Device and method for recovering boric acid from iron alloy XRF (X-Ray Fluorescence) tabletting sample

Abstract

The invention discloses a device for recovering boric acid from an iron alloy XRF tabletting sample and a recovery method thereof, and relates to the technical field of analytical chemistry sample pretreatment and resource recovery. The recovery device comprises a base, a sample pretreatment mechanism, a leaching mechanism, a solid-liquid separation mechanism, an evaporation concentration mechanism, a complex reaction mechanism and a directional condensation trapping mechanism, wherein a master controller is fixedly mounted on the side wall of the base; the recovery method comprises the steps of sample pretreatment, leaching reaction, solid-liquid separation, evaporation and concentration, complexation reaction, vaporization and gradient condensation, boric acid trapping and desorption and purification. According to the method, volatilization, decomposition and impurity adsorption loss of boric acid in the operation process are reduced to the maximum extent, the boric acid recovery rate is effectively improved and is remarkably higher than that of a traditional method, meanwhile, the selective recovery capacity of boric acid is enhanced through introduction of the complexing agent and design of the special trapping trap, and interference of other coexisting components is reduced.

Description

Technical Field

[0001] This invention relates to the field of analytical chemistry sample pretreatment and resource recovery technology, and in particular to an apparatus and method for recovering boric acid from ferroalloy XRF pellet samples. Background Technology

[0002] The boron content in ferroalloys (such as ferroboron and ferrosilicon) is crucial to their properties, and X-ray fluorescence spectrometry (XRF) is a commonly used method for rapid determination of their boron content. In XRF analysis, the sample is typically mixed with a binder (such as boric acid, starch, or cellulose) and ground before being pressed into a pellet. For ferroalloy samples with low boron content, a certain amount of boric acid is sometimes intentionally added as a binder or flux to obtain a sufficiently strong pellet and a suitable count rate (although modern XRF techniques may have reduced this requirement, it still exists in historical samples or specific methods).

[0003] After analysis, these tablet samples containing ferroalloy powder and boric acid are typically discarded as waste. However, boron is an important strategic resource, and boric acid also has economic and environmental significance. Direct disposal not only wastes resources but may also negatively impact the environment due to improper handling of boron-containing waste residue. Therefore, recovering boric acid from discarded XRF tablet samples has significant resource recovery value and environmental benefits.

[0004] Existing technologies for recovering boric acid from solid waste mainly include water leaching, acid leaching, and alkaline leaching. However, these methods face many challenges when applied to ferroalloy XRF tablet samples:

[0005] Thermal instability of boric acid: Boric acid easily loses its water of crystallization or decomposes into boric anhydride at high temperatures, and some boric acid may be lost during XRF tablet preparation due to heat generated during grinding or improper subsequent storage; Volatility issues: Although pure boric acid has a high boiling point, it may be accompanied by other volatile substances under acidic or specific conditions, or lost during heating recovery due to problems such as the system's airtightness; Interference and adsorption of the iron matrix: Iron and other metal elements in ferroalloys may form hydroxide precipitates in aqueous solutions or certain solvents, or adsorb borate ions through ion exchange, surface adsorption, etc., leading to a decrease in boron leaching rate and difficulty in separation; Co-solubility of coexisting ions: Other coexisting elements such as iron, silicon, and aluminum may enter the solution together during the leaching process, increasing the difficulty and cost of subsequent separation and purification of boric acid.

[0006] In summary, existing simple heating evaporation or distillation devices are insufficient for the targeted and efficient recovery of low-concentration boric acid, and are prone to boric acid decomposition or loss with water vapor, resulting in low recovery rates and low purity. Therefore, there is an urgent need for a dedicated device and method that can overcome these shortcomings and achieve efficient, highly selective, and low-loss recovery of boric acid from ferroalloy XRF tablet samples. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides an apparatus and method for recovering boric acid from iron alloy XRF tablet samples, effectively solving the problems in the prior art.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] An apparatus for recovering boric acid from an iron alloy XRF tablet sample includes a base with a main controller fixedly mounted on the side wall, a sample pretreatment mechanism, a leaching mechanism, a solid-liquid separation mechanism, an evaporation and concentration mechanism, a complexation reaction mechanism, and a directional condensation and collection mechanism. The sample pretreatment mechanism includes a double-roll grinding assembly, a screw feeder, and a sieve-type pulverizing assembly, and the leaching mechanism includes a leachate conveying assembly and a stirring assembly.

[0010] The dual-roll grinding assembly includes a feeding bin, two grinding rollers rotatably mounted inside the lower part of the feeding bin, two transmission gears sequentially fixedly mounted on the outer ends of the two grinding rollers, a grinding motor fixedly mounted on the front outer wall of the feeding bin, and a drive gear fixedly mounted on the output shaft of the grinding motor.

[0011] The sieving and crushing assembly includes a crushing cylinder that is fixedly connected to the conveying cylinder, a rotating shaft that is rotatably installed inside the crushing cylinder, crushing blades that are fixedly connected to the lower part of the rotating shaft, a crushing motor that is fixedly connected to the outer wall of the top of the crushing cylinder through a motor support plate, and a sieving disc that is fixedly connected to the inner wall of the bottom opening of the crushing cylinder, with the bottom end of the rotating shaft penetrating through the center of the sieving disc.

[0012] The stirring assembly includes an leaching cylinder fixedly connected to the bottom of the grinding cylinder, an intelligent temperature-controlled heating rod fixedly connected to the bottom end of the rotating shaft via a connecting plate, and spiral stirring blades fixedly connected to the outer wall of the intelligent temperature-controlled heating rod.

[0013] The leachate delivery assembly includes a leachate storage tank fixedly connected to the outer wall of the crushing cylinder, a same delivery pipe fixedly connected to the bottom of the leachate storage tank and the upper part of the leachate cylinder, and a delivery solenoid valve and a flow sensor No. 1 installed sequentially on the delivery pipe.

