Method for leaching copper from silver separation furnace slag and application

Abstract

The invention belongs to the technical field of non-ferrous smelting, and particularly relates to a method for leaching copper from silver separation furnace slag and application. The method for leaching the copper from the silver separation slag comprises the following steps: (1) mixing and slurrying the silver separation slag and water, then adding concentrated sulfuric acid to carry out a leaching reaction, controlling the final pH value to be 1-4.5, and introducing hydrogen peroxide during the leaching reaction to obtain a leaching solution and leaching slag; (2) mixing the leached residues with concentrated sulfuric acid, curing, leaching, and filtering to obtain cured liquid and cured residues; the cured liquid is subjected to countercurrent circulation back to the step (1) to replace water and concentrated sulfuric acid. Most of copper is leached from the silver separation furnace slag through first-stage concentrated sulfuric acid oxidation leaching, so that the copper is separated from metals such as lead, bismuth, antimony and silver; and meanwhile, a second-stage curing reaction is introduced, the structure in the leaching slag is destroyed by concentrated sulfuric acid, copper and oxides thereof in a complex structure are released, the copper content in the cured slag is smaller than 0.1%, the copper leaching rate reaches 99% or above, and deep recovery of copper in the silver separation slag is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of non-ferrous smelting, and particularly relates to a method for leaching copper from silver separation furnace slag and application. BACKGROUND

[0002] Lead anode slime contains copper, lead, antimony, bismuth, tin, silver, arsenic, gold and a small amount of selenium and tellurium. After reduction smelting of lead anode slime by a precious lead furnace, precious lead is obtained, and after smelting of the precious lead by a silver separation furnace, coarse silver with a high content and silver separation furnace slag are obtained. Copper, bismuth, antimony and a small amount of silver are enriched in the silver separation furnace slag. At present, a large amount of silver separation furnace slag is produced by many copper smelting plants every year. Since there is no perfect recovery process, the valuable metals are not effectively recovered, the silver separation furnace slag is sold at the price of raw materials, and the enterprise causes certain economic loss. Therefore, it is of great significance to study the recovery of silver, copper, antimony, bismuth and other valuable metals from the silver separation slag to improve the resource utilization rate.

[0003] At present, the main treatment methods for copper in the silver separation furnace slag are as follows: 1. Returning to the copper smelting system for treatment, which will increase the smelting load and energy consumption of the copper smelting process, and mainly affect the quality of the main metal copper in the copper smelting process; 2. Directly adopting fire reduction smelting to form precious lead alloy to return to the process for recovering valuable metals, which has the problems of low metal recovery rate and high energy consumption; 3. Adopting wet pretreatment to recover copper, and most enterprises adopt sulfuric acid to remove copper, but due to the existing form and complex structure of copper in the silver separation furnace slag, the copper leaching rate is low, and traditional fire methods such as sulfur removal of copper need to be combined to remove and purify.

[0004] In view of the above many problems in the prior art method for recovering copper from the silver separation furnace slag, it is urgent to provide a method with simple process, short process, low investment cost, strong selective leaching of copper and high copper leaching rate. SUMMARY

[0005] The present application aims to solve one or more technical problems in the prior art, and at least provide a beneficial alternative. Specifically, the present application provides a method for leaching copper from silver separation furnace slag, which leaches copper through two-stage leaching countercurrent circulation, has high copper recovery rate, and has the advantages of short process, simple process, low recovery cost and easy industrial application.

[0006] The inventive concept of the present application is that the method for leaching copper from silver separation furnace slag comprises the following steps: (1) mixing and slurrying the silver separation furnace slag and water, then adding concentrated sulfuric acid for leaching reaction, controlling the final pH to be 1-4.5, and introducing hydrogen peroxide during the period to obtain a leaching solution and a leaching residue; (2) mixing the leaching residue obtained in step (1) and concentrated sulfuric acid, carrying out maturation reaction, then leaching and filtering to obtain a maturation solution and a maturation residue; and the maturation solution is returned to step (1) in countercurrent circulation to replace water and concentrated sulfuric acid.

