Method for treating copper slag by depleting arsenic sulfide slag based on plasma

Abstract

The invention provides a plasma-based method for treating copper slag by depleting arsenic sulfide slag, which comprises the following steps: under the action of a plasma torch, introducing the arsenic sulfide slag and the copper slag into a depleting furnace for sulfuration reaction to obtain hot slag, and slowly cooling the hot slag to obtain slowly cooled slag; the slow cooling slag comprises a metal sulfonium phase and a slag phase which are well bounded, and the arsenic element in the arsenic sulfide slag is fixed in the slag phase; the plasma torch takes at least one of N2, CO and CH4 as a working medium; the moisture content of the arsenic sulfide slag is not greater than 1.5%, and the average particle size is not less than 200 meshes; the dosage mass ratio of the copper slag to the arsenic sulfide slag is 100: (3-6). According to the method, the high-activity S < 2-> and valuable metal in the copper slag are subjected to the vulcanization reaction, materials in the thermal depletion furnace can be stirred through injection of the plasma torch, uniform mixing of the arsenic sulfide slag and the copper slag is promoted, and therefore the effect of accelerating and strengthening material vulcanization is achieved, and the vulcanization reaction time is remarkably shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste treatment, and in particular to a method for treating copper slag by depleting arsenic sulfide slag based on plasma. Background Art

[0002] Copper slag and arsenic sulfide slag are two common waste products in non-ferrous metal smelting. Copper slag, a major byproduct of pyrometallurgical copper smelting, exhibits a significant slag yield ratio—2-3 tons of copper slag are produced for every ton of refined copper produced. The copper phase in the slag primarily consists of bornite, chalcocite, and metallic copper, while the iron phase occurs in the form of magnetite, fayalite, and amorphous silicates, which readily release heavy metal ions during natural weathering. With the widespread adoption of oxygen-enriched smelting technology, the loss of oxidized copper in the silicate matrix in copper slag has gradually increased. However, mainstream copper slag flotation processes are only effective in recovering mechanically entrained sulfide particles, with insufficient efficiency in recovering oxidized copper. Furthermore, elements such as lead, zinc, and iron present in the raw copper concentrate enter the slag phase as impurities during the smelting process. Existing processes often utilize an "open-circuit discard" model, resulting in the loss of significant iron, lead, and zinc resources through slag stockpiling.

[0003] CN118792512A discloses a hot slag chute and its application in recovering valuable metals in copper slag, comprising the following steps: allowing hot copper slag discharged from a slag outlet of a smelting system to flow into the hot slag chute from the side where a first curved baffle is located; adding a sulfide conditioning agent from the upper part of the opposite side of the first curved baffle in the hot slag chute and immersing it in the hot copper slag; the hot copper slag to which the sulfide conditioning agent is added passes through the curved baffle and a buffer column, enters a slag ladle and is slowly cooled to room temperature to obtain slowly cooled slag. ; The slowly cooled slag is subjected to grinding treatment and flotation treatment in sequence to obtain metal sulfide, alloy and / or zinc ferrite; wherein the sulfidation conditioning agent includes gypsum slag and a carbonaceous reducing agent, the composition of the carbonaceous reducing agent includes fixed carbon, the composition of the gypsum slag includes calcium sulfate, and the molar ratio of the fixed carbon to calcium sulfate in the sulfidation conditioning agent is 2-5:1; the sulfur content in the sulfidation conditioning agent is 1 to 3 times the theoretical sulfur content required to sulfidize all the metal oxides in the hot copper slag into metal sulfides.

[0004] Although the above method discloses a method for comprehensively recovering valuable metals in copper slag using a slow cooling-flotation process, the depletion agents used in this method are all mixtures of a sulfate phase and a carbonaceous reducing agent. In the actual reaction process, the carbonaceous reducing agent is required to first convert the sulfate and then sulfide the oxides in the hot copper slag. In addition, incomplete combustion of the carbonaceous reducing agent will produce smoke.

[0005] Therefore, developing a method that can solve the problems of harmful smoke and insufficient sulfide reduction in the existing copper slag recovery process is of great significance to the field of copper slag solid waste treatment. Summary of the Invention

[0006] The main purpose of the present invention is to provide a method for treating copper slag by depleting arsenic sulfide slag based on plasma, so as to solve the problems of generating harmful smoke and insufficient sulfide reduction in the existing copper slag recovery process.

[0007] To achieve the above object, the present invention provides a method for treating copper slag by depleting arsenic sulfide slag based on plasma, comprising the following steps:

[0008] Under the action of a plasma torch, arsenic sulfide slag and copper slag are introduced into a depletion furnace for a sulfidation reaction to obtain hot slag, and the hot slag is slowly cooled to obtain slowly cooled slag; the slowly cooled slag comprises a clearly defined metal matte phase and a slag phase, and the arsenic element in the arsenic sulfide slag is fixed in the slag phase;

[0009] The plasma torch uses at least one of N2, CO and CH4 as a working medium;

[0010] The arsenic sulfide slag has a moisture content of ≯1.5% and an average particle size of ≮200 mesh;

[0011] The mass ratio of the copper slag to the arsenic sulfide slag is 100:3-6.

