Method for preparing copper ingot by refining waste copper

Abstract

The invention provides a method for preparing a copper ingot through waste copper refining, and belongs to the field of waste copper refining. The method comprises the following steps: sorting, crushing and drying a waste copper raw material to obtain a pretreated copper material; feeding the pretreated copper material into a cored power frequency induction furnace for melting; after the pretreated copper material is completely molten, adding a slag removing agent into the melt, then lowering the voltage, and salvaging slag after heat preservation; a magnetic refining agent is added into the melt obtained after slag fishing, stirring is carried out to adsorb impurity elements in the melt, then heat preservation and standing are carried out, and the magnetic refining agent is recycled; the refined melt is subjected to electromagnetic stirring and ultrasonic wave cooperative treatment, so that hydrogen and oxygen gas is deeply removed, and components are homogenized; and a slag conglomeration agent is added into the purified melt, stirring is conducted, slag is fished out after heat preservation, and casting is conducted to form an ingot. Therefore, deep and efficient removal of various types and trace harmful impurities (especially As, Pb, Sb and the like) in the waste copper is synergistically realized, and the metallurgical quality of final copper ingots is synchronously improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste copper refining production, and particularly relates to a method for preparing copper ingot from waste copper. BACKGROUND

[0002] With the continuous growth of copper resource demand and the rising of primary copper mining cost, waste copper as an important renewable resource, its recovery and refining to prepare copper ingot technology has attracted widespread attention. However, the source of waste copper raw material is complex (including waste electrical appliances, cables, industrial scraps, waste circuit boards, etc.), which leads to the significant characteristics of "multiple types, multiple forms, and micro trace" of impurity components. In addition to common metal impurities such as Fe, Zn, Sn, etc., it also generally contains toxic micro trace impurities such as As, Pb, Sb, etc. Such impurities are not only difficult to completely remove by conventional process, but also seriously affect the electrical conductivity, mechanical properties and subsequent processing safety of copper ingot, which cannot meet the demand of high purity copper material in the field of precision electronics and high-end cables.

[0003] The current waste copper refining technology has obvious limitations in impurity removal and copper ingot quality improvement. Traditional pyrorefining (such as one-stage method and two-stage method) mainly relies on single deslagging agent (such as sodium carbonate and borax) and high-temperature smelting to remove impurities. Such method can only effectively remove large oxide impurities and part of high-content metal impurities in the melt, and the removal rate of micro trace impurities (content is usually less than 0.01%) such as As, Pb and Sb dissolved in copper liquid is less than 30%. Because such impurities are easy to form solid solution or low melting point compounds with copper, conventional deslagging agent is difficult to react with them, and impurities are easy to be dissolved again due to insufficient reaction. Although some improved technologies try to use selenium-based and sulfide-based refining agents for targeted removal of impurities, they can only target a single type of impurity and cannot simultaneously remove As, Pb and Sb. In addition, the introduction of new harmful residues such as selenium and sulfur further deteriorates the performance of copper ingot. SUMMARY

[0004] The present application provides a method for preparing copper ingot from waste copper, which solves the technical problem of how to simultaneously remove multiple types of micro trace harmful impurities (especially As, Pb, Sb, etc.) in waste copper and improve the metallurgical quality of the final copper ingot.

[0005] The present application provides a method for preparing copper ingot from waste copper, which includes the following steps: S1, sorting, crushing and drying the waste copper raw material to obtain pretreated copper material; S2, sending the pretreated copper material into a cored power frequency induction furnace and melting at a first set voltage; S3, after the pre-treatment copper material is completely melted, the slag cleaning agent is added to the melt, and then the voltage is lowered to the second set voltage, and the first holding is followed by slagging; the slag cleaning agent is composed of sodium carbonate, boric anhydride, silicon dioxide, silicon carbide, cerium oxide and lithium fluoride; S4, the magnetic refining agent is added to the melt after the slagging and stirring is performed to adsorb the impurity elements in the melt, and then the holding is performed to recover the magnetic refining agent floating to the surface of the melt; the magnetic refining agent comprises: a magnetic core, a porous carrier layer coated on the surface of the magnetic core, and an active component loaded on the porous carrier layer, the active component comprises: a metal oxide with Lewis acidity, a metal organic framework material with molecular sieve effect and an ionic liquid; S5, the refined melt is subjected to electromagnetic stirring and ultrasonic wave cooperative treatment to deeply remove hydrogen and oxygen gas and uniformly distribute the components; S6, the slagging agent is added to the purified melt and stirred, the second holding is followed by slagging, and the ingot is cast; the slagging agent is composed of wollastonite, cryolite, calcium fluoride and sodium polyphosphate.

[0006] Optionally, in step S3, the mass of the slag cleaning agent added is 0.05-0.15% of the total mass of the melt; In terms of mass fraction, the content of each component in the slag cleaning agent is: sodium carbonate 35-45%, boric anhydride 15-25%, silicon dioxide 8-12%, silicon carbide 12-18%, cerium oxide 3-6%, and lithium fluoride 5-10%.

[0007] Optionally, in step S4, the mass of the magnetic refining agent added is 0.1-0.65% of the total mass of the melt; The magnetic core is ferroferric oxide; The porous carrier layer is a composite of γ-alumina and mesoporous silica; The metal oxide with Lewis acidity is nano cerium oxide, the metal organic framework material with molecular sieve effect is ZIF-8, and the ionic liquid is a quaternary phosphonium salt ionic liquid.

[0008] Optionally, in step S4, the preparation method of the magnetic refining agent comprises the following steps: S4a, ferroferric oxide magnetic core is synthesized by co-precipitation method; S4b, the magnetic core is dispersed in a solution containing aluminum source and silicon source, and after hydrolysis, aging and drying, the magnetic core is calcined at 400-500°C for 1-3h to form the porous carrier layer; S4c, nano cerium oxide is loaded on the porous carrier layer by equal-volume impregnation method, and then calcined at 450-550°C for 2-4h to form cerium oxide active sites; S4d, loading ZIF-8 on the porous carrier layer by in-situ growth method; S4e, loading quaternary phosphonium ionic liquid in the pores of the porous carrier layer by vacuum impregnation method; The vacuum impregnation method comprises the following parameters: vacuum degree is -0.05 to -0.08 MPa, impregnation temperature is 60-80℃, and impregnation time is 1-2h.

[0009] Optionally, in step S4, the particle size of the magnetic refining agent is 100-200nm, the thickness of the porous carrier layer is 50-100nm, the specific surface area is 200-500m 2 / g, and the mesopore volume with a pore size distribution of 2-50nm accounts for more than 60% of the total pore volume.

[0010] Optionally, in step S4, the recovered magnetic refining agent is regenerated by thermal desorption in an oxidizing atmosphere at 400-600℃ and then recycled to step S4.

[0011] Optionally, in step S2, the first set voltage is 450-500V; In step S3, the second set voltage is 200-220V.

[0012] Optionally, in step S5, the electromagnetic stirring and ultrasonic treatment comprise the following parameters: electromagnetic stirring frequency is 20-30Hz, ultrasonic power is 1-5kW, ultrasonic frequency is 18-25kHz, and the cooperative treatment time is 10-15min.

[0013] Optionally, in step S3, the temperature of the first holding is 1150-1200℃, and the holding time is 10-20min; In step S4, the temperature of the holding and standing is 1150-1180℃, and the holding time is 5-15min; In step S6, the temperature of the second holding is 1100-1150℃, and the holding time is 15-30min; In step S6, the temperature of the ingot casting is 1080-1120℃.

[0014] Optionally, in step S6, the added mass of the slag collecting agent is 0.15-0.3% of the total mass of the melt; In terms of mass fraction, the content of each component in the slag collecting agent is: 25-35% of wollastonite, 30-40% of ice crystal, 20-30% of calcium fluoride, and 5-10% of sodium polyphosphate.

[0015] Compared with the prior art, the above technical solution provided by the embodiments of the present application has the following advantages: The application provides a method for preparing copper ingots from waste copper. Through the whole process design of "staged targeted impurity removal + multi-dimensional process synergy", on the one hand, a multi-level impurity removal system from the source to the end is constructed to accurately solve the problem of deep removal of various types of trace harmful impurities such as As, Pb and Sb, and on the other hand, through physical field regulation and precise ingot casting control, the metallurgical quality of the copper ingot is simultaneously improved. The specific synergy logic is as follows: Firstly, the impurity removal "debt barrier" is constructed based on pretreatment (S1). By sorting out and removing the mixed bulk metal and non-metallic impurities in the waste copper, the impurity treatment load of the subsequent process is reduced from the source, and the bulk impurities wrapping trace harmful impurities (such as As, Pb and Sb which are often attached to the surface of waste copper or wrapped in the oxide layer) are avoided. Crushing makes the size of the waste copper raw material uniform, ensuring uniform heating during subsequent melting, so that the hidden trace impurities are fully exposed to the melt, facilitating the contact and adsorption of subsequent refining agents. Drying removes the moisture of the raw material, which not only avoids the reaction of moisture and copper liquid to generate hydrogen and oxygen gas (which affects the metallurgical quality), but also prevents water vapor from wrapping impurities to form small bubbles that are difficult to separate, creating a "clean initial environment" for subsequent deep impurity removal.

[0016] Secondly, the "rough removal - fine capture" of trace impurities is formed by preliminary slag cleaning (S3) and deep adsorption (S4). In S3, the composite slag cleaning agent first reacts with SnO2, ZnO and other oxides in the melt to generate low-melting-point slag phases through the fluxing effect of sodium carbonate and boric anhydride, and at the same time, the "foaming" effect of silicon carbide is used to stir the melt to release the compounds of trace impurities (such as As2O3, PbO and Sb2O3) wrapped inside the copper liquid, and then the cerium oxide adsorbs part of the fine inclusions, completing the dual role of "rough impurity removal + impurity exposure" to clear the obstacles for precise adsorption in S4. In S4, the magnetic refining agent relies on the core-shell structure to achieve "multi-mechanism targeted capture of impurities": the porous carrier layer provides a large specific surface area for the active components to fully contact the impurities, the Lewis acidic metal oxide adsorbs Sb2O3 and other basic impurities through coordination, the metal-organic framework material with molecular sieve effect traps As2O3 and other small molecule impurities, and the ionic liquid locks Pb 2+ and other heavy metal ions through chelation, and the three mechanisms cover different forms of As, Pb and Sb to achieve deep capture of trace impurities. At the same time, the magnetic core can quickly recover the refining agent to avoid its residual affecting the purity of the copper liquid, further ensuring the thoroughness of impurity removal.