[0007] The present application realizes the separation of copper from lead, bismuth, antimony, silver and other metals by leaching most of the copper from the silver separation furnace slag through the first stage of concentrated sulfuric acid oxidation leaching; meanwhile, the second stage of ripening reaction is introduced, the structure in the leaching residue is destroyed by concentrated sulfuric acid, so that the copper and its oxides in the complex structure are released, which can avoid the need for adding sulfur to remove copper in the subsequent traditional pyrometallurgical process, and the copper content in the ripening slag is less than 0.1%, realizing the deep extraction and recovery of copper in the silver separation furnace slag. At the same time, the ripening liquid can be recycled back to the concentrated sulfuric acid oxidation leaching stage in countercurrent, and the copper, lead, bismuth, antimony, silver and other metals do not form closed loop enrichment in the recycling process, and there is no need to continue to add other processes for open loop treatment. After the lead, bismuth, antimony and silver in the ripening slag are combined with pyrometallurgy and then reduced smelting, they are recovered through a vacuum furnace. The method has the advantages of simple process, short process, good raw material adaptability, simple operation, low investment cost, copper leaching rate of more than 99%, and easy industrial application.

[0008] Therefore, the first aspect of the present application provides a method for leaching copper from silver separation furnace slag.

[0009] Specifically, the method for leaching copper from silver separation furnace slag comprises the following steps:

[0010] (1) mixing and slurrying the silver separation furnace slag and water, then adding concentrated sulfuric acid for leaching reaction, controlling the final pH to be 1-4.5, and introducing hydrogen peroxide during the leaching reaction to obtain a leaching liquid and a leaching residue;

[0011] (2) mixing the leaching residue obtained in step (1) and concentrated sulfuric acid, and then performing ripening reaction, leaching and filtering to obtain a ripening liquid and a ripening residue; the ripening liquid is recycled back to step (1) in countercurrent to replace water and concentrated sulfuric acid.

[0012] Specifically, the main phases in the silver separation furnace slag are Cu2O, CuO, Bi2O3, Sb2O3, PbO, Ag, etc., wherein the copper oxide reacts with concentrated sulfuric acid to generate copper sulfate; the cuprous oxide undergoes disproportionation reaction with concentrated sulfuric acid to generate copper and copper sulfate; the bismuth oxide, lead oxide and antimony oxide respectively react with concentrated sulfuric acid to generate water-insoluble bismuth sulfate, lead sulfate and antimony sulfate; and silver does not react with concentrated sulfuric acid.

[0013] The reaction equations of the above chemical principles are as follows:

[0014] (1) Cu2O + H2SO4 = CuSO4 + Cu + H2O;

[0015] (2) CuO + H2SO4 = CuSO4 + H2O;

[0016] (3) Cu2O + 2H2SO4 + H2O2 = 2CuSO4 + 3H2O;

[0017] (4) Cu + H2SO4 + H2O2 = CuSO4 + 2H2O;

[0018] (5) Bi2O3 + 3H2SO4 = Bi2(SO4)3↓ + 3H2O;

[0019] (6) Sb2O3 + 3H2SO4 = Sb2(SO4)3↓ + 3H2O;

[0020] (7) PbO + H2SO4 = PbSO4↓ + H2O.

[0021] Preferably, in step (1), the silver separation furnace slag is obtained by fire metallurgy smelting of lead anode slime in a precious lead furnace and a silver separation furnace in sequence.

[0022] Preferably, in step (1), the silver separation furnace slag comprises copper 10-50wt%, lead 5-20wt%, bismuth 10-40wt%, antimony 1-10wt%, and silver 1-15wt%.

[0023] Preferably, in step (1), the mass fraction of the silver separation furnace slag with particle size less than or equal to 70μm is greater than or equal to 90%.

[0024] Specifically, the silver separation furnace slag is completed by ball milling according to the above particle size requirement.

[0025] Preferably, in step (1), the liquid-solid ratio of the water and the silver separation furnace slag is (1.8-6.5):1; further preferably, the liquid-solid ratio of the water and the silver separation furnace slag is (2-6):1.

[0026] Preferably, in step (1), the mass fraction of the concentrated sulfuric acid is ≥98%.

[0027] Preferably, in step (1), the theoretical reaction mass ratio of the hydrogen peroxide to copper in the silver separation furnace slag is (1.8-8.5):1; further preferably, the theoretical reaction mass ratio of the hydrogen peroxide to copper in the silver separation furnace slag is (2-8):1.

[0028] Specifically, the main existing form of copper in the silver separation furnace slag is copper oxide and cuprous oxide, cuprous oxide generates elemental copper by disproportionation reaction with sulfuric acid, and hydrogen peroxide is needed for oxidation.

