A method for recovering copper from scrap chips

Abstract

The application provides a method for recovering copper from waste chips, which comprises the following steps: performing roasting phase reconstruction on the waste chips to obtain copper-containing reconstruction slag; mixing the copper-containing reconstruction slag and Fe 3+ leaching liquid to obtain copper-containing leaching liquid and leaching residue; performing electrolysis on the copper-containing leaching liquid to obtain copper single substance and Fe 2+ electrolyte; and performing electrolytic oxidation on the Fe 2+ electrolyte, and then recycling the electrolyte for the leaching of the copper-containing reconstruction slag. The method has the characteristics of short process flow, continuous operation, green and clean, simple operation, low cost, high comprehensive recovery value and the like.

Description

Technical Field

[0001] This invention belongs to the field of metallurgy and environmental protection technology, and relates to a method for recovering copper from waste chips. Background Technology

[0002] With the rapid development of the information technology sector, the pace of electronic device upgrades is accelerating, resulting in an ever-increasing amount of electronic waste. Copper, due to its excellent ductility and conductivity, is widely used in various types of electronic devices. As the number of discarded electronic devices continues to rise, the recycling of copper-containing secondary resources has attracted widespread attention. The Chinese government attaches great importance to the recycling and utilization of discarded electronic equipment, and has formulated a series of policies and subsidies, as well as promulgated relevant laws and regulations to strengthen the recycling of electronic waste.

[0003] Currently, the main recycling and processing methods for waste chips are divided into biological methods, pyrometallurgical methods, and hydrometallurgical methods. Biological methods are very environmentally friendly, but the recovery volume is low and the recovery cycle is long. Although biological methods can effectively recover copper from waste chips, the high copper content in electronic waste makes them unsuitable for biological recycling. Pyrometallurgical methods have the advantages of large-scale processing, simple operation, and significant recovery results, but open-air incineration or smelting can produce toxic gases, posing serious harm to human health and the environment. Hydrometallurgical methods involve mixing a leaching agent with electronic waste to transfer copper from the waste to a solution in ionic form, which is then extracted and recovered. In this process, the choice of leaching agent largely determines whether toxic substances will be generated during leaching; furthermore, the consumption of large amounts of leaching agent can create new problems. Although different types of recycling processes have their advantages and disadvantages, in hydrometallurgical recycling, the generation of toxic substances can be effectively avoided by choosing the right leaching agent. Therefore, when processing waste chips using hydrometallurgy, selecting a green and efficient leaching agent is particularly important.

[0004] CN115029553A discloses a method for co-processing copper-containing electronic waste through oxygen-enriched bottom-blown smelting. Under oxygen-enriched conditions, the copper-containing waste is mixed with a flux and smelted at high temperature to obtain copper-rich material, followed by electrolytic refining to obtain cathode copper and precious metal-rich slag. While this method achieves copper recovery, the waste gas generated during high-temperature smelting is complex to treat and difficult to completely remove.

[0005] CN113528839B discloses a method for recovering tin, copper, and lead from copper-containing waste by leaching aluminum with hydrochloric acid and controlling potential oxidation leaching and electrodeposition. Although this method achieves comprehensive recovery of multiple metal elements, it generates flammable and explosive hydrogen gas during hydrochloric acid leaching and chlorine gas during controlled potential oxidation leaching, which poses a significant threat to the environment.

[0006] CN113528837B discloses a method for selectively leaching iron and aluminum from copper-containing waste using sulfuric acid, and recovering copper, tin and lead from the leaching residue through pyrometallurgical copper smelting and controlled-potential oxidation leaching. However, this recovery process is complex and energy-intensive, which is not conducive to large-scale industrial application.

[0007] CN111139360A discloses a method for leaching silver and copper from IC chips and components in waste mobile phone circuit boards using a mixed solution of sulfuric acid and sodium nitrate. However, this leaching process generates nitrogen oxide gas that is harmful to the environment and human health.

