Method and equipment for preparing stannous oxide by utilizing tinning tin sludge

Abstract

This invention relates to the field of electroplating waste resource utilization technology, specifically a method and equipment for preparing tin oxide from tin plating sludge. The method includes a box-type dryer, a crushing box, a box-type high-temperature furnace, a tubular atmosphere furnace, and a vibrating screen. A support frame is fixedly connected to the lower part of the crushing box, and a spring is fixedly connected to the top of the support frame. A screening plate is fixedly connected to the top of the spring. A rotating rod is rotatably connected through the crushing box, and an eccentric wheel is fixedly connected to the outer ring of the rotating rod. A discharge port is opened on the left side of the crushing box. Two rotating shafts are rotatably connected through the upper part of the crushing box, and crushing rollers and gears are fixedly connected to the outer rings of the rotating shafts. This method eliminates the need for acid washing or alkali washing to remove organic matter from the tin sludge, directly utilizing the carbon powder formed after the organic impurities in the tin sludge are carbonized as a reducing agent. The process involves fewer steps and is simple to operate.

Description

Technical Field

[0001] This invention relates to the field of electroplating waste resource utilization technology, specifically a method and equipment for preparing tin oxide from tin plating sludge. Background Technology

[0002] The continuous tin plating process generates a large amount of tin sludge waste. Currently, this tin sludge is usually treated as industrial waste, which not only wastes resources but also increases the environmental burden.

[0003] Stannous oxide (SnO) is an important chemical raw material, commonly used in the electroplating industry in tin dissolution systems for MSA (methanesulfonic acid) and PSA (phenolsulfonic acid). Traditional methods for preparing stannous oxide typically require high-purity tin raw materials and involve complex chemical reactions, resulting in high costs.

[0004] In existing technologies, there are two main methods for preparing stannous oxide: one is to dissolve stannous chloride dihydrate in hot concentrated hydrochloric acid, and then add an aqueous sodium carbonate solution to react and generate it; the other is to dissolve high-purity tin in hydrochloric acid solution, add concentrated ammonia to produce a precipitate, and then process it to obtain the oxide. These methods all require the use of high-purity tin raw materials, and the processes are complex and costly.

[0005] Regarding the resource utilization of tin mud, the existing technologies mainly include the following methods: The method for extracting tin oxide from tin plating sludge (CN 116102054 A) requires alkaline leaching and acid leaching treatment of the tin plating sludge, which is complex and costly. The main methods for utilizing tin mud resources are to prepare nano-tin dioxide or recover refined tin, rather than tin oxide. Carbothermal reduction technology is used, but it requires the addition of a large amount of reducing agent, and the process parameters are different from those of this invention.

[0006] These existing technologies all suffer from problems such as complex processes, high costs, and difficult operation, and none of them involve a method for preparing stannous oxide using tin plating sludge. Therefore, developing a simple, low-cost method for preparing stannous oxide using tin plating sludge has significant economic and environmental implications. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a method and equipment for preparing tin oxide using tin plating sludge resources, which solves the problems of complex processes and high costs in the prior art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method and equipment for preparing tin oxide using tin plating sludge, comprising a box dryer, a crushing box, a box-type high-temperature furnace, a tubular atmosphere furnace, and a vibrating screen. A support frame is fixedly connected to the lower part of the crushing box, a spring is fixedly connected to the top of the support frame, and a screening plate is fixedly connected to the top of the spring. A rotating rod is rotatably connected through the crushing box, and an eccentric wheel is fixedly connected to the outer ring of the rotating rod. A discharge port is provided on the left side of the crushing box. Two rotating shafts are rotatably connected through the upper part of the crushing box, crushing rollers are fixedly connected to the outer ring of the rotating shafts, and gears are fixedly connected to the outer ring of the rotating shafts. A second motor is provided on the outside of the crushing box, and the output end of the second motor is fixedly connected to the rear rotating shaft. A feed cylinder is rotatably connected through the top of the crushing box. A through groove is provided on the lower part of the outside of the crushing box, and a collection box is slidably connected through the through groove.

