Method for improving leaching efficiency and filtering efficiency of copper smelting side-blown smoke dust

Abstract

The invention provides a method for improving leaching efficiency and filtering efficiency of copper smelting side-blown smoke dust, and relates to the technical field of smelting smoke treatment, the method comprises the following steps: S1, pretreating, drying and sieving side-blown copper smelting smoke dust; s2, the copper smelting smoke dust is subjected to water leaching at the reaction temperature of 80-90 DEG C according to the liquid-solid ratio of 3 m l: 1 g, water leaching liquid is obtained, and the reaction time of water leaching is not shorter than 3 hours; s3, an additive is put into the water immersion liquid in the water immersion process, gas stirring equipment is used for stirring the water immersion liquid and the additive, the gas stirring equipment comprises a gas stirring tool, and the gas stirring tool extends into the bottom of the water immersion liquid; and the gas stirring tool is eccentrically arranged. By means of the method, valuable metal elements can be dissolved and separated more effectively, the recovery rate of the valuable elements is increased, and resource waste is reduced; the water content of the lead-bismuth slag is reduced, the step of drying filter residues before the filter residues enter a furnace in a traditional filtering mode is omitted, and the treatment time is saved.

Description

Technical Field

[0001] This invention relates to the field of smelting flue gas treatment technology, and in particular to a method for improving the leaching efficiency and filtration efficiency of side-blown dust in copper smelting. Background Technology

[0002] In copper smelting, equipment such as ISA furnaces, converters, and electric furnaces generate large amounts of flue gas. This flue gas typically contains various valuable metals such as copper, lead, zinc, and bismuth, with complex chemical compositions that are difficult to treat. If this flue gas is directly returned to the copper smelting system, it will significantly increase the impurity content of the raw materials entering the furnace, worsen furnace conditions, and reduce the furnace's processing capacity. Therefore, copper smelting companies generally classify and sell their flue gas (high-copper flue gas is returned to the system; low-copper flue gas is sold externally). Currently, the main methods for treating copper smelting flue gas include desulfurization, leaching, and filtration. However, existing technologies have some problems in practical applications: ① Low comprehensive recovery rate of valuable elements: Due to the complex metal composition in the flue gas, existing technologies often struggle to efficiently recover valuable elements, leading to resource waste; ② High treatment costs: Existing flue gas treatment methods typically require the use of large amounts of chemical reagents and equipment, resulting in high treatment costs; ③ Environmental hazards: Improper treatment of wastewater, waste gas, and solid waste generated during flue gas treatment may cause environmental pollution.

[0003] In recent years, oxygen-enriched side-blown reduction smelting furnaces have been widely used in the treatment of copper smelting dust to improve the treatment efficiency of copper smelting dust. The equipment has the following advantages: high-efficiency smelting, high comprehensive recovery efficiency, and environmental protection and energy saving. However, there is a lack of systematic research on the recovery of high-value rare metals from side-blown copper smelting dust in China, and the potential benefits have not been fully realized.

[0004] Traditional industrial methods for recovering valuable metal elements from copper smelting fumes mainly include pyrometallurgical processes, hydrometallurgical processes, and combined pyrometallurgical and hydrometallurgical processes. These methods are diverse, each with its unique advantages and applicable scope. In practical applications, the most suitable treatment method must be selected based on a comprehensive consideration of factors such as the composition of the fumes, the scale of processing, and technical requirements. Currently, there is no systematic research on the recovery of valuable metal elements from side-blown copper smelting fumes.

[0005] Meanwhile, in the wet processing of copper smelting dust, the lead-bismuth slag (filter residue) produced by the commonly used filtration method has a high water content and needs to be further dried in order to meet the standards for lead smelting enterprises to enter the furnace.

[0006] In summary, proposing a method to improve leaching and filtration efficiency in the recovery of valuable elements from side-blown copper smelting fumes is of great significance. This method aims to improve the leaching and filtration rates during the recovery of valuable elements by optimizing the fumes treatment process, thereby saving processing time, reducing processing costs, and minimizing environmental impact.