[0008] Due to the complexity of the composition of electronic waste, traditional recycling processes for discarded chips may generate toxic substances. Therefore, it is particularly important to develop a recycling method that produces no harmful substances during copper recovery. Summary of the Invention

[0009] To address the technical problems existing in the prior art, this invention provides a method for recovering copper from waste chips. This method features a short process flow, continuous operation, green and clean operation, simple operation, low cost, and high comprehensive recycling value. The copper leaching rate is as high as 99%, the precious metal enrichment multiple in the enrichment slag is as high as 3.5 times, the copper purity recovered is as high as 99.78%, the cathode efficiency and anode efficiency are 97.69% and 97.78% respectively, and the copper recovery rate is as high as 99.89%.

[0010] To achieve the above-mentioned technical effects, the present invention adopts the following technical solution:

[0011] This invention provides a method for recovering copper from waste chips, the method comprising the following steps:

[0012] (1) The waste chips are roasted and reconstructed to obtain copper-containing reconstruction slag. The waste chips contain 10-60 wt% copper, 5-50 wt% silicon, and 0.01-0.1% precious metals.

[0013] (2) The copper-containing reconstructed slag and Fe 3+ The leachate is mixed, and leaching yields a copper-containing leachate and a leaching residue;

[0014] (3) Using the copper-containing leachate obtained in step (2) as the cathode solution, copper is recovered by membrane electrolysis, and the anode solution is Fe. 2+ Solution, Fe 2+ The concentration was 0.1–5 mol / L; metallic copper and Fe were obtained in the cathode chamber. 2+ Solution, Fe in the anode chamber 2+ Solution oxidation to form Fe 3+ leachate.

[0015] (4) After the electrolytic recovery of copper is completed, the remaining Fe in the cathode chamber 2+ The solution serves as the anolyte to be electrolyzed, ultimately entering the anode chamber for electrolytic oxidation, forming Fe... 3+ The leachate is recycled for leaching of the copper-containing reconstructed slag.

[0016] As a preferred technical solution of the present invention, the roasting temperature in step (1) is 100-1000℃ and the roasting time is 20-200min.

[0017] As a preferred technical solution of the present invention, the Fe in step (2) 3+ The concentration of the leachate is 0.1–5 mol / L, containing copper-reconstructed slag and Fe. 3+ The mass-to-volume ratio of the leachate is 1:(1~20)g / mL, the leaching temperature is 10~100℃, and the leaching time is 10~180min.

[0018] As a preferred technical solution of the present invention, the electrolysis in step (3) is carried out in a diaphragm electrolytic cell with a current density of 50-500 A / m. 2 The electrolysis time is 20–200 min; after the electrolytic recovery of copper is completed, the remaining Fe in the cathode chamber 2+ Cu in solution 2+ Content ≤0.5g / L.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects:

[0020] (1) The phase reconstruction of waste chips is achieved by calcination, which exposes copper and improves the copper leaching effect.

[0021] (2) This invention provides a method for recovering copper from waste chips. This method has the characteristics of short process flow, continuous operation, green and clean operation, simple operation, low cost and high comprehensive recycling value. The copper immersion agent has the characteristics of being green, low cost, wide source and recyclable. The whole wet recycling process generates no wastewater and waste gas, and has significant economic and environmental benefits. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the process flow for the method of recovering copper from waste chips provided by the present invention.

[0023] Figure 2 The images shown are XRD patterns of the waste chips before and after high-temperature baking in Example 1 of this invention.

[0024] Figure 3 A comparison chart of copper leaching rates between unbaked (Comparative Example 1) and baked (Example 1) waste chips provided by the present invention.

[0025] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims. Detailed Implementation

[0026] The technical solution of this application will be further described below through specific implementation methods.