[0029] Preferably, in step (1), the amount of the concentrated sulfuric acid is added until the pH of the system after completion of the leaching reaction is 1-4, i.e. the final pH is controlled to be 1-4.

[0030] Specifically, the copper in the silver smelting slag is leached by oxidation and acid leaching, and the leaching rate is good. At this time, bismuth and antimony basically enter the leaching residue in the form of precipitation. At the same time, considering the subsequent step (1), the leaching liquid is mainly copper sulfate solution, and the copper in the copper sulfate solution is extracted by using the reduction iron powder replacement method. A certain acidity is needed to speed up the replacement speed and ensure complete replacement.

[0031] Preferably, in step (1), the temperature of the leaching reaction is 35-95℃; further preferably, the temperature of the leaching reaction is 40-90℃.

[0032] Preferably, in step (1), the leaching reaction has a holding time of 0.5-5.5h; further preferably, the leaching reaction has a holding time of 0.5-5h.

[0033] Preferably, in step (1), the leaching reaction is stirred, and the stirring rate is 180-650r / min; further preferably, the stirring rate is 200-600r / min.

[0034] Preferably, in step (1), the contents of bismuth, antimony, and copper in the leaching liquid are 0.01-0.05g / L, 0.003-0.007g / L, and 50-60g / L, respectively.

[0035] Preferably, in step (1), the composition of the leaching residue includes copper 2-5wt%, bismuth 30-50wt%, and antimony 2-12wt%.

[0036] Specifically, cuprous oxide will form a intergrowth with lead antimony oxide, and part of the cuprous oxide will be wrapped by lead antimony oxide. This part of the structure is complex and difficult to be destroyed, and needs to be ripened to destroy the structure.

[0037] Preferably, in step (1), the copper in the leaching liquid is recovered by a reduction iron powder replacement process or a traditional hydrometallurgy electrolysis process.

[0038] Specifically, the conventional reduction iron powder replacement process can be used to recover the copper in the leaching liquid to obtain sponge copper.

[0039] Preferably, in step (2), the molar ratio of the concentrated sulfuric acid to the concentrated sulfuric acid in step (1) is (1.1-2.2):1; further preferably, in step (2), the molar ratio of the concentrated sulfuric acid to the concentrated sulfuric acid in step (1) is (1.2-2):1.

[0040] Specifically, the concentrated sulfuric acid can destroy the structure of the leaching residue, and release the copper and its oxides in the complex structure.

[0041] Preferably, in step (2), the ripening reaction is natural ripening.

[0042] Specifically, the maturation reaction is carried out by using the latent heat generated naturally, and the initial temperature of the concentrated sulfuric acid can reach about 150℃, and then the temperature slowly decreases with time. If the heating maturation process is used, the leaching residue will be hardened and difficult to stir during the continuous heating in the maturation process, which will adversely affect the subsequent industrialization.

[0043] Preferably, in step (2), the time of the maturation reaction is 9-65 min; further preferably, the time of the maturation reaction is 10-60 min.

[0044] Preferably, in step (2), water is used for the leaching, and the liquid-solid ratio of the water to the leaching residue is (3-5):1; further preferably, the liquid-solid ratio of the water to the leaching residue is (3.5-4.5):1; still further preferably, the liquid-solid ratio of the water to the leaching residue is 4:1.

[0045] Preferably, in step (2), the temperature of the leaching is 18-95℃; further preferably, the temperature of the leaching is 20-90℃.

[0046] Preferably, in step (2), the holding time of the leaching is 18-110 min; further preferably, the holding time of the leaching is 20-100 min.

[0047] Preferably, in step (2), stirring is carried out during the leaching, and the stirring rate is 180-650 r / min; further preferably, the stirring rate is 200-600 r / min.

[0048] Preferably, in step (2), in the maturation liquid, the contents of bismuth and antimony are 0.6-3 g / L and 0.08-0.2 g / L, respectively.

[0049] Preferably, in step (2), the acidity of the maturation liquid needs to meet the requirement of the amount of concentrated sulfuric acid used in the leaching reaction in step (1).

[0050] Preferably, in step (2), the bismuth and antimony leached in the maturation liquid are hydrolyzed into precipitates into the residue in the leaching liquid obtained in step (1) by countercurrent circulation.

