Copper scrap regeneration smelting method

Abstract

The present invention provides a copper scrap recycling and smelting method, comprising the following steps: (a) collection; (b) pretreatment; (c) deoiling; (d) drying; (e) smelting; (f) deoxidation refining: sprinkling a covering agent on the surface of the molten copper for refining, raising the temperature to a blasting temperature of 1510-1560°C, blasting the surface of the molten copper multiple times, allowing it to stand for slagging after each blasting; the covering agent being used in an amount of 0.8-1.2% of the mass of the molten copper; (g) composition detection: pouring a sample block and detecting its composition using a spectrometer; (h) adding metal elements: adding desired alloying metal elements based on the composition detected by the spectrometer; (i) degassing; and (j) pouring: transferring the molten copper from a subcontractor to a casting ladle, pouring it into a steel mold ingot, and cooling it to obtain a copper ingot. This method can fully utilize the copper scrap resources recycled within the mold factory and achieve a high yield.

Description

Technical Field

[0001] The invention belongs to the field of metal material recycling and relates to a regeneration smelting method, in particular to a copper scrap regeneration smelting method. Background Art

[0002] In the glass mold (i.e., glass forming mold) industry, mold material is one of the key factors determining the maximum mold lifespan. Currently, copper alloys are increasingly used by domestic mold manufacturers due to their strong resistance to oxidation, corrosion, and fatigue. The casting process of copper alloys consumes large quantities of raw materials such as electrolytic copper, electrolytic aluminum, and electrolytic nickel. The procurement of these raw materials is a significant expense for companies. Recycling and refining copper scraps for reuse would significantly reduce production costs and offer an effective means of reducing costs and saving capital.

[0003] During the machining process of molds, the mold surface needs to be roughed, the interior cavity fine-machined, and the outer diameter machined after flat assembly. These processes, involving turning, milling, drilling, and planing, generate large amounts of copper chips. Mold manufacturers typically collect these chips and sell them to specialized recycling companies. These recyclers purchase them at low prices and then remelt them to extract metals such as copper and nickel. Furthermore, the processed copper chips are mixed with large amounts of impurities such as cutting fluid, emulsions, and water, resulting in severe adhesion. Residual moisture after cleaning can cause rust on the copper chips. Furthermore, the disposal of wastewater from industrial cleaning agents is a challenge. During the smelting process, copper chips are easily oxidized by the furnace atmosphere. The molten copper undergoes an oxidation reaction, and the precipitation of oxidation products forms oxide inclusions, which harm the castings. Furthermore, hydrogen absorption during the smelting process can cause porosity in the castings, affecting the mechanical properties of the mold and directly reducing its service life.

[0004] Chinese patent application number 202210931578.3 discloses a vacuum melting process for purifying low-silver, low-sulfur, ultra-high-purity copper. The process specifically includes the following steps: S1. Treatment of scrap copper: Pre-removing surface rust from the scrap copper and cleaning it. The pre-treated scrap copper is then fed into a crusher, which crushes it to a diameter of ≤150mm. A screening machine is used to screen the crushed material. The undersized material is kept ready for use, while the oversized material is returned to the crusher for crushing until it passes the screening. S2. Material heat treatment: The material screened in step S1 is placed in a roaster for heat treatment. This low-silver, low-sulfur, ultra-high-purity copper requires the use of electrolytic nickel and vacuum melting process conditions, which is costly and demanding. Summary of the Invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a copper scrap regeneration smelting method.