[0017] Finally, the physical field regulation (S5) and the final slag gathering (S6) realize the synchronous landing of "impurity removal and ending + metallurgical quality upgrading". In S5, electromagnetic stirring makes the composition and temperature of the copper liquid uniform through macroscopic melt flow, promotes the floating of residual impurity particles that are not completely separated in S4, and at the same time, ultrasonic waves break the small impurity clusters through cavitation effect, deeply remove the dissolved hydrogen and oxygen gas (to avoid air hole defects in copper ingots), and refine the grains through acoustic streaming effect, to improve the metallurgical quality from three dimensions of "composition uniformity, density, and microstructure"; in S6, the slag gathering agent adjusts the slag body structure through wollastonite, reduces the slag body melting point and viscosity through cryolite and calcium fluoride, gathers the trace impurity particles that are not completely removed in the previous process, and then "locks" the impurities through the network structure of sodium polyphosphate to prevent them from falling back to the melt, to complete the last impurity interception; finally, through precise control of the casting temperature, the grain growth is uniform during the copper ingot forming process, and defects such as shrinkage and cold shut are avoided, to realize the synergy of "deep impurity removal" and "high metallurgical quality copper ingot". BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, those skilled in the art can obtain other drawings from these drawings without any creative effort.

[0020] Figure 1 A flowchart of a method for preparing copper ingots from waste copper according to an embodiment of the present application is shown. Figure 2 An SEM image of a magnetic refining agent according to Embodiment 1 of the present application is shown. DETAILED DESCRIPTION

[0021] In order to make the objects, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort fall within the scope of protection of the present application.

[0022] Unless otherwise specifically indicated, all the various raw materials, reagents, instruments, and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0023] Figure 1A flowchart of a method for preparing copper ingots from scrap copper provided by an embodiment of the present application.

[0024] As shown in Figure 1 The present application provides a method for preparing copper ingots from scrap copper, which comprises the following steps: S1, sorting, crushing and drying the scrap copper raw material to obtain pretreated copper material; S2, feeding the pretreated copper material into a cored power frequency induction furnace and melting at a first set voltage; S3, after the pretreated copper material is completely melted, adding a slag cleaning agent to the melt, then adjusting the voltage to a second set voltage, and after the first holding, slagging; the slag cleaning agent is composed of sodium carbonate, boric anhydride, silicon dioxide, silicon carbide, cerium oxide and lithium fluoride; S4, adding a magnetic refining agent to the melt after slagging and stirring to adsorb impurity elements in the melt, and then holding and standing to recover the magnetic refining agent that floats to the surface of the melt; the magnetic refining agent comprises a magnetic core, a porous carrier layer coated on the surface of the magnetic core, and an active component loaded on the porous carrier layer, the active component comprises a metal oxide with Lewis acidity, a metal organic framework material with molecular sieve effect and an ionic liquid; S5, electromagnetic stirring and ultrasonic cooperative treatment are performed on the refined melt to deeply remove hydrogen and oxygen gas and uniformly distribute the components; S6, adding a slag collecting agent to the purified melt and stirring, slagging after the second holding, and casting into ingots; the slag collecting agent is composed of wollastonite, cryolite, calcium fluoride and sodium polyphosphate.

[0025] It should be noted that step S1 (pretreatment) is the basic guarantee link of the entire scrap copper refining process, which lays a foundation of high-quality raw materials for subsequent processes through combined operations of sorting, crushing and drying. Sorting can accurately remove metal impurities such as iron and stainless steel and non-metallic impurities such as plastic and rubber in scrap copper, greatly reducing the load of impurity treatment in the subsequent melting and refining process; crushing can process the scrap copper raw material into uniform-sized materials, avoiding the problem of uneven melting caused by size differences of raw materials and improving the melting efficiency; drying can completely remove the moisture in the raw material to prevent boiling and porosity caused by water entering the melt, while avoiding the risk of hydrogen embrittlement and ensuring the stability of the subsequent copper liquid.

[0026] Step S2 (melting) and step S3 (primary slag cleaning) together constitute the "foundation and primary purification" stage of the process, which is completed in the cored power frequency induction furnace to convert from solid waste copper to primary pure copper liquid. S2 provides heat to the furnace material by setting a high first voltage, accelerates the formation of a stable molten pool, shortens the melting period, and improves production efficiency; S3 is the first deep purification link, and the added composite slag cleaning agent has multiple functions. Sodium carbonate and boric anhydride can react with SnO2, ZnO and other oxides on the surface of the raw material and nascent slag to form a low-melting-point, high-flowing complex salt slag phase, which is easy to separate; silicon carbide can produce a "foaming" effect, slightly stirring the melt to promote the release of impurities wrapped in the copper liquid; cerium oxide can adsorb fine inclusions to further improve the purity of the copper liquid. Then, the voltage is adjusted to a second set value and kept constant to create a calm thermal environment for slag-copper separation, and most of the nascent slag is removed to clear the way for subsequent precise refining.

[0027] Step S4 (magnetic refining agent adsorption) is the technical core and innovation key of the entire method, which bears the dual functions of "deep refining and cost reduction". The designed core-shell structure magnetic refining agent belongs to "intelligent purification material", and the porous carrier layer (γ-alumina and mesoporous silica composite) provides a large specific surface area for impurity adsorption. The loaded active components form a synergistic effect, the Lewis acid cerium oxide adsorbs alkaline impurities through coordination, the ZIF-8 with molecular sieve effect traps small molecular impurities through confinement effect, and the quaternary phosphonium salt ionic liquid chelates heavy metal impurities through physical dissolution, which can efficiently remove trace amounts of toxic impurities such as As, Pb, Sb that are difficult to handle in traditional processes. At the same time, the magnetic core (ferric oxide) of the refining agent enables it to be quickly recovered by magnetic separation after reaction, realizing the transformation from "consumable material" to "recyclable asset", significantly reducing raw material cost and solid waste generation.

[0028] Step S5 (physical field synergistic treatment) is the "deep purification and performance improvement" stage of the process, which extends the purification dimension from the chemical level to the physical performance regulation. Electromagnetic stirring promotes the composition and temperature of the copper liquid to be highly uniform by generating macroscopic melt flow, and promotes the floating and removal of residual inclusions; ultrasonic treatment uses cavitation effect and acoustic streaming effect to not only break up small impurity clusters in the melt, but also deeply remove dissolved [H] and [O] gas to avoid air hole defects in copper ingots, and can also refine grains, directly improving the electrical conductivity, mechanical properties and density of subsequent copper ingots, providing key support for the final product quality.

[0029] Step S6 (final slag adjustment and ingot casting) is the final link of the process and provides the last guarantee for obtaining high-quality copper ingots. The added slag collector can capture the last traces of residual impurities that were not completely removed in the previous steps and the tiny particles that floated during the physical field treatment. Cryolite and calcium fluoride can reduce the melting point and viscosity of the slag and improve its fluidity. Sodium polyphosphate can form a network structure to "lock" impurities and prevent them from falling back, ultimately forming a dry slag shell that is easy to remove. Subsequently, the ingot is cast at a precisely controlled temperature to ensure that the copper ingot has excellent surface quality and internal organization and to avoid defects such as coarse grains and shrinkage holes caused by improper temperature.

[0030] At the same time, the advantages of the waste copper refining method are not a single-step technological breakthrough, but a multi-level and multi-dimensional synergy system formed by each step, which builds an efficient, economical, and environmentally friendly purification system.

[0031] From the perspective of "source reduction and depth of the back end", the pretreatment in step S1 lays the efficiency foundation for all subsequent refining steps. If a large amount of impurities is not removed through S1, these impurities will consume more slag cleaner in S2 and S3, increasing the energy consumption and time of the melting process, and will occupy the active sites of the magnetic refining agent in S4, leading to a decrease in the removal efficiency of trace impurities and a sharp increase in costs. S1 controls impurities at the source, allowing S4's precise adsorption and S5's deep purification to focus on solving key impurity problems, significantly improving the efficiency and economy of the back-end process.

[0032] From the perspective of "chemical purification and physical purification", the chemical purification of S3 and S4 and the physical purification of S5 form a complement. The preliminary slag cleaning of S3 and the magnetic adsorption of S4 remove most of the impurities through chemical reactions (slag making, coordination, and chelation), creating a "clean" melt environment for the physical field treatment of S5 and reducing the load of physical treatment. The electromagnetic-ultrasonic cooperative treatment of S5 can solve the problems of gas impurities and microscopic segregation that are difficult to handle by chemical methods, while optimizing the microstructure of the copper ingot. The combination of the two achieves the dual goals of "complete removal of impurities + comprehensive performance improvement", avoiding the limitations of a single purification method.

[0033] From the perspective of "refining agent recycling and process closed loop", S4 itself forms a closed loop of "use-recycle-regenerate" and interacts with other steps. The recycling and regeneration of the magnetic refining agent in S4 depend on the relatively pure melt environment after the preliminary slag cleaning in S3. If there is a large amount of coarse slag in the melt, it will interfere with the efficiency of magnetic separation and recovery. The recycled refining agent is reused in S4, reducing the burden of the slag collector in S6 and avoiding the increase in final slag treatment pressure caused by the presence of residual refining agent. This forms a double closed loop of material recycling and process flow, taking into account both economic benefits and environmental value.