[0051] Preferably, in step (2), the maturation liquid is circulated back to the leaching residue in step (1) by countercurrent circulation, and then the maturation liquid is obtained by step (2), i.e. one cycle is completed. When the number of cycles reaches 3, the leaching rate of bismuth and antimony reaches saturation, which indicates the feasibility of countercurrent circulation.

[0052] Preferably, in step (2), the mass fraction of copper in the maturation residue is less than 0.1%.

[0053] Preferably, in step (2), after the reduction of the roasting slag by pyrometallurgical smelting, a vacuum furnace is used to recover the lead, bismuth, antimony and silver metals.

[0054] Specifically, the present application first leaches by adding water and concentrated sulfuric acid in step (1), and the amount of concentrated sulfuric acid added in step (2) is 1.1-2.2 times the amount of concentrated sulfuric acid added in step (1) to perform roasting. The concentrated sulfuric acid is also excessive after leaching in step (2), which can be recycled back to step (1) to replace water and concentrated sulfuric acid, and then step (1) does not need to add water and concentrated sulfuric acid, and can use the roasting liquid for countercurrent leaching. If the concentrated sulfuric acid is not enough, add concentrated sulfuric acid again to control the end point pH.

[0055] The second aspect of the present application provides a method for leaching copper from silver separation furnace slag according to the first aspect of the present application in non-ferrous metal recovery.

[0056] Compared with the prior art, the technical scheme provided by the present application has the following beneficial effects:

[0057] The present application realizes the separation of copper from lead, bismuth, antimony, silver and other metals by first-stage concentrated sulfuric acid oxidation leaching, which leaches most of the copper from the silver separation furnace slag. At the same time, the second-stage roasting reaction is introduced, and the concentrated sulfuric acid destroys the structure of the leaching slag, so that the copper and its oxides in the complex structure are released, which can avoid the need for adding sulfur to remove copper in the subsequent traditional pyrometallurgical process. The copper content in the roasting slag is <0.1%, which realizes the deep extraction and recovery of copper in the silver separation furnace slag. At the same time, the roasting liquid can be recycled back to the sulfuric acid oxidation leaching in countercurrent, and the copper, lead, bismuth, antimony, silver and other metals do not form a closed-loop circulation enrichment in the recycling process, and there is no need to continue adding other processes for open-loop treatment. The subsequent lead, bismuth, antimony and silver are combined in the roasting slag, and are recovered by reduction smelting through a vacuum furnace. The method has the advantages of simple process, short process flow, good raw material adaptability, simple operation, low investment cost, copper leaching rate of more than 99%, easy industrialization, strong practicality and economic value, and great popularization significance. BRIEF DESCRIPTION OF DRAWINGS

[0058] Figure 1 The process flow chart of the method for leaching copper from silver separation furnace slag according to Example 1 of the present application is shown in the figure. DETAILED DESCRIPTION

[0059] In order to make those skilled in the art more clearly understand the technical scheme of the present application, the following examples are given for illustration. It should be pointed out that the following examples do not limit the scope of protection required by the present application.

[0060] The raw materials, reagents or devices used in the following examples, if not specifically stated, can be obtained from conventional commercial channels, or can be obtained by existing known methods.

[0061] In the present application, the calculation method of copper, bismuth and antimony leaching rate is as follows:

[0062] Copper leaching rate = (1-(W1xM1) / (WxM2))x100%;

[0063] Bismuth leaching rate = (C1xV) / (W2xM2)x100%;

[0064] Antimony leaching rate = (C2xV) / (W3xM2)x100%.

[0065] In the formula, W is the mass percentage content of copper in the silver separation furnace slag, W1 is the mass percentage content of copper in the leaching slag or the slaking slag, M1 is the mass of the leaching slag or the slaking slag, M2 is the mass of the silver separation furnace slag; C1 is the mass concentration of bismuth in the slaking liquid, V is the volume of the slaking liquid, W2 is the mass percentage content of bismuth in the silver separation furnace slag; C2 is the mass concentration of antimony in the slaking liquid, and W3 is the mass percentage content of antimony in the silver separation furnace slag.