[0027] This invention provides a method for recovering copper from waste chips, the method comprising the following steps:

[0028] (1) The waste chips are roasted and reconstructed to obtain copper-containing reconstruction slag. The waste chips contain 10-60 wt% copper, 5-50 wt% silicon, and 0.01-0.1% precious metals.

[0029] (2) Fe 3+ The leachate is mixed with the copper-containing reconstituted slag obtained in step (1) and leached to obtain copper-containing leachate and leaching slag;

[0030] (3) Using the copper-containing leachate obtained in step (2) as the cathode solution, copper is recovered by membrane electrolysis, and the anode solution is Fe. 2+ Solution, Fe 2+ The concentration is 0.1–5 mol / L; elemental copper and Fe are obtained in the cathode chamber. 2+ Solution, Fe in the anode chamber 2+ Solution oxidation to form Fe 3+ leachate.

[0031] (4) After the electrolytic recovery of copper is completed, the remaining Fe in the cathode chamber 2+ The solution serves as the anolyte to be electrolyzed, ultimately entering the anode chamber for electrolytic oxidation, forming Fe... 3+ The leachate is recycled for leaching of the copper-containing reconstructed slag.

[0032] In this invention, copper-containing waste chips are first subjected to phase reconstruction by high-temperature calcination. After phase reconstruction, the silicon-encapsulated surface of the copper-containing waste chips undergoes structural breakage, thereby exposing metallic Cu and facilitating copper leaching. Fe is then used... 3+ Cu was selectively leached from the reconstructed residue using a solution to obtain Cu-containing material. 2+ and Fe 2+ The solution and leaching residue rich in precious metals; the leaching solution is used as the cathode electrolyte for electrolytic recovery of copper, and the anolyte is Fe. 2+ The solution, after electrolytic oxidation, forms Fe. 3+ Leachate. Fe remaining in the cathode chamber after electrolytic copper recovery. 2+ The solution serves as the anolyte to be electrolyzed, ultimately entering the anode chamber for electrolytic oxidation, yielding Fe. 3+Solution, the Fe 3+ The solution can be further used for the selective leaching of copper from the reconstructed slag, thereby achieving Fe... 3+ The solution is recycled. This method achieves green and efficient recovery of copper, enrichment of precious metals, and Fe from copper-containing waste chips. 3+ The solution is recycled.

[0033] In one specific embodiment of the present invention, the waste chip includes silicon, copper, and precious metal elements. The precious metal elements include any one or more combinations of gold, silver, and palladium.

[0034] In one specific embodiment of the present invention, the gold content in the waste chips is 10-100 g / t, for example, it can be 10 g / t, 20 g / t, 30 g / t, 40 g / t, 50 g / t, 60 g / t, 70 g / t, 80 g / t, 90 g / t, or 100 g / t, etc.; the silver content is 0.01-0.08 wt%, for example, it can be 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.07 wt%, or 0.08 wt%, etc.; the platinum content is 0-3 g / t, for example, ... For example, the concentrations can be 0 g / t, 0.5 g / t, 1.0 g / t, 1.5 g / t, 2.0 g / t, 2.5 g / t, or 3.0 g / t, etc.; the palladium content is 50–100 g / t, for example, 50 g / t, 60 g / t, 70 g / t, 80 g / t, 90 g / t, or 100 g / t, etc.; the rhodium content is 0–1 g / t, for example, 0 g / t, 0.2 g / t, 0.4 g / t, 0.6 g / t, 0.8 g / t, or 1.0 g / t, etc., but are not limited to the listed values. Other unlisted values ​​within the above ranges also apply.

[0035] In one specific embodiment of the present invention, the calcination temperature is 100 to 1000°C, such as 100°C, 200°C, 300°C, 400°C, 500°C, 600°C, 700°C, 800°C, 900°C, or 1000°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 400 to 800°C.