[0034] From the perspective of "staged and multi-mechanism impurity removal", each step builds three purification lines to achieve the step-by-step and classified removal of impurities. The preliminary slag cleaning of S3 as a "rough cleaning" link targets a large number of common oxides and primary slag; the magnetic adsorption of S4 as a "precision strike" link focuses on specific micro-trace toxic impurities; the final slag adjustment of S6 as a "quality gatekeeper" handles trace residual impurities, forming a "from rough to fine, from more to less" impurity removal gradient, avoiding the problem of overburdening a single step and limited effect, and ensuring that each step can maximize its effectiveness to ultimately achieve dual protection of copper ingot purity and performance.

[0035] In some embodiments, in step S3, the mass of the slag cleaning agent added is 0.05-0.15% of the total mass of the melt; The content of each component in the slag cleaning agent is, by mass fraction: sodium carbonate 35-45%, boric anhydride 15-25%, silicon dioxide 8-12%, silicon carbide 12-18%, cerium oxide 3-6%, and lithium fluoride 5-10%.

[0036] The mass of the slag cleaning agent added (0.05-0.15% of the total mass of the melt): this amount can ensure that the slag cleaning agent reacts with the oxides and impurities in the melt to effectively remove common impurities such as SnO2 and ZnO, while avoiding excessive use that would increase the loss of copper liquid entrainment and increase the burden of subsequent slag removal, balancing the effects of slag removal and production economy.

[0037] The content of each component in the slag cleaning agent: sodium carbonate (35-45%) as the core fluxing agent can react with acidic oxides in the melt to form a low-melting-point complex slag phase; boric anhydride (15-25%) assists in reducing the melting point of the slag and improving the flowability of the slag; silicon dioxide (8-12%) precisely adjusts the viscosity of the slag to avoid affecting separation due to excessive thinning or thickening of the slag; silicon carbide (12-18%) can produce a mild "foaming" effect, slightly stirring the melt to release the encapsulated impurities; cerium oxide (3-6%) can adsorb fine inclusions, further improving the purity of the melt; and lithium fluoride (5-10%) cooperatively improves the flowability of the slag to ensure rapid separation of the slag and copper.

[0038] In the preliminary slag cleaning step of scrap copper refining, the core function of this composite slag cleaning agent is to react with oxide impurities (such as SnO2, ZnO, Cu2O) and primary slag in the melt to form a low-melting-point, high-flowability slag phase, while assisting in the release of fine impurities encapsulated in the copper liquid, creating a clean melt environment for subsequent deep purification. Through precise division of labor and close cooperation, each component of the composite slag cleaning agent works together to achieve the goal of efficient slag removal.

[0039] From the individual action of each component, sodium carbonate as the core fluxing agent of deslagging agent, with a high proportion of 35-45%, can quickly react with the acidic oxides in the melt to generate soluble double salts (such as Na2SnO3, Na2ZnO3), which fundamentally destroys the stable structure of oxide impurities, and lays the foundation for subsequent slag separation; boron trioxide (15-25%) acts as an auxiliary fluxing agent, which can further reduce the melting point of the slag, avoid the problem of high melting point and insufficient fluidity of the slag under the action of single sodium carbonate, and form stable borate with aluminum, calcium and other impurities in the copper liquid, expanding the range of impurity removal; the core role of silicon dioxide (8-12%) is to adjust the viscosity of the slag, and its content is accurately controlled in the range that can avoid the loss of copper liquid caused by too dilute slag, and prevent the slag from being too thick to separate, ensuring clear slag-copper interface; silicon carbide (12-18%) will slowly release gas and produce a "foaming" effect at high temperature, this mild stirring effect can break the oxide film on the surface of the copper liquid, release the fine impurity particles wrapped inside the melt, and make the impurities more fully contact with the deslagging agent; cerium oxide (3-6%) as a rare earth element oxide, with its high specific surface area and strong adsorption, can capture fine inclusions (such as micron-sized Fe3O4 particles) in the melt, making up for the deficiency of traditional fluxing agents in removing small impurities; lithium fluoride (5-10%) can react with alkaline earth metal impurities such as calcium and magnesium in the slag to form low-melting-point fluorides, and further improve the fluidity of the slag, ensuring that the formed slag phase can quickly float to the surface of the melt.

[0040] The synergistic effect between the components is the key to efficient deslagging: first, sodium carbonate, boron trioxide and lithium fluoride form a "main- auxiliary-supplementary" fluxing system, sodium carbonate dominates the reaction with acidic oxides, boron trioxide assists in reducing the melting point, and lithium fluoride supplements the removal of alkaline earth metal impurities, the three together reduce the melting point of the slag below the copper liquid refining temperature (1150-1200℃), and the fluidity is improved by more than 30%, creating the necessary conditions for slag separation; second, the foaming effect of silicon carbide and the fluidity optimization of the fluxing agent form a dynamic cooperation, the small bubbles produced by foaming drive the melt to flow slightly, allowing the fluxing agent to spread more evenly throughout the melt, avoiding the problem of local impurities remaining without contacting the deslagging agent, and the flowing slag can also more efficiently wrap the impurity particles released by silicon carbide; finally, the viscosity adjustment of silicon dioxide and the fine adsorption of cerium oxide form a synergistic effect of "macroscopic regulation + microscopic capture", silicon dioxide ensures that the slag has good overall floating performance, and cerium oxide simultaneously adsorbs fine impurities during the formation of the slag, the combination of the two not only ensures the smooth separation of the slag, but also achieves the comprehensive removal of macroscopic oxides and microscopic inclusions, ultimately forming a dry slag phase with uniform composition and easy to remove, which clears the obstacles for subsequent deep purification of magnetic refining agent.

[0041] In some embodiments, in step S4, the magnetic refining agent is added in an amount of 0.1-0.65% of the total mass of the melt. The magnetic core is ferroferric oxide. The porous carrier layer is a composite of γ-alumina and mesoporous silica. The metal oxide with Lewis acidity is nano cerium oxide, the metal organic framework material with molecular sieve effect is ZIF-8, and the ionic liquid is a quaternary phosphonium salt ionic liquid.

[0042] In some embodiments, in step S4, the preparation method of the magnetic refining agent comprises the following steps: S4a, synthesizing a ferroferric oxide magnetic core by co-precipitation; S4b, dispersing the magnetic core in a solution containing an aluminum source and a silicon source, hydrolyzing, aging, drying, and then calcining at 400-500°C for 1-3h to form the porous carrier layer; S4c, loading nano cerium oxide on the porous carrier layer by an equal-volume impregnation method, and then calcining at 450-550°C for 2-4h to form cerium oxide active sites; S4d, loading ZIF-8 on the porous carrier layer by in-situ growth; S4e, loading a quaternary phosphonium salt ionic liquid into the pores of the porous carrier layer by a vacuum impregnation method; The vacuum impregnation method comprises the following parameters: vacuum degree of -0.05 to -0.08 MPa, impregnation temperature of 60-80°C, and impregnation time of 1-2h.

[0043] In some embodiments, in step S4, the particle size of the magnetic refining agent is 100-200nm, the thickness of the porous carrier layer is 50-100nm, the specific surface area is 200-500m 2 / g, and the mesopore volume with a pore size distribution of 2-50nm accounts for more than 60% of the total pore volume.

[0044] The addition amount of the magnetic refining agent (0.1-0.65% of the total mass of the melt): this amount can make the refining agent uniformly dispersed in the melt, and the active components can fully contact and adsorb trace impurities, ensuring the removal rate of impurities and avoiding excessive use of the refining agent, which leads to agglomeration of the refining agent and increased recovery difficulty.

[0045] Structure and composition of the magnetic refining agent: the magnetic core is ferroferric oxide, which can be quickly recovered by magnetic separation to realize recycling; the porous carrier layer (a composite of γ-alumina and mesoporous silica) can provide stable support, and its particle size of 100-200nm can ensure uniform dispersion in the melt without sedimentation, and the carrier layer thickness of 50-100nm and the specific surface area of 200-500m 2The specific surface area of 400-600 m2 / g and the mesopore ratio (2-50 nm pore size) of more than 60% can efficiently load active components and provide sufficient sites for impurity adsorption; in the active components, nano cerium oxide can coordinate and adsorb alkaline impurities through Lewis acid sites, ZIF-8 can intercept small molecular impurities through molecular sieve confinement effect, and quaternary phosphonium salt ionic liquid can chelate heavy metal impurities through physical dissolution, so that the three components can realize the targeted removal of multiple types of impurities.

[0046] The magnetic refining agent preparation parameters: the porous carrier layer with stable structure can be formed by calcining at 400-500℃ for 1-3h in S4b; the nano cerium oxide can form active sites by calcining at 450-550℃ for 2-4h in S4c, so as to improve the adsorption capacity; the ionic liquid can be fully injected into the carrier channel by vacuum impregnation at a vacuum degree of-0.05 to-0.08 MPa, a temperature of 60-80℃ and a time of 1-2h in S4e, so as to avoid the influence of air residue on the adsorption effect.

[0047] In some embodiments, in step S4, the recovered magnetic refining agent is regenerated by thermal desorption in an oxidizing atmosphere at a temperature of 400-600℃, and then is returned to step S4 for recycling.

[0048] The refining agent regeneration temperature (400-600℃, oxidizing atmosphere): this temperature can effectively desorb the impurities adsorbed by the refining agent, without damaging the structure of the magnetic core and the porous carrier layer, so that the refining agent can be recycled in step S4, thereby reducing the raw material cost and the amount of solid waste.

[0049] The magnetic refining agent is a core functional material for deep purification of waste copper refining, which can target adsorb trace impurities (such as highly toxic heavy metals like As, Pb and Sb, and small molecular inclusions) that are difficult to be removed by traditional slag removers, and can be recycled and used efficiently due to the magnetic property, so as to improve the purity of copper liquid and reduce the cost of consumables and the amount of solid waste. The components (magnetic core, porous carrier layer and active component) of the magnetic refining agent do not work independently, but work in a hierarchical cooperation mode of "structural support-function loading-targeted adsorption-recycling", so as to realize the dual advantages of "efficient adsorption and economic environmental protection".