[0006] In order to solve the above technical problems, the present invention provides a copper scrap regeneration and smelting method, comprising the following steps:

[0007] (a) Collection: Collecting copper scraps to be smelted;

[0008] (b) pretreatment: removing solid impurities in the copper scraps, wherein the solid impurities include plastics, waste paper, iron scraps and / or scrap steel;

[0009] (c) deoiling: removing oil impurities in the copper chips, wherein the oil impurities include rust-proof cutting fluid and / or emulsified coolant;

[0010] (d) Drying: Drying the deoiled copper chips;

[0011] The following steps are also included:

[0012] (e) Melting: Melting the dried copper scraps until part of the copper scraps are in a molten state, adding part of the mixed salt flux and continuing to melt until the copper scraps are completely melted, then adding part of the mixed salt flux and continuing to melt, and finally adding the remaining mixed salt solvent;

[0013] (f) Deoxidation refining: Sprinkle a covering agent on the surface of the molten copper for refining, raise the temperature to a flame spraying temperature of 1510-1560°C, and spray the surface of the molten copper multiple times. After each spraying, let it stand and skim off the slag. The amount of the covering agent used is 0.8-1.2% of the mass of the molten copper.

[0014] (g) Composition detection: Cast the sample block and detect its composition using a spectrometer;

[0015] (h) Adding metal elements: adding the required alloy metal elements according to the composition detected by the spectrometer;

[0016] (i) Degassing: The copper liquid that has passed the composition test is blown by the subcontractor to further remove the slag;

[0017] (j) Pouring: The molten copper is transferred from the transfer ladle to the pouring ladle and poured into the steel mold ingot, and then cooled to obtain the copper ingot; the pouring temperature of the molten copper is 1260-1310°C, and the preheating temperature of the steel mold ingot is 150-230°C.

[0018] Optimally, in step (e), first, a medium frequency electric furnace is used to charge 10-20 kg of the same grade copper alloy into a pouring head, smelting to a molten state, and copper chips are added, where the amount of copper chips added is 1 / 2 of the required smelting amount; smelting is continued to a molten state, 1 / 3 of the mixed salt flux is pressed into the graphite bell jar, another 1 / 2 of the copper chips are continued to be added, and then another 1 / 3 of the mixed salt flux is pressed into the mixture, and the heat preservation and smelting are continued for 2-3 hours; finally, the remaining 1 / 3 of the mixed salt flux is pressed into the mixture, and the total amount of the mixed salt flux is 1.5-2.5% of the total mass of the molten copper.

[0019] Furthermore, in step (e), the mixed salt flux is in granular form, and is prepared by adding rare earth scandium, phosphorus copper, and strontium carbonate to a mixed salt of sodium fluoroaluminate, potassium chloride, and magnesium chloride, and pressing the mixture; the mass percentage of each component in the mixed salt flux is:

[0020] Mixed salt 40~50%;

[0021] Phosphor copper 20-30%, wherein the phosphorus content of the phosphor copper is 10-12%;

[0022] Rare earth scandium 10-15%;

[0023] Strontium carbonate 10~20%.

[0024] Furthermore, in step (e), the mass ratio of sodium fluoroaluminate, potassium chloride and magnesium chloride in the mixed salt is 5:3:2.

[0025] Optimally, in step (f), the mass contents of the components of the covering agent are: 40-50% dry distillation charcoal, 20-35% borax, 10-15% calcium carbonate, 10-15% sodium carbonate and 10-15% calcium oxide.

[0026] Furthermore, in step (f), the refining time is 5-6 hours; the flame is sprayed 3-5 times, each time for 15-25 minutes, the slag is skimmed, and the reaction is carried out under a ventilation device.

[0027] Optimally, in step (i), nitrogen is introduced into the molten copper through the first chamber (2) of the subcontractor for dehydrogenation at a flow rate of 5-10 L / min for 2-5 minutes; and then inert gas helium is introduced into the second chamber (4) at a flow rate of 10-15 L / min for 3-8 minutes for further slag blowing and refining.

[0028] Optimally, in step (b), the pretreatment operation is as follows: first, waste paper and plastic are removed by air separation, and then iron filings, nickel filings, and scrap steel are separated by a magnetic separator, and magnetic separation is performed 3-5 times.

[0029] Optimally, in step (c), the pretreated copper chips are subjected to centrifugal deoiling treatment using a copper chip vacuum centrifugal deoiling separator, with the speed of the vacuum centrifugal deoiling separator set at 960-1100 r / min and the deoiling time being 45-100 min.

[0030] Furthermore, in step (d), the deoiled copper scraps are dried at a temperature of 300-350° C. and a drying time of 35-55 minutes.