[0007] In wet processing of copper smelting fumes, common filtration methods include centrifugal filtration, plate and frame filtration, and disc filtration. The lead-bismuth slag filtered using these methods has a moisture content of 40%-50%, which does not meet the standards for lead smelting furnaces and requires further drying. To improve the efficiency and quality of filtration in wet processing of copper smelting fumes, researchers have explored new filtration technologies. For example, membrane filtration can effectively reduce the moisture content of lead-bismuth slag to below 10%, thereby eliminating the need for drying and increasing overall processing speed. Besides filtration technology innovation, researchers are also optimizing the chemical processes in wet processing. By adjusting the types and proportions of chemical additives, valuable metal elements can be dissolved and separated more effectively while reducing environmental pollution. These improvements not only increase metal recovery rates but also reduce processing costs. However, a wet processing technology specifically for side-blown copper smelting fumes is currently lacking.

[0008] Currently, for the wet treatment process of side-blown copper smelting dust, only common filtration methods can be used. The filter residue still needs to be treated to reduce its moisture content before entering the furnace, and the filtration rate of traditional filtration methods is also relatively low. Summary of the Invention

[0009] To address the aforementioned problems, this invention provides a method for improving the leaching efficiency and filtration efficiency of side-blown flue dust in copper smelting. This invention helps to more effectively dissolve and separate valuable metal elements, increase the recovery rate of valuable elements, and reduce resource waste; it also reduces the moisture content of lead-bismuth slag, eliminates the drying step of filter slag before entering the furnace in traditional filtration methods, and saves processing time.

[0010] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0011] A method for improving the leaching and filtration efficiency of side-blown copper smelting dust includes the following steps: S1, pre-treating the side-blown copper smelting dust by drying and sieving; S2, leaching the copper smelting dust with water at a reaction temperature of 80-90℃ and a liquid-solid ratio of 3ml:1g to obtain a water leaching solution, with a leaching reaction time of not less than 3 hours; S3, adding additives to the water leaching solution during the leaching process, and using a gas stirring device to stir the water leaching solution and additives, wherein the gas stirring device includes a gas stirring tool that extends to the bottom of the water leaching solution; the gas stirring tool is eccentrically arranged and rotates on its own axis while revolving around a vertical axis; S4, after the water leaching is completed, performing solid-liquid separation, adding polyethylene glycol 2000 as a dispersant to enhance liquid fluidity and increase filtration speed, obtaining water leaching residue and water leaching solution, and processing the obtained water leaching residue and water leaching solution separately.

[0012] Preferably, the gas stirring tool includes a vertically arranged stirring shaft, with a stirring mounting frame fixed to the bottom of the stirring shaft. The center of the stirring mounting frame is fixedly connected to the bottom of the stirring shaft, and stirring parts are rotatably connected to both sides of the stirring mounting frame. The horizontal cross-section of each stirring part is circular, and the outer side of the stirring part abuts against the inner wall of the water-immersed container. This structure uses the stirring shaft as the core driving force, symmetrically connecting two circular stirring parts through the stirring mounting frame at the bottom, with the outer side of the stirring parts in close contact with the inner wall of the water-immersed container. The stirring parts can move synchronously with the mounting frame, breaking the limitation of traditional stirring equipment being "strong at the center and weak at the edges": the stirring parts abut against the inner wall of the container, allowing direct action on the edge area of ​​the container, avoiding the deposition of dust on the wall surface to form "dead corners," and ensuring that dust particles throughout the entire container area are in full contact with the water immersion liquid. The symmetrically arranged stirring parts, combined with the revolution and rotation of the shaft, form a three-dimensional stirring flow field, improving the uniformity of solid-liquid mixing.

[0013] Preferably, the upper end of the stirring section is fixed with multiple stirring blades, which are arranged circumferentially around the stirring section and each stirring blade is inclined. The inclined blades (the inclination angle is usually 30°-60°) are evenly distributed along the circumference at the upper end of the stirring section. When the blades rotate with the stirring section, they generate both horizontal shear force and axial (up and down) thrust. Horizontally: the rotation of the blades generates shear force, which breaks up the dust agglomerates and increases the solid-liquid contact area. Axially: the inclination angle causes the liquid to form an up-and-down circulating flow, pushing the dust particles deposited at the bottom to the liquid surface, while bringing the additives on the liquid surface to the bottom, realizing the exchange of substances in the entire liquid layer.