[0050] From the individual functions of the components, the magnetite as the magnetic core not only provides a stable structural framework for the whole refining agent, but more importantly, it endows the material with strong magnetism, so that the refining agent after adsorbing impurities can be quickly separated from the surface of the copper liquid by an external magnetic separation device after the melt is kept and rested, thereby avoiding the influence of the residual refining agent on the electrical conductivity and mechanical properties of the copper ingot, and laying a foundation for subsequent regeneration and recycling; the porous carrier layer composed of γ-alumina and mesoporous silica has a specific surface area of 400-600 m2 / g and a mesopore ratio (2-50 nm pore size) of more than 60%, so as to efficiently load active components and provide sufficient sites for impurity adsorption; in the active components, nano cerium oxide can coordinate and adsorb alkaline impurities through Lewis acid sites, ZIF-8 can intercept small molecular impurities through molecular sieve confinement effect, and quaternary phosphonium salt ionic liquid can chelate heavy metal impurities through physical dissolution, so that the three components can realize the targeted removal of multiple types of impurities. 2high specific surface area, on the one hand, can provide sufficient loading sites for active components, ensuring uniform dispersion of nanometer cerium oxide, ZIF-8 and quaternary phosphonium salt ionic liquid, and on the other hand, its porous channels can guide micro-amount of impurities and active components to fully contact, avoiding impurities from being adsorbed due to diffusion obstruction; the active components form a "multi-mechanism targeted adsorption" system: nanometer cerium oxide as a Lewis acidic metal oxide can precisely adsorb basic impurities (such as Sb2O3, PbO) in the melt through acid site coordination, forming a stable metal oxide complex; ZIF-8 (metal organic framework material) relies on its regular pore structure and molecular sieve effect to intercept small molecular impurities (such as AsH3 decomposition products) to prevent them from redissolving in the copper liquid; quaternary phosphonium salt ionic liquid forms a chelate with heavy metal ions (such as Pb 2+ 、As 3+ ) through the cationic groups in its molecular structure, further strengthening the capture ability of toxic impurities.

[0051] The synergistic effect between the components is the key to realizing "high efficiency + recycling" purification: first, the porous carrier layer and the active components form a "loading-adsorption" synergy, the high specific surface area of the carrier ensures that the active components are dispersed at the nanometer scale, avoiding the waste of adsorption sites caused by agglomeration, and the multi-mechanism adsorption of the active components fully utilizes the porous channels of the carrier to achieve full coverage capture of different types and sizes of impurities, solving the defect of "narrow targeting" of single active component; secondly, the magnetic core, the carrier and the active components form a "recycling-function" synergy, the strong magnetism of the magnetic core ensures that the refining agent after adsorbing impurities can be quickly separated, and the high temperature stability of the carrier (not decomposed at 400-600℃ regeneration temperature) and the detachable characteristics of the active components (impurities and active components are separated at high temperature), let the refining agent regenerated by thermal desorption can be loaded with active components for recycling, which not only reduces the consumption cost of active components, but also reduces solid waste emissions; in addition, the "complementary adsorption" synergy (coordination adsorption of cerium oxide, molecular sieve interception of ZIF-8, chelation of ionic liquid) inside the active components can form a complete chain of "impurity capture-fixation-interception", avoiding the residual of some impurities due to single mechanism, finally realizing the removal rate of micro-amount of impurities to be improved to more than 95%, and the refining agent can be recycled for 3-5 times while still maintaining stable adsorption performance.

[0052] The magnetic refining agent can stably exist at the refining temperature (1100-1200 °C), which is attributed to the design of "core-shell structure + component matching": the melting point of the ferroferric oxide magnetic core is much higher than the refining temperature, and the outer layer of the γ-alumina / mesoporous silica porous carrier layer (both of which have a melting point of more than 1600 °C) can isolate the high-temperature copper liquid and slow down the sintering and oxidation of the magnetic core; among the active components, nano cerium oxide is resistant to high temperature and has stable adsorption activity, ZIF-8 can be in-situ converted into a substance with adsorption function although it is easy to decompose, and ionic liquid can play a "sacrificial" purification role in the early stage of refining although it is easy to volatilize and does not rely on long-term stability, and the overall key structural components can maintain short-time high-temperature stability.

[0053] The rationality of its recycling is based on "magnetic recovery + scientific regeneration": when the magnetic core is not damaged, the saturation magnetization of 45 emu / g can support efficient recovery by magnetic separation; the regeneration adopts oxidative thermal desorption at 400-600 °C, which is sufficient to remove impurities such as As2O3 and PbO, and is much lower than the refining temperature, avoiding damage to the structure of the refining agent; and the adsorption efficiency remains at 85%-92% after 3-5 cycles, and the performance degradation (such as slow oxidation of the magnetic core and slight blockage of the carrier pores) is reasonable and controllable, which meets the industrial practical scenarios.

[0054] In some embodiments, in step S2, the first set voltage is 450-500 V; In step S3, the second set voltage is 200-220 V.

[0055] The core of step S2 is to convert the pretreated copper material into a uniform melt, and the key parameter is the first set voltage of 450-500 V. This voltage range is highly matched with the power output characteristics of the core induction furnace, which can quickly provide sufficient heat for the materials in the furnace, while ensuring energy economy, accelerating the melting of waste copper raw materials to form a continuous melt pool, avoiding excessive heating and oxidation of local raw materials due to too low voltage, or energy waste caused by too high voltage, to provide an initial melt with uniform composition for the subsequent slag cleaning and refining processes.

[0056] The second set voltage (200-220 V): this voltage can maintain the stability of the furnace temperature without continuous heating, avoiding the loss of control of volatile impurities such as Zn and Cd due to high temperature, creating a calm thermal environment for slag-copper separation, and reducing energy consumption.

[0057] In some embodiments, in step S5, the electromagnetic stirring and ultrasonic wave cooperative treatment includes the following parameters: the electromagnetic stirring frequency is 20-30 Hz, the ultrasonic wave power is 1-5 kW, the ultrasonic wave frequency is 18-25 kHz, and the cooperative treatment time is 10-15 min.

[0058] Electromagnetic stirring frequency (20-30 Hz): This frequency can produce a gentle and continuous melt flow, which not only ensures the uniformity of copper liquid composition and temperature, avoids local composition segregation, but also promotes the floating of residual inclusions without causing melt splashing or excessive disturbance.

[0059] Ultrasonic parameters (power 1-5 kW, frequency 18-25 kHz): This power and frequency combination can produce significant cavitation effect and acoustic streaming effect, effectively break up small impurity clusters in the melt, and further remove dissolved [H] and [O] gas to avoid porosity defects in copper ingots; at the same time, ultrasonic vibration can refine grains, laying a foundation for subsequent improvement of copper ingot mechanical properties.

[0060] Synergistic treatment time (10-15 min): sufficient to complete the process of gas removal, composition uniformity and grain refinement, which not only ensures the treatment effect, but also does not prolong the production cycle, and takes into account efficiency and performance.

[0061] In some embodiments, in step S3, the temperature of the first holding is 1150-1200℃, and the holding time is 10-20 min; In step S4, the temperature of the holding and standing is 1150-1180℃, and the holding time is 5-15 min; In step S6, the temperature of the second holding is 1100-1150℃, and the holding time is 15-30 min; In step S6, the temperature of the casting into ingots is 1080-1120℃.

[0062] First holding (1150-1200℃, 10-20 min): The temperature is higher than the melting point of copper (1083℃), which ensures good fluidity of the melt, facilitating the floating of slag; 10-20 min of holding time is sufficient for slag and copper to fully separate, ensuring that most of the primary slag can be completely removed during slag removal, reducing impurity interference for subsequent precise refining.

[0063] Holding and standing (1150-1180℃, 5-15 min): The temperature is consistent with S3, maintaining the fluidity of the melt to ensure that the refining agent and impurities react sufficiently; 5-15 min is sufficient for the refining agent to float to the surface of the melt after adsorbing impurities, facilitating subsequent magnetic separation and recovery.

[0064] Second holding (1100-1150℃, 15-30 min): The temperature maintains the fluidity of the melt, and 15-30 min is sufficient for the slag collector to fully react with trace impurities and form a stable slag body, facilitating complete removal, and stabilizing the melt temperature for subsequent casting.

[0065] Pouring temperature (1080-1120℃): The temperature is slightly higher than the melting point of copper, which can ensure good fluidity of the melt, avoid defects such as insufficient pouring and cold separation during pouring, avoid the coarse grains of the ingot caused by too high temperature, and ensure the excellent surface quality and internal organization of the copper ingot.

[0066] In some embodiments, in step S6, the mass of the slag collector added is 0.15-0.3% of the total mass of the melt. The content of each component in the slag collector is, in mass fraction: 25-35% of wollastonite, 30-40% of cryolite, 20-30% of calcium fluoride, and 5-10% of sodium polyphosphate.

[0067] The mass of the slag collector (0.15-0.3% of the total mass of the melt): This amount can fully collect the trace amount of residual impurities and small particles that are not completely removed in the previous process, forming a slag body that is easy to remove, and avoiding the influence of residual impurities on the purity of the copper ingot.

[0068] The component content of the slag collector: wollastonite (25-35%) can adjust the structure of the slag body and enhance the wrapping capacity of the slag for impurities; cryolite (30-40%) and calcium fluoride (20-30%) cooperatively reduce the melting point and viscosity of the slag, improve the fluidity of the slag, and ensure that the impurities fully enter the slag body; sodium polyphosphate (5-10%) can form a network structure to "lock" the impurities and prevent them from falling back to the melt, ensuring the effect of the last impurity removal.

