A high-purity sodium monofluorophosphate production system and process

Abstract

The application provides a high-purity sodium monofluorophosphate production system and process, which comprises a feeding bin, the discharge port of the feeding bin conveying raw materials to a mixer, the mixer conveying materials to a distribution bin through a transfer mechanism, the distribution bin conveying materials to a graphite reactor through a feeding auger, characterized in that a heat preservation sleeve is arranged outside the furnace body of the graphite reactor, a spiral groove is arranged inside the heat preservation sleeve, heating wires are arranged in the spiral groove and tightly arranged on the furnace body of the graphite reactor, and the materials reacted in the graphite reactor are sequentially conveyed to cooling equipment, a material temporary storage bin, a pulverizer, a bag-type dust collector and a finished product bin, the finished product bin discharging the materials to an automatic packaging conveying line for packaging. The production system and process can improve the automatic operation level, improve the production capacity of a single graphite reactor and achieve the purpose of high-purity sodium monofluorophosphate production.

Description

Technical Field

[0001] This invention belongs to the field of sodium monofluorophosphate production technology, and more specifically, relates to a high-purity sodium monofluorophosphate production system and process. Background Technology

[0002] The existing sodium monofluorophosphate process suffers from high-temperature corrosion and the hygroscopic nature of raw materials, leading to discontinuous production, high levels of impurities, low purity, and a tendency to clump. Specifically: 1) The semi-automatic mixing of raw materials using a V-type mixer carries risks of inaccurate mixing time measurement and material accumulation inside the equipment; 2) The graphite reactor suffers from rapid dry-burning oxidation; 3) The chain conveyor has numerous components, which can generate foreign matter during material cooling; 4) The crushing and packaging process introduces large amounts of dust and high-humidity cold air, causing impurities and clumping in the product; 5) Material conveying, assembly, and packaging are all manually operated, with equipment not fully sealed, posing a risk of foreign matter ingress and resulting in poor process flow control stability. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a high-purity sodium monofluorophosphate production system and process, improve the level of automation, increase the production capacity of a single graphite reactor, and achieve the goal of producing high-purity sodium monofluorophosphate.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a high-purity sodium monofluorophosphate production system, including a feeding hopper, the discharge port of the feeding hopper conveys the raw materials to a mixer, the mixer conveys the materials to a distribution hopper through a transfer mechanism, the distribution hopper conveys the materials to a graphite reactor through a feeding auger, characterized in that the outside of the furnace body of the graphite reactor is provided with a heat insulation sleeve, the inside of the heat insulation sleeve is provided with a spiral groove, the heating wire is installed in the spiral groove and is set close to the furnace body of the graphite reactor, the material after the reaction in the graphite reactor is sequentially conveyed to a cooling device, a material storage hopper, a crusher, a bag filter dust collector and a finished product hopper, the finished product hopper discharges the material to an automatic packaging conveyor line for packaging.

[0005] In a preferred embodiment, the furnace body of the graphite reactor has dimensions of φ160mm×900mm and an effective volume of 15.5~16.5L.

[0006] In a preferred embodiment, the heating wires are configured as two sets, which are respectively located at the upper and lower parts of the graphite reactor and controlled separately.

[0007] In a preferred embodiment, a temperature sensor is installed at the feed inlet of the graphite reactor.

[0008] In a preferred embodiment, the cooling device includes a cooling chamber with a cooling inlet at the upper end and a cooling outlet at the bottom. A cooling drum is installed inside the cooling chamber, and the shaft of the cooling drum is rotatably mounted on the side wall of the cooling chamber via bearings. The cooling drum has a hollow structure, and a water inlet pipe and a water outlet pipe are respectively provided at both ends of the shaft of the cooling drum. A scraper is provided above the cooling outlet, and the scraper is set close to the cooling drum.

[0009] In a preferred embodiment, an anti-overflow roller is provided diagonally above the cooling roller, and the anti-overflow roller is set close to the cooling roller.

[0010] In a preferred embodiment, the pulverizer is provided with an air inlet, which is connected to the air outlet of the air filter via a pipe. The upper end of the bag filter is connected to the exhaust fan via a pipe, and the air outlet of the exhaust fan is connected to the air inlet of the air filter.

