in the precipitation rate. Controlling the reaction time to 0.3 to 0.5 hours provides a better precipitation rate and production efficiency.

[0046] In some embodiments of the present invention, after adding vulcanizing agent B, the mixture is stirred at 1000 r / min to 2000 r / min for 3 to 15 min; the purpose is to promote the dispersion of vulcanizing agent B.

[0047] In an embodiment of the present invention, the strong stirring is performed after the addition of vulcanizing agent B and collector.

[0048] In an embodiment of the present invention, the strong stirring time is 10 min to 20 min.

[0049] In embodiments of the present invention, after adding sulfiding agent B and collector, a frother is also added. Adding a frother is a routine operation before flotation, and in this scheme, it enables aggregates of useful minerals to enter the concentrate.

[0050] In an embodiment of the present invention, the strong stirring is performed after adding the vulcanizing agent B and the collector, and before adding the foaming agent.

[0051] In an embodiment of the present invention, the foaming agent comprises 2 # At least one of oil and BK204.

[0052] In an embodiment of the present invention, the amount of foaming agent used is 10g / t to 20g / t.

[0053] In embodiments of the present invention, a dispersant is added before adding the sulfiding agent B and the collector. The dispersant promotes the full dispersion of the useful minerals and gangue mineral solid particles.

[0054] In embodiments of the present invention, the dispersant comprises sodium hexametaphosphate.

[0055] In an embodiment of the present invention, the amount of the dispersant used is 200g / t to 300g / t.

[0056] In embodiments of the present invention, the sulfiding agent B includes at least one of sodium sulfide, sodium hydrosulfide, and ammonium sulfide.

[0057] In embodiments of the present invention, the collector includes at least one of butyl xanthate, BK404B, and ZH-1147.

[0058] In embodiments of the present invention, the amount of sulfiding agent B is 100g / t to 200g / t. Sulfiding agent B is added to sulfide copper-containing limonite, copper-iron-silicon-aluminum compounds, pseudomalachite, chrysocolla, malachite, and other copper-containing oxide minerals, and to adjust the pH value.

[0059] In an embodiment of the present invention, the amount of the collector is 300g / t to 400g / t.

[0060] In embodiments of the present invention, the flotation includes one or more stages, with the concentrate obtained from each stage being leaching residue concentrate; the tailings obtained from each stage of flotation (excluding the last stage) enter the next stage of flotation; the tailings obtained from the last stage of flotation are flotation tailings. The concentrate obtained from each stage of flotation is leaching residue concentrate and is not further refined, as refining would cause the already agglomerated concentrate to be partially broken up, reducing the recovery rate.

[0061] Example The following examples describe the disclosure of this invention in more detail. These examples are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight. Unless otherwise stated, all reagents used in the examples are available commercially or synthesized using conventional methods and are ready for use without further processing. Unless otherwise stated, all instruments used in the examples are available commercially.

[0062] Example 1: The process flow for the combined precipitation and shear flocculation recovery of copper from fine copper leaching residue in this embodiment is as follows: Figure 1 As shown.

[0063] The fine-particle copper leaching residue involved in this embodiment has a solid-liquid mass ratio of 1:2.6; after solid-liquid separation, a copper-ion-containing liquid and a leaching residue after removing the copper-ion-containing liquid are obtained. The main metallic elements contained in the copper-containing ionic liquid are as follows: Cu: 1.5 g / L, Fe: 3.6 g / L, Mn: 0.6 g / L, Ca: 0.9 g / L, Mg: 14.6 g / L, Al: 0.9 g / L.

[0064] The leaching residue for removing copper-containing liquid has a particle size of 90 wt% below 20 μm; the copper grade in the leaching residue for removing copper-containing liquid is 3.20 wt%; copper is mainly found in chalcopyrite, which accounts for 59 wt% to 61 wt% of the total copper; secondly, it is found in chalcocite, bornite, and chalcanthite, with a distribution rate of 18 wt% to 22 wt%; some copper is found in copper-containing limonite and copper-iron-silica-alumina compounds through isomorphism, mechanical mixing, or adsorption, with a distribution rate of 12 wt% to 15 wt%; less copper is found in pseudomalachite, chrysocolla, malachite, and chalcocite, with a distribution rate of 5 wt% to 8 wt%.

[0065] The copper-containing ionic liquid is further processed using the following method: (1) Iron removal: Lime milk is added to the copper ion-containing liquid until the pH value is 4.0. The iron element in the solution forms a precipitate. After solid-liquid separation, the iron-removed liquid and iron slag are obtained. (2) Copper precipitation: Lime milk is added to the iron removal liquid until the pH value is 6.0, sodium sulfide is added to form copper sulfide precipitate, and copper sulfide precipitate and copper precipitation liquid are obtained after solid-liquid separation; the amount of sodium sulfide is 1.5 times the mass of copper, i.e. 2.25 g / L; the copper precipitation process takes 0.3 h.