[0012] Furthermore, the method further comprises: before subjecting the arsenic sulfide slag to a sulfidation reaction with the copper slag, drying and grinding the arsenic sulfide slag to obtain the arsenic sulfide slag with a moisture content of ≯1.5% and an average particle size of ≮200 meshes.

[0013] Furthermore, the chemical composition (wt%) of the arsenic sulfide slag includes: As35-55, S20-60, in terms of mass fraction.

[0014] Furthermore, the chemical composition of the copper slag includes, by mass fraction (wt%): Fe 20-50, Cu 0.2-5.0, Pb 0.3-3.0, and Zn 1.0-5.0.

[0015] Preferably, the plasma torch is a non-transferred arc plasma torch, and the power of the plasma torch is 350-450 kW.

[0016] Preferably, the working medium flow rate of the plasma torch is 80-100m 3 / h.

[0017] Furthermore, the sulfidation reaction step includes: firstly introducing the copper slag into a depletion furnace, and then using the plasma torch to spray the arsenic sulfide slag into the depletion furnace for sulfidation reaction.

[0018] Furthermore, the sulfidation reaction step includes: firstly introducing the copper slag and the arsenic sulfide slag into a depletion furnace for sulfidation reaction, and simultaneously immersing the plasma torch in the reaction materials for spraying.

[0019] Furthermore, the conditions of the sulfurization reaction include at least: a temperature of 1200-1300° C. and a time of 0.5-1.5 h.

[0020] Furthermore, the slow cooling conditions at least include: a slow cooling rate of 1-10°C / min.

[0021] Furthermore, the method further comprises: the hot slag is slowly cooled to room temperature and then left to stand for treatment, and the time for the standing treatment is more than 24 hours.

[0022] Furthermore, the method further comprises: subjecting the slowly cooled slag to grinding treatment and flotation treatment in sequence, and further separating and recovering metal sulfides, alloys and depleted slag.

[0023] The beneficial effects of the present invention are as follows:

[0024] The method provided by the present invention generates high-energy electrons, active free radicals and excited-state particles through plasma torch excitation, and excites the sulfur element in the arsenic sulfide slag into highly active S 2- , the highly active S 2- The sulfidation reaction with the valuable metals in the copper slag can quickly stir the materials in the reaction system, enhance mass transfer, and promote uniform mixing of the two materials, arsenic sulfide slag and copper slag, thereby accelerating the sulfidation of the materials and significantly shortening the sulfidation reaction time.

[0025] The method provided by the present invention directly uses arsenic sulfide slag, which is also a solid waste, as a copper slag depletion agent without the need for additional reducing agents. Through the depletion-slow cooling process, the metal matte phase and the slag phase in the obtained slow cooling slag are clearly demarcated, and more than 96% of valuable metal sulfides such as copper, lead, and zinc are enriched to form particles larger than 40 μm, which is very convenient for subsequent flotation process and realizes comprehensive recovery of copper slag resources.

[0026] The treatment method provided by the present invention can also simultaneously treat arsenic sulfide slag, fix the arsenic element and other impurity elements therein in the slag phase, and no harmful smoke and dust is generated. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0028] Figure 1 A diagram of the device for treating copper slag with plasma-based arsenic sulfide slag depletion provided by the present invention.

[0029] Figure 2 This is the SEM image of the slowly cooled slag of Example 1 provided by the present invention.

[0030] Figure 3 This is a surface scanning analysis diagram of each element in the slowly cooled slag of Example 1 provided by the present invention.

[0031] Description of Reference Numerals

[0032] 1. Slag inlet 2. Detachable feeding port 3. Material entrance 4. Gas inlet 5. Plasma torch 6. Flue gas outlet 7. Slag discharge port 8. Heater 9. Side-blowing spray gun reserved opening 10. Reserved opening for bottom blowing spray gun

[0033] The realization of the objectives, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0034] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] Moreover, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0036] When numerical ranges are given in the examples, it should be understood that unless otherwise specified herein, both endpoints of each numerical range and any value between the two endpoints may be used. Unless otherwise defined, all technical and scientific terms used herein are consistent with the prior art as understood by those skilled in the art and the description of the present invention. Any prior art methods, devices, and materials similar or equivalent to those described in the examples of the present invention may also be used to implement the present invention.

[0037] The room temperature or normal temperature mentioned in the present invention refers to 25±5°C.

