Method for recovering copper from copper-based solid waste based on smelting

Abstract

The application provides a method for recovering copper from copper-based solid waste based on a smelting method, and belongs to the technical field of solid waste resource utilization.The method comprises the following steps: after being mixed with waste sodium-calcium glass particles in a certain proportion, the copper-based solid waste after being crushed is put into a smelting furnace and heated to the softening of the mixture; a composite fluxing agent composed of nano-carbon loaded ferrous sulfide, a borax-diatomite composition and a carbonate is added, air or oxygen is introduced for heating and smelting, and intermittent stirring is carried out; after complete melting, a reduction-slagging multifunctional additive composed of porous coke, calcium-aluminum-zinc composite oxide and silicon dioxide is added, inert gas is introduced for heat preservation and smelting, and intermittent stirring is carried out; slag is discharged after smelting is completed, the melt is discharged, and copper resource recovery is realized.The application processes copper-based solid waste based on a smelting method, adds waste glass in the raw material, and adds a composite fluxing agent and a reduction-slagging multifunctional additive with specific components, so that the copper recovery rate is improved, and a high-purity copper product is recovered.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid waste resource utilization, and particularly relates to a method for recovering copper from copper-based solid waste based on a smelting method. BACKGROUND

[0002] The copper-based solid waste is mainly derived from the mining, smelting, processing, use and recycling of waste products of copper, and usually contains copper or other valuable metals. The copper-based solid waste is characterized by high copper content and high recoverable value, but most of the copper-based solid waste (such as smelting slag, anode mud generated during electrolytic refining of copper, waste electrolyte, industrial sludge, etc.) has the difficulty of being not easy to recover.

[0003] At present, the methods for recovering copper from copper-based solid waste mainly include pyrometallurgical smelting, hydrometallurgy, biological leaching, electrolysis, ion exchange and the like. Although the smelting method has high energy consumption, it has large processing capacity, fast speed and is suitable for different grades of copper-containing solid waste materials, and can also be compatible with different forms of copper waste materials, and thus the smelting method is most widely used in actual engineering.

[0004] However, the smelting method has the defect of large copper loss, because during smelting, copper is easily retained in the slag in the form of oxide or sulfide (the slag contains 0.5wt%-2wt% of copper); and at high temperature, copper and its compounds can volatilize into smoke dust. In order to solve the technical problem, a fluxing agent, a deslagging agent and the like are added during smelting to reduce the loss of copper. The fluxing agent is mainly fluoride, such as calcium fluoride, aluminum fluoride and the like, which combines with copper oxide and cuprous oxide to form copper fluoride and peels off, and at the same time, the fluidity of the ash slag is improved. However, the recovery rate of copper resources is relatively low, generally not higher than 95%, and the recovered product is crude copper (the purity is not higher than 99%), in addition, a large amount of fluoride-containing pollutants are generated, which are harmful to the environment and need secondary treatment. SUMMARY

[0005] In view of this, the present application aims to provide a method for recovering copper from copper-based solid waste based on a smelting method, and aims to solve at least one technical problem in the background art.

[0006] The present application is implemented as follows:

[0007] The method for recovering copper from copper-based solid waste based on a smelting method comprises the following steps:

[0008] The crushed copper-based solid waste and waste sodium-calcium glass particles are mixed in proportion and then put into a smelting furnace, and heated to soften the mixture;

[0009] A predetermined proportion of a composite fluxing agent is added, air or oxygen is introduced for heating and smelting, and intermittent stirring is performed;

[0010] After complete melting, a reduction-slag-adjusting multifunctional additive is added, inert gas is introduced for heat preservation smelting, and intermittent stirring is performed;

[0011] After smelting, slag is discharged, and the melt is discharged to realize copper resource recovery;

[0012] The composite flux includes nano-carbon loaded ferrous sulfide, borax-diatomite composition, and carbonate; the borax-diatomite composition is in the form of diatomite coated borax.

[0013] The reducing-slag adjusting multifunctional flux includes porous coke, calcium-aluminum-zinc composite oxide, and silicon dioxide; the preparation steps of the porous coke include, in sequence, micro-oxygen drying pyrolysis, oxygen-free solidification maturation, water vapor activation, and micro-oxygen ablation.

[0014] Preferably, the amount of the composite flux is 1wt%-5wt% of the copper-based solid waste;

[0015] According to the weight ratio, in the composite flux, the borax-diatomite composition: nano-carbon loaded ferrous sulfide: carbonate = 3-5: 2-4: 1.

[0016] The carbonate is selected from at least one of sodium carbonate and potassium carbonate.

[0017] Preferably, the amount of the reducing-slag adjusting multifunctional flux is 0.5wt%-2.5wt% of the copper-based solid waste;

[0018] According to the weight ratio, in the reducing-slag adjusting multifunctional flux, the porous coke: calcium-aluminum-zinc composite oxide: silicon dioxide = 5-10: 2-4: 1.

[0019] The calcium-aluminum-zinc composite oxide is calcium oxide, aluminum oxide, and zinc oxide; according to the weight ratio, calcium oxide: aluminum oxide: zinc oxide = 1.1-1.3: 1: 1.

[0020] Preferably, the preparation steps of the nano-carbon loaded ferrous sulfide are as follows:

[0021] The iron-sulfur raw material is mixed with charcoal by ball milling;

[0022] In an inert atmosphere, calcination is performed at 300-400°C, and the nano-carbon loaded ferrous sulfide is obtained after cooling;

[0023] The iron-sulfur raw material is a mixture of ferrous sulfide powder or Fe element and S element;

[0024] According to the weight ratio, charcoal: iron-sulfur raw material = 3-5: 1.