[0069] In the final impurity removal process of scrap copper refining, the core function of the composite slag collector is to efficiently collect and fix the trace amount of residual impurities (such as micron-sized metal oxide particles and trace amount of impurities that are not adsorbed) that are not completely removed in the previous process (preliminary slag removal and magnetic refining), forming a dry slag body with good fluidity and easy separation from the copper liquid, avoiding the influence of residual impurities on the purity of the copper ingot, and ensuring that the impurities do not fall back to the melt during the slag removal process, providing protection for the final casting of high-quality copper ingot. The components form a closely coordinated impurity removal system through the functional division of "fluxing-structure adjustment-impurity locking", and together achieve the final purification goal.

[0070] From the individual action of each component, cryolite (30-40%) is the core fluxing component of the slag collector, with its low melting point (about 1011 ℃) characteristics, it can quickly reduce the overall melting point of the slag, keep it good fluidity at the copper liquid refining temperature (1100-1150 ℃), ensure that the slag can fully contact and wrap the dispersed trace impurities, avoid the impurities from escaping due to the solidification or viscosity of the slag; calcium fluoride (20-30%) as an auxiliary flux, on the one hand, it can further reduce the melting point of the slag with cryolite, make up for the insufficient effect of single cryolite on high melting point impurities (such as CaO, MgO), on the other hand, it can adjust the surface tension of the slag, enhance the adsorption capacity of the slag to impurity particles, so that the small impurities are more easily captured by the slag; the core role of wollastonite (25-35%) is to regulate the structure and viscosity of the slag, its main component calcium silicate (CaSiO3) can combine with the low melting point melt formed by cryolite and calcium fluoride, control the viscosity of the slag in the appropriate range of "easy flow and not entraining copper liquid", avoid the loss of copper liquid with slag due to too dilute slag, and prevent the slag from being too thick to be removed, at the same time, the layered structure of wollastonite can enhance the wrapping stability of the slag to impurities; sodium polyphosphate (5-10%) is the key component of "locking impurities", its chain molecular structure can remain stable at high temperature, it can be inserted into the interior of the slag, firmly wrap and fix the small impurity particles that have been adsorbed, prevent the impurities from falling back into the copper liquid during the slag removal process, and ensure the thoroughness of the final impurity removal.

[0071] The synergistic effect between the components is the core of realizing "high-efficiency slag collection and stable impurity locking": first, cryolite and calcium fluoride form a "main- auxiliary" fluxing synergistic system, cryolite dominates the reduction of the basic melting point of the slag, calcium fluoride supplements the fluxing ability for high melting point impurities, and the two together stably control the melting point of the slag at 1000-1050 ℃, which is much lower than the copper liquid refining temperature, creating the premise for the full contact between the slag and impurities; second, wollastonite and fluxing components form a "structure-flowability" synergy, fluxing components ensure the low melting point and high flow of the slag, and wollastonite adjusts the viscosity and structure to make the flowing slag not only cover the surface of the melt to capture impurities, but also form a complete and not easily broken slag shell, avoiding the entrainment of copper liquid and the escape of impurities; finally, sodium polyphosphate and the overall slag form a "impurity locking-stability" synergy, the chain structure of sodium polyphosphate relies on the stable framework of the slag to realize the "targeted fixation" of impurities, and the good fluidity and appropriate viscosity of the slag provide space for the uniform dispersion and full wrapping of sodium polyphosphate, the combination of the two eliminates the problem of "collecting but not locking". It is through this multi-dimensional synergy that the slag collector can improve the removal rate of residual impurities in the melt to more than 98%, and the final slag has good dryness and is easy to separate, providing a solid guarantee for the purity of copper ingot (copper content ≥ 99.99%).

[0072] In summary, the method for preparing copper ingot from waste copper according to the present application has the core advantage of constructing a complete process system with systematic optimization, innovative materials, deep purification, and economic and environmental protection. It is not a single technical breakthrough, but a full-process collaborative upgrade from raw material processing to finished product casting, which can effectively solve the problems of incomplete impurity removal, high material cost, high energy consumption, high environmental pressure, and unstable product quality in traditional waste copper refining.

[0073] From the systematization of process design, the method takes the purification logic of "stages and multiple dimensions" as the core, forming a complete impurity control chain from the source to the end. The pretreatment link eliminates a large number of non-copper impurities from the source, reducing the load for subsequent refining and avoiding the consumption of more consumables or occupying adsorption sites. The preliminary slag removal realizes "rough cleaning" of common oxides and primary slag, and the deep adsorption targets "precise attack" on trace toxic impurities. The final slag gathering completes the "last interception" of trace residual impurities. The three-stage purification gradient cooperates to avoid excessive burden on a single step and ensure the comprehensiveness of impurity removal. At the same time, chemical purification (slag removal and adsorption) and physical purification (electromagnetic-ultrasonic cooperation) form a complement. Chemical methods solve most impurity problems, and physical field treatment tackles problems such as gas residues, composition segregation, and coarse grains that are difficult to handle by chemical methods, improving copper liquid quality from two dimensions of "composition purity" and "performance optimization".

[0074] In terms of core material innovation, the design of magnetic refining agent breaks the limitations of traditional refining agents "consumption and difficult to recover". The core-shell structure gives it the dual ability of "targeted adsorption + magnetic recovery", the porous carrier ensures uniform dispersion of active components and sufficient contact with impurities, and multiple types of active components capture complex impurities through different mechanisms. The magnetic core realizes efficient separation and regeneration of the refining agent, reducing the cost pressure caused by consumable consumption and reducing the amount of solid waste, so that "efficient purification" and "economic and environmental protection" are no longer contradictory. In addition, the component matching of composite slag removal agent and slag gathering agent is also very targeted. The slag removal agent realizes the integration of fluxing, viscosity adjustment, and fine impurity adsorption through multi-component cooperation, and the slag gathering agent focuses on the dual functions of "impurity gathering-locking", avoiding the return of impurities during slagging, and further ensuring the purification effect.

[0075] From the practicality and economy of industrial application, the method fully considers production efficiency and cost control: high-voltage rapid pool formation in the melting stage and low-voltage holding in the slag removal stage cooperate to improve melting efficiency while avoiding energy waste; the design of crushing and drying in pretreatment not only accelerates melting uniformity but also avoids process risks caused by water, reducing the cost of subsequent rework due to defects; the recycling and regeneration of magnetic refining agent, and the reduction of consumable consumption in pretreatment, improve the industrial application value from the aspects of "cost reduction" and "efficiency improvement", and meet the economic needs of large-scale production.

[0076] In terms of environmental protection and product quality, this method also has significant advantages: the circulation of refining agent reduces solid waste emissions, pretreatment drying and precise temperature control reduce the impurity content in flue gas, and the method of regenerating refining agent in an oxidizing atmosphere is green and pollution-free, which meets the current environmental protection requirements; and the precise parameter control in the whole process (such as casting temperature, holding time, stirring frequency) ensures that the final copper ingot not only has high purity, but also has excellent density, electrical conductivity and mechanical properties, reduces defects such as porosity, shrinkage and coarse grains, and meets the needs of downstream precision machining, wire and cable and other high-quality copper materials, thereby improving the market competitiveness of the product.

[0077] The present application will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application. The experimental methods in the following examples are not specified, which are generally determined according to the industry standards. If there is no corresponding industry standard, it is determined according to the general international standard, the conventional condition, or according to the condition suggested by the manufacturer.

[0078] Example 1 In this example, low-grade waste copper raw materials (mainly from waste cables and scrap electronic component disassembly materials) are selected, and the initial chemical composition of the waste copper is as follows: Cu: 92.3%, Zn: 2.1%, Sn: 1.8%, Pb: 1.5%, As: 0.35%, Sb: 0.25%, Fe: 1.2%, Ni: 0.4%, and other impurities (such as trace dust and oxide scale): 0.1%.