[0009] Preferably, a motor is fixedly connected to the rear end of the crushing box, and the output end of the motor is fixedly connected to the rotating rod.

[0010] Preferably, a collection box is provided on the left side of the crushing box, and the collection box is located outside the discharge port.

[0011] Preferably, the gears are located on the outside of the crushing chamber, and the two gears are meshed together.

[0012] Preferably, the bottom of the second motor is fixedly connected to a fixing frame, and the fixing frame is fixedly connected to the outside of the crushing box.

[0013] Preferably, the collection box is located below the screening plate, and a handle is fixedly connected to the outside of the collection box.

[0014] Preferably, the eccentric wheel is positioned below the screening plate.

[0015] Preferably, the method for preparing stannous oxide using tin plating sludge includes the following steps: S1, Drying Stage: The raw tin plating sludge (with a moisture content typically between 40% and 60%) is spread evenly on the tray of box dryer 1, with a thickness controlled at 8-10 cm. The drying temperature is set at 110-120°C for 2-3 hours. The performance target at this stage is to reduce the residual moisture content of the tin plating sludge to below 1%.

[0016] S2. Crushing and sieving: Start motors 17 and 11. Feed the dry tin sludge through the feed cylinder 19. Powder is produced through the continuous operation of the two-stage crushing rollers 15. After being screened by the sieve plate 8, the 100-mesh passing rate should not be less than 95% to ensure the contact area for subsequent chemical reactions.

[0017] S3, Oxidation Calcination: The powder is transferred into a box-type high-temperature furnace 3. A PID temperature control program is used to raise the temperature to 500-600°C at a rate of 5°C / min. This temperature is maintained for 2 hours. The purpose of this step is to utilize oxygen in the air to initially oxidize and partially pyrolyze any metallic tin or organic additives that may be present in the tin slurry, generating an intermediate primarily composed of tin dioxide, while retaining or converting the organic carbon components in the tin slurry into carbon black.

[0018] S4, Carbothermic Reduction: This is the core step in the preparation of stannous oxide. The calcined product is placed in a tubular atmosphere furnace 4. The nitrogen cylinder is turned on, and the gas flow rate is adjusted to 0.5 L / min (quantitative range 0.3-1 L / min) using a flow meter to maintain a slightly positive pressure inside the furnace. The temperature is increased to 800°C (quantitative range 650-1000°C) at a rate of 5°C / min and held for 3 hours.

[0019] During this process, the carbon powder inside the material acts as a reducing agent, reducing tin dioxide (SnO2) to tin oxide (SnO). If the organic matter content in the tin sludge is detected to be too low, 4% activated carbon powder (specific surface area ≥1000m² / g) needs to be added after calcination to ensure a complete reduction reaction.

[0020] S5. Cooling and Finishing: After the reaction is complete, the heating is turned off, and nitrogen gas is maintained until the furnace temperature drops below 40°C to prevent the hot SnO from being instantly oxidized back to SnO2 upon contact with air. Finally, after sieving through a vibrating sieve (5 sieves), the stannous oxide powder is vacuum-packed with nitrogen using a vacuum packaging machine.

[0021] Quantitative results: The obtained tin oxide powder has a purity of ≥85%, and its appearance is blue-black or black crystalline powder with uniform particle size, which fully meets the addition requirements of the tin dissolving system in the electroplating production line.

[0022] Working principle: First, the entire process is completed sequentially by a box dryer, a crushing box, a box-type high-temperature furnace, a tubular atmosphere furnace, and a vibrating screen. The collected tin plating sludge is first placed inside the box dryer and dried at a constant temperature of 110–120℃ for 2–3 hours. This effectively removes free moisture from the tin sludge, preventing clumping during subsequent crushing and avoiding interference from moisture during high-temperature calcination, thus ensuring uniform and stable drying of the raw materials.

[0023] The dried, lumpy tin sludge is fed into the crushing chamber through the feed cylinder at the top. The controller starts motor two, which drives the rear shaft to rotate. The gears on the outer sides of the two shafts mesh with each other, causing the two crushing rollers to rotate synchronously in opposite directions. The dried tin sludge falling between the two crushing rollers is crushed and refined under the action of compression and shearing, achieving rapid crushing of the raw material.