[0025] Preferably, the preparation steps of the borax-diatomite composition are as follows:

[0026] The broken and dried diatomite is dispersed in a borax solution, stirred for more than 2 hours, and ultrasonic treatment is performed intermittently during the process;

[0027] The borax-diatomite composition is obtained by drying under reduced pressure at a low temperature of not higher than 40℃.

[0028] The diatomite:borax is in a weight ratio of 2-5:1.

[0029] Preferably, the porous coke is prepared by the following steps:

[0030] The mixed coal of the main coking coal, high-volatile coal and low metamorphic coal is mixed with biomass.

[0031] The temperature is raised to 200-400℃ under a micro-oxygen environment, and the temperature is maintained for 1-1.5h.

[0032] The temperature is raised to 1100-1200℃ under an oxygen-free environment, and the temperature is maintained for 10-15h.

[0033] After the temperature is lowered to 800-900℃, water vapor is introduced for activation treatment, and then a mixed gas of air and CO2 is introduced for ablation treatment.

[0034] The porous coke is obtained by natural cooling under the oxygen-free environment.

[0035] The particle size of the main coking coal, high-volatile coal and low metamorphic coal is 5-15mm.

[0036] The main coking coal:high-volatile coal:low metamorphic coal is in a weight ratio of 3-5:1-2:1.

[0037] The biomass is used in an amount of 5-10wt% of the mixed coal.

[0038] Preferably, the oxygen volume content in the micro-oxygen environment is 1-3%, and the temperature rising rate under the micro-oxygen environment is 10-50℃ / min.

[0039] The temperature rising rate under the oxygen-free environment is 50-100℃ / min.

[0040] Preferably, the water vapor is used in an amount of 3-5wt% of the mixed coal in the activation treatment, and the activation treatment time is 30-60min.

[0041] Preferably, the oxygen volume content in the mixed gas of air and CO2 is 5-10%, the mixed gas for ablation treatment is 10-15wt% of the mixed coal, and the ablation treatment time is 20-40min.

[0042] Preferably, the waste sodium-calcium glass particles are used in an amount of 5-15wt% of the copper-based solid waste.

[0043] Compared with the prior art, the present application has the following beneficial effects:

[0044] 1.The application is based on smelting method for processing low-grade copper-based solid waste, adding waste sodium-calcium glass in raw materials, and adding composite fluxing agent and reducing-slagging multifunctional fluxing agent with specific components, which improves copper recovery rate and recovers high-purity copper products.

[0045] 2.The composite fluxing agent and reducing-slagging multifunctional fluxing agent provided by the application are green and environmentally friendly, do not produce a large amount of fluorine-containing pollutants, have little harm to the environment, and do not need secondary treatment.

[0046] 3.The application adds waste sodium-calcium glass particles in copper-based solid waste raw materials, and the two form a eutectic, which reduces the subsequent smelting temperature, thereby saving energy.

[0047] 4.The application adds waste sodium-calcium glass particles in copper-based solid waste raw materials to promote the flowability of the slag phase, which can improve the flowability of the slag after the glass is melted, facilitate the separation of metal and slag phase, reduce the entrainment loss of copper in the slag, and integrate the oxide impurities in the copper-based solid waste to form a stable slag phase.

[0048] 5.The composite fluxing agent provided by the application is composed of nano-carbon loaded ferrous sulfide, borax-diatomite composition and carbonate, which reduces the melting point of copper-based solid waste, reduces copper loss and improves the purity of copper resource recovery products.

[0049] 6.The reducing-slagging multifunctional fluxing agent provided by the application is composed of porous coke, calcium-aluminum-zinc composite oxide and silicon dioxide, which forms a stable copper alloy in the melt, wherein the calcium-aluminum-zinc composite oxide can reduce the viscosity of the slag system, control the silica activity in the slag to inhibit the silication of copper, and reduce the copper content in the slag; the porous coke protects the copper metal from being oxidized again, thereby improving the copper recovery rate, and its pore structure increases the melt-slag phase interface area, and the silicon dioxide is beneficial to the entry of metal impurities into the slag phase. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical scheme and advantages of the application clearer, the application will be further described in detail below with examples. It should be understood that the specific implementation examples described herein are only used to explain the application and not to limit the application.

[0051] The method for recovering copper from copper-based solid waste based on smelting method includes the following steps S1 to S4:

[0052] S1, mix the crushed copper-based solid waste and waste sodium-calcium glass particles in proportion and then put them into a smelting furnace, and heat the mixture to softening; the specific temperature is adjusted according to the copper-based solid waste and waste sodium-calcium glass, and is generally in the range of 500-800°C.

[0053] Wherein, the reason for adding waste sodium-calcium glass particles in the copper-based solid waste raw material is:

[0054] (1) The two form a eutectic, wherein the Na2O and CaO in the sodium-calcium glass can react with the oxides in the copper-based solid waste raw material to form a low-temperature eutectic silicate, thereby reducing the subsequent smelting temperature and saving energy;

[0055] (2) Promote the flowability of the slag phase: the glass can improve the flowability of the slag after melting, which is beneficial to the separation of metal and slag phase and reduces the entrainment loss of copper in the slag;

[0056] (3) Slagging and impurity removal: capture oxide impurities, the sodium-calcium glass can integrate the metal oxides such as Fe, Zn, Pb, etc. in the copper-based solid waste to form stable slag phases such as fayalite and lead silicate, thereby reducing the volatilization of harmful impurities.

