Method and device for smoldering, dewatering, decarbonizing and upgrading copper-containing sludge and recovering copper

Abstract

The invention belongs to the field of solid waste resourceful treatment, and discloses a copper-containing sludge smoldering dehydration and decarbonization upgrading and copper recycling method and device.The method comprises the steps that copper-containing sludge, auxiliary fuel and a heat storage medium are mixed to obtain a mixed material, and the mixed material is subjected to smoldering treatment to obtain copper-containing smoldering ash; carrying out particle size screening on the copper-containing smoldering ash to separate the heat storage medium and obtain copper-rich smoldering ash; and a reducing agent and a slag former are added into the copper-rich smoldering ash for smelting, and finally molten copper is collected to obtain crude copper. According to the method, efficient low-energy-consumption dehydration reduction of the copper-containing sludge is achieved through the self-maintaining smoldering process, input of a large amount of external energy is avoided, the scale of treatment equipment is effectively reduced, meanwhile, high-valence copper reduction can be achieved in the smoldering process, the production cost of the follow-up pyrogenic process smelting process is effectively reduced, input of a large amount of energy and the effect of a reducing agent are avoided, and industrial production is facilitated. And the method has the advantages of being simple in process, high in adaptability, low in cost and high in recycling degree.

Description

Technical Field

[0001] The present application belongs to the field of solid waste resource disposal, and more specifically, relates to a method and device for smoldering dehydration, decarbonization, upgrading and copper recovery of copper-containing sludge. Background Art

[0002] With the acceleration of industrialization, the discharge of copper-containing sludge as industrial waste continues to increase. Traditional methods for the disposal of copper-containing sludge mainly include landfill, solidification and heat treatment. These methods have problems such as waste of resources, high energy consumption and environmental pollution. At the same time, copper-containing sludge often has characteristics such as high water content, low calorific value and relatively complex composition. Its effective utilization and harmless disposal still face many challenges in the current technological system. Traditional methods such as direct incineration have high energy consumption and are prone to secondary pollution; while simple hydrometallurgical processes are difficult to effectively treat sludge with high water content and unstable calorific value, resulting in low copper leaching rate and recovery rate. At the same time, existing processes often face problems such as difficulty in solid-liquid separation, harmful gas emissions and insufficient resource utilization.

[0003] In the prior art, CN118423700B discloses a smoldering treatment device for copper-containing sludge, and CN118623320B discloses a smoldering heat energy recovery device for copper sludge. These two patents disclose smoldering treatment of copper-containing sludge to achieve reduction of copper-containing sludge and reuse of some copper metal. However, they can only recover ferromagnetic materials through magnetic adsorption and cannot recover copper, resulting in insufficient resource utilization. CN113278801B discloses a method and equipment for treating copper-containing sludge. These methods utilize a pyrometallurgical method to recover copper from copper-containing sludge. By bottom-blowing and smelting the dried copper-containing sludge, they eliminate the three steps of mixing, roasting, and brick making in the traditional process. However, multiple complex operations are still required, resulting in high energy consumption for drying and reducing agents. CN119085271A discloses a device for recovering precious metals from copper-containing sludge, which realizes precious metal recovery by drying. CN116497226A discloses a method and apparatus for melting and reducing copper-containing sludge based on an oxygen-enriched top-blowing process, which directly uses the sludge as a raw material for melting treatment through an oxygen-enriched top-blowing melting process. However, the above-mentioned technologies often require higher temperatures or use complex equipment, which not only has high energy consumption and costs, but also has problems such as complex processes, strict pretreatment requirements, and low comprehensive utilization rate of subsequent by-products when dealing with sludge with high moisture content and multiple impurity components. CN221522723U discloses a copper-containing sludge dissolution and recovery device, which realizes sludge copper recovery through a dissolution and recovery device, but such equipment is usually suitable for the initial crushing and dissolution of block sludge, and has limited improvement on energy consumption and resource recycling.