[0079] The present application provides a method for preparing copper ingot from waste copper, which comprises the following steps: S11, the waste copper raw material is crushed to a particle size of ≤30mm by a hydraulic shearing machine to avoid large pieces of raw materials wrapping impurities and ensure uniform melting in the subsequent process; first, a vortex separator (sorting frequency 50Hz) is used to remove aluminum, plastic and other non-ferromagnetic impurities in the raw material, and then a high-strength magnetic separator (magnetic field strength 1.5T) is used to separate iron and its alloy impurities, thereby reducing the subsequent refining impurity treatment load; the sorted waste copper raw material is placed in a drum dryer and dried at 105°C for 1.5h to reduce the water content of the raw material to below 0.3%, thereby avoiding water entering the melt to cause boiling and generate pores; S21, 800kg of pretreated waste copper material is taken and sent into a 10-ton core power frequency induction furnace, the furnace voltage is set to 480V (first set voltage), and the induction heating system is started. The Joule heat generated by electromagnetic induction gradually heats the waste copper to a molten state, and after the raw material is completely melted into a uniform copper melt, the temperature is stopped and the initial stable state of the melt is maintained; S31, add 1.2 kg of deslagging agent (the mass of the deslagging agent accounts for 0.15% of the total mass of the melt) to the above-mentioned copper melt, the deslagging agent is composed of: sodium carbonate 40%, boric anhydride 20%, silicon dioxide 10%, silicon carbide 15%, cerium oxide 5%, lithium fluoride 10% by mass fraction. After adding the deslagging agent, stir at a speed of 40 r / min for 5 min to ensure that the deslagging agent is fully mixed with the melt; then adjust the furnace voltage to 210 V (second set voltage), control the melt temperature to be stable at 1180℃, and keep it for 15 min (first holding time). During this process, sodium carbonate, boric anhydride and lithium fluoride play a synergistic fluxing effect, react with ZnO, FeO and other oxides in the melt to form low-melting point complex salt slag phase, silicon carbide produces a mild "foaming" effect to stir the melt to release the wrapped impurities, and cerium oxide adsorbs fine inclusions; after the holding is completed, the surface scum is completely removed with a graphite skimmer, and a preliminarily purified copper melt is obtained; S41, add 3.2 kg of the above-mentioned prepared magnetic refining agent (the mass of the refining agent accounts for 0.4% of the total mass of the melt) to the copper melt after skimming in step S31, stir at a speed of 35 r / min for 8 min to make the refining agent uniformly dispersed in the melt, and through the synergistic effect of the active components (nano cerium oxide, ZIF-8, quaternary phosphonium salt ionic liquid), target adsorption of trace impurities such as As, Pb, Sb in the melt; after stirring is completed, control the melt temperature to be 1160℃, and keep it for 10 min; after the adsorbed impurities are adsorbed, the refining agent is floated to the surface of the melt under the action of its own magnetism, and the refining agent is recovered with a magnetic stainless steel skimmer; the recovered refining agent is regenerated (removes the adsorbed impurities) by thermal desorption in an oxidizing atmosphere at 500℃, and can be returned to this step for recycling use. The recycled refining agent in this batch is recycled for 3 times in the subsequent experiment, and still maintains an adsorption efficiency of 90%; The preparation steps of the magnetic refining agent are as follows: S41a, using the coprecipitation method, weigh 5.2 g of FeCl3·6H2O and 2.0 g of FeCl2·4H2O, dissolve them in 100 mL of deionized water to form a mixed salt solution; under a nitrogen protective atmosphere, heat the mixed solution to 80℃, keep the stirring speed at 500 rpm, slowly add 25% ammonia water solution by mass fraction, and adjust the pH value of the solution to 10.5; continue to stir for 60 min, then separate the generated magnetite particles by an external magnetic field, wash them repeatedly with deionized water until the washing liquid is neutral, and finally dry them in a 60℃ vacuum drying oven for 12 h to obtain magnetite magnetic cores with a particle size of 150±10 nm; S41b, 1 g of the magnetic core was dispersed in 200 mL of anhydrous ethanol and uniformly dispersed by ultrasonic treatment for 30 min; 0.8 g of aluminum isopropoxide and 2.0 g of tetraethyl orthosilicate were added to the dispersion, and stirred at room temperature for 30 min until mixed uniformly; 50 mL of an ethanol solution containing 0.5 mL of 0.1 mol / L hydrochloric acid was slowly added, and hydrolysis was carried out at 40°C for 12 h to form a sol; then the temperature was raised to 60°C for aging for 6 h, and dried at 100°C for 8 h to remove the solvent, and finally placed in a muffle furnace and calcined at 450°C for 2 h to obtain a γ-alumina / mesoporous silica composite carrier layer with a coating thickness of 80±5 nm; S41c, a 0.2 mol / L cerium nitrate solution was prepared, and the above carrier material was completely immersed in the cerium nitrate solution by an equal volume immersion method, and then placed at room temperature for 12 h, dried at 100°C for 6 h, and finally calcined in air at 500°C for 3 h to convert the cerium nitrate into nano cerium oxide, and the cerium oxide loading was 8 wt%; S41d, the cerium oxide-loaded carrier material was dispersed in 50 mL of methanol, 0.68 g of 2-methylimidazole (CAS No. 693-98-1) was added, and stirred for 30 min; 25 mL of a methanol solution containing 0.30 g of Zn(NO3)2·6H2O was slowly added, and reacted at room temperature for 24 h; after the reaction was completed, the product was collected by centrifugation, washed with methanol for 3 times to remove the unreacted raw materials, and dried at 60°C under vacuum for 12 h; S41e, the quaternary phosphonium ionic liquid ([P 66614 ]Cl, trishexyl-tetrakisdecyl phosphonium chloride, molecular formula C 26 H 58 PCl, four alkyl chains are connected to the phosphorus atom center) was dissolved in ethanol to prepare a 0.1 mol / L ionic liquid ethanol solution; the above carrier material was immersed in the solution by vacuum immersion method under the conditions of vacuum degree-0.06 MPa and temperature 70°C for 1.5 h; after taking out, dried at 100°C for 6 h to remove the ethanol solvent, and the ionic liquid loading was 5 wt%; The main properties of the prepared magnetic refining agent are as follows: core particle size 150±10 nm, carrier layer thickness 80±5 nm, specific surface area 350±15 m 2 / g, pore size distribution of mesoporous volume ratio 70±3% in the range of 2-50 nm, saturation magnetization 45 emu / g, and pore volume 0.35 cm 3 / g. Figure 2 The SEM image of the magnetic refining agent provided in Example 1 of the present application is shown. As Figure 2 shown, the magnetic refining agent particles have a certain agglomeration phenomenon, but the particle surface is loose and porous, has a large internal and external specific surface area, and the protruding part of the particle surface is in a relatively regular spherical shape.

[0080] S51, electromagnetic stirring and ultrasonic treatment of the copper melt after deep adsorption in step S41: set the electromagnetic stirring frequency to 25 Hz, generate macroscopic melt flow through the electromagnetic coil at the bottom of the furnace to ensure uniformity of the melt composition and temperature; at the same time, start the ultrasonic device, set the ultrasonic power to 3 kW and the ultrasonic frequency to 20 kHz, and perform collaborative treatment for 12 min; use the cavitation effect of ultrasonic waves to break up small impurity clusters remaining in the melt and deeply remove dissolved hydrogen and oxygen gas to avoid the occurrence of pores and porosity defects in the subsequent copper ingot; S61, add 2.0 kg of slag aggregation agent (the mass of the slag aggregation agent accounts for 0.25% of the total mass of the melt) to the copper melt after purification in step S51, and the slag aggregation agent has a composition comprising, by mass fraction: 30% of wollastonite, 35% of cryolite, 25% of calcium fluoride, and 10% of sodium polyphosphate. Stir for 3 min after adding the slag aggregation agent, control the melt temperature to 1120°C, and maintain for 20 min (second holding time) to allow the slag aggregation agent to fully aggregate the residual trace impurities in the melt and form a dry slag body; after completely removing the slag body, adjust the melt temperature to 1100°C (ingot casting temperature), introduce the melt into a cast iron mold with a size of 200x200x1000 mm, and naturally cool to room temperature to obtain a block-shaped copper ingot.

[0081] The copper ingot prepared in this example was tested for chemical composition, microstructure, mechanical properties, and physical properties, and the results were as follows: (1) Chemical composition: Cu: 99.921%, Zn: 0.018%, Sn: 0.0015%, Pb: 0.0009%, As: 0.0007%, Sb: 0.0004%, Fe: 0.008%, Ni: 0.003%, and other impurities: 0.046%; (2) Microstructure: The copper matrix grain size is uniform, the average grain size is 45 μm, there are no pores, inclusions, segregation, and other defects, and the residual trace impurities are uniformly dispersed in the form of nanoscale particles (particle size ≤ 50 nm); (3) Mechanical properties: tensile strength 215 MPa, yield strength 85 MPa, and elongation 45%; (4) Physical properties: electrical conductivity 101% IACS and thermal conductivity 397 W / (m·K); (5) Hardness: HV62.

[0082] Example 2 In this example, automobile water tank brass scrap (mainly from disassembled materials of waste automobile radiators) was used, and the initial chemical composition of the scrap copper, by mass fraction, was: Cu: 68.5%, Zn: 22.8%, Sn: 2.1%, Pb: 3.5%, Fe: 1.8%, Al: 0.8%, Ni: 0.3%, and other impurities 0.2%.

[0083] The embodiment provides a method for preparing copper ingots from waste copper, and the method comprises the following steps: S11, the automobile water tank brass waste is crushed to a size of less than or equal to 25 mm by a double-shaft shearing machine, and copper pipes and heat dissipation fins are effectively separated; a hot air drying system is used to treat the waste at 380 DEG C for 30 min, so that the surface solder is softened and separated; then the waste is separated from aluminum heat dissipation fins by an eddy current separator (separation frequency 60 Hz), and finally, iron accessories are removed by a high-strength magnetic separator (magnetic field strength 1.8 T); the separated raw material is placed in a fluidized dryer and dried at 110 DEG C for 2 h, so that the water content of the raw material is reduced to less than 0.25%; S21, 600 kg of the pretreated waste copper material is sent into an 8-ton core power frequency induction furnace, the furnace voltage is set to 520 V (first set voltage), and the induction heating system is started. The original material is quickly heated by electromagnetic induction, and after the original material is completely melted into a uniform copper melt, the melt is maintained in a stable state; S31, 0.9 kg of slag cleaning agent (the mass of the slag cleaning agent accounts for 0.15% of the total mass of the melt) is added to the above-mentioned copper melt, and the slag cleaning agent comprises, by mass fraction, 38% of sodium carbonate, 22% of boric anhydride, 12% of silicon dioxide, 13% of silicon carbide, 6% of cerium oxide and 9% of lithium fluoride. After the slag cleaning agent is added, stirring is performed at a speed of 45 r / min for 6 min to ensure sufficient mixing; then the furnace voltage is adjusted to 220 V (second set voltage), the melt temperature is controlled to be stable at 1190 DEG C, and the temperature is maintained for 18 min (first holding time); S41, 2.4 kg of magnetic refining agent (the mass of the refining agent accounts for 0.4% of the total mass of the melt) is added to the copper melt after slag removal in step S31, and stirring is performed at a speed of 40 r / min for 10 min to uniformly disperse the refining agent in the melt. Through the synergistic effect of the active components, Pb, Sn and other impurities in the melt are targetedly adsorbed; after the stirring is completed, the melt temperature is controlled to be 1170 DEG C, and the melt is maintained and placed for 12 min. When the refining agent for adsorbing impurities floats to the surface of the melt, the refining agent is recovered by using a magnetic stainless steel net. The recovered refining agent can be returned to the step for recycling after being regenerated by thermal desorption in an oxidizing atmosphere at 480 DEG C. The recovered and regenerated refining agent in this batch is recycled for 4 times in the subsequent experiment, and still maintains an adsorption efficiency of 88%; The preparation steps of the magnetic refining agent are the same as those in Embodiment 1; S51, electromagnetic stirring and ultrasonic wave are used for the cooper melt after deep adsorption in step S41: the electromagnetic stirring frequency is set to 28 Hz, the ultrasonic wave power is 3.5 kW, the ultrasonic wave frequency is 22 kHz, and the cooperative treatment is performed for 14 min; the physical field synergistic effect is used for further purifying the melt; S61, 1.5 kg of slagging agent (0.25% of the total mass of the melt) is added to the copper melt purified in step S51, and the slagging agent comprises, by mass fraction: 28% of wollastonite, 38% of cryolite, 22% of calcium fluoride, and 12% of sodium polyphosphate. After adding the slagging agent, stirring is performed for 4 min, the temperature of the melt is controlled at 1130 DEG C, and the melt is kept for 25 min (second holding time) to make the slagging agent fully gather the residual impurities in the melt; after the slag body is completely removed, the temperature of the melt is adjusted to 1110 DEG C, the melt is introduced into a cast iron mold with a size of 200*200*1000 mm, and the melt is naturally cooled to room temperature to obtain a blocky copper ingot.