[0057] In addition, since the sodium-calcium glass has a complex composition mainly composed of silicon dioxide, excessive addition will result in excessive slag in the subsequent process, and thus the amount of waste sodium-calcium glass particles is limited to 5wt% to 15wt% of the copper-based solid waste.

[0058] S2, add a predetermined proportion of a composite fluxing agent, and heat and smelt by passing in air or oxygen, with intermittent stirring.

[0059] The smelting temperature in this step can be adjusted according to the source of the copper-based solid waste, and is generally raised to 1100°C to 1300°C, which is not specifically limited herein. The purpose of smelting by passing in air or oxygen in this step is to promote the reaction of part of the impurities (iron, zinc, lead, sulfur) in the copper-based solid waste with oxygen to generate oxides and enter the slag phase, thereby realizing the enrichment of copper.

[0060] The composite fluxing agent includes nano-carbon loaded ferrous sulfide, borax-diatomite composition, and carbonate; according to the weight ratio, in the composite fluxing agent, the borax-diatomite composition: nano-carbon loaded ferrous sulfide: carbonate = 3 to 5: 2 to 4: 1. The amount of the composite fluxing agent is 1wt% to 5wt% of the copper-based solid waste.

[0061] The preparation steps of the nano-carbon loaded ferrous sulfide are: mixing according to the weight ratio of charcoal particles: iron and sulfur raw materials (ferrous sulfide powder or Fe element + S element mixture) = 3-5:1, ball milling treatment; then baking at 300-400 DEG C in an inert atmosphere, and obtaining the nano-carbon loaded ferrous sulfide after cooling. The ferrous sulfide is decomposed to release active sulfur at high temperature, and selectively sulfidizes copper oxides to generate low-melting-point Cu2S, avoiding copper entering the slag phase. The nano-carbon has the characteristics of high specific surface area, and as a carrier of the ferrous sulfide, the ferrous sulfide is more uniformly distributed, effectively promotes the stability of the above-mentioned reaction, and avoids the decomposition of the ferrous sulfide too fast. In addition, the introduction of air or oxygen can cooperate with the nano-carbon loaded ferrous sulfide to oxidize part of the iron and sulfur to generate copper matte and iron-rich slag, realize the selective enrichment of copper, and further improve the copper recovery rate.

[0062] The preparation steps of the borax-diatomite composition are: dispersing the broken and dried diatomite in a borax solution, stirring for more than 2 hours, and cooperating with intermittent ultrasonic treatment (generally ultrasonic treatment for 5-10 minutes every 30 minutes) in the process, so that the borax enters the porous structure of the diatomite; drying under reduced pressure at a low temperature of not more than 40 DEG C, and obtaining the borax-diatomite composition, in which the diatomite coats the borax; according to the weight ratio, diatomite: borax = 2-5:1. In the present application, the borax is the main force of fluxing agent, but its fluxing effect is not as good as that of fluoride, so the amount needs to be increased. A large amount of use will cause the slag amount to increase, which is not conducive to metal-slag separation. Therefore, the present application adopts the borax-diatomite composition in the form of borax coated by diatomite. In specific implementation, the porous structure of the diatomite can adsorb the borax solution or fine particles, realizing uniform dispersion of the borax; at high-temperature smelting, the borax has a large contact area with the diatomite, and the reaction is rapid and sufficient, effectively promoting the generation rate of borosilicate glass phase to be improved and the viscosity stability of the molten slag to be improved, thereby reducing the smelting temperature, shortening the reaction time, reducing the energy consumption, and improving the metal-slag separation efficiency. In addition, the pore structure of the diatomite can physically bind the borax, delaying its decomposition and volatilization, the silicon hydroxyl (Si-OH) on the surface of the diatomite forms a hydrogen bond or a borosilicon bond (such as Si-O-B) with the borax, and the thermal stability is enhanced. On the other hand, the borax-diatomite composition cooperates with the carbon source in the nano-carbon loaded ferrous sulfide, realizes gradient hydrogen release during high-temperature smelting, reduces high-valence copper, and at the same time inhibits the competitive reduction of other metals such as Fe 3+

[0063] The carbonate is selected from at least one of sodium carbonate and potassium carbonate; the carbonate acts as an alkaline fluxing agent, which can neutralize acidic oxides and improve the fluidity of the smelting slag.

[0064] S3, after complete melting, adding a reducing-slag-adjusting multifunctional fluxing agent, introducing inert gas for heat preservation smelting, and intermittent stirring.

[0065] ​The smelting time in the present step is adjusted according to the copper-based solid waste composition, such as high copper and low impurities, the smelting time is short, generally 2h-4h; containing iron, zinc, plastic and other impurities, then need longer time to oxidize and form slag, such as 4h-8h, which is not specifically limited here.

[0066] The reduction-slagging multifunctional agent includes porous coke, calcium-aluminum-zinc composite oxide and silicon dioxide, and the weight ratio of the porous coke: calcium-aluminum-zinc composite oxide: silicon dioxide is 5-10: 2-4: 1; the calcium-aluminum-zinc composite oxide is calcium oxide, aluminum oxide and zinc oxide; and the weight ratio of the calcium oxide: aluminum oxide: zinc oxide is 1.1-1.3: 1: 1. The amount of the reduction-slagging multifunctional agent is 0.5wt%-2.5wt% of the copper-based solid waste.