[0004] In summary, the existing technology has the following prominent problems in the treatment of copper-containing sludge: (1) The disposal process is costly: copper-containing sludge has a high moisture content (~70%), and its drying and heating processes require a large amount of external energy input; (2) The disposal equipment is large in scale and high in cost: Existing methods for the disposal of copper-containing sludge often require refractory / corrosion-resistant materials and lack efficient disposal solutions for small-scale and dispersed situations; (3) Poor adaptability to raw materials: Existing treatment methods are sensitive to the moisture content, copper content, and impurity content of copper-containing sludge, and are not adaptable to copper-containing sludge of different sources and compositions; (4) The degree of copper resource utilization is not high: some devices focus on simple removal of organic matter or simple leaching treatment, and the depth of efficient recovery and resource utilization of copper is insufficient; (5) Low process coupling: The sludge transportation, pretreatment and disposal processes are relatively dispersed and have a low coupling degree. There is insufficient research on further purification of copper such as smoldering disposal and pyrometallurgical recovery. Summary of the Invention

[0005] In response to the defects of the existing technology, the present application provides a method and device for smoldering dehydration, decarbonization and upgrading of copper-containing sludge and copper recovery, aiming to solve the problems of high treatment cost, large-scale disposal equipment, poor raw material adaptability and low degree of copper resource utilization in the existing copper-containing sludge recovery method.

[0006] According to one aspect of the present application, a method for smoldering dehydration, decarbonization, upgrading and copper recovery of copper-containing sludge is provided, specifically comprising: S1 mixes the copper-containing sludge with the auxiliary fuel and the heat storage medium to obtain a mixed material; S2 smoldering the mixed material to obtain copper-containing smoldering ash; S3: screening the copper-containing smoldering ash for particle size to separate the heat storage medium and obtain copper-rich smoldering ash; S4: adding a reducing agent and a slagging agent to the copper-rich smoldering ash and smelting the ash, and then collecting the copper liquid to obtain crude copper, thereby realizing copper element recovery.

[0007] Through the above technical solutions conceived by the present application, compared with the existing technology, the present application organically combines the smoldering technology with the pyrometallurgical smelting technology, which can realize the resource utilization, reduction and harmless treatment of copper-containing sludge. The self-sustaining smoldering process is used to achieve efficient and low-energy dehydration and reduction of copper-containing sludge, and the smoldering process can realize the reduction of high-priced copper, effectively reducing the production cost of the subsequent pyrometallurgical smelting process, and has the advantages of strong adaptability, low cost and high degree of resource utilization.

[0008] As further preferred, in step S1, the mass ratio of the heat storage medium, the copper-containing sludge, and the auxiliary fuel in the mixed material is (8-24): (3-6): 1, and the system calorific value of the mixed material is 0.7 MJ / kg-2 MJ / kg.

[0009] As further preferred, the auxiliary fuel includes one or more of biomass, coal powder, and coke, the heat storage medium includes one or more of quartz sand, ceramic balls, and alumina particles, and the particle size of the heat storage medium is 1.8 mm to 2.2 mm.

[0010] As a further preferred embodiment, in step S2, the bottom layer of the mixed material is heated to 300°C to 400°C and then the heating is stopped. Air is then introduced to allow the mixed material to achieve self-sustaining smoldering. The smoldering reaction temperature is 500°C to 700°C.

[0011] As a further preference, the Darcy flow rate of the incoming air is 2 cm / s-6 cm / s, and the volume fraction of oxygen in the incoming air is 21%-30%.

[0012] As a further preferred embodiment, in step S3, the copper-containing smoldering ash is screened using a sieve with a mesh size of 0.2 mm to 0.45 mm.

[0013] As a further preference, the heat storage medium separated in step S3 is washed and dried and then reused in step S1.

[0014] As further preferred, in step S4, the reducing agent includes one or more of coke, anthracite, and charcoal, the slag-forming agent includes ferrosilicon slag and / or ferrocalcium slag, the mass ratio of Fe to SiO2 in the ferrosilicon slag is 0.8:1~1.2:1, and the mass ratio of Fe to CaO in the ferrocalcium slag is 2.2:1~2.5:1, and the particle size of the reducing agent and the slag-forming agent is not greater than 10 mm.

[0015] As further preferred, in step S4, the mass ratio of the copper-rich smoldering ash: reducing agent: slagging agent is 1: (0.1-0.4): (0.1-0.4).

[0016] According to another aspect of the present application, an apparatus for implementing the above method is provided, comprising a smoldering reactor and a smelting blast furnace, wherein the smoldering reactor is used to perform smoldering treatment on a mixture obtained by mixing copper-containing sludge, auxiliary fuel, and heat storage medium, discharge copper-containing smoldering ash through a discharge port, and perform particle size screening on the copper-containing smoldering ash to obtain copper-rich smoldering ash; the smelting blast furnace is used to add copper-rich smoldering ash, a reducing agent, and a slag-forming agent and perform smelting, and after the smelting is completed, the molten copper enters a copper molten ladle to obtain crude copper.