[0031] The copper scrap recycling and smelting method of the present invention can fully utilize the copper scraps generated after turning and chip cutting, save raw materials and reduce costs; and the use of a mixed salt flux for smelting enables phosphorus in phosphorus copper to react with copper oxide in copper liquid to generate oxidizing substances that are precipitated in a gaseous form to form slag that floats, thereby achieving the effect of purifying and removing slag in the copper liquid; the copper liquid is further subjected to secondary slag removal by subcontracting, so that the copper liquid can be fully purified and adverse factors such as pores and oxidized slag are eliminated; that is, the copper scrap resources recycled within the mold factory can be fully utilized, the yield is high, and the castings are tested for mechanical properties, and various indicators all reach the level of castings smelted from new materials, thereby greatly reducing procurement costs, being conducive to the goal of green and sustainable development, and maintaining stable and reliable quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The process flow chart of the copper scrap regeneration and smelting method of the present invention is as follows;

[0033] Figure 2 This is a three-dimensional diagram of a transfer package in the copper scrap regeneration and smelting method of the present invention;

[0034] Figure 3 This is a cross-sectional view of a transfer package in the copper scrap regeneration and smelting method of the present invention;

[0035] Among them, 1. liquid inlet; 2. first cavity; 3. baffle; 4. second cavity; 5. liquid outlet; 6. first heat-resistant steel conduit; 7. second heat-resistant steel conduit.

[0036] The copper scrap regeneration and smelting method of the present invention comprises the following steps: (a) collecting: collecting copper scraps to be smelted; (b) pretreatment: removing solid impurities in the copper scraps, wherein the solid impurities include plastics, waste paper, iron scraps and / or scrap steel; (c) deoiling: removing oil impurities in the copper scraps, wherein the oil impurities include rust-proof cutting fluid and / or emulsified coolant; (d) drying: drying the deoiled copper scraps; (e) smelting: smelting the dried copper scraps to make part of the copper scraps molten, adding part of the mixed salt flux and continuing to smelt until the copper scraps are fully molten, adding part of the mixed salt flux and smelting, and finally adding the remaining mixed salt solvent; (f) deoxidation refining: sprinkling a coating on the surface of the copper liquid. The covering agent is refined and heated to a blasting temperature of 1510-1560° C., and the surface of the copper liquid is blasted multiple times. After each blasting, the copper liquid is allowed to stand and the slag is removed. The amount of the covering agent used is 0.8-1.2% of the mass of the copper liquid. (g) Composition detection: a sample block is cast and its composition is detected by a spectrometer. (h) Adding metal elements: the required alloy metal elements are added according to the composition detected by the spectrometer. (i) Degassing: the copper liquid that has passed the composition detection is blown through a transfer bag to further remove the slag. (j) Pouring: the copper liquid is transferred from the transfer bag to a casting ladle, poured into a steel mold ingot, and cooled to obtain a copper ingot. The pouring temperature of the copper liquid is 1260-1310° C., and the preheating temperature of the steel mold ingot is 150-230° C. Through the coordination of various steps, the copper chips generated after turning and chip cutting can be fully utilized, saving raw materials and reducing costs. Moreover, the use of mixed salt flux for smelting allows the phosphorus of phosphor copper to react with the copper oxide in the copper liquid to generate oxidizing substances that precipitate in gaseous form to form slag that floats on the surface, thereby achieving the effect of purifying and removing slag from the copper liquid. The copper liquid undergoes secondary slag removal by subcontracting, making it fully pure and eliminating undesirable factors such as pores and oxidized slag. That is, the copper chip resources recycled within the mold factory can be fully utilized, with a high yield. After mechanical property testing, the castings have all reached the level of castings smelted from new materials, greatly reducing procurement costs, contributing to the goal of green and sustainable development, and maintaining stable and reliable quality.