[0084] The copper ingot prepared in the embodiment is tested, and the results are as follows: (1) Chemical composition: Cu: 99.902%, Zn: 0.014%, Sn: 0.0018%, Pb: 0.0013%, Fe: 0.007%, Al: 0.002%, Ni: 0.001%, and other impurities: 0.071%; (2) Microstructure: The grain size of the copper matrix is uniform, the average grain size is 42 μm, and there are no pores, inclusions, and other defects; (3) Mechanical properties: tensile strength 225 MPa, yield strength 90 MPa, and elongation 40%; (4) Physical properties: electrical conductivity 99% IACS and thermal conductivity 388 W / (m·K); (5) Hardness: HV65.

[0085] Example 3 In the embodiment, motor winding scrap copper (containing an insulating paint layer) is selected, and the initial chemical composition of the scrap copper, by mass fraction, is as follows: Cu: 94.8%, Zn: 1.5%, Sn: 0.9%, Pb: 0.7%, Fe: 0.8%, Ni: 0.6%, and other impurities: 0.7%.

[0086] The embodiment provides a method for preparing a copper ingot from scrap copper, and the method comprises the following steps: S11, the motor winding scrap copper is first treated at 400 DEG C for 45 min by a low-temperature pyrolysis furnace to completely decompose the insulating paint layer; then the scrap copper is broken to a particle size of ≤20 mm by using an impact crusher; plastic fragments and impurities are separated by using a specific gravity separator; and the separated raw material is placed in a vibration fluidized bed dryer and dried at 115 DEG C for 1 h to reduce the water content of the raw material to below 0.2%; S21, 700 kg of the pretreated scrap copper material is put into a 10-ton cored power frequency induction furnace, the furnace voltage is set to 460 V (first set voltage), and the melt is melted by using a segmented heating method; S31, add 0.84 kg of slag cleaning agent (the mass of the slag cleaning agent accounts for 0.12% of the total mass of the melt) to the above copper melt, the slag cleaning agent is composed of: sodium carbonate 42%, boric anhydride 18%, silicon dioxide 9%, silicon carbide 16%, cerium oxide 4%, and lithium fluoride 11% by mass fraction. After adding the slag cleaning agent, stir at a speed of 38 r / min for 7 min; then adjust the furnace voltage to 205 V (second set voltage), control the melt temperature to be stable at 1170℃, and keep it for 20 min (first holding time); S41, add 2.8 kg of magnetic refining agent (the mass of the refining agent accounts for 0.4% of the total mass of the melt) to the copper melt after slagging in step S31, and stir at a speed of 32 r / min for 9 min; control the melt temperature to be 1150℃, and keep it for 15 min; the recovered refining agent can be returned to this step for recycling after heat desorption regeneration in a 520℃ oxidizing atmosphere, and the recovered and regenerated refining agent in this batch is recycled for 5 times in the subsequent experiment, and still maintains an adsorption efficiency of 85%; Wherein, the preparation steps of the magnetic refining agent are the same as those of Example 1; S51, electromagnetic stirring and ultrasonic wave synergistic treatment are performed on the copper melt after deep adsorption in step S41: set the electromagnetic stirring frequency to be 22 Hz, the ultrasonic wave power to be 2.5 kW, and the ultrasonic wave frequency to be 18 kHz, and synergistically treat for 10 min; S61, add 1.75 kg of slag gathering agent (the mass of the slag gathering agent accounts for 0.25% of the total mass of the melt) to the purified copper melt in step S51, the slag gathering agent is composed of: wollastonite 32%, cryolite 32%, calcium fluoride 28%, and sodium polyphosphate 8% by mass fraction. Stir for 3.5 min after adding the slag gathering agent, control the melt temperature to be 1110℃, and keep it for 22 min (second holding time); after completely removing the slag body, adjust the melt temperature to 1090℃, and cast into ingots.

[0087] The copper ingot prepared in this example is tested, and the results are as follows: (1) Chemical composition: Cu: 99.938%, Zn: 0.007%, Sn: 0.0007%, Pb: 0.0008%, Fe: 0.004%, Ni: 0.002%, and other impurities: 0.047%; (2) Microstructure: the copper matrix grain size is uniform, and the average grain size is 48 μm; (3) Mechanical properties: tensile strength 208 MPa, yield strength 80 MPa, and elongation 47%; (4) Physical properties: electrical conductivity 103% IACS, and thermal conductivity 405 W / (m·K); (5) Hardness: HV58.

[0088] Example 4 The electronic component disassembled scrap copper (containing solder and plating) is selected in the embodiment, and the initial chemical composition of the scrap copper is as follows in mass fraction: Cu: 90.2%, Zn: 2.8%, Sn: 3.5%, Pb: 1.9%, Fe: 0.6%, Ni: 0.4%, and other impurities: 0.6%.

[0089] The embodiment provides a method for preparing copper ingots from scrap copper, and the method comprises the following steps: S11, the electronic component disassembled scrap copper is crushed to a particle size of less than or equal to 15 mm by a precision crusher; plastic and ceramic fragments are separated by an electrostatic separator; light impurities are removed by high-pressure airflow separation; and the separated raw materials are placed in a microwave dryer and dried at 100 ℃ for 2.5 h to reduce the water content of the raw materials to less than 0.15%; S21, 500 kg of the pretreated scrap copper material is fed into a 6-ton core power frequency induction furnace, the furnace body voltage is set to 440 V (first set voltage), and melting is performed under nitrogen protection; S31, 0.75 kg of slag cleaning agent (0.15% of the total mass of the melt) is added to the above copper melt, and the slag cleaning agent comprises the following components in mass fraction: sodium carbonate 36%, boric anhydride 24%, silicon dioxide 11%, silicon carbide 14%, cerium oxide 7%, and lithium fluoride 8%. After adding the slag cleaning agent, stirring is performed at a speed of 42 r / min for 4 min; then the furnace body voltage is adjusted to 195 V (second set voltage), the melt temperature is controlled to be stable at 1160 ℃, and the temperature is maintained for 22 min (first holding time); S41, 2.0 kg of magnetic refining agent (0.4% of the total mass of the melt) is added to the copper melt after slagging in step S31, and stirring is performed at a speed of 37 r / min for 11 min; the melt temperature is controlled to be 1140 ℃, and the temperature is maintained for 8 min; the recovered refining agent is regenerated by thermal desorption in an oxidizing atmosphere at 460 ℃, and can be returned to the step for recycling; the recovered and regenerated refining agent in this batch is recycled for 3 times in subsequent experiments, and still maintains an adsorption efficiency of 92%; The preparation steps of the magnetic refining agent are the same as those in embodiment 1. S51, electromagnetic stirring and ultrasonic wave are cooperatively processed on the copper melt after deep adsorption in step S41: the electromagnetic stirring frequency is set to 26 Hz, the ultrasonic wave power is set to 4 kW, the ultrasonic wave frequency is set to 24 kHz, and the cooperative processing time is set to 16 min. S61, 1.25 kg of a slagging agent (0.25% of the total mass of the melt) is added to the copper melt after purification in step S51, and the slagging agent comprises, by mass fraction: 26% of wollastonite, 36% of cryolite, 24% of calcium fluoride, and 14% of sodium polyphosphate. After the slagging agent is added, stirring is performed for 2.5 min, the temperature of the melt is controlled at 1100°C, and the melt is kept at the temperature for 28 min (second holding time); after the slag body is completely removed, the temperature of the melt is adjusted to 1070°C, and the melt is cast into an ingot.

[0090] The copper ingot prepared in this example is tested, and the results are as follows: (1) Chemical composition: Cu: 99.891%, Zn: 0.016%, Sn: 0.0011%, Pb: 0.0010%, Fe: 0.006%, Ni: 0.002%, and other impurities: 0.083%; (2) Microstructure: The grain size of the copper matrix is uniform, and the average grain size is 40 μm; (3) Mechanical properties: tensile strength 232 MPa, yield strength 95 MPa, and elongation 36%; (4) Physical properties: electrical conductivity 97% IACS, and thermal conductivity ; (5) Hardness: HV 68.

[0091] Comparative Example 1 Based on the disclosure of Example 1, the following modifications are made: The magnetic core (triiron tetroxide) in the magnetic refining agent is omitted, and only the same proportion of active components (nano cerium oxide, ZIF-8, and quaternary phosphonium salt ionic liquid) are loaded on the γ-alumina / mesoporous silica composite carrier layer to prepare a magnetic refining agent.

[0092] The copper ingot prepared in this example is tested, and the results are as follows: (1) Chemical composition: Cu: 99.65%, As: 0.015%, Pb: 0.025%, Sb: 0.018%, and the impurity removal rate is significantly decreased; (2) The refining agent cannot be recovered by magnetic separation, resulting in the refining agent entering the waste slag, and the unit consumption of the refining agent is increased; (3) Electrical conductivity: 89% IACS.