[0036] In one specific embodiment of the present invention, the calcination time is 20 to 200 min, such as 20 min, 40 min, 60 min, 80 min, 100 min, 120 min, 140 min, 160 min, 180 min or 200 min, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] In this invention, roasting causes a phase transformation in the surface structure of the waste chip, resulting in surface structure breakage. If the holding time is too long, it may cause other components in the waste chip to undergo phase transformation, which is detrimental to the extraction of copper and enrichment of precious metals in the subsequent reconstruction slag.

[0038] In one specific embodiment of the present invention, calcination is carried out in an oxidizing atmosphere, such as air and oxygen.

[0039] In one specific embodiment of the present invention, Fe 3+ The concentration of the leachate is 0.1–5 mol / L, such as 0.1 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, 4.5 mol / L, or 5 mol / L, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, with 0.5–2 mol / L being the preferred concentration.

[0040] In one specific embodiment of the present invention, copper-containing reconstructed slag and Fe 3+ The mass-to-volume ratio of the leachate is 1:(1~20)g / mL, such as 1:1g / mL, 1:2g / mL, 1:4g / mL, 1:6g / mL, 1:8g / mL, 1:10g / mL, 1:12g / mL, 1:14g / mL, 1:16g / mL, 1:18g / mL or 1:20g / mL, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, and 1:(5~15)g / mL is preferred.

[0041] In one specific embodiment of the present invention, the leaching temperature is 10 to 100°C, such as 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, or 100°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, with 20 to 80°C being the preferred temperature.

[0042] In one specific embodiment of the present invention, the leaching time is 10 to 180 min, such as 10 min, 20 min, 40 min, 60 min, 80 min, 100 min, 120 min, 140 min, 160 min, 180 min or 200 min, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0043] In one specific embodiment of the present invention, leaching is performed to separate solids and liquids to obtain leachate and leachate residue. The solid-liquid separation method includes any one or a combination of at least two of filtration, centrifugation, or decantation, wherein typical but non-limiting combinations include a combination of filtration and centrifugation, a combination of filtration and decantation, a combination of centrifugation and decantation, a combination of filtration, centrifugation, and decantation, etc.

[0044] In one specific embodiment of the present invention, the leaching residue includes any one or at least two combinations of silicon, silicon dioxide, and precious metals, wherein typical but non-limiting combinations are combinations of silicon and silicon dioxide, combinations of silicon and precious metals, combinations of silicon, silicon dioxide, and precious metals, etc.

[0045] In one specific embodiment of the present invention, any one or at least two combinations of gold, silver, platinum, palladium, and rhodium are used, wherein typical but non-limiting combinations are combinations of gold and silver, combinations of silver and platinum, combinations of platinum and palladium, combinations of palladium and rhodium, combinations of gold, silver, and palladium, combinations of platinum, palladium, and rhodium, etc.

[0046] In one specific embodiment of the present invention, the current density for electrolysis is 50–500 A / m. 2 For example, 50A / m 2 100A / m 2 150A / m 2 200A / m 2 250A / m 2 300A / m 2 350A / m 2 400A / m 2 450A / m 2 Or 500A / m 2 The values ​​are not limited to those listed; other unlisted values ​​within this range also apply, with 100–300 A / m being preferred. 2 .

[0047] In one specific embodiment of the present invention, the electrolysis time is 20 to 200 min, such as 20 min, 40 min, 60 min, 80 min, 100 min, 120 min, 140 min, 160 min, 180 min or 200 min, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 50 to 150 min.

[0048] In one specific embodiment of the present invention, electrolysis is carried out in a diaphragm electrolyzer, such as a plate and frame diaphragm electrolyzer, and the diaphragm is an anion exchange membrane.

[0049] In one specific embodiment of the present invention, the leachate is used as the catholyte, Fe 2+The solution serves as the anolyte.

[0050] In one specific embodiment of the present invention, after the electrolytic recovery of copper is completed, the remaining Fe in the cathode chamber 2+ Cu in solution 2+ The content is ≤0.5g / L, and the remaining Fe in the cathode chamber 2+ The solution serves as the anolyte to be electrolyzed, ultimately entering the anode chamber for electrolytic oxidation, forming Fe... 3+ The leachate is recycled for leaching of the copper-containing reconstructed slag.