[0066] Copper is enriched in the copper sulfide precipitate.

[0067] The leaching residue from the copper-containing liquid is sheared and flocculated before being subjected to flotation, specifically processed as follows: (1) Shear flocculation: The leaching residue from the copper-containing liquid is slurryed to a pulp concentration of 28wt% and a pH of 6.0; then dispersant, sulfiding agent, collector and foaming agent are added in sequence. After adding the vulcanizing agent and before adding the collector, stir at 1100 r / min for 5 min; after adding the collector and before adding the foaming agent, stir at 2200 r / min for 10 min. The dispersant is sodium hexametaphosphate, with a dosage of 200 g / t; The vulcanizing agent is a combination of sodium sulfide and sodium hydrosulfide in a mass ratio of 2:1, and the amount of vulcanizing agent used is 100g / t; The collector is a combination of butyl xanthate and BK404B in a mass ratio of 1:3, and the amount of collector used is 300g / t. The foaming agent is BK204, and the dosage is 10g / t; (2) Flotation: Flotation includes a roughing stage and a scavenging stage. The concentrate obtained from each stage of flotation is the leaching residue concentrate; the tailings obtained from the roughing stage enter the scavenging stage; the tailings obtained from the scavenging stage are the final tailings in this embodiment.

[0068] Copper is enriched in the leaching residue concentrate. The leaching residue concentrate is rich in copper sulfide and partially sulfided copper oxide.

[0069] After processing the fine-grained copper leaching residue in this embodiment, copper minerals were recovered into the resulting copper sulfide precipitate and leaching residue concentrate. The test results of each product in this embodiment are shown in Table 1.

[0070] Table 1. Experimental results of combined precipitation and shear flocculation recovery of fine copper leaching residue in Example 1

[0071] The final product yielded a copper-rich product with a total copper grade of 46.40% and a recovery rate of 85.75%. Specifically, the copper sulfide precipitate had a copper grade of 60.11% and a recovery rate of 93.50%, while the leaching residue concentrate had a copper grade of 45.12% and a recovery rate of 84.88%. The high-grade copper sulfide precipitate and leaching residue concentrate can be further processed into roasted calcined ore. This calcined ore will then be used in a leaching-direct electrodeposition process to produce cathode copper.

[0072] Example 2 The fine-particle copper leaching residue involved in this embodiment has a solid-liquid mass ratio of 1:2.3; after solid-liquid separation, a copper-ion-containing liquid and a leaching residue after removing the copper-ion-containing liquid are obtained. The main metallic elements contained in the copper-containing ionic liquid are as follows: Cu: 1.61 g / L, Fe: 3.7 g / L, Mn: 0.65 g / L, Ca: 1.0 g / L, Mg: 15.2 g / L, Al: 0.99 g / L.

[0073] The leaching residue for removing copper-containing liquid has a particle size of 90 wt% below 20 μm; the copper grade in the leaching residue for removing copper-containing liquid is 3.36 wt%; copper is mainly found in chalcopyrite, which accounts for 60 wt% to 63 wt% of the total copper; secondly, it is found in chalcocite, bornite, and chalcanthite, with a distribution rate of 18 wt% to 22 wt%; some copper is found in copper-containing limonite and copper-iron-silica-alumina compounds through isomorphism, mechanical mixing, or adsorption, with a distribution rate of 12 wt% to 15 wt%; less copper is found in pseudomalachite, chrysocolla, malachite, and chalcocite, with a distribution rate of 5 wt% to 8 wt%.

[0074] The copper-containing ionic liquid is further processed using the following method: (1) Iron removal: Lime milk is added to the copper ion-containing liquid until the pH value is 4.2. The iron element in the solution forms a precipitate. After solid-liquid separation, the iron-removed liquid and iron slag are obtained. (2) Copper precipitation: Lime milk is added to the iron removal liquid until the pH value is 6.5, sodium sulfide is added to form copper sulfide precipitate, and copper sulfide precipitate and copper precipitation liquid are obtained after solid-liquid separation; the amount of sodium sulfide is 1.5 times the mass of copper, i.e. 2.42 g / L; the copper precipitation process takes 0.4 h.

[0075] Copper is enriched in the copper sulfide precipitate.