[0014] The solid-liquid separation mechanism includes a first delivery pump fixedly connected to the lower outer wall of the leaching cylinder via a first pump base and a microporous membrane filter fixedly connected to the top outer wall of the base.

[0015] The evaporation and concentration mechanism includes a protective gas delivery assembly, a second delivery pump fixedly connected to the lower outer wall of the microporous membrane filter via a second pump base, and an evaporation and concentration tank fixedly connected to the top outer wall of the base. The top of the evaporation and concentration tank is provided with a water vapor discharge pipe.

[0016] The complexation reaction mechanism includes an organic complexing agent storage tank fixedly connected to the top outer wall of the base, a delivery pipe fixedly connected to the bottom of the organic complexing agent storage tank and the top of the evaporation and concentration tank, and a second flow sensor and a delivery solenoid valve installed sequentially on the delivery pipe.

[0017] The directional condensation and collection mechanism includes a No. 3 delivery pump fixedly connected to the lower outer wall of the evaporation and concentration tank via a No. 3 pump base, a heating vaporization tank fixedly connected to the top outer wall of the base, a multi-stage gradient condenser connected to the outlet of the heating vaporization tank, a segmented temperature control jacket located outside the multi-stage gradient condenser and fixedly connected to the outer wall of the heating vaporization tank, a collection trap fixedly connected to the top outer wall of the base, and an adsorption component located inside the collection trap.

[0018] Preferably, a compression gap is provided between the two grinding rollers, the two transmission gears mesh with each other, and the drive gear meshes with an adjacent transmission gear.

[0019] Preferably, the screw feeder includes a hopper fixedly connected to the bottom of the feed bin, a conveying cylinder fixedly connected to the bottom of the hopper, a conveying motor fixedly connected to the side wall of the conveying cylinder via a motor mounting plate, a drive shaft rotatably installed inside the conveying cylinder, and screw conveying blades welded to the drive shaft, wherein the output shaft of the conveying motor is coaxially fixedly connected to one end of the drive shaft via a coupling.

[0020] Preferably, the output shaft of the crushing motor is coaxially and fixedly connected to the top end of the rotating shaft via a coupling, and the surface of the screening disc is provided with uniformly distributed screening holes. A cleaning brush rod is fixedly connected to the lower part of the rotating shaft, and the bristle structure at the bottom of the cleaning brush rod is in contact with the surface of the screening disc.

[0021] Preferably, the bottom outer wall of the leaching cylinder is fixedly connected to the top outer wall of the base, the top of the leaching liquid storage tank is provided with a leaching liquid injection pipe, and a sealing cap is threadedly connected to the leaching liquid injection pipe. The top of the organic complexing agent storage tank is provided with a complexing agent injection pipe, and a sealing cap is threadedly connected to the complexing agent injection pipe.

[0022] Preferably, the suction end of the first pump is fixedly connected to the lower part of the leaching cylinder via pipe one, and the delivery end of the first pump is fixedly connected to the input end of the microporous membrane filter via a long delivery pipe one. The suction end of the second pump is fixedly connected to the output end of the microporous membrane filter via pipe two, and the delivery end of the second pump is fixedly connected to the upper part of the evaporation and concentration tank via a long delivery pipe two. The suction end of the third pump is fixedly connected to the lower part of the evaporation and concentration tank via pipe three, and the delivery end of the third pump is fixedly connected to the upper part of the heating and vaporization tank via a long delivery pipe three.

[0023] Preferably, the protective gas delivery assembly includes a nitrogen storage tank fixedly connected to the rear outer wall of the evaporation and concentration tank, a gas delivery pipe fixedly connected to the top of the nitrogen storage tank, and a gas delivery solenoid valve installed on the gas delivery pipe, with the bottom end of the gas delivery pipe extending through to the inner end of the evaporation and concentration tank.

[0024] Preferably, the multi-stage gradient condenser is composed of three serpentine condenser tubes that are distributed at equal intervals and connected end to end in sequence, and the segmented temperature control jacket is composed of three temperature control jackets that are sequentially wrapped around the three serpentine condenser tubes.

[0025] Preferably, the adsorption assembly includes a mounting cover plate fixedly connected to the top outer wall of the trap by bolts and three adsorption plates detachably fixedly connected to the bottom outer wall of the mounting cover plate. All three adsorption plates are located inside the trap, and the air inlet end of the trap is fixedly connected to the tail end of the multi-stage gradient condenser.

[0026] The present invention also provides a method for recovering boric acid from an iron alloy XRF tablet sample, comprising the following steps:

[0027] S1 Sample Pretreatment: The waste iron alloy XRF tablet sample is fed into the feed hopper and ground by the double roller grinding assembly to break the tablet. The crushed material is then conveyed at a constant speed to the screening and crushing assembly by the screw feeder. The material enters the crushing cylinder and is further crushed. The screening disc intercepts large particles that are not fully crushed. At the same time, the cleaning brush at the bottom of the rotating shaft cleans the surface of the screening disc in real time to avoid blockage. The qualified fine material falls into the leaching cylinder below.

[0028] S2 Leaching Reaction: Weakly acidic leaching solution is added to the leaching cylinder through the leaching solution delivery component. At the same time, the intelligent temperature control heating rod is activated to control the stirring temperature at 40-80℃. The spiral stirring blades rotate and stir for 1-4 hours. The hydrogen ions in the leaching solution destroy the bond between the iron alloy matrix and boric acid, causing the boric acid to dissolve and enter the liquid phase. Meanwhile, impurities such as iron and silicon mainly form hydroxide precipitates or suspended particles.

[0029] S3 Solid-Liquid Separation: After leaching is completed, start the No. 1 transfer pump to pump the slurry into the microporous membrane filter to separate the supernatant containing boric acid and the filter residue containing impurities such as iron.