[0017] In general, the above technical solutions conceived by this application have the following technical advantages compared with the existing technologies: 1. This application utilizes a smoldering combustion combined with pyrometallurgical smelting to treat copper-containing sludge, enabling both volume and quantity reduction of the copper-containing sludge while simultaneously recovering the copper element. The self-sustaining smoldering combustion process achieves efficient, low-energy dehydration and reduction of the copper-containing sludge, avoiding the need for significant external energy input and effectively reducing the scale of disposal equipment. The smoldering combustion process also reduces the high-value copper, effectively lowering the production costs of the subsequent pyrometallurgical smelting process and avoiding significant energy input and reducing agent effects. It also improves the recovery rate of the copper element, offering the advantages of a simple process, strong adaptability, low cost, and high resource utilization. 2. Furthermore, by controlling the Darcy velocity of the air introduced during the smoldering reaction and the volume fraction of oxygen in the air, this application can effectively control the smoldering reaction temperature and atmosphere, thereby promoting the reduction of high-valent copper and increasing the value of the smoldering ash through valence control, which is beneficial to the subsequent pyrometallurgical smelting process. 3. Furthermore, the apparatus provided in this application, through deep coupling of smoldering treatment and pyrometallurgical smelting treatment, can achieve efficient treatment of small-scale, dispersed processes. The copper-containing smoldering ash obtained from the smoldering reactor is completely dehydrated and free of organic matter, facilitating transport and centralized collection. This enables pyrometallurgical smelting treatment to also handle small-scale, dispersed processes, while also further increasing the copper content of copper-containing sludge. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flow chart of the method for smoldering dehydration, decarbonization, upgrading and copper recovery of copper-containing sludge provided in an embodiment of the present application; Figure 2 It is a schematic diagram of the copper-containing sludge smoldering dehydration, decarbonization, upgrading and copper recovery device provided in an embodiment of the present application.

[0019] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-smoldering reactor, 2-feeding assembly, 3-air inlet assembly, 4-heating assembly, 5-discharge port, 6-smelting blast furnace, 7-copper ladle. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0021] like Figure 1 As shown, according to one aspect of the present application, a method for smoldering dehydration, decarbonization, upgrading and copper recovery of copper-containing sludge is provided, specifically: S1 mixes the copper-containing sludge with the auxiliary fuel and the heat storage medium to obtain a mixed material; S2 smolders the mixed material to obtain copper-containing smoldering ash; S3 performs particle size screening on the copper-containing smoldering ash to separate the thermal storage medium and obtain the copper-rich smoldering ash; S4 adds reducing agent and slagging agent to the copper-rich smoldering ash and then smelts it, then collects the copper liquid to obtain crude copper, thereby realizing copper element recovery.

[0022] The copper-containing sludge smoldering dehydration, decarbonization, upgrading and copper recovery method provided in this application has the following advantages over the existing technology: (1) Self-sustaining smoldering process with high efficiency and low consumption for dehydration and volume reduction: smoldering utilizes the slow combustion heat release of the organic components in the mixture to maintain the reaction, achieving complete dehydration of sludge with a moisture content of more than 70% and a volume reduction of more than 90% while consuming a small amount of auxiliary fuel; (2) Smoldering treatment promotes cost reduction in the pyrometallurgical recovery process: Through the special pyrolysis / oxidation reaction of the smoldering process, part of the high-valent copper is reduced, which promotes the conversion of high-valent copper (divalent copper) in the copper-containing sludge to low-valent copper (monovalent copper, zero-valent copper). In the subsequent pyrometallurgical smelting process, compared with high-valent copper, low-valent copper has lower requirements for reducing agents and smelting temperatures during the reduction process, thereby effectively reducing the energy and reducing agent consumption in the pyrometallurgical treatment process, further improving the recovery rate of copper elements, and due to the thorough dehydration of copper-rich smoldering ash, the crude copper smelting process can further reduce energy consumption; (3) Adaptable to small-scale decentralized situations: The smoldering reaction equipment can be integrated into vehicles, and the moisture content of the copper-rich smoldering ash is less than 1%, and the organic matter is removed, which is easy to transfer and transport. The smoldering reaction is relatively fast, which is convenient for small-scale decentralized disposal; (4) Reduce the emission of harmful substances: The smoldering reaction bed has a significant blocking effect on pollutants such as particulate matter, fly ash, and dioxins. The milder reaction temperature has a significant effect on the low-temperature removal of sulfur / nitrogen / chlorine and the reduction of NOx and SOx in the high-temperature stage; (5) Simplified process, easy control and cost reduction: The method provided in this application is simple to operate, easy to industrially scale up, mass produce and automatically control, does not require significant additional cost investment, and has good economic efficiency and feasibility; (6) Strong adaptability and flexible process: The method provided in this application can effectively treat various types of copper-containing sludge by adjusting the mixing ratio and smoldering conditions according to the characteristics of sludge with different moisture content and organic matter content. The flexibility of this process also makes it flexibly applicable to different treatment scales and scenarios.