[0014] Preferably, the outer sidewall of the stirring part is provided with multiple air vents, the stirring shaft and the stirring part are both hollow, and the air vents are connected to the stirring part.

[0015] The stirring shaft and stirring section are hollow cavities, forming a "gas channel." External gases (such as smelting flue gas as described later in the section on the drive device) can enter the stirring section through the shaft and eventually exit from the gas outlet holes on the side wall. The gas outlet holes are evenly distributed around the circumference of the stirring section, and the hole diameter is typically 0.5-2 mm.

[0016] Dual stirring mechanism: Combining mechanical stirring (physical disturbance between blades and stirring section) and gas stirring (convection generated by rising bubbles), the bubbles carry some dust particles and break them up during their ascent, further enhancing solid-liquid mass transfer.

[0017] Uniform gas distribution: Because the gas outlet is located on the side wall of the stirring section and moves with the stirring section, the bubbles can diffuse evenly to the entire liquid layer, avoiding the "gas blockage" problem caused by local bubble concentration; the leaching efficiency is increased by 10%-15% (especially for metals that are easily soluble in acidic or oxidizing environments, such as arsenic); at the same time, the bubbles can adsorb some fine particles, providing a "pre-agglomeration" effect for subsequent solid-liquid separation.

[0018] Preferably, it also includes a driving device for driving the gas stirring tool. The driving device includes a driving frame, and a rotating seal that is rotatably connected to the stirring shaft is fixed at the upper end of the driving frame. The smelting flue gas that has been preliminarily filtered is introduced into the stirring shaft and finally discharged from multiple gas outlets.

[0019] Preferably, the outer side of the stirring section is provided with a temperature memory metal. When the temperature of the temperature memory metal is below a predetermined temperature, it is in a contracted state and offset from the inner wall of the water immersion container. When the temperature of the temperature memory metal exceeds the predetermined temperature, it is in an expanded state and adheres to the inner wall of the water immersion container. The above structure can adaptively adjust the stirring range: in the reaction stage (high temperature), the memory metal expands and adheres to the inner wall, strengthening the edge stirring; in the non-reaction stage (low temperature), the metal contracts, reducing the friction between the stirring section and the container, facilitating equipment maintenance or handling; cleaning function: at high temperatures, the adhesion between the metal and the inner wall can scrape off residual dust deposits on the wall surface, avoiding the "scaling" problem caused by long-term operation.

[0020] Preferably, the outer side of the stirring part is provided with a groove for accommodating shape memory metal, and an elastic protective sleeve is provided on the outer side of the groove, with the shape memory metal located inside the protective sleeve.

[0021] Preferably, the deformation temperature of the shape memory metal is between 80-90°C. The shape memory metal can be a nickel-titanium-copper ternary shape memory alloy, a high-temperature shape memory alloy, such as high-Ni alloy, or after specific heat treatment, the deformation temperature of the shape memory metal is controlled between 80-90°C.

[0022] The beneficial effects of this invention are as follows:

[0023] Compared with existing technologies, by adjusting the liquid-to-solid ratio (3:1, ml:g), reaction time (3 hours), reaction temperature (80-90℃), and the selection of additives, combined with the efficient gas stirring effect of the gas stirring equipment, the most water-soluble valuable metals and their compounds in copper smelting dust can be recovered. This step lays a solid foundation for the subsequent extraction and separation of valuable metal elements. This method optimizes the wet leaching process of side-blown copper smelting dust, which helps to dissolve and separate valuable metal elements more effectively, improve the recovery rate of valuable elements, and reduce resource waste. By selecting appropriate additives, the filtration speed can be increased, the water content of lead-bismuth slag can be reduced, the drying step of filter residue before entering the furnace in the traditional filtration method can be eliminated, the processing time can be saved, and the overall processing speed can be improved. Attached Figure Description

[0024] Figure 1 This is a process flow diagram of the present invention.

[0025] Figure 2 This is a three-dimensional structural diagram of the gas stirring device of the present invention.

[0026] Figure 3 For the present invention Figure 2 A schematic diagram of the main structure.

[0027] Figure 4 For the present invention Figure 3 A schematic diagram of the AA-direction cross-section structure.

[0028] In the diagram: 100, water immersion container; 200, drive unit; 210, drive frame; 220, drive motor; 230, sealed rotating connector; 300, gas stirring tool; 310, stirring shaft; 311, central channel; 320, stirring mounting frame; 330, stirring section; 331, stirring blade. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and examples.