[0024] The crushed tin sludge particles fall onto the screening plate below. A motor at the rear of the crushing box drives a rotating rod to rotate continuously, with an eccentric wheel on the outside of the rod rotating synchronously. The eccentric wheel periodically pushes against the bottom of the screening plate. Combined with the elastic extension and contraction of the spring at the top of the support frame, this causes the screening plate to vibrate continuously at high frequency. Under vibration, qualified fine materials with a particle size ≤100 mesh fall through the screen holes and are collected in the collection box below the screening plate. Larger, substandard materials are pushed out from the left-side outlet by the vibration of the inclined screening plate and ultimately fall into the outer collection box for centralized storage, facilitating unified recycling and secondary crushing to ensure uniform particle size.

[0025] The tin mud powder that has passed the crushing and screening process is fed into a box-type high-temperature furnace. Under an air atmosphere, the temperature is raised to 500-600℃ at a uniform rate of 5℃ / min and held at a constant temperature for 2 hours to complete the high-temperature calcination treatment, remove organic matter and impurities, and complete the preliminary oxidation pretreatment. If the carbon content of the material is insufficient, 3%-5% activated carbon powder can be added in advance to meet the conditions for the subsequent reduction reaction.

[0026] The calcined intermediate product is transferred into a tubular atmosphere furnace, where an inert protective atmosphere such as nitrogen or argon is introduced throughout the process, with the gas flow rate controlled at 0.3–1 L / min to isolate the material from air and prevent secondary oxidation. The temperature is then increased to 650–1000°C at a rate of 5°C / min and held for 3 hours to carry out a carbothermic reduction reaction, which causes the tin oxides to be directionally converted into crude tin oxide.

[0027] After the reduction reaction is completed, the material is naturally cooled to room temperature in a closed environment with inert gas continuously introduced to prevent the high-temperature material from oxidizing and deteriorating upon contact with air. The cooled material is then fed into a vibrating screen and sieved through a 100-mesh screen to remove coarse impurities and incompletely reacted particles. Finally, high-purity tin oxide powder is obtained, completing the resource recovery and preparation of tin plating mud.

[0028] This invention provides a method and apparatus for preparing stannous oxide using tin plating sludge as a resource. It has the following beneficial effects: Simple process: This invention eliminates the need for acid washing or alkali washing to remove organic matter from tin sludge. It directly utilizes the carbon powder formed after carbonization of organic impurities in the tin sludge as a reducing agent, resulting in fewer process steps and simpler operation. Low cost: This invention directly utilizes tin sludge generated from the tin plating production line as raw material, eliminating the need for adding large amounts of reducing agent and reducing production costs. High resource utilization: This invention achieves resource utilization of waste from the tin plating production line, reducing environmental pollution. Good product quality: The stannous oxide prepared by this invention has a purity of ≥85%, fully meeting the requirements of MSA (methanesulfonic acid) and PSA (phenolsulfonic acid) tin dissolving systems. Suitable for industrial production: The process of this invention is simple and easy to operate, making it suitable for industrial production. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a cross-sectional view of the pulverizing chamber of the present invention; Figure 3 This is a side view of the pulverizing chamber of the present invention.