[0011] In a preferred embodiment, the blades of the feeding auger comprise three parts: a positive spiral blade, a negative spiral blade, and a crushing blade. The crushing blade is positioned below the feed inlet of the feeding auger and is arranged in multiple sets along the circumference of the feeding auger's conveying shaft. Each set of crushing blades consists of multiple blades, distributed along the length of the feeding auger's conveying shaft. The crushing blades are inclined, and the positive spiral blade and the negative spiral blade convey the material toward the feed auger's discharge outlet.

[0012] In a preferred embodiment, the transfer mechanism includes an RGV trolley located below the discharge port of the mixer, with a transfer tank on the RGV trolley. The RGV trolley moves along a first track to the lifting platform of the elevator. A second track is located above the distribution bin, and the RGV trolley moves along the second track to the top of the distribution bin.

[0013] This invention also provides a process for producing high-purity sodium monofluorophosphate, comprising the following steps:

[0014] Step 1: Put the raw materials into the feeding hopper, open the valve of the feeding hopper discharge port, and transport the raw materials to the mixer for mixing. The mixed raw materials are then transported to the distribution hopper for temporary storage via the transfer mechanism.

[0015] Step 2: Open the valve at the discharge port at the lower end of the distribution hopper to convey the material to the feed inlet of the feeding auger. The feeding auger conveys and crushes the material and then conveys it to the graphite reactor for heating and reaction.

[0016] Step 3: After the material reaction in the graphite reactor is completed, it is discharged into the cooling equipment for cooling. The cooled material product is discharged into the material temporary storage bin for temporary storage.

[0017] Step 4: The material in the material temporary storage bin is conveyed to the crusher for crushing. The crushed material is then conveyed to the bag filter for filtration. The filtered material is then conveyed to the finished product bin for storage. The material in the finished product bin is then conveyed to the automatic packaging conveyor line for packaging.

[0018] The present invention provides a high-purity sodium monofluorophosphate production system and process, which has the following beneficial effects:

[0019] 1. To achieve automated production of high-purity sodium monofluorophosphate and improve production efficiency.

[0020] 2. We have innovatively developed a large-diameter flow furnace graphite reactor and a dual-line adjustable resistance wire heating system. First, it expands the reaction volume of the graphite reactor, fundamentally releasing the production capacity of the equipment. Second, it combines the feeding and discharging characteristics of the graphite reactor to design adjustable high-temperature and low-temperature current loads, which better meet the heating needs of the furnace charge reaction mechanism in the graphite reactor.

[0021] 3. By setting a temperature sensor at the feed inlet of the graphite reactor and designing an automatic feeding interlocking system through temperature control technology and interlocking logic, the automatic feeding interlocking system is more timely and accurate than manual feeding, making the reaction inside the furnace more stable and the product quality more stable. At the same time, it greatly reduces the probability of dry burning in the mobile furnace and significantly reduces the failure rate of the mobile furnace.

[0022] 4. Improve the existing feeding auger to ensure uniform raw material feeding system and to perform preliminary crushing of raw materials to prevent agglomeration from affecting the reaction.

[0023] 5. By installing air filters and exhaust fans, the problem of product clumping caused by high-temperature materials coming into contact with high-humidity cold air during the conveying process was solved.

[0024] 6. The designed cooling equipment makes sheet production more efficient, reduces the frequency of equipment maintenance, improves material cooling effect, and results in more uniform material forming, while greatly reducing the risk of foreign matter in the product. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0026] Figure 1 This is a process flow diagram of the present invention;

[0027] Figure 2 This is a device connection diagram for the present invention;

[0028] Figure 3 This is a schematic diagram of the heating wire installation.

[0029] Figure 4 This is a schematic diagram of the internal structure of the cooling equipment;

[0030] Figure 5 This is a side view of the cooling equipment;

[0031] Figure 6 This is a diagram showing the connection of the air filter;

[0032] Figure 7 This is a schematic diagram of the feed auger structure;

[0033] Figure 8 This is a partial structural diagram of a broken blade.