[0093] Comparative Example 2 Based on the disclosure of Example 1, the following modifications are made: ZIF-8 and ionic liquid are omitted from the active components of the magnetic refining agent, and only nano cerium oxide is retained as the active component.

[0094] The copper ingot prepared in this example is tested, and the results are as follows: (1) Chemical composition: Cu: 99.78%, As: 0.008%, Pb: 0.012%, Sb: 0.009%, the removal effect on Pb and Sb is obviously worse than that of Example 1; (2) Microstructure found that there are obvious Pb and Sb segregation areas; (3) Electrical conductivity: 93% IACS.

[0095] Comparative Example 3 Based on the disclosure of Example 1, the following modifications are made: The electromagnetic stirring and ultrasonic treatment step (S51) is omitted, and only the conventional static treatment is performed, and the other process parameters remain the same as those of Example 1.

[0096] The copper ingot prepared in this comparative example is tested, and the results are as follows: (1) Chemical composition: Cu: 99.918%, Zn: 0.021%, Sn: 0.0018%, Pb: 0.0011%, As: 0.0008%, Sb: 0.0005%, Fe: 0.011%, Ni: 0.004%, other impurities: 0.042%; (2) Microstructure found that the grain size is uneven, and the average grain size increases to 85 μm; (3) There are obvious porosity defects, and the density decreases; (4) Mechanical properties: tensile strength 185 MPa, elongation 32%, both of which are significantly lower than those of Example 1; (5) Electrical conductivity: 95% IACS.

[0097] Comparative Example 4 Based on the disclosure of Example 1, the following modifications are made: The traditional copper-selenium alloy refining agent (mass ratio of copper-selenium alloy 2:3) is used instead of the magnetic refining agent of the present application, and the addition amount is 0.4% of the melt mass, and the other process parameters remain the same as those of Example 1.

[0098] The copper ingot prepared in this comparative example is tested, and the results are as follows: (1) Chemical composition: Cu: 99.70%, As: 0.025%, Pb: 0.018%, Sb: 0.015%, Se: 0.028%; (2) The residual selenium greatly reduces the electrical conductivity to 82% IACS; (3) The refining agent cannot be recycled, producing selenium-containing hazardous waste.

[0099] The Cu, Pb, As, and Sb components in the copper ingots obtained from the examples and comparative examples are compared, and the results are shown in Table 1.

[0100] Table 1 Cu, Pb, As, Sb content (wt.%) in copper ingot From the examples and comparative examples and Table 1, it can be seen that the waste copper refining process of the application can efficiently improve the purity of the copper ingot and deeply remove harmful impurities such as Pb, As, Sb, and the specific conclusions are as follows: (1) The impurity removal and purification effect of the process of the examples is remarkable: the Cu purity of the copper ingot of Examples 1-4 is all above 99.89% (the highest is 99.938%), the Pb content is only 0.0008-0.0013%, and the As (0.0007%) and Sb (0.0004%) in Example 1 are even extremely low, which shows that after the whole process of "pretreatment + composite slag cleaning + magnetic refining agent adsorption + physical field synergy", the high-purity refining and deep removal of harmful impurities of low-grade waste copper can be effectively realized; (2) The magnetic refining agent key component is indispensable: after omitting the magnetic core in Comparative Example 1, the Cu purity is reduced to 99.65%, and the Pb (0.025%), As (0.015%), and Sb (0.018%) are greatly increased compared with Example 1, which proves that the magnetic core is the key to ensure the recovery of the refining agent, avoid its loss and pollution of the melt, and maintain the impurity removal efficiency; after omitting ZIF-8 and ionic liquid and only retaining nano cerium oxide in Comparative Example 2, the Pb, As, and Sb contents are significantly higher than those in Example 1, which shows that the synergy of multiple active components is the core of targeted removal of different harmful impurities; (3) Better than traditional process and simplified process: the traditional copper-selenium alloy refining agent is used in Comparative Example 4, not only the Cu purity (99.70%) is lower than that of the examples, but also Se residues are introduced, and the Pb, As, and Sb contents are much higher than those of the examples; although the Cu purity (99.918%) and impurity content of Comparative Example 3 are close to those of Example 1 because only the physical field synergy is omitted, but it can be known from the previous test that the microstructure and mechanical properties have been significantly deteriorated, which further embodies the necessity of the whole process of the application.

[0101] Various embodiments of the application can exist in the form of a range; it should be understood that the description in the form of a range is only for the convenience and brevity, and should not be understood as a hard limitation on the scope of the application; therefore, it should be considered that the range described has been specifically disclosed all possible sub-ranges and single values within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated in this text, it means that any quoted number (fraction or integer) within the indicated range is included.

[0102] In addition, in the description of the application, the terms "include", "contain" and the like are intended to mean "including but not limited to". In this document, relational terms such as "first" and "second", and the like can be used solely to distinguish one entity or action from another, without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0103] The above description is merely that of a specific implementation of the present application, enabling a person skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the generic principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of producing copper ingots from scrap copper, characterized in that, The method comprises the following steps: S1, sorting, crushing and drying the waste copper raw material to obtain pretreated copper material; S2, sending the pretreated copper material into a cored power frequency induction furnace and melting at a first set voltage; S3, after the pretreated copper material is completely melted, adding a slag cleaning agent to the melt, then adjusting the voltage to a second set voltage, and after the first holding, slagging; the slag cleaning agent is composed of sodium carbonate, boric anhydride, silicon dioxide, silicon carbide, cerium oxide and lithium fluoride; S4, adding a magnetic refining agent to the melt after slagging and stirring to adsorb impurity elements in the melt, and then holding and standing to recover the magnetic refining agent that floats to the surface of the melt; the magnetic refining agent comprises a magnetic core, a porous carrier layer coated on the surface of the magnetic core, and an active component loaded on the porous carrier layer, the active component comprises a metal oxide with Lewis acidity, a metal organic framework material with molecular sieve effect and an ionic liquid; S5, electromagnetic stirring and ultrasonic wave synergistic treatment of the refined melt to deeply remove hydrogen and oxygen gas and uniformly distribute the components; S6, adding a slag gathering agent to the purified melt and stirring, second holding and slagging, and casting into ingots; the slag gathering agent is composed of wollastonite, cryolite, calcium fluoride and sodium polyphosphate.

2. The method of copper ingot production from scrap copper according to claim 1, characterized in that, In step S3, the mass of the slag cleaning agent added is 0.05-0.15% of the total mass of the melt; In terms of mass fraction, the content of each component in the slag cleaning agent is: sodium carbonate 35-45%, boric anhydride 15-25%, silicon dioxide 8-12%, silicon carbide 12-18%, cerium oxide 3-6%, and lithium fluoride 5-10%.

3. The method of producing copper ingots from scrap copper according to claim 1, characterized in that, In step S4, the mass of the magnetic refining agent added is 0.1-0.65% of the total mass of the melt; The magnetic core is ferroferric oxide; The porous carrier layer is a composite of γ-alumina and mesoporous silica; The metal oxide with Lewis acidity is nano cerium oxide, the metal organic framework material with molecular sieve effect is ZIF-8, and the ionic liquid is a quaternary phosphonium salt ionic liquid.

4. The method of producing copper ingots from scrap copper according to claim 3, characterized in that, In step S4, the preparation method of the magnetic refining agent comprises the following steps: S4a, synthesizing ferroferric oxide magnetic core by co-precipitation method; S4b, dispersing the magnetic core in a solution containing aluminum source and silicon source, hydrolyzing, aging, drying, and then calcining at 400-500℃ for 1-3h to form the porous carrier layer; S4c, loading nano cerium oxide on the porous carrier layer by equal-volume impregnation method, and then calcining at 450-550℃ for 2-4h to form cerium oxide active sites; S4d, loading ZIF-8 on the porous carrier layer by in-situ growth method; S4e, loading quaternary phosphonium salt ionic liquid into the pores of the porous carrier layer by vacuum impregnation method; The vacuum impregnation method comprises the following parameters: vacuum degree -0.05 to -0.08MPa, impregnation temperature 60-80℃, and impregnation time 1-2h.

5. The process for the production of copper ingots from scrap copper according to claim 4, characterized in that, In step S4, the magnetic refining agent has a particle size of 100-200 nm, the porous carrier layer has a thickness of 50-100 nm, a specific surface area of 200-500 m 2 / g, and the mesopore volume with a pore size distribution of 2-50 nm accounts for more than 60% of the total pore volume.

6. The method of producing copper ingots from scrap copper according to claim 1, wherein In step S4, the recycled magnetic refining agent is returned to step S4 after being regenerated by thermal desorption in an oxidizing atmosphere at 400-600°C.

7. The method of producing copper ingots from scrap copper according to claim 1, wherein In step S2, the first set voltage is 450-500V. In step S3, the second set voltage is 200-220V.

8. The method of producing copper ingots from scrap copper according to claim 1, wherein In step S5, the electromagnetic stirring and ultrasonic treatment includes the following parameters: electromagnetic stirring frequency is 20-30Hz, ultrasonic power is 1-5kW, ultrasonic frequency is 18-25kHz, and the treatment time is 10-15min.

9. The method of producing copper ingots from scrap copper according to claim 1, wherein In step S3, the first holding temperature is 1150-1200°C, and the holding time is 10-20min. In step S4, the holding temperature for standing is 1150-1180°C, and the holding time is 5-15min. In step S6, the second holding temperature is 1100-1150°C, and the holding time is 15-30min. In step S6, the temperature for casting into ingots is 1080-1120°C.

10. The method of producing copper ingots from scrap copper according to claim 1, wherein In step S6, the added mass of the slag collector is 0.15-0.3% of the total mass of the melt. In the slag collector, the content of each component is as follows: wollastonite 25-35%, ice 30-40%, calcium fluoride 20-30%, and sodium polyphosphate 5-10%.

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