[0030] S4 Evaporation and Concentration: Start the No. 2 transfer pump to pump the supernatant into the evaporation and concentration tank. Nitrogen gas is introduced into the evaporation and concentration tank through the protective gas delivery component to prevent oxidation. Under normal pressure, most of the water is evaporated to obtain the concentrated liquid, which significantly increases the boric acid concentration.

[0031] S5 Complexation Reaction: An organic complexing agent is added to the concentrate through the delivery tube, and the amount added is controlled by the No. 2 flow sensor, so that boric acid and the complexing agent form a stable water-soluble complex, which improves the thermal stability and anti-interference ability of boric acid in subsequent treatment.

[0032] S6 vaporization and gradient condensation: Start the No. 3 transfer pump to pump the complexed concentrate into the heating vaporization tank, slowly raise the temperature to 80-120℃, and the generated mixed steam enters the multi-stage gradient condenser. The jacket temperature decreases gradually from the steam inlet to the outlet, and the steam gradually condenses into liquid to avoid high-concentration boric acid from precipitating out due to sudden cooling and clogging the pipeline.

[0033] S7 Boric acid capture: After condensation, the boric acid droplets enter the capture trap, which is filled with adsorption materials that have high adsorption selectivity for boric acid or specific binding ability for boric acid complexes. Thus, the boric acid vapor entering the capture trap is adsorbed by three adsorption plates in sequence to complete the efficient enrichment of boric acid.

[0034] S8 Desorption and Purification: Remove the adsorption plate from the trap and add a small amount of high-purity water or a specific eluent to desorb the adsorbed boric acid, obtaining a preliminarily purified boric acid solution. Then, further purification is carried out by recrystallization or ion exchange chromatography to obtain the final boric acid substance.

[0035] The beneficial effects of this invention are as follows:

[0036] 1. This invention achieves the resource recovery of boric acid from waste XRF tablets through the coordinated operation of sample pretreatment mechanism, leaching mechanism, solid-liquid separation mechanism, evaporation and concentration mechanism, complexation reaction mechanism and directional condensation and collection mechanism, turning waste into treasure, with significant economic and environmental benefits;

[0037] 2. This invention minimizes the volatilization, decomposition, and adsorption loss of boric acid during operation, effectively improving the boric acid recovery rate, which is significantly higher than that of traditional methods. At the same time, the introduction of complexing agents and the design of dedicated traps enhance the selective recovery capability of boric acid and reduce interference from other coexisting components.

[0038] 3. This invention utilizes a complexing agent to form a stable complex with boric acid, which can mask or separate some metal impurities to a certain extent. At the same time, combined with the selective adsorption and collection of the trap and the subsequent desorption and purification steps, it can effectively remove coexisting impurities such as iron and silicon, and the obtained boric acid product has high purity.

[0039] 4. This invention effectively prevents the decomposition of boric acid at high temperatures and the volatilization loss due to improper operation by a series of measures, including evaporation concentration (using atmospheric pressure bubbling evaporation and introducing inert nitrogen gas to prevent oxidation and local overheating, avoiding decomposition of boric acid due to high temperature), complexation to enhance thermal stability, gradient condensation and low temperature collection. Attached Figure Description

[0040] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0041] Figure 1 This is a three-dimensional structural diagram of the entire invention;

[0042] Figure 2 This is a front view of the overall structure of the present invention;

[0043] Figure 3 This is a three-dimensional enlarged structural schematic diagram of the sample pretreatment mechanism of the present invention;

[0044] Figure 4 This is a three-dimensional enlarged structural diagram of the dual-roll grinding assembly and the screw feeder of the present invention;

[0045] Figure 5 This is a three-dimensional enlarged structural diagram of the inside of the pulverizing cylinder of the present invention;

[0046] Figure 6 This is a three-dimensional enlarged structural diagram of the interior of the leaching cylinder of the present invention;

[0047] Figure 7 This is a three-dimensional enlarged structural diagram of the area below the screening disc of the present invention;

[0048] Figure 8 This is a three-dimensional structural diagram of the solid-liquid separation mechanism, evaporation and concentration mechanism, complexation reaction mechanism, and directional condensation and collection mechanism of the present invention;

[0049] Figure 9 This is a three-dimensional enlarged structural diagram of the evaporation and concentration tank area of ​​the present invention;

[0050] Figure 10 This is a three-dimensional exploded view of the directional condensation and collection mechanism of the present invention.

[0051] In the diagram: 1. Base; 2. Main controller; 3. Feed hopper; 4. Grinding roller; 5. Transmission gear; 6. Grinding motor; 7. Drive gear; 8. Conveying cylinder; 9. Discharge hopper; 10. Conveying motor; 11. Drive shaft; 12. Spiral conveyor blades; 13. Crushing cylinder; 14. Rotating shaft; 15. Crushing blades; 16. Crushing motor; 17. Screening disc; 18. Cleaning brush; 19. Leaching cylinder; 20. Intelligent temperature-controlled heating rod; 21. Spiral stirring blades; 22. Leachate storage tank; 23. Liquid delivery pipe; 24. Liquid delivery tube. 25. Solenoid valve; 26. Flow sensor No. 1; 27. Transfer pump No. 1; 28. Microporous membrane filter; 29. ​​Transfer pump No. 2; 30. Evaporation and concentration tank; 31. Nitrogen storage tank; 32. Gas delivery pipe; 33. Gas delivery solenoid valve; 34. Organic complexing agent storage tank; 35. Agent delivery pipe; 36. Flow sensor No. 2; 37. Agent delivery solenoid valve; 38. Transfer pump No. 3; 39. Heating vaporization tank; 40. Multi-stage gradient condenser; 41. Segmented temperature control jacket; 42. Trapping trap; 43. Mounting cover; 44. Adsorption plate. Detailed Implementation

[0052] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0053] Example 1, referring to Figure 1-5 An apparatus for recovering boric acid from an iron alloy XRF tablet sample includes a base 1 with a main controller 2 fixedly mounted on its sidewall, a sample pretreatment mechanism, a leaching mechanism, a solid-liquid separation mechanism, an evaporation and concentration mechanism, a complexation reaction mechanism, and a directional condensation and collection mechanism. The main controller 2 is used to control the electrical components in each of the above mechanisms.