[0034] Figure 9 for Figure 8 The left view;

[0035] Figure 10 This is a schematic diagram of the transfer mechanism;

[0036] In the diagram: 1. Feeding hopper; 2. Mixer; 3. Distributor hopper; 4. Feed auger; 5. Graphite reactor; 6. Cooling equipment; 7. Material storage hopper; 8. Crusher; 9. Baghouse dust collector; 10. Finished product hopper; 11. Air filter; 12. Exhaust fan; 13. RGV trolley; 14. Transfer tank; 15. First track; 16. Elevator; 17. Second track; 401. Positive spiral blade; 402. Reverse spiral blade; 403. Crushing blade; 501. Insulation jacket; 502. Spiral groove; 503. Heating wire; 601. Cooling chamber; 602. Cooling inlet; 603. Cooling outlet; 604. Cooling drum; 605. Water inlet pipe; 606. Water outlet pipe; 607. Scraper; 608. Anti-overflow drum. Detailed Implementation

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] like Figures 1-2 As shown, a high-purity sodium monofluorophosphate production system includes a feeding hopper 1. The discharge port of the feeding hopper 1 conveys the raw materials to a mixer 2. The mixer 2 is a dual-motion automatic mixer, which makes the raw materials more uniform and meets the product characteristics requirements.

[0039] The mixer 2 transports materials to the distribution bin 3 via a transfer mechanism. In this embodiment, the transfer mechanism is as follows: Figure 10 As shown, the system includes an RGV trolley 13 positioned below the discharge port of the mixer 2. The RGV trolley 13 carries a transfer tank 14. The RGV trolley 13 moves along a first track 15 to the lifting platform of the elevator 16. A second track 17 is located above the distribution bin 3, and the RGV trolley 13 moves along the second track 17 to the top of the distribution bin 3. After the RGV trolley 13 transfers the transfer tank 14 to the top of the distribution bin 3, it opens the discharge valve of the transfer tank 14, thus transferring the material. By using the RGV trolley, unmanned operation is achieved.

[0040] The feed bin 3 is conveyed to the graphite reactor 5 via the feed auger 4, such as Figures 7-9 As shown, the blades of the feeding auger 4 consist of three parts: a positive spiral blade 401, a negative spiral blade 402, and a crushing blade 403. The crushing blade 403 is arranged below the feed inlet of the feeding auger 4, and multiple sets are arranged along the circumference of the conveying shaft of the feeding auger 4. Each set of crushing blades 403 consists of multiple pieces, which are distributed along the length of the conveying shaft of the feeding auger 4. The crushing blades 403 are arranged at an angle. The positive spiral blade 401 and the negative spiral blade 402 convey the material towards the discharge outlet of the feeding auger 4.

[0041] In practical use, the auger reduction ratio is increased to ensure uniform feeding of the entire auger cage. A temperature sensor is installed at the feed inlet of the graphite reactor 5. The temperature sensor is electrically connected to the controller, which controls the start and stop of the feeding auger 4. The start and stop of the feeding auger are linked by temperature range values, and automatic feeding is achieved through interlocking logic set by high and low temperature thresholds. The high and low temperature thresholds can be finely adjusted at any time according to the life cycle of the flow furnace.

[0042] In practical use, when the feed inlet temperature of graphite reactor 5 is higher than 900℃, the feed auger 4 is automatically started to prevent graphite reactor 5 from burning dry; the graphite reactor as a whole is enlarged, the internal cavity is expanded from Φ160 to Φ250, and the corresponding thyristor heating system is optimized, so that the feed per batch of a single furnace is 2.5 times that of the original.

[0043] like Figure 3 As shown, the graphite reactor 5 has an insulation sleeve 501 on the outside of its furnace body, and a spiral groove 502 on the inside of the insulation sleeve 501. The heating wire 503 is installed in the spiral groove 502 and is tightly attached to the furnace body of the graphite reactor 5. The insulation sleeve 501 is made of silicon carbide. By setting the insulation sleeve 501, it serves two purposes: heat preservation and securing the heating wire 503, thus reducing the risk of the heating wire falling off at high temperatures.

[0044] In this embodiment, the furnace body of the graphite reactor 5 has dimensions of φ160mm × 900mm and an effective volume of 15.5~16.5L. This expands the reaction volume of the graphite reactor, fundamentally releasing the equipment's production capacity.