[0038] As mentioned above, the present invention provides a method for treating copper slag by depleting arsenic sulfide slag based on plasma, comprising the following steps:

[0039] Under the action of a plasma torch, arsenic sulfide slag and copper slag are introduced into a depletion furnace for a sulfidation reaction to obtain hot slag, and the hot slag is slowly cooled to obtain slowly cooled slag; the slowly cooled slag comprises a clearly defined metal matte phase and a slag phase, and the arsenic element in the arsenic sulfide slag is fixed in the slag phase;

[0040] The plasma torch uses at least one of N2, CO and CH4 as a working medium;

[0041] The arsenic sulfide slag has a moisture content of ≯1.5% and an average particle size of ≮200 mesh;

[0042] The mass ratio of the copper slag to the arsenic sulfide slag is 100:3-6.

[0043] The method provided by the present invention is to carry out a sulfurization reaction on arsenic sulfide slag and copper slag under the enhanced effect of a plasma torch, wherein the plasma excitation generates high-energy electrons, active free radicals and excited-state particles, and the sulfur element in the arsenic sulfide slag is excited to form highly active S 2- , highly active S 2- The sulfidation reaction with the valuable metals in the copper slag can quickly stir the materials in the depletion furnace, enhance mass transfer, and promote uniform mixing of the two materials, arsenic sulfide slag and copper slag, thereby accelerating the sulfidation of the materials and significantly shortening the sulfidation reaction time.

[0044] The method provided by the present invention mixes copper slag and arsenic sulfide slag that has been subjected to plasma torch enhanced excitation in a specific proportion, then combines the valuable metals in the copper slag with the sulfur element in the arsenic sulfide and fixes them in the metal matte phase through a depletion-slow cooling process, and then enriches the valuable metal sulfides through a slow cooling process to obtain slow-cooling slag with a clear boundary between the metal matte phase and the slag phase. In addition, more than 96% of the valuable metal sulfides such as copper, lead, and zinc are enriched to form particles larger than 40 μm, which is very convenient for subsequent flotation process and realizes comprehensive recovery of copper slag resources.

[0045] In some embodiments, the method further includes: before subjecting the arsenic sulfide slag to a sulfide reaction with the copper slag, drying and grinding the arsenic sulfide slag to obtain the arsenic sulfide slag with a moisture content of ≯1.5% and an average particle size of ≮200 mesh.

[0046] The inventors of the present invention have discovered that pre-treating the arsenic sulfide slag before mixing and controlling its moisture content and average particle size within an appropriate range can further make the contact and mixing of the arsenic sulfide slag and the copper slag in the depletion furnace more uniform, which not only improves the binding efficiency and capacity of valuable metals and sulfur elements, but also helps to better separate the metal matte phase and the slag phase in the subsequent recovery process.

[0047] The moisture content of the arsenic sulfide slag can be, for example, 0.5%, 0.8%, 1%, 1.2%, 1.5% or any value between 0.5-1.5%; if the moisture content is too high, it may cause temperature fluctuations in the smelting furnace, affect the reaction stability, and even cause splashing or explosion risks. At the same time, the evaporation of water may carry volatile arsenic (such as As2O3) into the flue gas, increasing the difficulty of flue gas treatment and environmental risks.

[0048] The average particle size of the arsenic sulfide slag is 200 mesh, 210 mesh, 220 mesh, 230 mesh, 240 mesh, 250 mesh, 260 mesh, 270 mesh, 280 mesh, 290 mesh, 300 mesh, or any value between 200 and 300 mesh. If the average particle size is too large, the mixing with the copper slag is uneven, the reaction contact area is small, and the reaction is insufficient. However, the incompletely reacted arsenic sulfide slag may hinder the uniform crystallization of the copper slag, resulting in an increase in the copper residue in the depleted slag and a reduction in the metal recovery rate.

[0049] The method provided by the present invention is mainly aimed at arsenic sulfide slag produced in the process of disposing of high-concentration arsenic-containing waste acid and arsenic-containing electrolyte. The arsenic grade in these arsenic sulfide slag materials is more than 35wt%. In some embodiments, the chemical composition (wt%) of the arsenic sulfide slag includes: As 35-55, S20-60, measured by mass fraction. The long-term storage and disposal of such arsenic sulfide slag materials is likely to cause secondary pollution to the environment. On the one hand, it limits the sulfidation treatment process of acidic wastewater from metallurgical enterprises, and on the other hand, it also poses huge safety hazards. The present invention creatively activates it with a plasma torch and uses it as a sulfidation curing agent in combination with copper slag, which can not only achieve efficient sulfidation enrichment of valuable metals in copper slag, but also achieve efficient reuse of solid waste resources, reduce copper losses, and improve the recovery rate of valuable metals such as copper.

[0050] During the copper smelting process, a large amount of copper slag is produced. Copper slag is a product of matte smelting and matte converting during pyrometallurgy. Based on the slag-producing equipment, it can be divided into reverberatory slag, converter slag, and flash smelting slag. Based on the different slag cooling methods, it can be divided into water-quenched slag, naturally cooled slag, and thermally cooled slag. Based on the production process, it can be divided into smelting slag and converting slag.