[0054] In this embodiment, the sample pretreatment mechanism includes a double-roller grinding assembly, a screw feeder, and a sieve-type pulverizing assembly.

[0055] The dual-roll grinding assembly includes a feed bin 3, two grinding rollers 4 rotatably mounted inside the lower part of the feed bin 3, two transmission gears 5 sequentially fixedly mounted on the outer ends of the two grinding rollers 4, a grinding motor 6 fixedly mounted on the front outer wall of the feed bin 3, and a drive gear 7 fixedly mounted on the output shaft of the grinding motor 6. Furthermore, a compression gap is provided between the two grinding rollers 4, the two transmission gears 5 mesh with each other, and the drive gear 7 meshes with an adjacent transmission gear 5. In this way, the dual-roll grinding assembly can perform preliminary grinding and crushing of waste XRF tablet samples.

[0056] The sieving and crushing assembly includes a crushing cylinder 13 fixedly connected to the conveying cylinder 8, a rotating shaft 14 rotatably installed inside the crushing cylinder 13, crushing blades 15 fixedly connected to the lower part of the rotating shaft 14, a crushing motor 16 fixedly connected to the top outer wall of the crushing cylinder 13 via a motor support plate, and a screening disc 17 fixedly connected to the inner wall of the bottom opening of the crushing cylinder 13. The bottom end of the rotating shaft 14 passes through the center of the screening disc 17. Furthermore, the output shaft of the crushing motor 16 is coaxially fixedly connected to the top end of the rotating shaft 14 via a coupling. The surface of the screening disc 17 is provided with evenly distributed screening holes. A cleaning brush rod 18 is fixedly connected to the lower part of the rotating shaft 14. The brush bristles at the bottom of the cleaning brush rod 18 contact the surface of the screening disc 17. In this way, the high-speed rotation of the crushing blades 16 further refines the material after preliminary grinding, and the fine material after crushing can be screened out through the screening holes on the surface of the screening disc 17. The cleaning brush rod 18 removes the clogging particles on the surface of the screening disc 17 in real time, ensuring stable screening efficiency.

[0057] The screw feeder includes a hopper 9 fixedly connected to the bottom of the feed bin 3, a conveying cylinder 8 fixedly connected to the bottom of the hopper 9, a conveying motor 10 fixedly connected to the side wall of the conveying cylinder 8 via a motor mounting plate, a drive shaft 11 rotatably installed inside the conveying cylinder 8, and screw conveying blades 12 welded to the drive shaft 11. Furthermore, the output shaft of the conveying motor 10 is coaxially fixedly connected to one end of the drive shaft 11 via a coupling. The inner wall of the conveying cylinder 8 is provided with an anti-stick coating (such as polytetrafluoroethylene). In this way, the screw feeder can feed materials at a uniform and low speed, avoiding material accumulation or splashing. The anti-stick coating prevents boric acid adhesion and ensures continuous and stable material conveying to the subsequent crushing stage.

[0058] In practical use, this embodiment works as follows: First, the waste XRF tablet sample is added to the feed hopper 3. At this time, the grinding motor 6 drives the drive gear 7 to rotate forward, which in turn drives one of the transmission gears 5 to rotate in the opposite direction, thereby driving the other transmission gear 5 to rotate forward. This causes the two transmission gears 5 to drive the two grinding rollers 4 to rotate relative to each other, thus initially grinding and crushing the waste XRF tablet sample. Second, the ground and crushed sample enters the conveying cylinder 8 from the feed hopper 9. At this time, the conveying motor 10 drives the spiral conveying blades 12 on the transmission shaft 11 to rotate, pushing the sample forward so that the sample can enter the crushing cylinder 13 at a uniform and low speed. Finally, the crushing motor 16 drives the crushing blades 15 at the bottom of the rotating shaft 14 to rotate, further refining the initially ground material. The crushed fine material can be screened out through the screening holes on the surface of the screening disc 17. The cleaning brush rod 18 rotates with the rotating shaft 14 to remove the clogging particles on the surface of the screening disc 17 in real time, ensuring stable screening efficiency.

[0059] Example 2, refer to Figure 3 and Figure 6-7This embodiment is an optimization based on embodiment 1. Specifically, the leaching mechanism includes a leaching liquid conveying assembly and a stirring assembly.

[0060] The stirring assembly includes an leaching cylinder 19 fixedly connected to the bottom of the crushing cylinder 13, an intelligent temperature-controlled heating rod 20 coaxially fixedly connected to the bottom end of the rotating shaft 14 via a connecting plate, and a spiral stirring blade 21 fixedly connected to the outer wall of the intelligent temperature-controlled heating rod 20. The intelligent temperature-controlled heating rod 20 can flexibly adjust the required stirring temperature as needed, and it is electrically connected to the external main controller 2 via an electric slip ring installed at the bottom of the rotating shaft 14. In this way, high-temperature decomposition of boric acid is avoided through precise temperature control, and the rotation of the spiral stirring blade 21 promotes full contact between the material and the leachate, and the leaching rate is significantly improved compared with static leaching.

[0061] The leachate delivery assembly includes a leachate storage tank 22 fixedly connected to the outer wall of the crushing cylinder 13, a delivery pipe 23 fixedly connected to the bottom of the leachate storage tank 22 and the upper part of the leachate cylinder 19, and a delivery solenoid valve 24 and a flow sensor 25 installed sequentially on the delivery pipe 23. In this way, the addition of leachate can be automatically controlled by opening and closing the delivery solenoid valve 24, and the flow sensor 25 can easily detect the amount of leachate added in real time, so as to achieve the effect of quantitative addition of leachate.