[0067] The calcium-aluminum-zinc composite oxide can reduce the viscosity of the slag system, and the zinc oxide preferentially forms stable olivine structure compounds with metal impurities such as arsenic / lead and silicon dioxide, thereby inhibiting the silication of copper by controlling the silicon dioxide activity in the slag and reducing the copper content in the slag. The main role of the porous coke is to protect the copper metal from secondary oxidation as a reducing agent, thereby improving the copper recovery rate, and the pore structure of the porous coke increases the melt-slag phase interface area.

[0068] The preparation steps of the porous coke include micro-oxygen drying pyrolysis, oxygen-free solidification maturation, water vapor activation and micro-oxygen ablation in sequence, and the specific steps are as follows: first, mixed coal of main coking coal, high-volatile coal and low metamorphic coal is used as raw material, and biomass is added; then the temperature is rapidly increased to 200-400℃ under a micro-oxygen environment, and the temperature is maintained for 1-1.5h; then the temperature is rapidly increased to 1100-1200℃ under an oxygen-free environment, and the temperature is maintained for 10-15h; then the temperature is decreased to 800-900℃, and water vapor is introduced for activation treatment, and then a mixed gas of air and CO2 is introduced for ablation treatment; finally, the porous coke is obtained by natural cooling under an oxygen-free environment. The present application combines main coking coal (high adhesion), high-volatile coal (increasing pore precursor), low metamorphic coal (adjusting reaction activity) and biomass (renewable carbon source, introducing unique pore structure), and optimizes pore development through multi-component synergistic effect.

[0069] The particle size of the main coking coal, high-volatile coal and low metamorphic coal is 5-15mm, so as to avoid too small particle size which is not easy to form pores and too large particle size which is not easy to fully and uniformly carbonize.

[0070] The weight ratio of the main coking coal: high-volatile coal: low metamorphic coal is 3-5: 1-2: 1; the high-volatile coal and the low metamorphic coal are coal allowed in the field, such as gas coal and weakly caking coal for the high-volatile coal, and long flame coal for the low metamorphic coal. The high-volatile coal will form pores at high temperature, and the low-rank coal can increase the pores.

[0071] The biomass is 5wt% to 10wt% of the mixed coal, and the biomass is agricultural waste such as straw, fruit shell, rice husk, etc.

[0072] The oxygen volume content in the micro-oxygen environment is 1% to 3% (the rest is nitrogen and / or argon and other inert gases), and the process is slightly oxidized, the oxygen-containing functional groups are increased, the pore generation during pyrolysis is improved, and the coke strength is avoided from being damaged by excessive oxidation; the heating rate in the micro-oxygen environment is 10℃ / min to 50℃ / min, and a large amount of volatile matter is precipitated in this stage, and the rapid heating can reduce the secondary condensation and retain more initial pores.

[0073] The heating rate in the oxygen-free environment is 50℃ / min to 100℃ / min, the rapid heating promotes the rapid escape of volatile matter, forms a through pore, and avoids densification, and the rapid heating causes thermal stress cracks.

[0074] In the activation stage, the amount of water vapor is 3wt% to 5wt% of the mixed coal, and the activation treatment time is 30min to 60min. In the activation treatment, the pores are selectively expanded by the reaction of C and water, and the ratio of mesopores / macropores is particularly improved.

[0075] In the ablation stage, the oxygen volume content in the mixed gas of air and CO2 is 5% to 10%, the ablation treatment mixed gas is 10wt% to 15wt% of the mixed coal, and the ablation treatment is 20min to 40min. The mixed gas of carbon dioxide and oxygen is introduced for short-time treatment, the weak area is rapidly oxidized, the carbon atoms are selectively ablated to expand the pores, and the through pores are formed. The activation+ablation realizes the pore size gradient control.

[0076] S4, after the smelting is finished, the slag is discharged, the melt is discharged, and the copper resource recovery is realized.

[0077] Example 1

[0078] The composite flux is prepared, and the steps are as follows:

[0079] (1) Synthesis of nano-carbon loaded ferrous sulfide: mixed according to the weight ratio of charcoal particles: ferrous sulfide powder = 4:1, ball milling treatment; then baked at 300℃ for about 1 hour in an inert atmosphere, and obtained after cooling;

[0080] (2) Synthesis of borax-diatomite composition: disperse the broken and dried diatomite in the borax solution (according to the weight ratio, diatomite: borax = 4:1), stir for 3 hours, and ultrasonic treatment for 5min every 30min during the process to make the borax enter the porous structure of the diatomite; under the condition of low temperature of 30℃ to 35℃, dry under reduced pressure, and obtain the borax-diatomite composition in the form of diatomite coated borax;

[0081] (3) According to the borax-diatomaceous earth composition: nano-carbon loaded ferrous sulfide: sodium carbonate = 3:2:1 mass ratio of raw materials, mixed in proportion to obtain the composite flux.

[0082] A reducing-slagging multifunctional flux was prepared, and the steps were as follows:

[0083] (1) Synthesis of porous coke: first, the mixed coal was weighed according to the mass ratio of 3:1:1, and then 5wt% of rice husk was added; then, in a micro-oxygen environment (1% oxygen + 99% nitrogen), the temperature was raised at a rate of 30℃ / min, and the temperature was kept in the range of 200℃-400℃ for 1h; then, in an oxygen-free environment, the temperature was raised at a rate of 80℃ / min, and the temperature was kept in the range of 1100℃-1200℃ for 12h; then, the temperature was lowered, and 3wt% water vapor was introduced for activation treatment for 60min, followed by 10wt% mixed gas (air and CO2, and the oxygen content was 5%) for ablation treatment for 40min; finally, the temperature was naturally cooled down in an oxygen-free environment to obtain the porous coke;

[0084] (2) Preparation of calcium-aluminum-zinc composite oxide: according to the mass ratio of calcium oxide: aluminum oxide: zinc oxide = 1.2:1:1, the metal oxides were weighed and stirred to obtain the calcium-aluminum-zinc composite oxide;

[0085] (3) According to the mass ratio of porous coke: calcium-aluminum-zinc composite oxide: silicon dioxide = 5:2:1, the raw materials were weighed and mixed in proportion to obtain the reducing-slagging multifunctional flux.