[0051] In one specific embodiment of the present invention, the method for recovering copper from waste chips includes:

[0052] (1) The waste chips with a copper content of 10-60 wt% are calcined at 400-800℃ for 20-200 min to reconstruct the phase and obtain copper-containing reconstructed slag;

[0053] (2) The copper-containing reconstructed slag and Fe 3 Fe concentration of 0.1–5 mol / L 3+ The leachate was mixed at a mass-to-volume ratio of 1:(1~20)g / mL and leached at 10~100℃ for 10~180min to obtain copper-containing leachate and leaching residue;

[0054] (3) The copper-containing leachate is electrolyzed in a diaphragm electrolytic cell, wherein the current density of the electrolysis is 50–500 A / m. 2 The time is 20–200 min, and elemental copper and Fe are obtained in the cathode chamber. 2+ After the electrolyte and electrolytic recovery of copper are completed, the remaining Fe in the cathode chamber 2+ Cu in solution 2+ With a content ≤0.5g / L, Fe is obtained in the anode chamber. 3+ The leachate is recycled for leaching of the copper-containing reconstructed slag;

[0055] (4) After the electrolytic recovery of copper is completed, the remaining Fe in the cathode chamber 2+ The solution serves as the anolyte to be electrolyzed, ultimately entering the anode chamber for electrolytic oxidation, forming Fe... 3+ The leachate is recycled for leaching of the copper-containing reconstructed slag.

[0056] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0057] Example 1

[0058] This embodiment provides a method for recovering copper from waste chips, the process of which is as follows: Figure 1 As shown, the method includes the following steps:

[0059] (1) 500g of untreated waste chips were calcined at 600℃ for 120min to reconstruct the phase and obtain a copper-containing reconstructed slag with a copper leaching rate of 99%.

[0060] (2) The reconstituted slag was reacted with 1 mol / L Fe... 3+ The solutions were mixed and leached for 120 min at 80℃ and a solid-liquid ratio of 1:12 g / mL. Solid-liquid separation was then performed to obtain Cu. 2+ and Fe 2+ Solutions and enriched residues containing precious metals;

[0061] (3) Using this leaching solution as the cathode solution, Fe 2+ The solution is the anolyte, and titanium and graphite sheets serve as the cathode and anode, respectively, at a current density of 220 A / m. 2 Copper was recovered under an electrolysis time of 90 minutes, achieving a copper purity of up to 99.78%. The remaining Fe in the cathode chamber... 2+ Cu in solution 2+ The content is 0.05 g / L;

[0062] (4) Fe remaining in the cathode chamber 2+ The solution, serving as the anolyte to be electrolyzed, ultimately enters the anode chamber for electrolytic oxidation, forming a 1 mol / L Fe solution. 3+ The leachate is recycled for leaching the copper-containing reconstructed slag, with cathode efficiency and anode efficiency of 97.69% and 97.78%, respectively, and copper recovery rate as high as 99.89%.

[0063] Example 2

[0064] This embodiment provides a method for recovering copper from waste chips, the method comprising the following steps:

[0065] (1) 500g of untreated waste chips were calcined at 600℃ for 120min to reconstruct the phase and obtain a reconstructed slag containing copper phase;

[0066] (2) The reconstituted slag was reacted with 1 mol / L Fe... 3+ The solutions were mixed and leached for 120 min at 60℃ and a solid-liquid ratio of 1:12 g / mL. Solid-liquid separation was then performed to obtain Cu. 2+ and Fe 2+ Solutions and enriched residues containing precious metals;