[0062] In addition, the bottom outer wall of the leaching cylinder 19 is fixedly connected to the top outer wall of the base 1. The top of the leaching solution storage tank 22 is provided with a leaching solution filling pipe. A sealing cap is threaded onto the leaching solution filling pipe. Leaching solution is added into the leaching solution storage tank 22 from the leaching solution filling pipe. The leaching solution is dilute acetic acid or dilute hydrochloric acid with pH=3-6. The solid-liquid ratio is controlled at 1:3-1:8. The weakly acidic environment dissolves boric acid while inhibiting the hydrolysis of iron ions (avoiding the precipitation and adsorption of boric acid by ferric hydroxide), and at the same time avoids the decomposition of boric acid or other side reactions caused by strong acid.

[0063] In this embodiment, during actual use: the sample sieved through the sieve plate 17 enters the leaching cylinder 19. At this time, the leaching solution in the leaching solution storage tank 22 is fed into the leaching cylinder 19 through the delivery pipe 23 by opening the liquid delivery solenoid valve 24; secondly, the spiral stirring blades 21 on the intelligent temperature-controlled heating rod 20 are rotated by the rotating shaft 14 to promote full contact between the material and the leaching solution.

[0064] Example 3, referring to Figure 1-2 and Figure 8-9This embodiment is an optimization based on embodiment 1. Specifically, the solid-liquid separation mechanism includes a first delivery pump 26 fixedly connected to the lower outer wall of the leaching cylinder 19 via a first pump base and a microporous membrane filter 27 fixedly connected to the top outer wall of the base 1. The material extraction end of the first delivery pump 26 is fixedly connected to the lower part of the leaching cylinder 19 via a pipe, and the delivery end of the first delivery pump 26 is fixedly connected to the input end of the microporous membrane filter 27 via a long delivery pipe. In this way, the leached slurry is separated into solid and liquid by the solid-liquid separation mechanism to obtain a supernatant containing boric acid and a residue containing impurities such as iron.

[0065] Specifically, the evaporation and concentration mechanism includes a protective gas delivery assembly, a second delivery pump 28 fixedly connected to the lower outer wall of the microporous membrane filter 27 via a second pump base, and an evaporation and concentration tank 29 fixedly connected to the top outer wall of the base 1. The top of the evaporation and concentration tank 29 is equipped with a water vapor discharge pipe. The suction end of the second delivery pump 28 is fixedly connected to the output end of the microporous membrane filter 27 via a second pipe, and the delivery end of the second delivery pump 28 is fixedly connected to the upper part of the evaporation and concentration tank 29 via a second delivery pipe. Further, the protective gas delivery assembly includes a nitrogen storage tank 30 fixedly connected to the rear outer wall of the evaporation and concentration tank 29, a gas supply pipe 31 fixedly connected to the top of the nitrogen storage tank 30, and a gas supply solenoid valve 32 installed on the gas supply pipe 31. The bottom end of the gas supply pipe 31 extends through to the inner end of the evaporation and concentration tank 29. In this way, the supernatant containing boric acid is gently evaporated and concentrated to remove most of the water. Atmospheric pressure bubbling evaporation is used, and inert nitrogen gas is introduced to prevent oxidation and local overheating, avoiding the decomposition of boric acid due to high temperature.

[0066] In this embodiment, during specific use: First, the slurry mixture after leaching in the leaching cylinder 19 is extracted by the first transfer pump 26 and sent to the microporous membrane filter 27 for solid-liquid separation, resulting in a supernatant containing boric acid and a residue containing impurities such as iron. Second, the supernatant containing boric acid is extracted by the second transfer pump 28 and sent to the evaporation and concentration tank 29 for gentle evaporation and concentration to remove most of the water. The evaporated water vapor is discharged from the water vapor discharge pipe, and the inert nitrogen gas in the nitrogen storage tank 30 is sent into the evaporation and concentration tank 29 through the gas supply pipe 31 by opening the gas supply solenoid valve 32 to prevent oxidation and local overheating, and to avoid the decomposition of boric acid due to high temperature.

[0067] Example 4, refer to Figure 1-2 and Figure 8-9This embodiment is an optimization based on Embodiment 1. Specifically, the complexation reaction mechanism includes an organic complexing agent storage tank 33 fixedly connected to the top outer wall of the base 1, a delivery pipe 34 fixedly connected to the bottom of the organic complexing agent storage tank 33 and the top of the evaporation and concentration tank 29, and a second flow sensor 35 and a delivery solenoid valve 36 sequentially installed on the delivery pipe 34. Furthermore, the top of the organic complexing agent storage tank 33 is provided with a complexing agent injection pipe, and a sealing cap is threaded onto the complexing agent injection pipe. In this way, a specific organic complexing agent (such as mannitol, glycerol, sorbitol and other polyols, or specific amine compounds) is added to the concentrate to form a stable water-soluble complex (such as mannitol borate ester) with boric acid. This mechanism can significantly improve the stability and selectivity of boric acid in subsequent processing and can form more unstable complexes or separate with certain metal ions.

[0068] In this embodiment, when in use: by opening the delivery solenoid valve 36, the organic complexing agent in the organic complexing agent storage tank 33 is sent from the delivery pipe 34 into the evaporation and concentration tank 29 to form a stable water-soluble complex with boric acid, and the delivery dose is detected in real time by the second flow sensor 35 to achieve the effect of quantitative addition.