[0076] The leaching residue from the copper-containing liquid is sheared and flocculated before being subjected to flotation, specifically processed as follows: (1) Shear flocculation: The leaching residue from the copper-containing liquid is slurryed to a pulp concentration of 29wt% and a pH of 6.5; then dispersant, sulfiding agent, collector and foaming agent are added in sequence. After adding the vulcanizing agent and before adding the collector, stir at 1400 r / min for 7 min; after adding the collector and before adding the foaming agent, stir at 2600 r / min for 15 min. The dispersant is sodium hexametaphosphate, with a dosage of 250 g / t; The vulcanizing agent is a combination of sodium sulfide and sodium hydrosulfide in a mass ratio of 2:1, and the amount of vulcanizing agent used is 150g / t; The collector is a combination of butyl xanthate and BK404B in a mass ratio of 1:3, and the amount of collector used is 350g / t; The foaming agent is BK204, and the dosage is 15g / t; (2) Flotation: Flotation includes a roughing stage and a scavenging stage. The concentrate obtained from each stage of flotation is the leaching residue concentrate; the tailings obtained from the roughing stage enter the scavenging stage; the tailings obtained from the scavenging stage are the final tailings in this embodiment.

[0077] Copper is enriched in the leaching residue concentrate. The leaching residue concentrate is rich in copper sulfide and partially sulfided copper oxide.

[0078] After processing the fine-grained copper leaching residue in this embodiment, copper minerals were recovered into the resulting copper sulfide precipitate and leaching residue concentrate. The test results of each product in this embodiment are shown in Table 2.

[0079] Table 2. Experimental results of combined precipitation and shear flocculation recovery of fine copper leaching residue in Example 2

[0080] The final product yielded a copper-rich product with a total copper grade of 49.57% and a recovery rate of 85.51%. Specifically, the copper sulfide precipitate had a copper grade of 62.07% and a recovery rate of 91.46%, while the leaching residue concentrate had a copper grade of 48.28% and a recovery rate of 84.78%. The high-grade copper sulfide precipitate and leaching residue concentrate can be further processed into roasted calcined ore. This calcined ore will then be used in a leaching-direct electrodeposition process to produce cathode copper.

[0081] Example 3 The fine-particle copper leaching residue involved in this embodiment has a solid-liquid mass ratio of 1:2; after solid-liquid separation, a copper-ion-containing liquid and a leaching residue from which the copper-ion-containing liquid has been removed are obtained. The main metallic elements contained in the copper-containing ionic liquid are as follows: Cu: 1.56 g / L, Fe: 4.3 g / L, Mn: 0.75 g / L, Ca: 1.1 g / L, Mg: 16.6 g / L, Al: 1.25 g / L.

[0082] The particle size of the leaching residue for removing copper-containing liquid is 90 wt% below 20 μm; the copper grade in the leaching residue for removing copper-containing liquid is 3.71 wt%; copper is mainly found in chalcopyrite, which accounts for 57 wt% to 62 wt% of the total copper; secondly, it is found in chalcocite, bornite, and chalcanthite, with a distribution rate of 18 wt% to 22 wt%; some copper is found in copper-containing limonite and copper-iron-silica-alumina compounds through isomorphism, mechanical mixing, or adsorption, with a distribution rate of 12 wt% to 15 wt%; less copper is found in pseudomalachite, chrysocolla, malachite, and chalcocite, with a distribution rate of 5 wt% to 8 wt%.

[0083] The copper-containing ionic liquid is further processed using the following method: (1) Iron removal: Lime milk is added to the copper ion-containing liquid until the pH value is 4.5. The iron element in the solution forms a precipitate. After solid-liquid separation, the iron-removed liquid and iron slag are obtained. (2) Copper precipitation: Lime milk is added to the iron removal liquid until the pH value is 7.0, sodium sulfide is added to form copper sulfide precipitate, and copper sulfide precipitate and copper precipitation liquid are obtained after solid-liquid separation; the amount of sodium sulfide is 1.5 times the mass of copper, i.e. 2.34 g / L; the copper precipitation process takes 0.5 h.

[0084] Copper is enriched in the copper sulfide precipitate.

[0085] The leaching residue from the copper-containing liquid is sheared and flocculated before being subjected to flotation, specifically processed as follows: (1) Shear flocculation: The leaching residue from the copper-containing liquid is slurryed to a pulp concentration of 30wt% and a pH of 7.0; then dispersant, sulfiding agent, collector and foaming agent are added in sequence. After adding the vulcanizing agent and before adding the collector, stir at 1500 r / min for 10 min; after adding the collector and before adding the foaming agent, stir at 2800 r / min for 19 min. The dispersant is sodium hexametaphosphate, with a dosage of 300 g / t; The vulcanizing agent is a combination of sodium sulfide and sodium hydrosulfide in a mass ratio of 2:1, and the amount of vulcanizing agent used is 200g / t; The collector is a combination of butyl xanthate and BK404B in a mass ratio of 1:3, and the amount of collector used is 400g / t. The foaming agent is BK204, and the dosage is 19g / t; (2) Flotation: Flotation includes a roughing stage and a scavenging stage. The concentrate obtained from each stage of flotation is the leaching residue concentrate; the tailings obtained from the roughing stage enter the scavenging stage; the tailings obtained from the scavenging stage are the final tailings in this embodiment.