[0086] A method for recovering copper from copper-based solid waste based on smelting method, comprising the following steps S1 to S4:

[0087] S1, the copper-based solid waste (copper content is 25.4%) is mechanically broken and dried, and the waste sodium-calcium glass is mechanically broken into particles; 5wt% of waste sodium-calcium glass particles is added to the copper-based solid waste, and then mixed and put into a smelting furnace, heated to about 720℃, and the mixture is softened at this time;

[0088] S2, 1wt% of the above-mentioned composite flux is added to the copper-based solid waste, and air is introduced to heat to about 1300℃, and intermittent stirring is carried out during the process;

[0089] S3, after complete melting, stop blowing air, add 0.5wt% of the above-mentioned reducing-slagging multifunctional flux to the copper-based solid waste, introduce argon, and keep the temperature in the range of 1100℃-1300℃ for 3h, and intermittent stirring is carried out during the process.

[0090] S4, after the smelting is completed, the slag is discharged by side blowing, and the molten copper alloy is obtained by cooling after the molten metal is discharged, and the copper resource recovery is realized. The copper content in the molten copper alloy and the slag is tested by ICP-OES method, and the copper recovery rate is calculated.

[0091] The copper content in the copper-based solid waste, copper alloy, and slag refers to the ratio of the mass of copper to the total mass of the copper-based solid waste / copper alloy / slag; m1 is the mass of the copper alloy, C1 is the copper content in the copper alloy, m0 is the mass of the copper-based solid waste, and C0 is the copper content in the copper-based solid waste.

[0092] The test results show that the copper content in the copper alloy and slag is 99.14% and 0.37%, respectively, and the copper recovery rate is 97.17%. It can be seen that the copper content in the copper alloy is more than 99%, which belongs to a high-purity copper resource and can be directly applied in industry.

[0093] Example 2

[0094] This example studies the effect of different amounts of waste sodium-calcium glass on copper resource recovery. In this example, the amount of waste sodium-calcium glass in step S1 is adjusted to 0wt%, 3wt%, 8wt%, 10wt%, 12wt%, and 15wt% of the copper-based solid waste based on Example 1, and the other reaction conditions and steps are consistent with Example 1.

[0095] The copper content in the molten copper alloy and slag is tested by the same method as in Example 1, and the copper recovery rate is calculated and compared with Example 1. See Table 1 below for details.

[0096] Table 1

[0097]

[0098] As shown in Table 1, when no waste sodium-calcium glass is added during smelting, the copper content in the molten product decreases slightly, the copper content in the slag increases, and the copper recovery rate decreases significantly. The reason is that without the addition of waste sodium-calcium glass, part of the impurities cannot enter the slag phase and remain in the melt, thereby reducing the copper content in the molten product. At the same time, the slag phase has poor fluidity, resulting in a significant increase in slag volume, part of the copper oxide is trapped, thereby significantly increasing the copper loss and significantly reducing the copper recovery rate.

[0099] In addition, as the amount of waste sodium-calcium glass increases, the copper content in the molten product as a whole shows an increasing trend, but the copper content in the slag fluctuates up and down, and the copper recovery rate shows a trend of first increasing and then decreasing. The reason is that too much waste sodium-calcium glass is added, resulting in excessive slag volume, even if the copper content in the slag phase does not change significantly, but the copper loss increases, so the amount of waste sodium-calcium glass particles is limited to 5wt% to 15wt% of the copper-based solid waste, preferably 5wt% to 10wt%.

[0100] Example 3

[0101] The embodiment studies the influence of different amounts of composite flux on copper resource recovery. On the basis of embodiment 1, the amount of composite flux in step S2 is adjusted to 0wt%, 2wt%, 3wt%, 4wt%, 5wt% of copper-based solid waste, and other reaction conditions and steps are consistent with embodiment 1.

[0102] The same method as in embodiment 1 is used to test the copper content in the melt copper alloy and the slag, and the copper recovery rate is calculated and compared with embodiment 1, as shown in Table 2 below.

[0103] Table 2

[0104]

[0105] As can be seen from the data in Table 2, when no composite flux is added during smelting, the copper content in the melt product is significantly reduced, the copper content in the slag is increased, and the copper recovery rate is significantly reduced. The reason is that, on the one hand, without the addition of composite flux, the slag phase has poor fluidity, resulting in a significant increase in slag amount, part of the copper oxide is trapped, and thus the copper loss increases significantly, and the copper recovery rate decreases significantly. On the other hand, it cannot effectively promote the removal of impurities and improve the stability of copper in the melt, thereby reducing the copper content in the melt product.

[0106] In addition, as the amount of composite flux increases, the copper content in the melt product as a whole shows an increasing trend, but the increase is not obvious; the copper content in the slag as a whole first decreases significantly and then increases slowly, and the copper recovery rate shows a trend of first increasing steadily and then decreasing significantly. The reason is that too much composite flux added leads to an increase in iron impurities and an increase in matte phase in the slag phase, thereby increasing the loss of copper. Therefore, the amount of composite flux is limited to 1wt% to 5wt% of the copper-based solid waste, preferably 2wt% to 4wt%.