[0066] Example 1

[0067] A method for leaching copper from a silver separation furnace slag, comprising the following steps:

[0068] (1) Take 100g of silver separation furnace slag, add 400mL of water, gradually add concentrated H2SO4 with a mass fraction of 98%, take H2O2 with a mass fraction of 30% at a theoretical reaction mass ratio of hydrogen peroxide to copper in the silver separation furnace slag of 6:1, slowly add from the bottom during the leaching process, react for 40min under the condition that the leaching temperature is 70℃, finally control the end point pH at 2, filter to obtain leaching slag and leaching liquid (the leaching liquid is mainly copper sulfate solution), and detect that the copper leaching rate is 92.45%; the bismuth and antimony contents are 0.0356g / L and 0.0038g / L respectively; the copper in the leaching liquid is replaced by using reduced iron powder to obtain sponge copper;

[0069] (2) Pour concentrated sulfuric acid (mass fraction 98%) with a concentration ratio of 1.4:1 to the leaching slag obtained in step (1), and naturally slake for 15min, then add water to leach for 30min at a liquid-solid ratio of 4:1, the water leaching temperature is 80℃, filter to obtain slaking slag and slaking liquid (acidity: H + =1.82mol / L), detect that the copper mass content in the slaking slag is 0.068%, and the copper leaching rate is 99.79%; the slaking slag is recovered by fire process to recover lead, bismuth, antimony and silver;

[0070] (3) The leaching liquid obtained in step (2) is countercurrently circulated to replace water and concentrated sulfuric acid in the next step (1), and the slaking liquid is obtained by performing step (2), to complete one cycle, and the subsequent can be repeated countercurrently circulated according to the steps.

[0071] Example 2

[0072] A method for leaching copper from silver separation furnace slag, comprising the following steps:

[0073] (1) Take 100g silver separation furnace slag, add 450mL water, gradually add concentrated H2SO4 with mass fraction of 98%, take H2O2 with mass fraction of 30% and slowly add from the bottom during the leaching process, react for 40min under the condition of leaching temperature of 70℃, finally control the end point pH at 1, filter to obtain leaching residue and leaching solution (mainly copper sulfate solution), detect that the copper leaching rate is 91.85%; the bismuth and antimony contents are 0.0416g / L and 0.0042g / L respectively; the copper in the leaching solution is replaced by reduced iron powder to obtain sponge copper;

[0074] (2) Pour concentrated sulfuric acid (mass fraction of 98%) with a concentration ratio of 1.3:1 to the leaching residue obtained in step (1) into the leaching residue obtained in step (1), and naturally mature for 30min, add water with liquid-solid ratio of 5:1 to leach for 30min, the water leaching temperature is 60℃, filter to obtain matured residue and matured liquid (acidity: H + =1.75mol / L), detect that the copper mass content in the matured residue is 0.062%, and the copper leaching rate is 99.81%; the matured residue is recovered by fire process to recover lead, bismuth, antimony and silver;

[0075] (3) The leaching solution obtained in step (2) is countercurrently circulated back to the next step (1) to replace water and concentrated sulfuric acid, and the matured liquid is obtained by performing step (2), to complete one cycle, and the subsequent can be repeated countercurrently circulated according to the steps.

[0076] Example 3

[0077] A method for leaching copper from silver separation furnace slag, comprising the following steps:

[0078] (1) Take 100g silver separation furnace slag, add 500mL water, gradually add concentrated H2SO4 with mass fraction of 98%, take H2O2 with mass fraction of 30% and slowly add from the bottom during the leaching process, react for 3h under the condition of leaching temperature of 60℃, finally control the end point pH at 3, filter to obtain leaching residue and leaching solution (mainly copper sulfate solution), detect that the copper leaching rate is 92.25%; the bismuth and antimony contents are 0.0416g / L and 0.0042g / L respectively; the copper in the leaching solution is replaced by reduced iron powder to obtain sponge copper;

[0079] (2) The concentrated sulfuric acid (mass fraction of 98%) with a concentration ratio of 1.2:1 to the concentrated sulfuric acid in step (1) is poured into the leaching residue obtained in step (1), and is naturally matured for 40 min, then water is added at a liquid-solid ratio of 6:1 for leaching for 30 min, the water leaching temperature is 60 DEG C, and the matured residue and matured liquid (acidity: H + =1.62 mol / L) are obtained, and it is detected that the copper mass content in the matured residue is 0.072%, and the copper leaching rate is 99.75%; the matured residue is recovered by a fire process to recover lead, bismuth, antimony and silver;

[0080] (3) The leaching liquid obtained in step (2) is circulated back to the next step (1) to replace water and concentrated sulfuric acid, and the matured liquid is obtained by step (2), and one cycle is completed, and subsequent steps can be repeated in reverse circulation.