[0067] (3) Using this Cu 2+ and Fe 2+ The solution is used as the cathode solution, and titanium and graphite sheets are used as the cathode and anode, respectively, at a current density of 220 A / m. 2Copper was recovered under an electrolysis time of 90 minutes, achieving a copper purity of up to 99.75%. The remaining Fe in the cathode chamber... 2+ Cu in solution 2+ The content is 0.1 g / L;

[0068] (4) Fe remaining in the cathode chamber 2+ The solution, serving as the anolyte to be electrolyzed, ultimately enters the anode chamber for electrolytic oxidation, forming a 1 mol / L Fe solution. 3+ The leachate is recycled for leaching the copper-containing reconstructed slag, with cathode efficiencies of 96.43% and anodic efficiencies of 97.71%, and copper recovery rate as high as 95.99%.

[0069] Example 3

[0070] This embodiment provides a method for recovering copper from waste chips, the method comprising the following steps:

[0071] (1) 500g of untreated waste chips were calcined at 800℃ for 120min to reconstruct the phase and obtain a reconstructed slag containing copper phase;

[0072] (2) The reconstituted slag with 1 mol / L Fe 3+ The solutions were mixed and leached for 60 minutes at 80℃ and a solid-liquid ratio of 1:12 g / mL. Solid-liquid separation was then performed to obtain Cu. 2+ and Fe 2+ Solutions and enriched residues containing precious metals;

[0073] (3) Using this Cu 2+ and Fe 2+ The solution is used as the cathode solution, and titanium and graphite sheets are used as the cathode and anode, respectively, at a current density of 220 A / m. 2 Copper was recovered under an electrolysis time of 60 minutes, achieving a copper purity of up to 99.77%. The remaining Fe in the cathode chamber... 2+ Cu in solution 2+ The content is 0.08 g / L;

[0074] (4) Fe remaining in the cathode chamber 2+ The solution, serving as the anolyte to be electrolyzed, ultimately enters the anode chamber for electrolytic oxidation, forming a 1 mol / L Fe solution. 3+ The leachate is recycled for leaching the copper-containing reconstructed slag, with cathode efficiency and anode efficiency of 95.69% and 96.28%, respectively, and copper recovery rate as high as 96.99%.

[0075] Example 4

[0076] This embodiment provides a method for recovering copper from waste chips, the method comprising the following steps:

[0077] (1) 2 kg of untreated waste chips were calcined at 600℃ for 60 min to reconstruct the phase and obtain a reconstructed residue containing copper phase;

[0078] (2) The reconstituted slag with 3 mol / L Fe 3+ The solutions were mixed and leached for 120 min at 80℃ and a solid-liquid ratio of 1:4 g / mL. Solid-liquid separation was then performed to obtain Cu. 2+ and Fe 2+ Solutions and enriched residues containing precious metals;

[0079] (3) Using this Cu 2+ and Fe 2+ The solution is used as the cathode solution, and titanium and graphite sheets are used as the cathode and anode, respectively, at a current density of 220 A / m. 2 Copper was recovered under an electrolysis time of 90 minutes, achieving a copper purity of up to 99.78%. The remaining Fe in the cathode chamber... 2+ Cu in solution 2+ The content is 0.06 g / L;

[0080] (4) Fe remaining in the cathode chamber 2+ The solution, serving as the anolyte to be electrolyzed, ultimately enters the anode chamber for electrolytic oxidation, forming a 3 mol / L Fe solution. 3+ The leachate is recycled for leaching the copper-containing reconstructed slag, with cathode efficiency and anode efficiency of 98.51% and 98.73%, respectively, and copper recovery rate as high as 99.88%.