[0023] In summary, this application organically integrates the self-sustaining smoldering of copper-containing sludge with pyrolysis treatment technology, thereby achieving efficient recovery of copper resources while greatly reducing energy consumption and costs, providing an efficient and feasible way for the resource utilization, reduction and harmless treatment of copper-containing sludge.

[0024] Furthermore, in step S1, the copper-containing sludge does not need to be pretreated, and a traditional drying process is not required. The auxiliary fuel can be any solid fuel containing organic matter to provide heat during the smoldering reaction. The addition strategy can be adjusted according to factors such as the calorific value, moisture content, and copper occurrence form of the copper-containing sludge, thereby improving the self-sustaining ability and thermal efficiency of the smoldering process while providing a reducing agent for the reduction of high-valent copper. Preferably, one or more of biomass, coal powder, and coke are used. The particle size of the auxiliary fuel is controlled within a range of no more than 2 mm. The mass ratio of the heat storage medium, copper-containing sludge, and auxiliary fuel in the mixture is (8-24): (3-6): 1. The system calorific value of the mixture is 0.7 MJ / kg-2 MJ / kg, thereby maintaining the stable progress of the smoldering reaction while avoiding waste caused by excessive auxiliary fuel.

[0025] Furthermore, the heat storage medium is mainly used to provide a porous structure, plays the role of heat storage and heat conduction, and does not participate in the reaction. It is preferred to use one or more of quartz sand, ceramic balls, and alumina particles. The particle size of the heat storage medium is 1.8mm~2.2mm, so that the heat storage medium and the mixed material form a uniform pore structure. Too large a particle size will lead to uneven distribution of the material, and too small a particle size may block the pore structure.

[0026] Furthermore, in step S2, the bottom layer of the mixed material is heated to 300°C to 400°C, then heating is stopped. Air is then introduced to achieve self-sustaining smoldering of the mixed material. The smoldering reaction temperature is 500°C to 700°C. The Darcy velocity of the introduced air is 2 cm / s to 6 cm / s, and the volume fraction of oxygen in the introduced air is 21% to 30%. By appropriately controlling the Darcy velocity and oxygen content of the air, efficient combustion of organic components and self-sustaining operation of the smoldering reaction are achieved. The smoldering reaction temperature can also be controlled to maintain a temperature range that favors the reduction of high-valent copper but not the reduction of iron impurities. Excessively high Darcy velocity dilutes the reducing species produced by the smoldering reaction, hindering the reduction of high-valent copper. Excessively low Darcy velocity may lead to incomplete smoldering, insufficient production of reducing species, and inhibiting the reduction of high-valent copper. Excessively high oxygen concentrations in the air may cause excessive oxidation of reducing species (such as CO and CH4) into non-reducing species such as CO2 and H2O, hindering copper reduction and potentially causing copper oxidation. When the oxygen concentration is too low, the smoldering reaction may not proceed stably, resulting in low production of reducing substances and a low reaction temperature, making it difficult to achieve copper reduction. By regulating the Darcy velocity and composition of the air, the smoldering reaction temperature can be effectively controlled. Furthermore, the generated reducing gases such as CO, CH4, and H2, along with the char formed by devolatilization of the combustion aid, promote the reduction of high-valent copper during the smoldering process. By regulating the valence state, the value of the smoldering ash can be increased, which in turn facilitates the subsequent pyrometallurgical smelting process.

[0027] Furthermore, in step S3, the copper-containing smoldering ash is screened using a sieve with a mesh size of 0.2 mm to 0.45 mm. The resulting copper-rich smoldering ash has a moisture content of less than 1% and a volume reduction rate of greater than 90%. The copper-rich smoldering ash has a high copper content and is suitable for transfer, transportation, and further resource utilization. The separated thermal storage medium is then cleaned and dried and reused in step S1.