[0081] Example 4

[0082] A method for leaching copper from silver separation furnace slag, comprising the following steps:

[0083] (1) 100g of silver separation furnace slag is taken, 400mL of water is added, and concentrated H2SO4 with a mass fraction of 98% is gradually added, the theoretical reaction mass ratio of hydrogen peroxide to copper in the silver separation furnace slag is 4.8:1, the mass fraction of 30% H2O2 is taken and slowly added from the bottom during the leaching process, the reaction is carried out at a leaching temperature of 80 DEG C for 2h, the final control end point pH is 2.5, and the leaching residue and leaching liquid (the leaching liquid is mainly copper sulfate solution) are obtained by filtration, it is detected that the copper leaching rate is 91.37%, the bismuth and antimony contents are 0.0543g / L and 0.0065g / L respectively, and the copper in the leaching liquid is replaced by reduced iron powder to obtain sponge copper;

[0084] (2) The concentrated sulfuric acid (mass fraction of 98%) with a concentration ratio of 1.2:1 to the concentrated sulfuric acid in step (1) is poured into the leaching residue obtained in step (1), and is naturally matured for 40 min, then water is added at a liquid-solid ratio of 6:1 for leaching for 30 min, the water leaching temperature is 60 DEG C, and the matured residue and matured liquid (acidity: H + =1.62 mol / L) are obtained, and it is detected that the copper mass content in the matured residue is 0.072%, and the copper leaching rate is 99.75%; the matured residue is recovered by a fire process to recover lead, bismuth, antimony and silver;

[0085] (3) The leaching liquid obtained in step (2) is circulated back to the next step (1) to replace water and concentrated sulfuric acid, and the matured liquid is obtained by step (2), and one cycle is completed, and subsequent steps can be repeated in reverse circulation.

[0086] Example 5

[0087] A method for leaching copper from silver separation furnace slag, comprising the following steps:

[0088] (1) Take 100 g of silver separation furnace slag, add the slaking liquid obtained in step (1) of Example 4, and use hydrogen peroxide and the copper in the silver separation furnace slag at a theoretical reaction mass ratio of 4.8:1. Take 30% H2O2 by mass and slowly add it from the bottom during the leaching process. React for 2 h at a leaching temperature of 80°C, and finally control the end point pH at 2.5. Filter to obtain leaching residue and leaching liquid (the leaching liquid is mainly copper sulfate solution). It is detected that the copper leaching rate is 91.64%; the bismuth and antimony contents are 0.053 g / L and 0.0057 g / L, respectively; copper in the leaching liquid is replaced by reducing iron powder to obtain sponge copper; the slaking liquid is countercurrently recycled for the oxidation leaching of the silver separation furnace slag, and the bismuth and antimony leached in the slaking liquid will hydrolyze into precipitates and enter the slag after one cycle of recycling, and will not be enriched in the leaching liquid, which does not affect copper recovery.

[0089] (2) Pour concentrated sulfuric acid (98% by mass) with a concentration ratio of 1.3:1 with the concentrated sulfuric acid used in step (1) into the leaching residue obtained in step (1), and naturally slake for 40 min. Then add water at a liquid-solid ratio of 4.5:1 and leach for 60 min. The water leaching temperature is 70°C. Filter to obtain slaked residue and slaking liquid. It is detected that the copper mass content in the slaked residue is 0.068%, and the copper leaching rate is 99.79%. The slaked residue is recycled for lead, bismuth, antimony and silver by fire process.

[0090] (3) The leaching liquid obtained in step (2) is countercurrently recycled to replace water and sulfuric acid in the next step (1) and slaking liquid is obtained by step (2). Complete one cycle, and then follow the steps to repeat countercurrent recycling. Then, the effect of the number of cycles on the leaching rate of copper, bismuth and antimony in the slaking process of the leaching residue is investigated. A total of 4 cycles are performed. The effects of the recycling process on the copper leaching rate, bismuth leaching rate and antimony leaching rate are shown in Table 1.