[0051] The copper slag material in the copper slag of the present invention includes one or more of copper smelting slag, copper converting slag, refining slag, depleted slag, copper sulfide ore smelting slag, matte converting slag, laterite ore reduction smelting slag, and copper oxide ore reduction smelting slag. For example, the copper slag is in a molten state and can be connected to the pyrometallurgical copper smelting process. The copper slag after pyrometallurgical copper smelting is directly recycled and processed to achieve integrated processing of copper-containing ore and copper slag. In some embodiments, the chemical composition (wt%) of the copper slag includes, by mass fraction, Fe 20-50, Cu 0.2-5.0, Pb 0.3-3.0, and Zn 1.0-5.0.

[0052] In some embodiments, the plasma torch is a non-transferred arc plasma torch, and the power of the plasma torch is 350-450 kW.

[0053] In some embodiments, the working medium flow rate of the plasma torch is 80-100m 3 / h.

[0054] In some embodiments, the volume ratio of N2 to CO or CH4 in the plasma torch is 3-5:1. For example, the volume ratio of N2 to CO can be 3:1, 4:1, 5:1, or any value between 3-5:1; and the volume ratio of N2 to CH4 can be 3:1, 4:1, 5:1, or any value between 3-5:1. The inventors discovered that this preferred embodiment can achieve higher recovery rates for valuable metals such as copper, lead, and zinc, with copper recovery rates exceeding 96% and lead and zinc recovery rates exceeding 93%.

[0055] In some embodiments, the sulfidation reaction step includes: first introducing the copper slag into a depletion furnace, and then using the plasma torch to spray the arsenic sulfide slag into the depletion furnace for a sulfidation reaction.

[0056] It should be noted that in the above embodiment, the sulfurization reaction step is to directly pass the arsenic sulfide slag through the material inlet of the plasma torch, enter the plasma torch for enhanced excitation, and then introduce it into the depletion furnace to react with the copper slag for sulfurization, directly introducing the highly active S 2- It reacts with copper slag to accelerate and strengthen the sulfidation of materials.

[0057] In other embodiments, the sulfidation reaction step includes: first introducing the copper slag and the arsenic sulfide slag into a depletion furnace for sulfidation reaction, and simultaneously immersing the plasma torch in the reaction materials for spraying.

[0058] It should be noted that in the above embodiment, the sulfidation reaction step is to introduce the arsenic sulfide slag into the depletion furnace through a detachable feeding port, undergo a sulfidation reaction with the copper slag, and then use a plasma torch to enhance the excitation of the reaction melt to achieve the effect of enhancing the material sulfidation process.

[0059] In some embodiments, the sulfurization reaction conditions include at least: a temperature of 1200-1300° C. and a time of 0.5-1.5 h.

[0060] The specific reactions that occur in the present invention include:

[0061] Under the action of plasma, the As–S covalent bond in arsenic sulfide is broken by high-energy electron bombardment, and the sulfur element is excited to become highly active S 2- (sulfide ion):

[0062] As2S3+e - →As2S3 * +e -

[0063] As2S3+e - →2As 3+ +3S 2- +e -

[0064] The oxidized valuable metals (MeO) in copper smelting slag and arsenic sulfide slag will undergo the following sulfidation reaction, realizing the sulfidation separation of the difficult-to-recover oxidized valuable metals in the copper slag material:

[0065] 3[MeO]+As2S3 * →3[MeS]+As2O3

[0066] [MeO]+S 2- →3[MeS]+O 2-

[0067] Valuable metal oxides are converted into sulfides through the above reactions and enter the sulfonium phase to aggregate and grow.

[0068] The method provided by the present invention can combine valuable metals such as copper, lead, and zinc in copper slag with sulfur and then enrich and fix them in the metal matte phase. The arsenic in the arsenic sulfide slag reacts with other components in the copper slag to be fixed in the slag phase, and the iron and other impurity elements are all fixed in the slag phase. Subsequently, efficient separation of the valuable metals can be achieved through grinding and flotation.

[0069] In some embodiments, the slow cooling conditions include at least a slow cooling rate of 1-10°C / min.

[0070] In some embodiments, the method further comprises: slowly cooling the hot slag to room temperature and then allowing it to stand for a period of more than 24 hours.

[0071] It should be noted that the slow-cooling slag obtained using the method of the present invention is a general solid waste. After recovering metals such as copper, lead, zinc, and iron through flotation, it can be sold as a raw material for cement and building materials, meeting the green and clean development requirements of the metallurgical industry. In some embodiments, the method further includes subjecting the slow-cooling slag to sequential grinding and flotation to further separate and recover metal sulfides, alloys, and depleted slag.

[0072] Among them, flotation, as a commonly used mineral processing method, has the advantages of low cost, strong applicability, easy process control, and environmental friendliness compared to hydrometallurgy and pyrometallurgy, and therefore has received more widespread attention. Flotation has been proven to achieve excellent flotation indicators when treating most copper slags and has been applied industrially on a large scale. However, there are certain limitations on the sulfide particle size (required to be above 40 microns) and the ore size (required to be between 0.01mm and 0.25mm). When the growth of metal sulfides is insufficient, they are mainly distributed in fine particles and have a complex interpenetration relationship with gangue minerals, resulting in poor separation effect. When the ore size is too large, grinding treatment is required to meet the flotation requirements. Otherwise, the ore particles are prone to sinking in the flotation process and enriched in the flotation tailings, affecting the recovery rate of valuable metals.