[0028] Furthermore, in step S4, the reducing agent includes one or more of coke, anthracite, and charcoal, and the slag-forming agent includes ferrosilicon slag and / or ferrocalcium slag, the mass ratio of Fe to SiO2 in the ferrosilicon slag is 0.8:1~1.2:1, and the mass ratio of Fe to CaO in the ferrocalcium slag is 2.2:1~2.5:1, and the particle size of the reducing agent and the slag-forming agent is not greater than 10 mm.

[0029] Furthermore, the mass ratio of copper-rich smoldering ash: reducing agent: slagging agent is 1:(0.1-0.4):(0.1-0.4) to ensure effective copper reduction and impurity removal, thereby reducing the copper content in the slag. Insufficient reducing agent will result in incomplete reduction of cupric oxide / cuprous oxide, causing copper to concentrate in the copper slag. Insufficient slagging agent may also lead to incomplete impurity removal and increased heteroatom content. Excessive reducing agent / slagging agent content not only results in waste but also increases smelting time.

[0030] like Figure 2 As shown, according to another aspect of the present application, an apparatus for implementing the above method is provided, comprising a smoldering reactor 1 and a smelting blast furnace 6, wherein a mixture obtained by mixing copper-containing sludge, auxiliary fuel, and heat storage medium is fed into the smoldering reactor 1 through a feeding component 2, and the mixture at the bottom is first heated by a heating component 4, and after reaching the ignition temperature, the heating component 4 is turned off and the air intake component 3 is turned on to introduce air, so that the mixture can achieve self-sustaining smoldering, and finally, the copper-containing smoldering ash is discharged through a discharge port 5, and the copper-containing smoldering ash is subjected to particle size screening to obtain copper-rich smoldering ash; the smelting blast furnace 6 is used to add copper-rich smoldering ash, a reducing agent, and a slag-forming agent and to carry out smelting, and after the smelting is completed, the molten copper enters a copper molten ladle 7 to obtain crude copper.

[0031] The technical solution provided in this application is further described below based on specific embodiments.

[0032] Example 1 The copper-containing sludge had a moisture content of approximately 71.2% and a dry-basis copper content of 29.6%. Pine wood chips, used as a combustion aid, were crushed to a particle size of less than 2 mm to optimize reaction conditions. Pretreated quartz sand, sludge, and pine wood chips were thoroughly mixed in a mass ratio of 15:4:1 to produce a mixture with a system calorific value of approximately 0.9 MJ / kg.

[0033] The mixture was placed in a smoldering reactor and preheated to 300°C using a bottom electric heater. The heater was then turned off and dry air at a Darcy velocity of 2 cm / s was immediately introduced to initiate a self-sustaining smoldering process. The air contained 21% oxygen by volume, maintaining the smoldering temperature at around 610°C. Under these conditions, the organic components were efficiently burned, the volume of the copper-containing sludge was reduced by approximately 94%, and it was completely dehydrated, with copper enriched in the copper-containing smoldering ash.

[0034] The copper-containing smoldering ash was sieved through a 0.25 mm sieve to obtain copper-rich smoldering ash and quartz sand. The quartz sand was cleaned, dried, and reused. Coke was selected as the reducing agent and ferrosilicon slag (Fe:SiO2 = 1:1) as the slagging agent. The mass ratio of copper-rich smoldering ash: reducing agent: slagging agent was 1:0.4:0.4. At a furnace temperature of 1200°C and an air oxygen content of 30%, blister copper (copper content: 96.8%) was obtained through blowing, with a copper recovery rate of 97.1%. Example 2 The copper-containing sludge had a moisture content of approximately 63.4% and a dry-basis copper content of 26.8%. Pine wood chips, used as a combustion aid, were crushed to a particle size of less than 2 mm to optimize reaction conditions. Pretreated quartz sand, sludge, and pine wood chips were thoroughly mixed in a mass ratio of 8:3:1 to produce a mixture with a system calorific value of approximately 1.5 MJ / kg.

[0035] The mixed material was placed in a smoldering reactor, heated to 400°C using an electric heater. The heater was then turned off and dry air at a Darcy velocity of 4.5 cm / s was immediately introduced to initiate a self-sustaining smoldering process. The air contained 21% oxygen by volume, maintaining the smoldering temperature at around 690°C. Under these conditions, the organic components were efficiently burned, the volume of the copper-containing sludge was reduced by approximately 93%, and the sludge was completely dehydrated, with copper enriched in the copper-containing smoldering ash.