[0037] In step (e), first, a medium frequency electric furnace is used to charge 10-20 kg of the same grade copper alloy into a pouring head, smelting to a molten state, and copper chips are added, where the amount of copper chips added is 1 / 2 of the required smelting amount; the smelting is continued to a molten state, 1 / 3 of the mixed salt flux is pressed into the graphite bell jar, another 1 / 2 of the copper chips are continued to be added, and another 1 / 3 of the mixed salt flux is pressed into the mixture, and the heat preservation and smelting are continued for 2-3 hours; finally, the remaining 1 / 3 of the mixed salt flux is pressed into the mixture, and the total amount of the mixed salt flux is 1.5-2.5% of the total mass of the copper water. The mixed salt solvent is added in batches multiple times to ensure that the oxidized impurities in the copper alloy solution are fully decomposed. In step (e), the mixed salt flux is in granular form and is formed by adding rare earth scandium, phosphorus copper, and strontium carbonate to a mixed salt of sodium fluoroaluminate, potassium chloride, and magnesium chloride, followed by mixing and pressing. The weight percentages of the components in the mixed salt flux are as follows: 40-50% mixed salt; 20-30% phosphorus copper, where the phosphorus copper has a phosphorus content of 10-12%; 10-15% rare earth scandium; and 10-20% strontium carbonate. The addition of phosphorus copper as an intermediate alloy provides excellent deoxidation and reduces the formation of subcutaneous pores. The rare earth elements solid-solution-strengthen the alloy, enhancing the mechanical properties of the material. In step (e), the mass ratio of sodium fluoroaluminate, potassium chloride, and magnesium chloride in the mixed salt is 5:3:2. The chloride in the mixed salt can both degas and adsorb suspended impurities. In step (f), the mass content of the components of the covering agent is: 40-50% dry distilled charcoal, 20-35% borax, 10-15% calcium carbonate, 10-15% sodium carbonate and 10-15% calcium oxide, forming a protective film on the surface of the copper alloy solution to prevent gas from entering the solution. In step (f), the refining time is 5-6 hours; the flame is sprayed 3-5 times, each time for 15-25 minutes, and the slag is removed. The reaction is carried out under a ventilation device. Multiple flame spraying is conducive to the discharge of gas dissolved in the copper alloy solution. In step (i), nitrogen is introduced into the copper liquid through the first chamber (2) of the subcontractor for dehydrogenation at a flow rate of 5-10L / min and a time of 2-5 minutes; then, helium, an inert gas, is introduced into the second chamber (4) at a flow rate of 10-15L / min and a time of 3-8 minutes for further slag blowing and refining. The two blows discharge hydrogen in the copper alloy and reduce the generation of pores. In step (b), the pretreatment process is as follows: first, waste paper and plastics are removed by air separation, followed by separation of iron, nickel, and steel scraps using a magnetic separator. This process is repeated 3-5 times to remove impurities. In step (c), the pretreated copper scraps are centrifugally deoiled using a vacuum centrifugal deoiling separator. The speed of the centrifugal deoiling separator is set at 960-1100 rpm, and the deoiling time is 45-100 minutes to completely separate the oil and contaminants. In step (d), the deoiled copper scraps are dried at a temperature of 300-350°C for 35-55 minutes to ensure dryness and prevent detonation during the smelting and feeding process.

[0038] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

[0039] Example 1

[0040] This embodiment provides a mixed salt flux for copper scrap regeneration and smelting and a preparation method thereof, comprising the following steps:

[0041] (S1) sodium fluoroaluminate, potassium chloride, and magnesium chloride are uniformly mixed in a ratio of 50%, 30%, and 20% (i.e., a mass ratio of 5:3:2) to obtain a mixed salt (total amount of 1 ton), and the obtained mixed salt is sieved through a 250-mesh filter sieve;

[0042] (S2) The screened mixed salt is mixed with industrial phosphor copper (synthesized from electrolytic copper and red phosphorus at high temperature, in powder form, with a phosphorus content of 10-12%; the phosphorus content fluctuates to a certain extent during actual preparation, and this range has little effect on product performance), rare earth scandium (nano-level powder form), and strontium carbonate (white powder) in the following proportions of 40%, 30%, 15%, and 15%, respectively, to obtain a uniform mixture, which is then pressed into granules and dried before use.