[0069] Example 5, refer to Figure 1-2 , Figure 8 and Figure 10 This embodiment is an optimization based on Embodiment 1. Specifically, the directional condensation trapping mechanism includes a No. 3 delivery pump 37 fixedly connected to the lower outer wall of the evaporation and concentration tank 29 via a No. 3 pump base, a heating vaporization tank 38 fixedly connected to the top outer wall of the base 1, a multi-stage gradient condenser pipe 39 connected to the outlet of the heating vaporization tank 38, a segmented temperature control jacket 40 located outside the multi-stage gradient condenser pipe 39 and fixedly connected to the outer wall of the heating vaporization tank 38, a trapping trap 41 fixedly connected to the top outer wall of the base 1, and a trapping trap 41 located outside the base 1. The adsorption component in the trap 41 has its suction end of the third transfer pump 37 fixedly connected to the lower part of the evaporation and concentration tank 29 via pipe three, and its delivery end of the third transfer pump 37 fixedly connected to the upper part of the heating vaporization tank 38 via a long delivery pipe three. In this way, the solution containing boric acid complex is gently heated in the heating vaporization tank 38 (the temperature is controlled slightly above the upper limit of the stable existence of the complex but below the decomposition temperature of boric acid, such as 80-120℃, depending on the complexing agent), causing the water and excess volatile complexing agent to vaporize.

[0070] The multi-stage gradient condenser 39 consists of three serpentine condenser tubes connected end to end at equal intervals. The segmented temperature control jacket 40 consists of three temperature control jackets that are sequentially wrapped around the three serpentine condenser tubes. By adjusting the temperature of the medium inside the jacket or changing the type of medium, the temperature of the serpentine condenser tubes inside the jacket can be precisely controlled. In this way, the multi-stage gradient condenser 39 increases the gas-liquid contact area and condensation path. The segmented temperature control jacket 40 is provided outside the condenser tubes, and the temperature decreases gradually from the inlet to the outlet (e.g., from 60℃ to 5℃), ensuring that the steam can be condensed gradually and avoiding the high-concentration boric acid vapor from precipitating out and blocking the pipeline due to sudden cooling or decomposing due to excessive temperature.

[0071] The adsorption assembly includes a mounting cover plate 42 fixedly connected to the top outer wall of the trap 41 by bolts and three adsorption plates 43 detachably fixedly connected to the bottom outer wall of the mounting cover plate 42. All three adsorption plates 43 are located inside the trap 41. The air inlet end of the trap 41 is fixedly connected to the tail end of the multi-stage gradient condenser 39. In this way, the adsorption plates 43 are filled with adsorption materials that have high adsorption selectivity for boric acid or specific binding ability for boric acid complexes (such as specially treated cation exchange resin, molecular sieve or silica gel loaded with specific functional groups) to efficiently capture condensed boric acid droplets or crystals at low temperature and prevent them from volatilizing again or being carried away by the airflow.

[0072] In this embodiment, during specific use: the complexation reaction liquid in the evaporation and concentration tank 29 is extracted by the No. 3 transfer pump 37 and transported to the heating and vaporization tank 38, where it is slowly heated to 100°C (at this temperature, the mannitol-boric acid complex is stable, and water and excess mannitol vaporize). The vaporized steam then enters the multi-stage gradient condenser 39. The segmented temperature control jacket 40 outside the condenser is supplied with circulating water at 60°C, 40°C, 20°C, and 5°C from the inlet to the outlet to achieve gradient condensation. Finally, the steam enters the boric acid-specific trap 41. The adsorption plate 43 inside the trap 41 can directly and efficiently capture the condensed boric acid droplets or crystals at low temperature, preventing them from evaporating again or being carried away by the airflow.

[0073] In summary: Reference Figure 1-10 The present invention provides a method for recovering boric acid from ferroalloy XRF tablet samples, comprising the following steps:

[0074] S1 Sample Pretreatment: The waste iron alloy XRF tablet sample is put into the feed hopper 3 and ground by the double roller grinding assembly to break the tablet. The crushed material is then conveyed at a constant speed to the screening and crushing assembly by the screw feeder. The material enters the crushing cylinder 13 and is further crushed. Then the screening disc 17 intercepts large particles that are not fully crushed. At the same time, the cleaning brush rod 18 at the bottom of the rotating shaft 14 cleans the surface of the screening disc 17 in real time to avoid blockage. The qualified fine material falls into the leaching cylinder 19 below.

[0075] S2 Leaching Reaction: Weakly acidic leaching solution is added to the leaching cylinder 19 through the leaching solution delivery assembly. At the same time, the intelligent temperature control heating rod 20 is started to control the stirring temperature at 40-80℃. The spiral stirring blade 21 rotates and stirs. Leaching takes 1-4 hours. Hydrogen ions in the leaching solution destroy the bond between the iron alloy matrix and boric acid, causing boric acid to dissolve and enter the liquid phase. Iron, silicon and other impurities mainly form hydroxide precipitates or suspended particles.

[0076] S3 Solid-Liquid Separation: After leaching is completed, start the No. 1 delivery pump 26 to pump the slurry into the microporous membrane filter 27 to separate the supernatant containing boric acid and the filter residue containing impurities such as iron.

[0077] S4 Evaporation and Concentration: Start the No. 2 transfer pump 28 to pump the supernatant into the evaporation and concentration tank 29. Nitrogen gas is introduced into the evaporation and concentration tank 29 through the protective gas delivery component to prevent oxidation. Under normal pressure, most of the water is evaporated to obtain the concentrated liquid, which significantly increases the boric acid concentration.

[0078] S5 Complexation Reaction: An organic complexing agent is added to the concentrate through the delivery tube 34, and the amount added is controlled by the second flow sensor 35, so that boric acid and the complexing agent form a stable water-soluble complex, which improves the thermal stability and anti-interference ability of boric acid in subsequent treatment.

[0079] S6 vaporization and gradient condensation: Start the No. 3 transfer pump 37 to pump the complexed concentrate into the heating vaporization tank 38, slowly raise the temperature to 80-120℃, and the generated mixed steam enters the multi-stage gradient condenser 39. The jacket temperature decreases gradually from the steam inlet to the outlet, and the steam gradually condenses into liquid to avoid high-concentration boric acid from precipitating out due to sudden cooling and clogging the pipeline.