[0091] Table 1: Effect of recycling process on copper leaching rate, bismuth leaching rate and antimony leaching rate

[0092] Number of cycles Copper leaching rate / % Copper mass content in the aged residue / % Bismuth leaching rate / % Antimony leaching rate / % 1 99.79 0.068 2.371 2.796 2 99.767 0.076 3.125 3.527 3 99.812 0.061 3.205 3.512 4 99.776 0.073 3.096 3.627

[0093] As shown in Table 1, bismuth and antimony in the slaking liquid will be enriched after countercurrent recycling. When the number of countercurrent cycles reaches 3, the bismuth and antimony leaching rates will reach saturation, with a bismuth leaching rate of about 3.1% and an antimony leaching rate of about 3.6%. Bismuth and antimony will not continue to be enriched, which verifies the feasibility of countercurrent recycling. At the same time, the copper mass content in the slaked residue is <0.1%, which realizes the deep extraction and recovery of copper in the silver separation furnace slag, and is beneficial to the subsequent recovery of other valuable metals by fire vacuum furnace.

[0094] Comparative Example 1

[0095] A method for leaching copper from silver separation furnace slag, comprising the following steps:

[0096] (1)Take 100g of silver separation furnace slag, add 400mL of water, gradually add concentrated H2SO4 with mass fraction of 98%, take the mass fraction of 30% H2O2 in the leaching process from the bottom slowly, and react for 40min at a leaching temperature of 70℃. Filter to obtain leaching residue and leaching liquid. The copper leaching rate is 65.45% after detection.

[0097] As can be seen from the comparison of Comparative Example 1 and Example 1, when the amount of hydrogen peroxide is small, the elemental copper in the silver separation furnace slag and the elemental copper generated by the disproportionation reaction cannot be leached, resulting in a significant decrease in the copper leaching rate.

[0098] Comparative Example 2

[0099] A method for leaching copper from silver separation furnace slag, comprising the following steps:

[0100] (1) Take 100g of silver separation furnace slag, add 450mL of water, gradually add concentrated H2SO4 with mass fraction of 98%, take the mass fraction of 30% H2O2 in the leaching process from the bottom slowly, and react for 40min at a leaching temperature of 70℃. Finally control the end point pH at 1. Filter to obtain leaching residue and leaching liquid. The copper leaching rate is 91.85% after detection; the bismuth and antimony contents are 0.0416g / L and 0.0042g / L, respectively;

[0101] (2) Pour concentrated sulfuric acid (mass fraction of 98%) with a concentration of 1.3:1 compared to the amount of concentrated sulfuric acid in step (1) into the leaching residue obtained in step (1), and use the heating and curing process. Heat and keep at 100℃ for 20min, then add water with a liquid to solid ratio of 5:1 and leach for 30min at a water leaching temperature of 60℃. Filter to obtain cured residue. The copper mass content in the cured residue is 0.045% after detection.

[0102] As can be seen from the comparison of Comparative Example 2 and Example 2, when the continuous heating and curing temperature is 100℃, although there is a good copper leaching rate, the slag will be hardened during the continuous heating and curing process, which is difficult to stir and will have some impact on the subsequent industrialization. Considering the energy consumption cost and other problems, natural curing is selected during curing.

[0103] Comparative Example 3

[0104] A method for leaching copper from silver separation furnace slag, comprising the following steps:

[0105] (1) take 100g of silver separation furnace slag, add 500ml of water, gradually add mass fraction of 98% concentrated H2SO4, with the theoretical reaction mass ratio of hydrogen peroxide and copper in the silver separation furnace slag being 5.5:1, take mass fraction of 30% H2O2 and slowly add from the bottom during the leaching process, react for 3h under the condition of leaching temperature being 60℃, finally control the end point pH at 6, filter to obtain leaching residue and leaching solution, and through detection, the copper leaching rate is 82.25%.

[0106] It can be seen from the comparison of the comparative example 3 and the example 3 that when the amount of sulfuric acid is small, the copper is not conducive to leaching.

[0107] Comparative example 4

[0108] A method for leaching copper from silver separation furnace slag, comprising the following steps:

[0109] (1) take 100g of silver separation furnace slag, add 500ml of water, gradually add HCl, with the theoretical reaction mass ratio of hydrogen peroxide and copper in the silver separation furnace slag being 5.5:1, take mass fraction of 30% H2O2 and slowly add from the bottom during the leaching process, react for 3h under the condition of leaching temperature being 60℃, finally control the end point pH at about 2, filter to obtain leaching residue and leaching solution, and through detection, the copper leaching rate is 80.25%; the bismuth leaching rate is 75.15%; and the antimony leaching rate is 42.67%.

[0110] It can be seen from the comparison of the comparative example 4 and the example 3 that the hydrochloric acid is not suitable for selectively leaching copper, and a part of bismuth and antimony will be leached according to the pH condition, which affects the recovery of valuable metals, and the copper leaching rate is not high.