[0030] The components are as follows: 1. Box-type dryer; 2. Crushing box; 3. Box-type high-temperature furnace; 4. Tubular atmosphere furnace; 5. Vibrating screen; 6. Support frame; 7. Spring; 8. Screening plate; 9. Rotating rod; 10. Eccentric wheel; 11. Motor 1; 12. Discharge port; 13. Collection box; 14. Rotating shaft; 15. Crushing roller; 16. Gear; 17. Motor 2; 18. Fixing frame; 19. Feed cylinder; 20. Through groove; 21. Collection box; 22. Handle. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1: like Figure 1-3 As shown, this invention provides a method and equipment for preparing tin oxide using tin plating sludge resources, including a box dryer 1, a crushing box 2, a box-type high-temperature furnace 3, a tubular atmosphere furnace 4, and a vibrating screen 5. The crushing box 2 is characterized by: a support frame 6 fixedly connected to the lower part of the crushing box 2; a spring 7 fixedly connected to the top of the support frame 6; a screening plate 8 fixedly connected to the top of the spring 7; a rotating rod 9 penetrating and rotatably connected inside the crushing box 2; an eccentric wheel 10 fixedly connected to the outer ring of the rotating rod 9; a discharge port 12 on the left side of the crushing box 2; two rotating shafts 14 penetrating and rotatably connected to the upper part of the crushing box 2; a crushing roller 15 fixedly connected to the outer ring of the rotating shaft 14; a gear 16 fixedly connected to the outer ring of the rotating shaft 14; a second motor 17 located on the outside of the crushing box 2, with its output end fixedly connected to the rear rotating shaft 14; a feed cylinder 19 penetrating and fixedly connected to the top of the crushing box 2; a through groove 20 located on the lower part of the outside of the crushing box 2; and a collection box 21 penetrating and slidably connected within the through groove 20.

[0033] Specifically, the crushing box 2, as the key to raw material preparation, adopts a design combining gravity extrusion and high-frequency vibrating screening. The shell of the crushing box 2 is preferably made of 304 stainless steel to resist potential corrosion from residual electroplating solution in the tin sludge. Its top feed cylinder 19 adopts a funnel-shaped design with an upper diameter of 300mm, which facilitates the feeding of bulk tin sludge.

[0034] Inside the crushing chamber 2, two sets of parallel crushing rollers 15 are installed at the top. The surface of the crushing rollers 15 is not smooth, but is machined with staggered V-shaped crushing teeth (tooth depth is 5-8mm). The two sets of crushing rollers 15 are meshed by gears 16 on the outer side. The motor 17 is a 1.5kW variable frequency speed control motor, which is firmly connected to the outer wall of the crushing chamber 2 through the fixing frame 18. By controlling the reverse rotation of the crushing rollers 15, the blocky dry tin sludge can be forcibly crushed into particles smaller than 5mm. The crushed material falls onto the inclined screening plate 8 below. The screening plate 8 is supported on the support frame 6 by multiple symmetrically distributed springs 7. The springs 7 are preferably made of 65Mn manganese steel high-strength springs to ensure fatigue strength under long-term vibration.

[0035] A rotating rod 9 is located below the screening plate 8 and is driven by a motor 11. An eccentric wheel 10 is fixed to the rotating rod 9, with an eccentricity of 10-15 mm. When the rotating rod 9 rotates at a speed of 1200 r / min, the eccentric wheel periodically impacts the bottom of the screening plate 8, and in conjunction with the spring's rebound, forms a high-frequency vibration with a frequency of 20 Hz and an amplitude of more than 10 mm.

[0036] The mesh size of the sieve plate 8 is precisely 100 mesh. Fine powder that meets the requirements passes through the mesh and falls into the collection box 21. Unqualified coarse particles are guided by the vibration inertia and the 3-5 degree tilt angle of the sieve plate 8, and discharged from the discharge port 12 on the left into the collection box 13 for re-feeding and crushing.

[0037] The rear end of the crushing box 2 is fixedly connected to a motor 11, and the output end of the motor 11 is fixedly connected to the rotating rod 9.

[0038] The motor 11 can drive the rotating rod 9 to rotate.

[0039] A collection box 13 is provided on the left side of the crushing box 2, and the collection box 13 is located outside the discharge port 12.

[0040] Large particles can be collected using the collection box 13.

[0041] Gear 16 is located on the outside of the crushing chamber 2, and two gears 16 are meshed together.

[0042] It serves as a transmission mechanism, with two gears 16 meshing with each other to achieve reverse rotation of the two crushing rollers 15, which facilitates the crushing of materials.

[0043] The bottom of motor 217 is fixedly connected to a fixing frame 18, and the fixing frame 18 is fixedly connected to the outside of the crushing box 2.