[0080] S7 Boric acid capture: After condensation, the boric acid droplets enter the capture trap 41. The capture trap 41 is filled with adsorption material that has high adsorption selectivity for boric acid or specific binding ability for boric acid complexes. Thus, the boric acid vapor entering the capture trap 41 is adsorbed by the three adsorption plates 43 in sequence to complete the efficient enrichment of boric acid.

[0081] S8 Desorption and Purification: Remove the adsorption plate 43 from the trap 41 and add a small amount of high-purity water or a specific eluent to desorb the adsorbed boric acid and obtain a preliminarily purified boric acid solution. Then, it is purified by recrystallization or further ion exchange chromatography to obtain the final boric acid substance.

[0082] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An apparatus for recovering boric acid from an iron alloy XRF tablet sample, comprising a base (1) with a main controller (2) fixedly mounted on its sidewall, characterized in that, It also includes a sample pretreatment mechanism, a leaching mechanism, a solid-liquid separation mechanism, an evaporation and concentration mechanism, a complexation reaction mechanism, and a directional condensation and collection mechanism. The sample pretreatment mechanism includes a double-roll grinding assembly, a screw feeder, and a sieve-type pulverizing assembly, and the leaching mechanism includes a leachate conveying assembly and a stirring assembly. The dual-roll grinding assembly includes a feeding bin (3), two grinding rollers (4) rotatably mounted inside the lower part of the feeding bin (3), two transmission gears (5) fixedly mounted on the outer ends of the two grinding rollers (4), a grinding motor (6) fixedly mounted on the front outer wall of the feeding bin (3), and a drive gear (7) fixedly mounted on the output shaft of the grinding motor (6). The sieving and crushing assembly includes a crushing cylinder (13) fixedly connected to the conveying cylinder (8), a rotating shaft (14) rotatably installed inside the crushing cylinder (13), a crushing blade (15) fixedly connected to the lower part of the rotating shaft (14), a crushing motor (16) fixedly connected to the outer wall of the top of the crushing cylinder (13) through a motor support plate, and a sieving disc (17) fixedly connected to the inner wall of the bottom opening of the crushing cylinder (13), and the bottom end of the rotating shaft (14) passes through the center of the sieving disc (17); The stirring assembly includes an leaching cylinder (19) fixedly connected to the bottom of the crushing cylinder (13), an intelligent temperature-controlled heating rod (20) fixedly connected to the bottom end of the rotating shaft (14) via a connecting plate, and a spiral stirring blade (21) fixedly connected to the outer wall of the intelligent temperature-controlled heating rod (20). The leachate delivery assembly includes a leachate storage tank (22) fixedly connected to the outer wall of the crushing cylinder (13), a same delivery pipe (23) fixedly connected to the bottom of the leachate storage tank (22) and the upper part of the leachate cylinder (19), and a delivery solenoid valve (24) and a flow sensor (25) installed sequentially on the delivery pipe (23). The solid-liquid separation mechanism includes a first delivery pump (26) fixedly connected to the lower outer wall of the leaching cylinder (19) via a first pump base and a microporous membrane filter (27) fixedly connected to the top outer wall of the base (1). The evaporation and concentration mechanism includes a protective gas delivery assembly, a second delivery pump (28) fixedly connected to the lower outer wall of the microporous membrane filter (27) via a second pump seat, and an evaporation and concentration tank (29) fixedly connected to the top outer wall of the base (1), and the top of the evaporation and concentration tank (29) is provided with a water vapor discharge pipe; The complexation reaction mechanism includes an organic complexing agent storage tank (33) fixedly connected to the top outer wall of the base (1), a delivery pipe (34) fixedly connected to the bottom of the organic complexing agent storage tank (33) and the top of the evaporation and concentration tank (29), and a second flow sensor (35) and a delivery solenoid valve (36) installed sequentially on the delivery pipe (34). The directional condensation trapping mechanism includes a No. 3 delivery pump (37) fixedly connected to the lower outer wall of the evaporation and concentration tank (29) via a No. 3 pump base, a heating vaporization tank (38) fixedly connected to the top outer wall of the base (1), a multi-stage gradient condenser tube (39) connected to the outlet of the heating vaporization tank (38), a segmented temperature control jacket (40) located outside the multi-stage gradient condenser tube (39) and fixedly connected to the outer wall of the heating vaporization tank (38), a trapping trap (41) fixedly connected to the top outer wall of the base (1), and an adsorption component located in the trapping trap (41).

2. The apparatus for recovering boric acid from ferroalloy XRF tablet samples according to claim 1, characterized in that, A pressing gap is provided between the two grinding rollers (4), the two transmission gears (5) mesh with each other, and the drive gear (7) meshes with an adjacent transmission gear (5).

3. The apparatus for recovering boric acid from ferroalloy XRF tablet samples according to claim 1, characterized in that, The screw feeder includes a hopper (9) fixedly connected to the bottom of the feed bin (3), a conveying cylinder (8) fixedly connected to the bottom of the hopper (9), a conveying motor (10) fixedly connected to the side wall of the conveying cylinder (8) via a motor mounting plate, a drive shaft (11) rotatably installed in the conveying cylinder (8), and screw conveying blades (12) welded to the drive shaft (11). The output shaft of the conveying motor (10) is coaxially fixedly connected to one end of the drive shaft (11) via a coupling.

4. The apparatus for recovering boric acid from ferroalloy XRF tablet samples according to claim 1, characterized in that, The output shaft of the crushing motor (16) is coaxially and fixedly connected to the top of the rotating shaft (14) through a coupling, and the surface of the screening disc (17) is provided with uniformly distributed screening holes. The lower part of the rotating shaft (14) is fixedly connected to a cleaning brush rod (18), and the brush bristles at the bottom of the cleaning brush rod (18) are in contact with the surface of the screening disc (17).