[0043] Example 2

[0044] This embodiment provides a mixed salt flux for copper scrap regeneration and smelting and a preparation method thereof. The method is basically the same as that in Example 1, except that the mixed salt is mixed and stirred with industrial phosphor copper, rare earth scandium, and strontium carbonate (white powder) in the following proportions: 50%, 20%, 10%, and 20%.

[0045] Example 3

[0046] This embodiment provides a mixed salt flux for copper scrap regeneration and smelting and a preparation method thereof. The method is basically the same as that in Example 1, except that the mixed salt is mixed and stirred with industrial phosphor copper, rare earth scandium, and strontium carbonate (white powder) in the following proportions: 48%, 28%, 12%, and 12%.

[0047] Example 4

[0048] This embodiment provides a copper scrap regeneration smelting method, such as Figure 1 As shown, the following steps are included:

[0049] (a) Collection: Collection of copper scraps generated by machining and other processes (i.e., collection of copper scraps that need to be smelted);

[0050] (b) Pretreatment: Removal of solid impurities from copper scraps, including plastic, waste paper, iron scraps, and / or scrap steel. Specifically, air separation is used to remove light impurities such as waste paper and plastic, followed by magnetic separation to separate iron scraps, nickel scraps, and scrap steel, with 3-5 magnetic separation cycles.

[0051] (c) Deoiling: Removing oil impurities from the copper chips, including anti-rust cutting fluid and / or emulsified coolant. Specifically, the pretreated copper chips are subjected to centrifugal deoiling using a commercially available vacuum centrifugal deoiling separator at a speed of 960-1100 rpm and a deoiling time of 45-100 min to remove oil substances such as the anti-rust cutting fluid and emulsified coolant from the copper chips.

[0052] (d) Drying: Dry the deoiled copper scraps (drying temperature is 300-350°C, drying time is 35-55 min, the numerical range has little effect on product performance, the same above and below);

[0053] (e) Smelting: Smelting the dried copper scraps until a portion of the copper scraps is molten, adding a portion of the mixed salt flux and continuing to melt until the scraps are completely melted, then adding a portion of the mixed salt flux and continuing to melt, and finally adding the remaining mixed salt solvent (the mixed salt solvent in this step is the mixed salt flux in Example 1);

[0054] Specifically, 10-20 kg of the same grade of copper alloy casting riser is first added to a commercially available medium-frequency electric furnace (this dosage range has no effect on the final product), and the mixture is melted to a molten state (the temperature is approximately 1100° C.). The treated copper chips (i.e., the copper chips obtained in step (d)) are added, and the amount of copper chips added is 1 / 2 of the required amount to be melted, and the mixture is continued to be melted to a molten state; 1 / 3 of the mixed salt flux is pressed into the mixture through a graphite bell jar, and another 1 / 2 of the copper chips is continued to be added, and then another 1 / 3 of the mixed salt flux is pressed into the mixture, and the mixture is continued to be melted for 2-3 hours, and finally the remaining 1 / 3 of the mixed salt flux is pressed into the mixture (the total amount of the mixed salt flux accounts for 1.5% of the total amount of molten copper);

[0055] (f) Deoxidation refining: Sprinkling a covering agent on the surface of the molten copper for refining (the amount of the covering agent is 0.8% of the mass of the molten copper, and the composition of the covering agent (covering agent content per 100kg) is: 40% dry distillation charcoal, 22% borax, 13% calcium carbonate, 15% sodium carbonate, and 10% calcium oxide), raising the temperature to a blasting temperature of 1510°C, blasting the surface of the molten copper multiple times, and letting it stand after each blasting, and skimming off the slag; specifically, sprinkling a covering agent accounting for 0.8% of the mass of the molten copper on the surface of the molten copper, refining for 5-6 hours; raising the temperature to a blasting temperature of 1510°C, blasting three times, each blasting time being 25 minutes, skimming off the slag, and the reaction is carried out under a draft device;