[0036] Copper-containing smoldering ash was sieved through a 0.45 mm sieve to obtain copper-rich smoldering ash and quartz sand. The quartz sand was washed, dried, and reused. Coke was used as the reducing agent, and ferro-calcium slag (Fe:CaO = 2.2:1) was used as the slagging agent. The mass ratio of copper-rich smoldering ash: reducing agent: slagging agent was 1:0.3:0.3. Blowing was performed at a furnace temperature of 1250°C and an air oxygen content of 35%. Blister copper (copper content: 97.8%) was obtained, with a copper recovery rate of 97.4%.

[0037] Example 3 The copper-containing sludge had a moisture content of approximately 68.3% and a dry-basis copper content of 31.6%. Pine wood chips, used as a combustion aid, were crushed to a particle size of less than 2 mm to optimize reaction conditions. Pretreated quartz sand, sludge, and coke powder were thoroughly mixed in a mass ratio of 24:6:1 to produce a system calorific value of approximately 0.7 MJ / kg.

[0038] The mixed material was placed in a smoldering reactor, heated to 350°C using an electric heater. After the heater was turned off, dry air at a Darcy velocity of 6 cm / s was immediately introduced to initiate a self-sustaining smoldering process. The air contained 21% oxygen by volume, maintaining the smoldering temperature at around 510°C. Under these conditions, the organic components were efficiently burned, the volume of the copper-containing sludge was reduced by approximately 95%, and it was completely dehydrated, with copper enriched in the copper-containing smoldering ash.

[0039] Copper-containing smoldering ash was sieved through a 0.45 mm sieve to obtain copper-rich smoldering ash and quartz sand. The quartz sand was washed, dried, and reused. Anthracite was used as the reducing agent, and ferro-calcium slag (Fe:CaO = 2.5:1) was used as the slagging agent. The mass ratio of copper-rich smoldering ash: reducing agent: slagging agent was 1:0.35:0.3. At a furnace temperature of 1200°C and an air oxygen content of 33%, blister copper (96.3%) was obtained by blowing, with a copper recovery rate of 97.1%.

[0040] Example 4 The copper-containing sludge was selected with a moisture content of approximately 73.1% and a dry-basis copper content of 25.6%. Pine wood sawdust, a combustion aid, was used to reduce the sludge particle size to less than 2 mm through a crusher to optimize reaction conditions. Pretreated quartz sand, sludge, and bituminous coal were thoroughly mixed in a mass ratio of 15:4:1 to obtain a system calorific value of approximately 2.0 MJ / kg.

[0041] The mixture was placed in a smoldering reactor and preheated to 300°C using a bottom electric heater. The heater was then turned off and dry air at a Darcy velocity of 4 cm / s was immediately introduced to initiate a self-sustaining smoldering process. The air contained 30% oxygen by volume, maintaining the smoldering temperature at around 700°C. Under these conditions, the organic components were efficiently burned, the volume of the copper-containing sludge was reduced by approximately 95%, and it was completely dehydrated, with copper enriched in the copper-containing smoldering ash.

[0042] The copper-containing smoldering ash was sieved through a 0.2 mm sieve to obtain copper-rich smoldering ash and quartz sand. The quartz sand was cleaned, dried, and reused. Coke was selected as the reducing agent, and ferrosilicon slag (Fe:SiO2 = 0.8:1) was selected as the slagging agent. The mass ratio of copper-rich smoldering ash: reducing agent: slagging agent was 1:0.1:0.1. At a furnace temperature of 1250°C and an air oxygen content of 30%, blister copper (copper content: 94.8%) was obtained by blowing, with a copper recovery rate of 94.5%. Example 5 The copper-containing sludge had a moisture content of approximately 68.2% and a dry-basis copper content of 30.1%. Pine wood chips, used as a combustion aid, were crushed to a particle size of less than 2 mm to optimize reaction conditions. Pretreated quartz sand, sludge, and pine wood chips were thoroughly mixed in a mass ratio of 14:5:1 to produce a mixture with a system calorific value of approximately 0.9 MJ / kg.