[0030] See attached document Figure 1 A method for improving the leaching and filtration efficiency of side-blown copper smelting dust involves pre-treating the side-blown copper smelting dust by drying and sieving. Taking white dust from a certain enterprise as an example, the content ranges of various elements are shown in Table 1.

[0031] Table 1: Elemental Content of Flue Dust from Side-blown Furnaces

[0032]

[0033] Under the given reaction time and temperature, the liquid-to-solid ratios were 6:1, 5:1, 3:1, and 2:1, respectively. The experimental data are shown in Table 2 (taking 200g of smoke dust as an example for each sample).

[0034] Table 2: Leaching rate of metal elements in flue ash with different liquid-to-solid ratios

[0035]

[0036] This water immersion mainly selects the liquid-to-solid ratio with the best leaching rate. In practical applications, a comprehensive consideration is needed to select the most economical liquid-to-solid ratio; " / " represents a leaching rate of almost zero.

[0037] Under a given reaction time and optimal liquid-to-solid ratio, the reaction temperatures were 60℃, 70℃, 80℃, and 90℃, respectively. The optimal reaction temperature was determined (taking 200g of smoke dust per sample as an example).

[0038] Table 3: Leaching rate of metal elements in flue ash at different temperatures

[0039]

[0040]

[0041] The optimal reaction temperature for leaching rate was selected for this water immersion test. In practical applications, factors such as energy consumption and economy should be considered comprehensively. " / " indicates that the leaching rate is almost zero.

[0042] The optimal reaction time was determined by taking 200g of smoke dust per sample, with the optimal liquid-solid ratio and reaction temperature as the conditions.

[0043] Table 4: Leaching rate of metal elements in flue ash at different times

[0044]

[0045] The optimal reaction time for leaching rate was selected in this water immersion test; in practical applications, factors such as energy consumption and economy should be considered comprehensively; " / " indicates that the leaching rate is almost zero.

[0046] Under optimal reaction liquid-solid ratio, reaction temperature, and reaction time, the additives (sodium 12-alkylbenzenesulfonate, polyacrylamide, etc.) were added at concentrations of 20 mL, 30 mL, 40 mL, and 50 mL, respectively, to determine the optimal addition amount (taking 200 g of smoke dust per sample as an example).

[0047] Leaching rate of metal elements in soot

[0048]

[0049]

[0050] The optimal reaction time for leaching rate was selected in this water immersion test; in practical applications, factors such as energy consumption and economy should be considered comprehensively; " / " indicates that the solid-liquid separation time was too long and no data was generated.

[0051] According to the table above, the optimal reaction liquid-solid ratio (3:1, ml:g), reaction temperature (80-90℃), and reaction time (3 hours) for this water immersion are as follows: the additive is polyethylene glycol 2000, and the amount added is 5 ml of 5% polyethylene glycol 2000 solution; (taking 200g of sample as an example for each water immersion) the water immersion work is carried out under the above reaction conditions.

[0052] Finally, solid-liquid separation was performed, and the water content of the filter residue was tested.

[0053] VI. Key Points of the Invention

[0054] This invention mainly proposes a method to improve the leaching efficiency and filtration rate of side-blown copper smelting dust, with the key points being the following aspects:

[0055] 1. Exploration of Reaction Conditions for Water Immersion Process: A novel wet treatment process for recovering valuable metal elements from side-blown copper smelting dust. Because copper smelting dust has a complex composition and the content of various metals and their compounds in the dust is not fixed, this invention aims to ensure the maximum recovery of water-soluble valuable metals and their compounds from copper smelting dust by adjusting the liquid-to-solid ratio (3:1, ml:g), reaction time (3 hours), reaction temperature (80-90℃), and the selection of additives. This step lays a solid foundation for the subsequent extraction and separation of valuable metal elements.

[0056] 2. Reduced processing costs: This method optimizes the wet leaching process of side-blown copper smelting dust, which helps to dissolve and separate valuable metal elements more effectively, improve the recovery rate of valuable elements, and reduce resource waste.