[0056] (g) Composition detection: The sample blocks were cast and their composition was detected using a commercially available direct reading spectrometer;

[0057] (h) Adding metal elements: Add the required alloy metal elements according to the composition detected by the spectrometer (if there is burn-off or some elements are low, just add the corresponding elements);

[0058] (i) Degassing: The copper liquid that has passed the composition test is blown by the subcontractor to further remove the slag;

[0059] In this embodiment, the Figure 2 and Figure 3 The subpackage shown is used for blowing, and the subpackage includes a cavity body, a liquid inlet 1 connected to the cavity body, and a liquid outlet 5 connected to the cavity body and arranged opposite to the liquid inlet 1. A baffle 3 is provided in the cavity body to separate the cavity body into a first cavity 2 and a second cavity 4 that are connected (the connection point is the interval between the baffle 3 and the top of the cavity body). At this time, the liquid inlet 1 is connected to the first cavity 2, and the liquid outlet 5 is connected to the second cavity 4; the subpackage also includes a first heat-resistant steel conduit 6 installed on both sides and connected to the first cavity 2, and a second heat-resistant steel conduit 7 installed on both sides and connected to the second cavity 4.

[0060] Specifically, the copper liquid that has passed the component test is blown through the above-mentioned subcontractor. First, the copper liquid passes through the first chamber 2 in the subcontractor and is introduced with nitrogen for dehydrogenation at a flow rate of 5L / min for 5 minutes. Then, it passes through the second chamber and is introduced with inert gas (helium) at a flow rate of 10L / min for 8 minutes for further slag blowing and refining.

[0061] (j) Pouring: The molten copper is transferred from the transfer ladle to the pouring ladle and poured into the steel mold ingot, and then cooled to obtain the copper ingot. The pouring temperature of the molten copper is 1260°C, and the preheating temperature of the steel mold ingot is 230°C.

[0062] Example 5

[0063] This embodiment provides a copper scrap regeneration and smelting method, which is basically the same as that in Example 4, except that: in step (e), the mixed salt flux is the same as that in Example 2.

[0064] Example 6

[0065] This embodiment provides a copper scrap regeneration and smelting method, which is basically the same as that in Example 4, except that: in step (e), the mixed salt flux is the same as that in Example 3.

[0066] Example 7

[0067] This embodiment provides a copper scrap regeneration and smelting method, which is basically the same as that in Example 4, except that: in step (f), the covering agent is composed of: 50% dry distillation charcoal, 20% borax, 10% calcium carbonate, 10% sodium carbonate, and 10% calcium oxide.

[0068] Example 8

[0069] This embodiment provides a copper scrap regeneration and smelting method, which is basically the same as that in Example 4, except that in step (f), the covering agent is composed of: 42% dry distillation charcoal, 22% borax, 12% calcium carbonate, 12% sodium carbonate, and 12% calcium oxide.

[0070] Example 9

[0071] This embodiment provides a copper scrap regeneration and smelting method, which is basically the same as that in Example 4, except that: in step (f), a covering agent accounting for 1.2% of the mass of the molten copper is sprinkled on the surface of the molten copper.

[0072] Example 10

[0073] This embodiment provides a copper scrap regeneration and smelting method, which is basically the same as that in Example 4, except that: in step (f), a covering agent accounting for 1.0% of the mass of the molten copper is sprinkled on the surface of the molten copper.

[0074] Example 11

[0075] This embodiment provides a copper scrap regeneration and smelting method, which is basically the same as that in Example 4, except that in step (e), the total amount of the mixed salt flux accounts for 2.5% of the total amount of molten copper.

[0076] Example 12

[0077] This embodiment provides a copper scrap regeneration and smelting method, which is basically the same as that in Example 4, except that in step (e), the total amount of the mixed salt flux accounts for 2.0% of the total amount of molten copper.