[0086] Copper is enriched in the leaching residue concentrate. The leaching residue concentrate is rich in copper sulfide and partially sulfided copper oxide.

[0087] After processing the fine-grained copper leaching residue in this embodiment, copper minerals were recovered into the resulting copper sulfide precipitate and leaching residue concentrate. The test results of each product in this embodiment are shown in Table 3.

[0088] Table 3. Results of the combined precipitation and shear flocculation method for recovering copper from fine copper leaching residue in Example 3.

[0089] The final product obtained was a copper-rich product with a total copper grade of 50.07% and a recovery rate of 85.99%. Specifically, the copper sulfide precipitate had a copper grade of 61.59% and a recovery rate of 90.59%, while the leaching residue concentrate had a copper grade of 49.02% and a recovery rate of 85.49%. The high-grade copper sulfide precipitate and leaching residue concentrate can be further processed into roasted calcined ore. This calcined ore will then be used in a leaching-direct electrodeposition process to produce cathode copper.

[0090] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0091] Comparative Example 1 The fine copper leaching residue raw material used in this comparative example comes from the same source as that in Example 3 and has a similar composition. Compared with Example 3, the leaching residue obtained after removing copper-containing liquid is not subjected to shear flocculation, but is directly subjected to conventional flotation after slurry conditioning; the slurry concentration is 30 wt% and the pH value is 7.0. The specific flotation process is as follows: A roughing stage and a scavenging stage are performed by adding a sulfidizing agent, a collector, and a frother. The concentrate obtained from each stage of flotation is the leaching residue concentrate. The tailings from the roughing stage are then fed into the scavenging stage. The tailings from the scavenging stage are the final tailings of this comparative example. The types of sulfidizing agents, collectors, and frothers used are the same as in Example 3, with the dosage adjusted according to actual flotation requirements. Other processes remain consistent with Example 3.

[0092] After processing the fine-grained copper leaching residue, copper minerals were recovered into the resulting copper sulfide precipitate and leaching residue concentrate. The test results of each product in this comparative example are shown in Table 4.

[0093] Table 4. Results of copper recovery tests in Comparative Example 1 from fine-particle copper leaching residue.

[0094] The final product obtained was a copper-rich product with a total copper grade of 39.98% and a recovery rate of 80.32%. Specifically, the copper sulfide precipitate had a copper grade of 60.01% and a recovery rate of 91.51%, while the leaching residue concentrate had a copper grade of 38.42% and a recovery rate of 79.15%. This comparative example, due to the use of conventional flotation technology, resulted in a significant reduction in the copper grade and recovery rate of the leaching residue concentrate, and the flotation reagent dosage was 1.5 to 2 times that of shear flocculation flotation, leading to higher processing costs.

[0095] Comparative Example 2 The fine-particle copper leaching residue raw material used in this comparative example is from the same source as that in Example 3 and Comparative Example 1, and has a similar composition. In terms of process, compared with Example 3, the leaching residue containing copper ions and the leaching residue after removing the copper ion-containing liquid are not distinguished. Instead, the fine-particle copper leaching residue raw material is directly subjected to conventional flotation after slurry preparation. The slurry concentration is 30wt% and the pH value is 7.0. The specific flotation process is as follows: a roughing stage and a scavenging stage are carried out by adding sulfiding agent, collector and frother. The concentrate obtained from each stage of flotation is the leaching residue concentrate. The tailings obtained from the roughing stage are sent to the scavenging stage. The tailings obtained from the scavenging stage are the final tailings of this comparative example. The types of sulfiding agent, collector and frother used are the same as those in Example 3. The dosage is adjusted according to the actual flotation requirements.

[0096] After processing the fine-grained copper leaching residue, copper minerals were recovered into the resulting leaching residue concentrate. The test results of each product in this comparative example are shown in Table 5.