[0044] Motor 2 17 is fixedly connected to the crushing box 2 via the bottom fixing bracket 18.

[0045] The collection box 21 is located below the screening plate 8, and a handle 22 is fixedly connected to the outside of the collection box 21.

[0046] The collection box 21 can be horizontally pulled out from the through slot 20 at the bottom of the crushing box 2 via the handle 22.

[0047] The eccentric wheel 10 is positioned below the screening plate 8.

[0048] Vibration can be generated by striking the sieve plate 8 with the eccentric wheel 10.

[0049] Example 2: like Figure 1-3 As shown, this embodiment of the invention provides a method for preparing tin oxide using tin plating sludge resources, comprising the following steps: S1, Drying Stage: The raw tin plating sludge (with a moisture content typically between 40% and 60%) is spread evenly on the tray of box dryer 1, with a thickness controlled at 8-10 cm. The drying temperature is set at 110-120°C for 2-3 hours. The performance target at this stage is to reduce the residual moisture content of the tin plating sludge to below 1%.

[0050] S2. Crushing and sieving: Start motors 17 and 11. Feed the dry tin sludge through the feed cylinder 19. Powder is produced through the continuous operation of the two-stage crushing rollers 15. After being screened by the sieve plate 8, the 100-mesh passing rate should not be less than 95% to ensure the contact area for subsequent chemical reactions.

[0051] S3, Oxidation Calcination: The powder is transferred into a box-type high-temperature furnace 3. A PID temperature control program is used to raise the temperature to 500-600°C at a rate of 5°C / min. This temperature is maintained for 2 hours. The purpose of this step is to utilize oxygen in the air to initially oxidize and partially pyrolyze any metallic tin or organic additives that may be present in the tin slurry, generating an intermediate primarily composed of tin dioxide, while retaining or converting the organic carbon components in the tin slurry into carbon black.

[0052] S4, Carbothermic Reduction: This is the core step in the preparation of stannous oxide. The calcined product is placed in a tubular atmosphere furnace 4. The nitrogen cylinder is turned on, and the gas flow rate is adjusted to 0.5 L / min (quantitative range 0.3-1 L / min) using a flow meter to maintain a slightly positive pressure inside the furnace. The temperature is increased to 800°C (quantitative range 650-1000°C) at a rate of 5°C / min and held for 3 hours.

[0053] During this process, the carbon powder inside the material acts as a reducing agent, reducing tin dioxide (SnO2) to tin oxide (SnO). If the organic matter content in the tin sludge is detected to be too low, 4% activated carbon powder (specific surface area ≥1000m² / g) needs to be added after calcination to ensure a complete reduction reaction.

[0054] S5. Cooling and Finishing: After the reaction is complete, the heating is turned off, and nitrogen gas is maintained until the furnace temperature drops below 40°C to prevent the hot SnO from being instantly oxidized back to SnO2 upon contact with air. Finally, the stannous oxide powder is sieved through a vibrating screen and then vacuum-packed with nitrogen using a vacuum packaging machine.

[0055] Testing showed that the tin oxide prepared in this example had a purity of 86%, a loose packing density of 1.2 g / cm³, and a specific surface area of ​​5.6 m² / g, fully meeting the requirements of MSA (methanesulfonic acid) and PSA (phenolsulfonic acid) tin dissolving systems.

[0056] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An apparatus for preparing tin oxide using tin plating sludge resources, comprising a box dryer (1), a crushing box (2), a box high-temperature furnace (3), a tubular atmosphere furnace (4), and a vibrating screen (5), characterized in that: A support frame (6) is fixedly connected to the lower part of the crushing box (2). A spring (7) is fixedly connected to the top of the support frame (6). A screening plate (8) is fixedly connected to the top of the spring (7). A rotating rod (9) is rotatably connected through the crushing box (2). An eccentric wheel (10) is fixedly connected to the outer ring of the rotating rod (9). A discharge port (12) is opened on the left side of the crushing box (2). Two rotating shafts (14) are rotatably connected through the upper part of the crushing box (2). A crushing roller (15) is fixedly connected to the outer ring of the rotating shaft (14). A gear (16) is fixedly connected to the outer ring of the rotating shaft (14). A second motor (17) is provided on the outside of the crushing box (2). The output end of the second motor (17) is fixedly connected to the rear rotating shaft (14). A feed cylinder (19) is rotatably connected through the top of the crushing box (2). A through groove (20) is opened on the lower part of the outside of the crushing box (2). A collection box (21) is slidably connected through the through groove (20).