[0078] Example 13

[0079] This embodiment provides a copper scrap regeneration and smelting method, which is basically the same as that in Example 4, except that:

[0080] In step (f), the temperature is raised to a blasting temperature of 1560°C, blasting is performed 5 times, each blasting time is 15 minutes, slag is removed, and the reaction is carried out under a draft device;

[0081] In step (i), nitrogen is introduced to remove hydrogen at a flow rate of 10 L / min for 2 minutes, and then an inert gas (helium) is introduced through the second chamber at a flow rate of 15 L / min for 3 minutes to further blow out the slag and refine it;

[0082] (j) Pouring: The molten copper is transferred from the sub-lender to the pouring ladle and poured into the steel mold ingot, and cooled to obtain the copper ingot. The pouring temperature of the molten copper is 1310°C, and the preheating temperature of the steel mold ingot is 150°C.

[0083] Example 14

[0084] This embodiment provides a copper scrap regeneration and smelting method, which is basically the same as that in Example 4, except that:

[0085] In step (f), the temperature is raised to a flaming temperature of 1530°C, and flaming is performed four times, each flaming time being 20 minutes. The slag is then removed, and the reaction is carried out under a draft device;

[0086] In step (i), nitrogen is introduced to remove hydrogen at a flow rate of 8 L / min for 4 minutes, and then an inert gas (helium) is introduced through the second chamber at a flow rate of 12 L / min for 5 minutes to further blow out the slag and refine it;

[0087] (j) Pouring: The molten copper is transferred from the transfer ladle to the pouring ladle and poured into the steel mold ingot, and then cooled to obtain the copper ingot. The pouring temperature of the molten copper is 1390°C, and the preheating temperature of the steel mold ingot is 200°C.

[0088] Comparative Example 1

[0089] This embodiment provides a copper scrap regeneration smelting method, which is basically the same as that in Example 4, except that in step (e), all the copper scraps and mixed salt flux are added at one time for smelting.

[0090] Comparative Example 2

[0091] This embodiment provides a copper scrap regeneration and smelting method, which is basically the same as that in Example 4, except that in step (f), the total amount of mixed salt flux used is excessive, accounting for 5% of the total amount of molten copper.

[0092] Comparative Example 3

[0093] This embodiment provides a copper scrap regeneration smelting method, which is basically the same as that in Example 4, except that in step (f), sodium fluoroaluminate and phosphorus copper are absent in the mixed salt flux.

[0094] Comparative Example 4

[0095] This embodiment provides a copper scrap regeneration and smelting method, which is basically the same as that in Example 4, except that in step (f), the amount of covering agent used is excessive, namely 1.5% of the mass of the molten copper.

[0096] Comparative Example 5

[0097] This embodiment provides a copper scrap regeneration and smelting method, which is basically the same as that in Example 4, except that in step (f), the covering agent lacks borax and calcium carbonate.

[0098] Comparative Example 6

[0099] This embodiment provides a copper scrap regeneration smelting method, which is basically the same as that in embodiment 4, except that: in step (i), the method Figure 2and Figure 3 The subcontract shown is blown.

[0100] The copper ingots obtained in Examples 4-14 and Comparative Examples 1-6 were subjected to performance testing according to YS / T815-2012 "Method for preparing mechanical and process performance patterns of copper and copper alloys". The results are shown in Table 1.

[0101] Table 1 Mechanical properties data of various examples

[0102]