[0073] The metal sulfides in the slowly cooled slag obtained by the present invention aggregate and grow, and are enriched in sulfide particles with a particle size greater than 40 μm, thereby achieving a particle size requirement that is beneficial to subsequent flotation.

[0074] In some embodiments, the grinding process conditions are controlled so that the average particle size of the slowly cooled slag is 80-200 mesh.

[0075] It's also important to note that grinding, a common flotation process, crushes ore particles in copper slag to an appropriate size, fully separating useful minerals from gangue minerals, thus facilitating subsequent flotation operations. Grinding creates finer copper slag particles with a larger surface area, making them more suitable for flotation agent adsorption and foam transport, thereby improving flotation recovery and concentrate grade.

[0076] In some embodiments, the flotation process may include the steps of adding a flotation agent to allow the matte particles to sink to the bottom, thereby separating the matte from the slag, and separating and recovering the metal sulfide and the floating zinc ferrite.

[0077] Metal sulfides are separated from the silicate copper slag after slow cooling to form a single metal matte phase, which is then recovered through a flotation process to recover valuable metals such as lead, zinc, and copper. The recovered metal matte / alloy (sulfides and alloys such as copper, lead, zinc, and iron) is sent to the next step of blowing for further recovery. The flotation tailings of the copper slag are then washed again to recover zinc ferrite and magnetite.

[0078] The present invention utilizes hazardous waste arsenic sulfide slag as a sulfurization curing agent, which can sulfurize and enrich the valuable metals in the copper slag, realize the efficient recycling of solid waste resources, and achieve the goal of waste-free production. It is in line with the national strategic orientation of "treating waste with waste" and is expected to promote the smelting industry to move towards the goal of "zero waste".

[0079] The method provided by the present invention also has the characteristics of simple process flow, cleanliness and high efficiency, and meets the requirements of environmentally friendly production.

[0080] refer to Figure 1The present invention also provides a device for treating copper slag by depleting arsenic sulfide slag based on plasma, comprising:

[0081] A furnace body is provided with a slag inlet 1, a flue gas outlet 6 and a slag discharge port 7. A reaction zone for accommodating the melt is provided inside the furnace body, and a heater 8 for maintaining the furnace body temperature is also provided outside the furnace body;

[0082] A furnace cover, the furnace cover is covered on the furnace body, and the furnace cover is provided with a detachable feeding port 2 for feeding arsenic sulfide slag;

[0083] A plasma torch 5 is used for reactive blowing into the melt or transporting plasma-strengthened materials into the furnace body; the plasma torch is provided with a material inlet 3 and a gas inlet 4 connected to the furnace body, the material inlet 3 is used for feeding materials that need to be plasma-strengthened, and the gas inlet 4 is used for introducing a gaseous working medium.

[0084] It should be noted that the slag inlet provided on the furnace body can be connected to the pyrometallurgical copper smelting process, and the copper slag after pyrometallurgical copper smelting can be directly introduced into the furnace body through the slag inlet to form a molten pool. The arsenic sulfide slag enters the furnace body through the detachable feeding port or the material inlet on the plasma torch, and undergoes a sulfide reaction with the copper slag therein. After the reaction, the hot slag flows out through the slag discharge port and slowly cools to room temperature, and enters the post-processing step.

[0085] The device provided by the present invention only needs to add a plasma torch to the existing depletion furnace to achieve the purpose of simultaneously treating two solid wastes, arsenic sulfide slag and copper slag from pyrometallurgical copper smelting, thereby improving resource utilization and reducing treatment costs.

[0086] In the device provided by the present invention, the plasma can be set on the furnace cover and blown into the melt by top blowing, or it can be set on the side wall of the furnace body through the side blowing gun reserved port 9, or it can be set at the bottom of the furnace body through the bottom blowing gun reserved port 10, and blown into the melt by side blowing or bottom blowing.

[0087] In some embodiments, the heater 8 is an electromagnetic induction heater.

[0088] In some embodiments, the plasma torch is disposed on the furnace cover, and the furnace cover is further provided with a lifting mechanism for moving the plasma torch in a direction perpendicular to the melt.

[0089] The present invention has no special requirements for the lifting mechanism, and any lifting device structure known in the art can be used, as long as it can enable the plasma torch to move up and down in a direction perpendicular to the melt. For example, the lifting mechanism used in the present invention is the lifting device shown in CN213652602U.