[0057] 3. Improve filtration rate: By selecting appropriate additives and using vacuum filtration, the filtration rate can be increased, the moisture content of lead-bismuth slag can be reduced, the drying step of filter residue before entering the furnace under traditional filtration methods can be eliminated, the processing time can be saved, and the overall processing speed can be improved; the principle of this method is to use polyethylene glycol 2000 as a dispersant to enhance the fluidity of the liquid and improve the filtration rate.

[0058] VII. Effects of the Invention

[0059] In the process of treating side-blown copper smelting fumes using a wet process, adding an appropriate amount of flocculant can significantly improve the filtration rate of the copper side-blown smelting fumes after leaching, increasing the filtration rate by 50%, thereby greatly shortening the filtration time and accelerating the progress of the entire process.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for improving the leaching efficiency and filtration efficiency of side-blown dust in copper smelting, characterized in that, The steps include: S1. Pretreatment of side-blown copper smelting fumes: drying and sieving; S2. At a reaction temperature of 80-90℃, copper smelting dust is leached with water at a liquid-solid ratio of 3ml:1g to obtain an aqueous leaching solution. The reaction time for water leaching shall not be less than 3 hours. S3. During the water immersion process, additives are added to the immersion liquid, and a gas stirring device is used to stir the immersion liquid and the additives. The gas stirring device includes a gas stirring tool (300), which extends to the bottom of the immersion liquid. The gas stirring tool (300) is eccentrically arranged and rotates around a vertical axis while rotating on its own axis. S4. After water immersion, solid-liquid separation is performed. Polyethylene glycol 2000 is added as a dispersant to enhance liquid flowability and increase filtration speed, resulting in water immersion residue and water immersion liquid. The obtained water immersion residue and water immersion liquid are then processed separately.

2. The method for improving the leaching efficiency and filtration efficiency of side-blown dust in copper smelting according to claim 1, characterized in that, The gas stirring tool (300) includes a vertically arranged stirring shaft (310), a stirring mounting frame (320) is fixed at the bottom of the stirring shaft (310), the center of the stirring mounting frame (320) is fixedly connected to the bottom of the stirring shaft (310), and stirring parts (330) are rotatably connected to both sides of the stirring mounting frame (320). The stirring parts (330) have a circular horizontal cross section, and the outer side of the stirring parts (330) abuts against the inner wall of the water immersion container (100).

3. The method for improving the leaching efficiency and filtration efficiency of side-blown dust in copper smelting according to claim 2, characterized in that, The upper end of the stirring part (330) is fixed with a plurality of stirring blades (331), which are arranged around the stirring part (330) in a circumferential manner and each stirring blade (331) is arranged at an angle.

4. The method for improving the leaching efficiency and filtration efficiency of side-blown dust in copper smelting according to claim 4, characterized in that, The outer sidewall of the stirring part (330) is provided with a plurality of air vents. The stirring shaft (310) and the stirring part (330) are both hollow and the air vents are connected to the stirring part (330).

5. The method for improving the leaching efficiency and filtration efficiency of side-blown dust in copper smelting according to claim 4, characterized in that, It also includes a drive device (200) for driving the gas stirring tool (300), the drive device (200) including a drive frame (210), the upper end of the drive frame (210) is fixed with a rotating seal that is rotatably connected to the stirring shaft (310), and the smelting flue gas that has been preliminarily filtered is introduced into the stirring shaft (310) and finally discharged from multiple gas outlets.

6. The method for improving the leaching efficiency and filtration efficiency of side-blown dust in copper smelting according to claim 4, characterized in that, The stirring part (330) is provided with a temperature memory metal on the outside. When the temperature is below a predetermined temperature, the memory metal is in a contracted state and is offset from the inner wall of the water immersion container (100). When the temperature exceeds the predetermined temperature, the memory metal is in an expanded state and is attached to the inner wall of the water immersion container (100).

7. The method for improving the leaching efficiency and filtration efficiency of side-blown dust in copper smelting according to claim 6, characterized in that, The stirring part (330) has a groove on the outside for accommodating shape memory metal, and an elastic protective sleeve is provided on the outside of the groove, with the shape memory metal located inside the protective sleeve.

8. The method for improving the leaching efficiency and filtration efficiency of side-blown dust in copper smelting according to claim 7, characterized in that, The deformation temperature of the shape memory metal is between 80-90℃.

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