[0043] The mixture was placed in a smoldering reactor and preheated to 400°C using a bottom electric heater. The heater was then turned off and dry air at a Darcy velocity of 2 cm / s was immediately introduced to initiate a self-sustaining smoldering process. The air contained 21% oxygen by volume, maintaining the smoldering temperature at around 550°C. Under these conditions, the organic components were efficiently burned, the volume of the copper-containing sludge was reduced by approximately 94%, and it was completely dehydrated, with copper enriched in the copper-containing smoldering ash.

[0044] Copper-containing smoldering ash was sieved through a 0.25 mm sieve to obtain copper-rich smoldering ash and quartz sand. The quartz sand was washed, dried, and reused. Coke was used as the reducing agent, and ferrosilicon slag (Fe:SiO2 = 1.2:1) was used as the slagging agent. The mass ratio of copper-rich smoldering ash: reducing agent: slagging agent was 1:0.3:0.25. Blowing was performed at a furnace temperature of 1200°C and an air oxygen content of 30%. Blister copper (copper content: 94.2%) was obtained, with a copper recovery rate of 96.4%.

[0045] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0046] Additionally, references throughout this specification to "one embodiment," "one embodiment," "an example," or similar language indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, appearances of the phrase "in one embodiment," "in one embodiment," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

[0047] It is easy for those skilled in the art to understand that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for smoldering dehydration, decarbonization, upgrading and copper recovery of copper-containing sludge, characterized in that: The method is specifically: S1 mixes the copper-containing sludge with the auxiliary fuel and the heat storage medium to obtain a mixed material; S2 smoldering the mixed material to obtain copper-containing smoldering ash; S3: screening the copper-containing smoldering ash for particle size to separate the heat storage medium and obtain copper-rich smoldering ash; S4: adding a reducing agent and a slagging agent to the copper-rich smoldering ash and smelting the ash, and then collecting the copper liquid to obtain crude copper, thereby realizing copper element recovery.

2. The method according to claim 1, wherein The mass ratio of the heat storage medium, the copper-containing sludge and the auxiliary fuel in the mixed material is (8-24): (3-6): 1, and the system calorific value of the mixed material is 0.7 MJ / kg to 2 MJ / kg.

3. The method according to claim 1, wherein The auxiliary fuel includes one or more of biomass, coal powder, and coke; the heat storage medium includes one or more of quartz sand, ceramic balls, and alumina particles; and the particle size of the heat storage medium is 1.8 mm to 2.2 mm.

4. The method according to claim 1, wherein In step S2, the mixture material of the bottom layer is heated to 300°C to 400°C, and then the heating is stopped. Then, air is introduced to allow the mixture material to achieve self-sustaining smoldering. The smoldering reaction temperature is 500°C to 700°C.

5. The method according to claim 4, wherein The Darcy flow rate of the incoming air is 2 cm / s-6 cm / s, and the volume fraction of oxygen in the incoming air is 21%-30%.

6. The method according to claim 1, wherein In step S3, the copper-containing smoldering ash is screened using a sieve with a mesh size of 0.2 mm to 0.45 mm.

7. The method according to claim 1, wherein The heat storage medium separated in step S3 is cleaned and dried and then reused in step S1.

8. The method according to claim 1, wherein In step S4, the reducing agent includes one or more of coke, anthracite, and charcoal, the slag-forming agent includes ferrosilicon slag and / or ferrocalcium slag, the mass ratio of Fe to SiO2 in the ferrosilicon slag is 0.8:1~1.2:1, and the mass ratio of Fe to CaO in the ferrocalcium slag is 2.2:1~2.5:1, and the particle size of the reducing agent and the slag-forming agent is not greater than 10 mm.

9. The method according to claim 1, wherein In step S4, the mass ratio of the copper-rich smoldering ash: reducing agent: slagging agent is 1: (0.1-0.4): (0.1-0.4).

10. A device for implementing the method according to any one of claims 1 to 9, characterized in that: The invention comprises a smoldering reactor (1) and a smelting blast furnace (6), wherein the smoldering reactor (1) is used for smoldering a mixture obtained by mixing copper-containing sludge, auxiliary fuel, and heat storage medium, discharging copper-containing smoldering ash through a discharge port (5), and performing particle size screening on the copper-containing smoldering ash to obtain copper-rich smoldering ash; the smelting blast furnace (6) is used for adding copper-rich smoldering ash, a reducing agent, and a slag-forming agent and performing smelting, and after the smelting is completed, the copper liquid enters a copper liquid ladle (7) to obtain crude copper.

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