[0107] Embodiment 4

[0108] The embodiment studies the influence of different amounts of reduction-slag adjusting multifunctional additives on copper resource recovery. On the basis of embodiment 1, the amount of reduction-slag adjusting multifunctional additives in step S3 is adjusted to 0wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt% of copper-based solid waste, and other reaction conditions and steps are consistent with embodiment 1.

[0109] The same method as in embodiment 1 is used to test the copper content in the melt copper alloy and the slag, and the copper recovery rate is calculated and compared with embodiment 1, as shown in Table 3 below.

[0110] Table 3

[0111]

[0112] From the data in Table 3, when smelting without adding the reduction-slagging multifunctional additive, the copper content in the melt product is greatly reduced, the copper content in the slag is significantly increased, and the copper recovery rate is sharply reduced. The reason is that part of the copper remains in the slag phase in the form of oxide, increasing the loss of copper. In addition, part of the metal impurities in the slag phase are unstable and enter the melt in the form of alloy during smelting, resulting in a decrease in the copper content in the melt, and thus a decrease in the copper recovery rate.

[0113] In addition, as the amount of reduction-slagging multifunctional additive increases, the copper content in the melt product as a whole first increases significantly and then decreases; the copper content in the slag first decreases significantly and then increases slowly, and the copper recovery rate first increases steadily and then decreases significantly. The reason is that too much reduction-slagging multifunctional additive leads to an increase in metal impurities, changes in the viscosity of the slag phase, and thus an increase in copper loss. Therefore, the amount of reduction-slagging multifunctional additive is limited to 0.5wt% to 2.5wt% of the copper-based solid waste, preferably 1wt% to 1.5wt%.

[0114] Example 5

[0115] This example studies the effect of different ratios of composite fluxing agent on copper resource recovery. In this example, the ratio of borax-diatomite composition, nano-carbon loaded ferrous sulfide, and carbonate in the composite fluxing agent in step S2 is adjusted based on Example 1, and the other reaction conditions and steps are consistent with Example 1.

[0116] The copper content in the melt and slag is tested using the same method as in Example 1, and the copper recovery rate is calculated and compared with Example 1, as shown in Table 4 below.

[0117] Table 4

[0118]

[0119] From the data in Table 4, as the proportion of nano-carbon loaded ferrous sulfide in the composite fluxing agent increases during smelting, the copper content in the melt product as a whole first increases significantly and then decreases, the copper content in the slag as a whole first decreases and then increases, and the copper recovery rate as a whole first increases significantly and then decreases. The reason is that when the proportion of nano-carbon loaded ferrous sulfide is too high, the amount of copper matte is excessive, resulting in an increase in iron content and thus an increase in copper loss.

[0120] When smelting, with the increase of the proportion of borax-diatomite composition in the composite flux, the copper content in the melt product as a whole shows a trend of first significant increase and then decrease, the copper content in the slag shows a trend of first decrease and then increase, and the copper recovery rate shows an up-down fluctuation, because: when the proportion of borax-diatomite composition increases, the melting point is reduced while the copper in the melt is stabilized, but the amount of slag is also increased, so it causes the up-down fluctuation of copper loss, when it is too much, the amount of slag increases significantly, causing the copper loss to increase significantly.

[0121] When smelting, with the increase of the proportion of carbonate, the copper content in the melt product decreases slightly, the copper content in the slag increases, and the copper recovery rate decreases, because: under the condition that the total amount does not change, the amount of carbonate increases, and the amount of borax-diatomite composition and nano-carbon loaded ferrous sulfide decreases, so the effect of reducing copper loss is not obvious.

[0122] Therefore, according to the weight ratio, borax-diatomite composition: nano-carbon loaded ferrous sulfide: carbonate = 3-5: 2-4: 1.

[0123] Example 6

[0124] This example studies the effect of different proportions of reduction-slag adjusting multifunctional flux on copper resource recovery. Based on Example 1, the proportions of porous coke, calcium-aluminum-zinc composite oxide, and silicon dioxide in the reduction-slag adjusting multifunctional flux in step S3 are adjusted, and other reaction conditions and steps are consistent with Example 1.

[0125] The copper content in the melt and the slag is tested by the same method as in Example 1, and the copper recovery rate is calculated and compared with Example 1, as shown in Table 5 below.

[0126] Table 5

[0127]

[0128] As shown in Table 5, when smelting, with the increase of the proportion of calcium-aluminum-zinc composite oxide in the reduction-slag adjusting multifunctional flux, the copper content in the melt product as a whole shows a trend of first increase and then decrease, the copper content in the slag shows a trend of decrease, and the copper recovery rate shows a trend of first significant increase and then decrease, because: when the proportion of calcium-aluminum-zinc composite oxide is too much, the impurities in the melt increase, which in turn leads to an increase in copper loss.

[0129] When smelting, as the proportion of porous coke in the reduction-slagging multifunctional additive increases, the copper content in the melt product as a whole shows a trend of first significant increase and then slow decrease, the copper content in the slag shows a trend of first decrease and then increase, and the copper recovery rate shows a trend of first significant increase and then decrease, which is because: when the proportion of porous coke increases, the copper in the melt is stabilized, avoiding the copper entering the slag phase in the form of oxide, but excessive use of it leads to a decrease in the amount of calcium-aluminum-zinc composite oxide, thereby causing the poor flowability of the slag phase and the fluctuation of copper loss.