[0090] As mentioned above, in the present invention, the arsenic sulfide slag can be introduced into the depletion furnace through a detachable feeding port to undergo a sulfidation reaction with the copper slag, and then the reaction melt can be enhanced and excited by the liftable plasma torch provided on the furnace cover; or it can be directly introduced into the plasma torch through the material inlet for enhanced excitation, and then introduced into the depletion furnace for a sulfidation reaction with the copper slag. Both of the above methods can excite the sulfur element in the arsenic sulfide slag into highly active S under the action of the plasma torch. 2- , which accelerates the vulcanization of strengthened materials and significantly shortens the vulcanization reaction time.

[0091] The following combination Figure 1 A process flow of a preferred embodiment of the method for treating copper slag by plasma-based arsenic sulfide slag depletion of the present invention is provided:

[0092] (1) pretreating the arsenic sulfide slag to obtain arsenic sulfide slag I;

[0093] (2) firstly introducing the copper slag into the depletion furnace through the slag inlet, then introducing the arsenic sulfide slag I into the plasma torch from the material inlet, and after excitation and strengthening, spraying it into the depletion furnace for sulfidation reaction to obtain hot slag; or

[0094] First, the copper slag is introduced into the depletion furnace through the slag inlet, and then the arsenic sulfide slag I is introduced into the depletion furnace through the detachable feeding port for sulfidation reaction, while the plasma torch is immersed in the sulfidation reaction material for spraying to obtain hot slag;

[0095] (3) The hot slag is slowly cooled from the slag outlet to obtain slowly cooled slag, and the slowly cooled slag is post-processed.

[0096] The present invention will be described in detail below by way of examples. In the following examples, unless otherwise specified, all raw materials and instruments used are commercially available.

[0097] It should be noted that the arsenic sulfide slags in the following examples all come from Shandong Hengbang Smelting Co., Ltd.; and the copper slags all come from Bayannur Feishang Copper Co., Ltd.

[0098] In the following examples, the main components and contents of the arsenic sulfide slag and copper slag used are shown in Table 1 and Table 2, respectively.

[0099] Table 1 Main chemical composition and content of arsenic sulfide slag used in the examples

[0100]

[0101]

[0102] Table 2 Main chemical composition and content of copper slag used in the examples

[0103] Ingredient content Fe / wt% Cu / wt% Pb / wt% Zn / wt% Copper slag-1 43.29 4.12 1.21 3.24 Copper slag-2 45.31 3.64 1.08 2.77 Copper slag-3 42.34 4.53 2.11 3.03

[0104] Example 1

[0105] This embodiment provides a method for treating copper slag by depleting arsenic sulfide slag based on plasma. Figure 1 The method is carried out in the device shown in the figure, which specifically includes the following steps:

[0106] (1) drying and grinding the arsenic sulfide slag-1 in sequence to obtain arsenic sulfide slag I-1 having a moisture content of 1.5% and an average particle size of 200 mesh;

[0107] (2) 100 g of copper slag-1 was flowed into the depletion furnace through the slag inlet, the electromagnetic induction heating device was started, the insulation temperature in the electric furnace was controlled to be 1250 °C, 5 g of arsenic sulfide slag I-1 was added through the material inlet of the plasma torch (the mass ratio of copper slag-1 to arsenic sulfide slag I-1 was 100:5), and N2-CO mixed gas (N2 80%, CO 20%) was introduced into the plasma torch as the working medium, and the flow rate of the working medium was 100 m 3 / h, controlling the plasma torch power to 400kW to excite and activate the arsenic sulfide slag I-1, and spraying it into the depletion furnace through the plasma torch to undergo a sulfidation reaction for 0.5h to obtain hot slag-1;

[0108] (3) After the hot slag-1 is discharged through the slag outlet, it is slowly cooled to room temperature at 4°C / min and then allowed to stand for 24 hours to obtain slowly cooled slag; the slowly cooled slag is ground to 150 mesh and then subjected to flotation treatment to separate and recover metal sulfides. Finally, the copper recovery rate is calculated to be 96.64%, the lead recovery rate is 93.36%, and the zinc recovery rate is 93.63%.

[0109] Example 2

[0110] This embodiment provides a method for treating copper slag by depleting arsenic sulfide slag based on plasma. Figure 1 The method is carried out in the device shown in the figure, which specifically includes the following steps:

[0111] (1) drying and grinding the arsenic sulfide slag-2 in sequence to obtain arsenic sulfide slag I-2 having a moisture content of 1.0% and an average particle size of 300 mesh;

[0112] (2) 100 g of copper slag-2 was flowed into the depletion furnace through the slag inlet, the electromagnetic induction heating device was started, the insulation temperature in the electric furnace was controlled to be 1250 °C, 5 g of arsenic sulfide slag I-2 (the mass ratio of copper slag-2 to arsenic sulfide slag I-2 was 100:5) was added through the detachable feeding port and placed in the depletion furnace, and N2-CH4 mixed gas (N2 80%, CH4 20%) was introduced into the plasma torch as the working medium, and the flow rate of the working medium was 100 m 3 / h, control the plasma torch power to 400kW, and spray the plasma torch into the melt to react for 1h to obtain hot slag-2;

[0113] (3) After the hot slag-2 is discharged through the slag outlet, it is slowly cooled to room temperature at 5°C / min and allowed to stand for 24 hours to obtain a slowly cooled slag; the slowly cooled slag is ground to 200 mesh and then subjected to flotation treatment to separate and recover metal sulfides. Finally, the copper recovery rate is calculated to be 96.32%, the lead recovery rate is 92.81%, and the zinc recovery rate is 93.04%.