5. The apparatus for recovering boric acid from an iron alloy XRF tablet sample according to claim 1, characterized in that, The bottom outer wall of the leaching cylinder (19) is fixedly connected to the top outer wall of the base (1). The top of the leaching liquid storage tank (22) is provided with a leaching liquid injection pipe, and a sealing cap is threadedly connected to the leaching liquid injection pipe. The top of the organic complexing agent storage tank (33) is provided with a complexing agent injection pipe, and a sealing cap is threadedly connected to the complexing agent injection pipe.

6. The apparatus for recovering boric acid from an iron alloy XRF tablet sample according to claim 1, characterized in that, The first pump (26) is fixedly connected to the lower part of the leaching cylinder (19) through a pipe, and the pumping end of the first pump (26) is fixedly connected to the input end of the microporous membrane filter (27) through a long pumping pipe. The second pump (28) is fixedly connected to the output end of the microporous membrane filter (27) through a pipe, and the pumping end of the second pump (28) is fixedly connected to the upper part of the evaporation and concentration tank (29) through a long pumping pipe. The third pump (37) is fixedly connected to the lower part of the evaporation and concentration tank (29) through a pipe, and the pumping end of the third pump (37) is fixedly connected to the upper part of the heating and vaporization tank (38) through a long pumping pipe.

7. The apparatus for recovering boric acid from an iron alloy XRF tablet sample according to claim 1, characterized in that, The protective gas delivery assembly includes a nitrogen storage tank (30) fixedly connected to the rear outer wall of the evaporation and concentration tank (29), a gas delivery pipe (31) fixedly connected to the top of the nitrogen storage tank (30), and a gas delivery solenoid valve (32) installed on the gas delivery pipe (31), with the bottom end of the gas delivery pipe (31) extending through to the inner end of the evaporation and concentration tank (29).

8. The apparatus for recovering boric acid from an iron alloy XRF tablet sample according to claim 1, characterized in that, The multi-stage gradient condenser (39) is composed of three serpentine condensers that are distributed at equal distances and connected end to end in sequence, and the segmented temperature control jacket (40) is composed of three temperature control jackets that are wrapped around the three serpentine condensers in sequence.

9. The apparatus for recovering boric acid from an iron alloy XRF tablet sample according to claim 1, characterized in that, The adsorption assembly includes a mounting cover plate (42) fixedly connected to the top outer wall of the trap (41) by bolts and three adsorption plates (43) fixedly connected to the bottom outer wall of the mounting cover plate (42). The three adsorption plates (43) are all located inside the trap (41), and the air inlet end of the trap (41) is fixedly connected to the tail end of the multi-stage gradient condenser (39).

10. A recovery method using the apparatus for recovering boric acid from ferroalloy XRF tablet samples as described in claim 1, characterized in that, Includes the following steps: S1 Sample pretreatment: The waste iron alloy XRF tablet sample is put into the feed hopper (3) and crushed by grinding with a double roller grinding assembly. The crushed material is then conveyed at a constant speed to the sieve crushing assembly by a screw feeder. The material enters the crushing cylinder (13) and is further crushed. Then the sieve disc (17) intercepts large particles that are not fully crushed. At the same time, the cleaning brush rod (18) at the bottom of the rotating shaft (14) cleans the surface of the sieve disc (17) in real time to avoid blockage. The qualified fine material falls into the leaching cylinder (19) below. S2 Leaching Reaction: Weakly acidic leachate is added to the leaching cylinder (19) through the leachate delivery assembly. At the same time, the intelligent temperature control heating rod (20) is started to control the stirring temperature at 40-80℃. The spiral stirring blade (21) rotates and stirs. Leaching takes 1-4 hours. Hydrogen ions in the leachate destroy the combination between the iron alloy matrix and boric acid, causing boric acid to dissolve and enter the liquid phase. Iron, silicon and other impurities mainly form hydroxide precipitates or suspended particles. S3 Solid-liquid separation: After leaching is completed, start the No. 1 delivery pump (26) to pump the slurry into the microporous membrane filter (27) to separate the supernatant containing boric acid and the filter residue containing impurities such as iron. S4 Evaporation and Concentration: Start the No. 2 transfer pump (28) to pump the supernatant into the evaporation and concentration tank (29). Nitrogen gas is introduced into the evaporation and concentration tank (29) through the protective gas delivery assembly to prevent oxidation. Under normal pressure, most of the water is evaporated to obtain the concentrated liquid, which significantly increases the boric acid concentration. S5 Complexation reaction: Organic complexing agent is added to the concentrate through the delivery tube (34), and the amount added is controlled by the second flow sensor (35) so that boric acid and complexing agent form a stable water-soluble complex, thereby improving the thermal stability and anti-interference ability of boric acid in subsequent treatment. S6 vaporization and gradient condensation: Start the No. 3 transfer pump (37) to pump the complexed concentrate into the heating vaporization tank (38), slowly raise the temperature to 80-120℃, and the generated mixed steam enters the multi-stage gradient condenser (39). The jacket temperature decreases in a gradient from the steam inlet to the outlet, and the steam gradually condenses into liquid to avoid high concentration boric acid precipitating out due to sudden cooling and blocking the pipeline. S7 Boric acid capture: After condensation, the boric acid droplets enter the capture trap (41). The capture trap (41) is filled with adsorption materials that have high adsorption selectivity for boric acid or specific binding ability for boric acid complexes. Thus, the boric acid vapor entering the capture trap (41) is adsorbed by the three adsorption plates (43) in sequence to complete the efficient enrichment of boric acid. S8 Desorption and purification: Remove the adsorption plate (43) in the trap (41) and add a small amount of high-purity water or eluent to desorb the adsorbed boric acid and obtain a pre-purified boric acid solution. Then, it is purified by recrystallization or further ion exchange chromatography to obtain the final boric acid substance.

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