[0130] When smelting, as the proportion of porous coke in the reduction-slagging multifunctional additive increases, the copper content in the melt product as a whole shows a trend of first significant increase and then slow decrease, the copper content in the slag shows a trend of first decrease and then increase, and the copper recovery rate shows a trend of first significant increase and then decrease, which is because: when the proportion of porous coke increases, the copper in the melt is stabilized, avoiding the copper entering the slag phase in the form of oxide, but excessive use of it leads to a decrease in the amount of calcium-aluminum-zinc composite oxide, thereby causing the poor flowability of the slag phase and the fluctuation of copper loss.

[0131] Therefore, according to the weight ratio, porous coke: calcium-aluminum-zinc composite oxide: silicon dioxide = 5-10: 2-4: 1.

[0132] Comparative Example 1

[0133] This comparative example is based on Example 1, and the borax-diatomite composition in step S2 of the composite fluxing agent is adjusted to a mixture of borax and diatomite, i.e. diatomite: borax = 4: 1 (weight ratio) mixed, and other reaction conditions and steps are consistent with Example 1.

[0134] The copper content in the melt copper alloy and the slag is tested by the same method as in Example 1, and the copper recovery rate is calculated and compared with Example 1, as shown in Table 6 below.

[0135] Comparative Example 2

[0136] This comparative example is based on Example 1, and the nano-carbon loaded ferrous sulfide in step S2 of the composite fluxing agent is adjusted to a mixture of charcoal particles and ferrous sulfide powder, i.e. charcoal particles: ferrous sulfide powder = 4: 1 (weight ratio) mixed, and other reaction conditions and steps are consistent with Example 1.

[0137] The copper content in the melt copper alloy and the slag is tested by the same method as in Example 1, and the copper recovery rate is calculated and compared with Example 1, as shown in Table 6 below.

[0138] Comparative Example 3

[0139] This comparative example is based on Example 1, and the porous coke in step S3 of the reduction-slagging multifunctional additive is adjusted to conventional coke, and other reaction conditions and steps are consistent with Example 1.

[0140] The copper content in the melt copper alloy and the slag is tested by the same method as in Example 1, and the copper recovery rate is calculated and compared with Example 1, as shown in Table 6 below.

[0141] The preparation steps of the coke in the present comparative example are as follows: first, mixed coal is weighed according to a mass ratio of 3:1:1 of main coking coal, weakly caking coal and long flame coal, and 5wt% of rice husk is added to the mixed coal; then, the temperature is rapidly increased at a rate of 80℃ / min in an oxygen-free environment, and the temperature is kept in the range of 1100℃-1200℃ for 12h; and the coke is obtained by natural cooling.

[0142] Comparative Example 4

[0143] The present comparative example is based on Example 1, and the porous coke in the step S3 reduction-slagging multifunctional additive is adjusted to porous coke without steam activation, and other reaction conditions and steps are consistent with Example 1.

[0144] The copper content in the melt copper alloy and the slag is tested by the same method as in Example 1, and the copper recovery rate is calculated, and compared with Example 1, and the specific data are shown in Table 6 below.

[0145] The preparation steps of the coke in the present comparative example are as follows: first, mixed coal is weighed according to a mass ratio of 3:1:1 of main coking coal, weakly caking coal and long flame coal, and 5wt% of rice husk is added to the mixed coal; then, the temperature is rapidly increased at a rate of 30℃ / min in a micro-oxygen environment (1% oxygen + 99% nitrogen), and the temperature is kept in the range of 200℃-400℃ for 1h; then, the temperature is rapidly increased at a rate of 80℃ / min in an oxygen-free environment, and the temperature is kept in the range of 1100℃-1200℃ for 12h; then, the temperature is decreased, and 10wt% mixed gas (air and CO2, and the oxygen content is 5%) is introduced in the range of 800℃-900℃ for 40min for ablation treatment; finally, the porous coke is obtained by natural cooling in an oxygen-free environment.

[0146] Comparative Example 5

[0147] The present comparative example is based on Example 1, and the porous coke in the step S3 reduction-slagging multifunctional additive is adjusted to porous coke without ablation treatment, and other reaction conditions and steps are consistent with Example 1.

[0148] The copper content in the melt copper alloy and the slag is tested by the same method as in Example 1, and the copper recovery rate is calculated, and compared with Example 1, and the specific data are shown in Table 6 below.

[0149] The preparation steps of the coke in the present comparative example are as follows: first, the main coking coal, weakly caking coal and long flame coal are weighed according to the mass ratio of 3:1:1 to obtain mixed coal, and 5wt% of rice husk is added to the mixed coal; then, the mixed coal is rapidly heated at a rate of 30℃ / min in a micro-oxygen environment (1% oxygen + 99% nitrogen), and the temperature is kept in the range of 200℃-400℃ for 1h; then, the mixed coal is rapidly heated at a rate of 80℃ / min in an oxygen-free environment, and the temperature is kept in the range of 1100℃-1200℃ for 12h; then, the temperature is reduced, 3wt% of water vapor is introduced into the mixed coal in the range of 800℃-900℃ for activation treatment for 60min; finally, the mixed coal is naturally cooled in an oxygen-free environment to obtain the porous coke.

[0150] Table 6

[0151]

[0152] According to the comparison of the data of comparative example 1 and example 1 in table 6, when the borax-diatomite composition in step S2 is adjusted to a mixture of borax and diatomite, the copper content in the melt copper alloy slightly decreases, the copper content in the slag increases, and the copper recovery rate significantly decreases.