[0114] Example 3

[0115] This embodiment provides a plasma-based method for treating copper slag by depleting arsenic sulfide slag. Figure 1 The process is carried out in the apparatus shown in FIG. 1 , with reference to the method of Example 1, except that: in step (2), the mass ratio of copper slag-1 to arsenic sulfide slag I-1 is 100:3.

[0116] Example 4

[0117] This embodiment provides a method for treating copper slag by depleting arsenic sulfide slag based on plasma. Figure 1 The process is carried out in the device shown in the figure, referring to the method of Example 1, except that: in step (2), the electromagnetic induction heating device is started and the insulation temperature in the electric furnace is controlled to be 1200°C.

[0118] Example 5

[0119] This embodiment provides a method for treating copper slag by depleting arsenic sulfide slag based on plasma. Figure 1 The process is carried out in the device shown in the figure, referring to the method of Example 1, except that: in step (2), the electromagnetic induction heating device is started and the insulation temperature in the electric furnace is controlled to be 1300°C.

[0120] Example 6

[0121] This embodiment provides a method for treating copper slag by depleting arsenic sulfide slag based on plasma. Figure 1The process is carried out in the apparatus shown in FIG. 1 , with reference to the method of Example 1, except that: in step (2), the plasma torch power is controlled to 350 kW to excite and activate the arsenic sulfide slag I-1.

[0122] Example 7

[0123] This embodiment provides a method for treating copper slag by depleting arsenic sulfide slag based on plasma. Figure 1 The process is carried out in the apparatus shown in FIG. 1 , with reference to the method of Example 1, except that: in step (2), the plasma torch power is controlled to 450 kW to excite and activate the arsenic sulfide slag I-1.

[0124] Comparative Example 1

[0125] This comparative example provides a method for depleting copper slag, except that no arsenic sulfide slag is added and no plasma torch is used.

[0126] The specific steps include:

[0127] Copper slag-3 was directly cooled to room temperature at a slow cooling rate of 3°C / min, and then allowed to stand for 24 hours to obtain slow cooling slag. The slow cooling slag was ground to 200 mesh and then subjected to flotation treatment to separate and recover metal sulfides. The final calculation showed that the copper recovery rate was only 89.72%, and lead and zinc could not be recovered.

[0128] Comparative Example 2

[0129] This comparative example provides a method for treating copper slag by depleting arsenic sulfide slag based on plasma, which is carried out with reference to the method of Example 1, except that: in step (1), the arsenic sulfide slag is not pretreated.

[0130] The specific steps include:

[0131] (1) 100 g of copper slag-1 was flowed into the depletion furnace through the slag inlet, the electromagnetic induction heating device was started, the insulation temperature in the electric furnace was controlled to be 1250 °C, 5 g of arsenic sulfide slag-1 was added through the material inlet of the plasma torch (the mass ratio of copper slag-1 to arsenic sulfide slag-1 was 100:5), and N2-CO mixed gas (N2 80%, CO 20%) was introduced into the plasma torch as the working medium, the plasma torch power was controlled to be 400 kW to excite and activate the arsenic sulfide slag I-1, and the arsenic sulfide slag I-1 was sprayed into the depletion furnace through the plasma torch for a sulfidation reaction for 0.5 h to obtain hot slag-1;

[0132] (3) After the hot slag-1 is discharged through the slag outlet, it is slowly cooled to room temperature at 4°C / min and then allowed to stand for 24 hours to obtain slowly cooled slag; the slowly cooled slag is ground to 150 mesh and then subjected to flotation treatment to separate and recover metal sulfides. Finally, the copper recovery rate is calculated to be 92.76%, the lead recovery rate is 79.01%, and the zinc recovery rate is 83.12%.

[0133] The slow cooling slags of Examples 1-7 and Comparative Examples 1-2 were ground and then subjected to flotation. The copper recovery rate, lead recovery rate and zinc recovery rate in the slow cooling slags were calculated. The calculation results are shown in Table 3.