[0081] Example 5

[0082] This embodiment provides a method for recovering copper from waste chips, the method comprising the following steps:

[0083] (1) 200g of untreated waste chips were calcined at 600℃ for 120min to reconstruct the phase and obtain a reconstructed slag containing copper phase;

[0084] (2) The reconstituted slag with 1.5 mol / L Fe 3+ The solutions were mixed and leached for 120 min at 80℃ and a solid-liquid ratio of 1:12 g / mL. Solid-liquid separation was then performed to obtain Cu. 2+ and Fe 2+ Solutions and enriched residues containing precious metals;

[0085] (3) Using this Cu 2+ and Fe 2+ The solution is used as the cathode solution, and titanium and graphite sheets are used as the cathode and anode, respectively, at a current density of 220 A / m. 2Copper was recovered under an electrolysis time of 90 minutes, achieving a copper purity of up to 99.77%. The remaining Fe in the cathode chamber... 2+ Cu in solution 2+ The content is 0.07 g / L;

[0086] (4) Fe remaining in the cathode chamber 2+ The solution, used as the anolyte to be electrolyzed, ultimately enters the anode chamber for electrolytic oxidation, forming a 1.5 mol / L Fe solution. 3+ The leachate is recycled for leaching the copper-containing reconstructed slag, with cathode efficiency and anode efficiency of 95.29% and 96.48%, respectively, and copper recovery rate as high as 97.99%.

[0087] Example 6

[0088] This embodiment provides a method for recovering copper from waste chips, the method comprising the following steps:

[0089] (1) 500g of untreated waste chips were calcined at 400℃ for 200min to reconstruct the phase and obtain a reconstructed slag containing copper phase.

[0090] (2) The reconstituted slag with 5 mol / L Fe 3+ The solutions were mixed and leached for 180 min at a temperature of 20℃ and a solid-liquid ratio of 1:1 g / mL. Solid-liquid separation was then performed to obtain Cu. 2+ and Fe 2+ Solutions and enriched residues containing precious metals;

[0091] (3) Using this Cu 2+ and Fe 2+ The solution is used as the cathode solution, and titanium and graphite sheets are used as the cathode and anode, respectively, at a current density of 100 A / m. 2 Copper was recovered under an electrolysis time of 150 min, with a copper purity as high as 98.93%. The remaining Fe in the cathode chamber... 2+ Cu in solution 2+ The content is 0.06 g / L;

[0092] (4) Fe remaining in the cathode chamber 2+ The solution, serving as the anolyte to be electrolyzed, ultimately enters the anode chamber for electrolytic oxidation, forming a 5 mol / L Fe solution. 3+ The leachate is recycled for leaching the copper-containing reconstructed slag, with cathode efficiency and anode efficiency of 97.32% and 98.56%, respectively, and copper recovery rate of 52.5%.

[0093] Example 7

[0094] This embodiment provides a method for recovering copper from waste chips, the method comprising the following steps:

[0095] (1) 500g of untreated waste chips were calcined at 1000℃ for 20min to reconstruct the phase and obtain a reconstructed slag containing copper phase;

[0096] (2) The reconstituted slag with 0.5 mol / L Fe 3+ The solutions were mixed and leached for 20 minutes at 100℃ and a solid-liquid ratio of 1:15 g / mL. Solid-liquid separation was then performed to obtain Cu. 2+ and Fe 2+ Solutions and enriched residues containing precious metals;

[0097] (3) Using this Cu 2+ and Fe 2+ The solution is used as the cathode solution, and titanium and graphite sheets are used as the cathode and anode, respectively, at a current density of 300 A / m. 2 Copper was recovered under an electrolysis time of 50 minutes, with a copper purity as high as 95.21%. The remaining Fe in the cathode chamber... 2+ Cu in solution 2+ The content is 0.06 g / L;

[0098] (4) Fe remaining in the cathode chamber 2+ The solution, used as the anolyte to be electrolyzed, ultimately enters the anode chamber for electrolytic oxidation, forming a 0.5 mol / L Fe solution. 3+ The leachate is recycled for leaching the copper-containing reconstructed slag, with cathode efficiency and anode efficiency of 98.01% and 97.43%, respectively, and copper recovery rate as high as 77.22%.