2. The apparatus for preparing tin oxide using tin plating sludge as described in claim 1, characterized in that: The rear end of the crushing box (2) is fixedly connected to a motor (11), and the output end of the motor (11) is fixedly connected to the rotating rod (9).

3. The apparatus for preparing tin oxide using tin plating sludge as described in claim 1, characterized in that: A collection box (13) is provided on the left side of the crushing box (2), and the collection box (13) is located outside the discharge port (12).

4. The apparatus for preparing tin oxide using tin plating sludge as described in claim 1, characterized in that: The gear (16) is located outside the crushing box (2), and the two gears (16) are meshed with each other.

5. The apparatus for preparing tin oxide using tin plating sludge as described in claim 1, characterized in that: The bottom of the motor 2 (17) is fixedly connected to a fixing frame (18), and the fixing frame (18) is fixedly connected to the outside of the crushing box (2).

6. The apparatus for preparing tin oxide using tin plating sludge as described in claim 1, characterized in that: The collection box (21) is located below the screening plate (8), and a handle (22) is fixedly connected to the outside of the collection box (21).

7. The apparatus for preparing tin oxide using tin plating sludge as described in claim 1, characterized in that: The eccentric wheel (10) is positioned below the screening plate (8).

8. A method for preparing stannous oxide from tin plating sludge according to any one of claims 1-7, characterized in that: Includes the following steps: S1, Drying Stage: The raw tin plating sludge (with a moisture content typically between 40% and 60%) is spread evenly on the tray of box dryer 1, with a thickness controlled at 8-10 cm. The drying temperature is set at 110-120°C for 2-3 hours. The performance target at this stage is to reduce the residual moisture content of the tin plating sludge to below 1%. S2. Crushing and sieving: Start motors 17 and 11. Feed the dry tin sludge through the feed cylinder 19. Powder is produced through the continuous operation of the two-stage crushing rollers 15. After being screened by the sieve plate 8, the 100-mesh passing rate should not be less than 95% to ensure the contact area for subsequent chemical reactions. S3, Oxidation Calcination: The powder is transferred into a box-type high-temperature furnace 3. A PID temperature control program is used to raise the temperature to 500-600°C at a rate of 5°C / min. This temperature is maintained for 2 hours. The purpose of this step is to utilize oxygen in the air to initially oxidize and partially pyrolyze any metallic tin or organic additives that may be present in the tin slurry, generating an intermediate primarily composed of tin dioxide, while retaining or converting the organic carbon components in the tin slurry into carbon black. S4, Carbothermic Reduction: This is the core step in the preparation of stannous oxide. The calcined product is placed in a tubular atmosphere furnace 4. The nitrogen cylinder is turned on, and the gas flow rate is adjusted to 0.5 L / min (quantitative range 0.3-1 L / min) using a flow meter to maintain a slightly positive pressure inside the furnace. The temperature is increased to 800°C (quantitative range 650-1000°C) at a rate of 5°C / min and held for 3 hours. During this process, the carbon powder inside the material acts as a reducing agent, reducing tin dioxide (SnO2) to tin oxide (SnO). If the organic matter content in the tin sludge is detected to be too low, 4% activated carbon powder (specific surface area ≥1000m² / g) needs to be added after calcination to ensure a complete reduction reaction. S5. Cooling and Finishing: After the reaction is complete, the heating is turned off, and nitrogen gas is maintained until the furnace temperature drops below 40°C to prevent the hot SnO from being instantly oxidized back to SnO2 upon contact with air. Finally, the stannous oxide powder is sieved through a vibrating screen and then vacuum-packed with nitrogen using a vacuum packaging machine.

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