[0134] Table 3

[0135] Copper recovery rate, % Lead recovery rate, % Zinc recovery rate, % Example 1 96.64 93.36 93.63 Example 2 96.32 92.81 93.04 Example 3 95.85 91.63 91.32 Example 4 96.78 93.42 93.91 Example 5 97.25 94.38 94.53 Example 6 96.37 92.14 92.57 Example 7 97.52 93.06 94.79 Comparative Example 1 89.72 / / Comparative Example 2 92.76 79.01 83.12

[0136] Through comparison, it was found that the present invention mixes copper slag and arsenic sulfide slag that has been excited by a plasma torch in a specific proportion, and then uses a depletion-slow cooling process to combine the valuable metals in the copper slag with the sulfur element in the arsenic sulfide and fix them in the metal matte phase. Then, the valuable metal sulfides are enriched through a slow cooling process to obtain a slow-cooling slag with a clear boundary between the metal matte phase and the slag phase. In addition, more than 96% of the valuable metal sulfides such as copper, lead, and zinc are enriched to form particles larger than 40 μm, which is very convenient for the subsequent flotation process to achieve comprehensive recovery of copper slag resources.

[0137] In Comparative Example 1 in which no arsenic sulfide slag was added, the sulfide enrichment rate was significantly reduced, and valuable metals such as lead and zinc could not be recovered.

[0138] Analysis example 1

[0139] The slow cooling slag obtained in Example 1 was subjected to SEM-EDS testing. The specific test results are shown in Figure 2-Figure 3 .

[0140] in, Figure 2 This is the SEM image of the slowly cooled slag of Example 1 provided by the present invention. Figure 3 This is a surface scanning analysis diagram of each element in the slowly cooled slag of Example 1 provided by the present invention.

[0141] from Figure 2 It can be seen that most of the metal sulfides can be enriched to form particles larger than 40μm, and the mineral phase boundaries between the metal matte phase and the slag phase are clear, which is very beneficial to the subsequent flotation process.

[0142] from Figure 3As can be seen from the figure, the distribution of Cu, S, Zn, and Pb is essentially uniform, indicating that they primarily form sulfides and enter the matte phase. The distribution of the remaining elements, such as Fe, Si, and Ca, is essentially uniform, indicating that these elements constitute the slag phase. Due to the relatively small amount of arsenic sulfide used, the As signal is relatively weak, but As is observed to be primarily distributed in the slag region, indicating that As is fixed in the slag and no harmful smoke is generated. This is likely due to the As being fixed through coupling reactions with other substances in the slag phase.

[0143] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements that are inherent to such process, method, article or apparatus.

[0144] The above technical solutions of the present invention are only preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention's description and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for treating copper slag by depleting arsenic sulfide slag based on plasma, characterized in that: The following steps are involved: Under the action of a plasma torch, arsenic sulfide slag and copper slag are introduced into a depletion furnace for a sulfidation reaction to obtain hot slag, and the hot slag is slowly cooled to obtain slowly cooled slag; the slowly cooled slag comprises a clearly defined metal matte phase and a slag phase, and the arsenic element in the arsenic sulfide slag is fixed in the slag phase; The plasma torch uses at least one of N2, CO and CH4 as a working medium; The arsenic sulfide slag has a moisture content of ≯1.5% and an average particle size of ≮200 mesh; The mass ratio of the copper slag to the arsenic sulfide slag is 100:3-6.

2. The method according to claim 1, characterized in that The method further comprises: before subjecting the arsenic sulfide slag to a sulfidation reaction with the copper slag, drying and grinding the arsenic sulfide slag to obtain the arsenic sulfide slag with a moisture content of ≯1.5% and an average particle size of ≮200 mesh; and / or Calculated by mass fraction, the chemical composition (wt%) of the arsenic sulfide slag includes: As 35-55, S20-60.

3. The method according to claim 1, characterized in that Calculated by mass fraction, the chemical composition of the copper slag (wt%) includes: Fe 20-50, Cu 0.2-5.0, Pb 0.3-3.0, and Zn 1.0-5.

0.

4. The method according to claim 1, wherein The plasma torch is a non-transferred arc plasma torch, and the power of the plasma torch is 350-450 kW; and / or The working medium flow rate of the plasma torch is 80-100m 3 / h.

5. The method according to claim 1, wherein The sulfidation reaction step includes: firstly introducing the copper slag into a depletion furnace, and then using the plasma torch to spray the arsenic sulfide slag into the depletion furnace for a sulfidation reaction.

6. The method according to claim 1, characterized in that The sulfidation reaction step includes: firstly introducing the copper slag and the arsenic sulfide slag into a depletion furnace to carry out a sulfidation reaction, and at the same time immersing the plasma torch in the reaction materials to spray.

7. The method according to claim 5 or 6, characterized in that The conditions of the sulfurization reaction include at least: a temperature of 1200-1300° C. and a time of 0.5-1.5 h.

8. The method according to claim 1, characterized in that The slow cooling conditions at least include: a slow cooling rate of 1-10°C / min.

9. The method according to claim 8, characterized in that The method further comprises: slowly cooling the hot slag to room temperature and then allowing it to stand for treatment, and the time for the standing treatment is more than 24 hours.

10. The method according to claim 1, characterized in that The method further comprises: subjecting the slowly cooled slag to grinding and flotation treatments in sequence, and further separating and recovering metal sulfides, alloys and depleted slag.

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