[0153] According to the comparison of the data of comparative example 2 and example 1, when the nano-carbon loaded ferrous sulfide in step S2 is adjusted to a mixture of charcoal particles and ferrous sulfide powder, the copper content in the melt copper alloy significantly decreases, the copper content in the slag slightly increases, and the copper recovery rate significantly decreases.

[0154] According to the comparison of the data of comparative examples 3-5 and example 1, when the porous coke in step S3 is adjusted to the conventional coke without activation / ablation treatment, the copper content in the melt copper alloy presents different degrees of decrease, the copper content in the slag presents different degrees of increase, and the copper recovery rate significantly decreases.

[0155] The above examples only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for recovering copper from copper-based solid waste based on smelting, characterized by, The method comprises the following steps: After the crushing treatment, the copper-based solid waste is mixed with waste sodium-calcium glass particles in proportion and then put into a smelting furnace and heated to the softening point of the mixture; A preset proportion of a composite fluxing agent is added, air or oxygen is introduced for heating and smelting, and intermittent stirring is performed; After complete melting, a reduction-slagging multifunctional additive is added, inert gas is introduced for heat preservation and smelting, and intermittent stirring is performed; After the smelting is completed, the slag is discharged, the melt is discharged, and copper resource recovery is achieved; The composite fluxing agent comprises nano-carbon loaded ferrous sulfide, a borax-diatomite composition, and a carbonate; the borax-diatomite composition is in the form of diatomite-coated borax; The reduction-slagging multifunctional additive comprises porous coke, calcium-aluminum-zinc composite oxide, and silicon dioxide; the preparation steps of the porous coke comprise, in sequence, micro-oxygen dry pyrolysis, oxygen-free solidification maturation, water vapor activation, and micro-oxygen ablation; The amount of the composite fluxing agent is 1wt%-5wt% of the copper-based solid waste; According to the weight ratio, in the composite fluxing agent, the borax-diatomite composition:nano-carbon loaded ferrous sulfide:carbonate = 3-5:2-4:1; The carbonate is selected from at least one of sodium carbonate and potassium carbonate; The amount of the reduction-slagging multifunctional additive is 0.5wt%-2.5wt% of the copper-based solid waste; According to the weight ratio, in the reduction-slagging multifunctional additive, the porous coke:calcium-aluminum-zinc composite oxide:silicon dioxide = 5-10:2-4:1; The calcium-aluminum-zinc composite oxide comprises calcium oxide, aluminum oxide, and zinc oxide; according to the weight ratio, calcium oxide:aluminum oxide:zinc oxide = 1.1-1.3:1:1; The amount of the waste sodium-calcium glass particles is 5wt%-15wt% of the copper-based solid waste.

2. The method for recovering copper from copper-based solid waste based on a smelting method according to claim 1, characterized by, The preparation steps of the nano-carbon loaded ferrous sulfide are as follows: Iron-sulfur raw materials are mixed with charcoal by ball milling; The mixture is calcined at 300-400°C in an inert atmosphere, and the nano-carbon loaded ferrous sulfide is obtained after cooling; The iron-sulfur raw materials are ferrous sulfide powder or a mixture of Fe and S elements; According to the weight ratio, charcoal:iron-sulfur raw materials = 3-5:

1.

3. The method for recovering copper from copper-based solid waste based on smelting according to claim 1, characterized by, The preparation steps of the borax-diatomite composition are as follows: After the crushing and drying, the diatomite is dispersed in a borax solution, stirred for more than 2 hours, and in the process, ultrasonic treatment is performed in an intermittent manner; The mixture is dried under reduced pressure at a temperature not higher than 40°C, and the borax-diatomite composition is obtained; According to the weight ratio, diatomite:borax = 2-5:

1.

4. The method for recovering copper from copper-based solid waste based on smelting according to claim 1, characterized by, The preparation steps of the porous coke are as follows: Mixed coal of main coking coal, high-volatile coal, and low metamorphic coal is used as raw material, and biomass is added; The mixture is heated to 200-400°C in a micro-oxygen environment and kept for 1-1.5 hours; The mixture is heated to 1100-1200°C in an oxygen-free environment and kept for 10-15 hours; After being cooled to 800-900°C, the mixture is activated by introducing water vapor and then ablated by introducing a mixture of air and CO2; The mixture is naturally cooled in an oxygen-free environment, and the porous coke is obtained; The particle size of the main coking coal, high-volatile coal, and low metamorphic coal is 5-15 mm; According to the weight ratio, main coking coal:high-volatile coal:low metamorphic coal = 3-5:1-2:

1. The biomass is used in an amount of 5wt%-10wt% of the mixed coal.

5. The method for recovering copper from copper-based solid waste based on smelting according to claim 4, characterized by, The oxygen volume content in the micro-oxygen environment is 1%-3%, and the heating rate in the micro-oxygen environment is 10°C / min-50°C / min. The heating rate in the oxygen-free environment is 50°C / min-100°C / min.

6. The method for recovering copper from copper-based solid waste based on a smelting method according to claim 4, characterized by, The water vapor is used in an amount of 3wt%-5wt% of the mixed coal in the activation treatment, and the activation treatment time is 30min-60min.

7. The method for recovering copper from copper-based solid waste based on a smelting method according to claim 4, characterized by, The oxygen volume content in the air and CO2 mixed gas is 5%-10%, the ablation treatment mixed gas is 10wt%-15wt% of the mixed coal, and the ablation treatment time is 20min-40min.

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