[0103] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A copper scrap regeneration smelting method comprising the following steps: (a) Collection: Collecting copper scraps to be smelted; (b) pretreatment: removing solid impurities in the copper scraps, the solid impurities including plastics, waste paper, iron scraps and scrap steel; (c) deoiling: removing oil impurities in the copper chips, wherein the oil impurities include rust-proof cutting fluid and / or emulsified coolant; (d) Drying: Drying the deoiled copper chips; It is characterized in that it also includes the following steps: (e) Melting: Melting the dried copper scraps until part of the copper scraps are in a molten state, adding part of the mixed salt flux and continuing to melt until the copper scraps are completely melted, then adding part of the mixed salt flux and continuing to melt, and finally adding the remaining mixed salt solvent; (f) Deoxidation refining: Sprinkle a covering agent on the surface of the molten copper for refining, raise the temperature to a flame spraying temperature of 1510-1560°C, and spray the surface of the molten copper multiple times. After each spraying, let it stand and skim off the slag. The amount of the covering agent used is 0.8-1.2% of the mass of the molten copper. (g) Composition detection: Cast the sample block and detect its composition using a spectrometer; (h) Adding metal elements: adding the required alloy metal elements according to the composition detected by the spectrometer; (i) Degassing: The copper liquid that has passed the composition test is blown by the subcontractor to further remove the slag; (j) Pouring: The molten copper is transferred from the sub-contractor to a pouring ladle and poured into a steel mold ingot, whereupon the copper ingot is cooled to obtain a copper ingot; the pouring temperature of the molten copper is 1260-1310°C, and the preheating temperature of the steel mold ingot is 150-230°C; In step (e), the mixed salt flux is in granular form and is prepared by adding rare earth scandium, phosphorus copper, and strontium carbonate to a mixed salt of sodium fluoroaluminate, potassium chloride, and magnesium chloride, and pressing the mixture; the mass percentage of each component in the mixed salt flux is: Mixed salt 40~50%; Phosphor copper 20-30%, wherein the phosphorus content of the phosphor copper is 10-12%; Rare earth scandium 10-15%; Strontium carbonate 10~20%.

2. The copper scrap regeneration smelting method according to claim 1, characterized in that: In step (e), first, a medium frequency electric furnace is used to charge 10-20 kg of the same grade copper alloy into a pouring head, smelting to a molten state, and copper chips are added, where the amount of copper chips added is 1 / 2 of the required smelting amount; the smelting is continued to a molten state, 1 / 3 of the mixed salt flux is pressed into a graphite bell jar, and another 1 / 2 of the copper chips is continued to be added, and then another 1 / 3 of the mixed salt flux is pressed into the smelting, and the heat preservation and smelting are continued for 2-3 hours; finally, the remaining 1 / 3 of the mixed salt flux is pressed into the molten copper. The total amount of the mixed salt flux is 1.5-2.5% of the total mass of the molten copper.

3. The copper scrap regeneration smelting method according to claim 1, characterized in that: In step (e), the mass ratio of sodium fluoroaluminate, potassium chloride and magnesium chloride in the mixed salt is 5:3:

2.

4. The copper scrap regeneration smelting method according to claim 1, characterized in that: In step (f), the mass contents of the components of the covering agent are: 40-50% dry distillation charcoal, 20-35% borax, 10-15% calcium carbonate, 10-15% sodium carbonate and 10-15% calcium oxide.

5. The copper scrap regeneration smelting method according to claim 1 or 4, characterized in that: In step (f), the refining time is 5-6 hours; the flame is sprayed 3-5 times, each time for 15-25 minutes, the slag is skimmed, and the reaction is carried out under a ventilation device.

6. The copper scrap regeneration smelting method according to claim 1, characterized in that: In step (i), nitrogen is introduced into the molten copper through the first chamber (2) of the subcontractor to remove hydrogen at a flow rate of 5-10 L / min for 2-5 minutes; and then inert gas helium is introduced into the second chamber (4) at a flow rate of 10-15 L / min for 3-8 minutes for further slag blowing and refining.

7. The copper scrap regeneration smelting method according to claim 1, characterized in that: In step (b), the pretreatment operation is as follows: first, waste paper and plastic are removed by air separation, and then iron chips, nickel chips and scrap steel are separated by a magnetic separator, and magnetic separation is performed 3-5 times.

8. The copper scrap regeneration smelting method according to claim 1, characterized in that: In step (c), the pretreated copper chips are subjected to centrifugal deoiling treatment using a copper chip vacuum centrifugal deoiling separator, with the speed of the vacuum centrifugal deoiling separator set at 960-1100 r / min and the deoiling time being 45-100 min.

9. The copper scrap regeneration and smelting method according to claim 1, 7 or 8, characterized in that: In step (d), the deoiled copper scraps are dried at a temperature of 300-350° C. for 35-55 minutes.

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