[0097] Table 5. Comparative Example 2: Results of Conventional Flotation Recovery of Copper from Fine-Particle Copper Leaching Slag

[0098] The final product obtained was a leaching residue concentrate with a total copper grade of 39.55% and a recovery rate of 69.85%. This comparative example used a conventional flotation process and did not separate soluble copper ions. Soluble copper ions and other metal ions consume flotation reagents and may form a hydrophilic film covering the surface of copper minerals, resulting in a significant decrease in the copper grade and recovery rate of the leaching residue concentrate. The required amount of flotation reagents also increases to 2 to 3 times that of shear flocculation flotation, resulting in higher processing costs.

Claims

1. A method for recovering copper from fine-particle copper leaching residue by combining precipitation and shear flocculation, characterized in that, The fine copper leaching residue is subjected to solid-liquid separation to obtain a liquid containing copper ions and a leaching residue from which the liquid containing copper ions has been removed; The copper-containing ionic liquid contains 0.9 g / L to 2.0 g / L of copper, 3.5 g / L to 4.7 g / L of iron, and has a pH value below 2.5; The pH value of the copper-containing ionic liquid is adjusted to 4.0~4.5 to remove iron. After solid-liquid separation, iron-removed liquid and iron slag are obtained. The pH value of the iron-removed liquid is adjusted to 5.5~7.0 and mixed with sulfiding agent A to precipitate copper. After solid-liquid separation, copper sulfide precipitate and copper-precipitated liquid are obtained. The copper grade in the leaching residue for removing copper-containing liquid is 2.80wt%~4.10wt%, and the copper contained in the copper blue accounts for 55wt%~70wt% of its total copper content; the particle size of the leaching residue for removing copper-containing liquid is: 90wt% below 20μm; The leaching residue from the copper-containing liquid is slurryed to a pulp concentration of 25wt%~38wt% and a pH value of 6.0~7.0; reagents including sulfiding agent B and collector are added, and the mixture is strongly stirred at a speed of 2100r / min~2800r / min, and then flotation is carried out to obtain leaching residue concentrate and flotation tailings. Copper is enriched in the copper sulfide precipitate and leaching residue concentrate.

2. The method for recovering copper from fine-particle copper leaching residue by combined precipitation and shear flocculation according to claim 1, characterized in that, The pH value of the copper-containing liquid is adjusted by adding lime milk; the pH value of the liquid after iron removal is adjusted by adding lime milk; sulfurizing agent A includes at least one of sodium hydrosulfide and sodium sulfide.

3. The method for recovering copper from fine-particle copper leaching residue by combined precipitation and shear flocculation according to claim 1 or 2, characterized in that, The dosage of sulfiding agent A is 2.1 g / L to 2.55 g / L; the copper plating process takes less than 0.5 hours.

4. The method for recovering copper from fine-particle copper leaching residue by combined precipitation and shear flocculation according to claim 1, characterized in that, The strong stirring is carried out after adding vulcanizing agent B and collector; the strong stirring time is 10 min to 20 min.

5. The method for recovering copper from fine-particle copper leaching residue by combined precipitation and shear flocculation according to claim 1, characterized in that, After adding vulcanizing agent B and collector, a foaming agent is also added; the strong stirring is carried out after adding vulcanizing agent B and collector and before adding foaming agent.

6. The method for recovering copper from fine-particle copper leaching residue by combined precipitation and shear flocculation according to claim 5, characterized in that, The foaming agent includes 2 # The foaming agent is selected from at least one of oil and BK204; the amount of foaming agent used is 10g / t to 20g / t.

7. The method for recovering copper from fine-particle copper leaching residue by combined precipitation and shear flocculation according to any one of claims 1, 4 to 6, characterized in that, Before adding sulfiding agent B and collector, a dispersant is also added; the dispersant includes sodium hexametaphosphate; the amount of the dispersant is 200g / t~300g / t.

8. The method for recovering copper from fine-particle copper leaching residue by combined precipitation and shear flocculation according to any one of claims 1, 4 to 7, characterized in that, The sulfiding agent B includes at least one of sodium sulfide, sodium hydrosulfide, and ammonium sulfide; the collector includes at least one of butyl xanthate, BK404B, and ZH-1147.

9. The method for recovering copper from fine-particle copper leaching residue by combined precipitation and shear flocculation according to any one of claims 1, 4 to 8, characterized in that, The amount of vulcanizing agent B is 100g / t to 200g / t; the amount of collector is 300g / t to 400g / t.

10. The method for recovering copper from fine-particle copper leaching residue by combined precipitation and shear flocculation according to any one of claims 1, 4 to 9, characterized in that, The flotation process includes one or more stages, with the concentrate obtained from each stage being the leaching residue concentrate; the tailings obtained from each stage of flotation (excluding the last stage) enter the next stage of flotation; and the tailings obtained from the last stage of flotation are the flotation tailings.

Images