[0111] In summary, in the application, the first stage of concentrated sulfuric acid oxidation leaching is used to leach most of the copper from the silver separation furnace slag, so as to realize the separation of copper from lead, bismuth, antimony, silver and other metals; and the second stage of ripening reaction is introduced, the concentrated sulfuric acid destroys the structure of the leaching residue, so that the copper and its oxides in the complex structure are released, so that the mass content of copper in the ripening residue is less than 0.1%, the copper leaching rate can reach more than 99%, and the deep extraction and recovery of copper in the silver separation furnace slag are realized.

[0112] The above examples are only used to illustrate the technical solutions of the application but not to limit the protection scope of the application, and although the application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the application can be modified or replaced equivalently without departing from the essence and scope of the technical solutions of the application.

Claims

1. A method for leaching copper from silver- bearing furnace slag, characterized in that, The method comprises the following steps: (1) mixing and slurrying the silver separation furnace slag and water, then adding concentrated sulfuric acid to perform leaching reaction, controlling the final pH to be 1-4.5, and introducing hydrogen peroxide during the leaching reaction to obtain leaching solution and leaching residue; (2) mixing the leaching residue obtained in step (1) and concentrated sulfuric acid to perform aging reaction, then leaching and filtering to obtain aging solution and aging residue; the aging solution is countercurrently recycled back to step (1) to replace water and concentrated sulfuric acid.

2. The method of claim 1, wherein, In step (1), the silver separation furnace slag is obtained by sequentially subjecting lead anode slime to fire metallurgy smelting in a lead-rich furnace and a silver separation furnace; and / or, the components of the silver separation furnace slag include copper 10-50wt%, lead 5-20wt%, bismuth 10-40wt%, antimony 1-10wt%, and silver 1-15wt%; and / or, in the silver separation furnace slag, the mass fraction of particles with a particle size of less than or equal to 70μm is greater than or equal to 90%.

3. The method of claim 1, wherein, In step (1), the liquid-solid ratio of the water and the silver separation furnace slag is (1.8-6.5):1; and / or, the mass fraction of the concentrated sulfuric acid is ≥98%; and / or, the theoretical reaction mass ratio of the hydrogen peroxide to copper in the silver separation furnace slag is (1.8-8.5):

1.

4. The method of claim 1, wherein, In step (1), the temperature of the leaching reaction is 35-95℃; and / or, the holding time of the leaching reaction is 0.5-5.5h.

5. The method of claim 1, wherein, In step (1), in the leaching solution, the contents of bismuth, antimony and copper are 0.01-0.05g / L, 0.003-0.007g / L and 50-60g / L, respectively; and / or, the components of the leaching residue include copper 2-5wt%, bismuth 30-50wt% and antimony 2-12wt%.

6. The method of claim 1, wherein, In step (1), the copper in the leaching solution is recovered by a reduction iron powder displacement process or a traditional hydrometallurgy electrolysis process.

7. The method of claim 1, wherein, In step (2), the mass fraction of the concentrated sulfuric acid is ≥98%; and / or, the aging reaction is natural aging; and / or, the time of the aging reaction is 9-65min; and / or, water is used for the leaching, and the liquid-solid ratio of the water and the leaching residue is (3-5):1; and / or, the temperature of the leaching is 18-95℃; and / or, the holding time of the leaching is 18-110min.

8. The method of claim 1, wherein, In step (2), the molar ratio of the concentrated sulfuric acid to the concentrated sulfuric acid in step (1) is (1.1-2.2):1; and / or, in the aging solution, the contents of bismuth and antimony are 0.6-3g / L and 0.08-0.2g / L, respectively; and / or, the acidity of the aging solution needs to reach the requirement of the amount of the concentrated sulfuric acid in the leaching reaction in step (1); and / or, the aging solution is countercurrently recycled back to leach the silver separation furnace slag in step (1), and then the aging solution is obtained through step (2), i.e., one cycle is completed.

9. The method of claim 1, wherein, In step (2), in the aging residue, the mass fraction of copper is less than 0.1%; and / or, after the aging residue is reduced by fire metallurgy smelting, a vacuum furnace is used to recover lead, bismuth, antimony and silver metals.

10. Use of the method according to any one of claims 1-9 in non-ferrous metal recovery.

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