[0099] Comparative Example 1

[0100] This comparative example provides a method for leaching copper from copper-containing waste chips. The only difference from Example 1 is that the waste chips and Fe... 3+ The waste chips were not subjected to high-temperature calcination before solution mixing; all other conditions remained unchanged. Cu was obtained through solid-liquid separation. 2+ and Fe 2+ In the solution and the enriched slag containing precious metals, the leaching rate of Cu was 51%.

[0101] Comparative results show that after phase reconstruction through high-temperature calcination, the silicon phase undergoes a transformation. The diffraction peaks of crystalline silicon disappear before and after calcination, and the dense crystalline silicon encapsulating copper transforms into loose, porous silicon dioxide, exposing more copper and thus significantly increasing the copper leaching rate. The results indicate that calcination helps improve the copper leaching rate.

[0102] Test methods

[0103] Using ICP-OES to analyze Cu in solution 2+The concentration of total Fe was measured using the method specified in GB / T7315.1-1987. 2+ The concentration.

[0104] The test results show that:

[0105] (1) As can be seen from Examples 1-5, the present invention utilizes the reconstructed slag containing the copper phase after high-temperature calcination and Fe... 3+ After the solutions are mixed, with Fe 3+ With increasing concentration, mixing temperature, and mixing time, the copper leaching rate increases and the enrichment factor of precious metals also increases.

[0106] (2) As can be seen from Example 1 and Comparative Example 1, when the waste chip is not calcined and the surface of the waste chip is not reconstructed, the Fe... 3+ When the solutions were mixed, the copper leaching rate was only 51%, and the enrichment factor was only 1.7.

[0107] (3) XRD tests were performed on the waste chips before and after calcination in Example 1, such as... Figure 2 As shown, after calcination, the diffraction peaks of crystalline silicon disappear, while other diffraction peaks still exist.

[0108] The applicant declares that the detailed structural features of the present invention are illustrated through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components selected in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0109] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0110] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0111] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for recovering copper from waste chips, characterized in that, The method includes the following steps: (1) Untreated waste chips are calcined for phase reconstruction, and the surface of the silicon encapsulation is structurally broken and transformed into loose and porous silicon dioxide to obtain copper-containing reconstruction slag. The waste chips contain 10~60wt% copper, 5~50wt% silicon, and 0.01~0.1wt% precious metals; (2) Fe 3+ The leachate is mixed with the copper-containing reconstituted residue obtained in step (1) and leached to obtain copper-containing leachate and leaching residue; (3) Using the copper-containing leaching solution obtained in step (2) as the cathode solution, copper is recovered by membrane electrolysis. The membrane is an anion exchange membrane, and the anolyte is Fe. 2+ Solution, Fe 2+ The concentration was 0.1–5 mol / L; metallic copper and Fe were obtained in the cathode chamber. 2+ Solution, Fe in the anode chamber 2+ Solution oxidation to form Fe 3+ leachate; (4) Fe remaining in the cathode chamber after the electrolytic recovery of copper. 2+ The solution serves as the anolyte to be electrolyzed, ultimately entering the anode chamber for electrolytic oxidation, forming Fe... 3+ The leachate is recycled for leaching of the copper-containing reconstructed slag.

2. The method according to claim 1, characterized in that, The roasting temperature in step (1) is 100~1000℃ and the roasting time is 20~200 min.

3. The method according to claim 1, characterized in that, The Fe mentioned in step (2) 3+ The leachate concentration is 0.1~5 mol / L, containing copper-reconstructed slag and Fe. 3+ The mass-to-volume ratio of the leachate is 1:(1~20)g / mL, the leaching temperature is 10~100℃, and the leaching time is 10~180 min.

4. The method according to claim 1, characterized in that, The electrolysis in step (3) is carried out in a diaphragm electrolytic cell with a current density of 50~500 A / m. 2 The electrolysis time is 20-200 min; after the electrolytic recovery of copper is completed, the remaining Fe in the cathode chamber 2+ Cu in solution 2+ Content ≤0.5 g / L.

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