[0045] Preferably, the heating wires 503 are configured in two sets, which are respectively installed in the upper and lower parts of the graphite reactor 5 and controlled separately. The two sets of heating wires 503 are configured in parallel, which facilitates the design of adjustable high-temperature and low-temperature current loads based on the feeding and discharging characteristics of the graphite reactor. This better meets the heating requirements of the furnace charge reaction mechanism in the graphite reactor. The upper and lower parts of the graphite reactor are heated in two stages according to the production situation, and the temperature is adjusted in real time by remote control via silicon controlled rectifier.

[0046] The material after reaction in graphite reactor 5 is sequentially conveyed to cooling equipment 6, material storage bin 7, crusher 8, bag filter dust collector 9, and finished product bin 10. Finished product bin 10 discharges the material to an automatic packaging conveyor line for packaging.

[0047] We developed automated packaging machines and palletizing lines, and upgraded and improved the manual feeding and heat sealing methods to enable unmanned operation in the packaging area.

[0048] In this embodiment, as Figures 4-5 As shown, the cooling device 6 includes a cooling chamber 601, with a cooling inlet 602 at the upper end and a cooling outlet 603 at the bottom. A cooling drum 604 is installed inside the cooling chamber 601. The rotating shaft of the cooling drum 604 is rotatably mounted on the side wall of the cooling chamber 601 via bearings. The cooling drum 604 is a hollow structure. Water inlet pipe 605 and water outlet pipe 606 are respectively provided at both ends of the rotating shaft of the cooling drum 604. The water inlet pipe 605 and water outlet pipe 606 are connected to the rotating shaft of the cooling drum 604 via bearings. The water inlet pipe 605 is connected to a water tank via a water pump, and the water outlet pipe 606 is connected to a water tank to form a circulating cooling water supply pipeline, which delivers cooling water to the cooling cavity of the cooling drum 604. The material falls onto the upper side of the cooling drum 604 to cool the liquid material after the reaction.

[0049] A scraper 607 is provided above the cooling outlet 603, and the scraper 607 is set close to the cooling roller 604. The scraper 607 is mounted on the side wall of the cooling chamber 601 via a scraper holder. The scraper 607 is used to scrape off the material adhering to the cooling roller 604, and the material is discharged from the cooling outlet 603 after falling off, preventing the material adhering to the cooling roller 604 from accumulating too thickly and affecting subsequent cooling.

[0050] Preferably, an anti-overflow roller 608 is provided diagonally above the cooling roller 604, and the anti-overflow roller 608 is set in close contact with the cooling roller 604. If the falling liquid material is too large, the anti-overflow roller 608 is used to block the material and prevent it from overflowing.

[0051] In the traditional sodium monofluorophosphate production process, the main method used is a melting reaction. After the material melts and polymerizes, it flows out as a liquid through a graphite cylinder and column. The liquid material is then rapidly cooled by an aluminum chain conveyor. The cooling principle mainly relies on the surrounding environment and the thermal conductivity of aluminum. However, this process has two drawbacks: first, there is a risk of aluminum chain plates falling into the finished product, posing a significant risk of foreign matter; second, the cooling effect of the chain conveyor is poor, resulting in uneven sheet production and a significant quality risk.

[0052] The self-designed cooling equipment 6 cools liquid materials into sheet-like materials, making the cooling effect more efficient. The metal parts are simple and have a low risk of falling off, greatly reducing the risk of metal foreign objects in the product. The structure is simple, the failure rate is low, and the labor intensity of operators and maintenance personnel is greatly reduced.

[0053] Preferred, such as Figure 6 As shown, the crusher 8 is provided with an air supply port, which is connected to the air outlet of the air filter 11 through a pipe. The upper end of the bag filter 8 is connected to the exhaust fan 12 through a pipe, and the air outlet of the exhaust fan 12 is connected to the air inlet of the air filter 11.

[0054] During the pulverization process of sodium monofluorophosphate semi-finished product, supplemental air is required for material conveying airflow. Food additive products have high requirements for foreign matter and dust. During the pulverization process, a large amount of dust and high-humidity cold air can be introduced through the supplemental air system, causing abnormal phenomena such as impurities and product clumping in the product.

[0055] By installing air filter 11 and exhaust fan 12, theoretically balanced airflow is achieved, realizing circulating airflow. Firstly, this effectively prevents impurities in the air from entering the material system with the airflow, resulting in significant improvements in product appearance, filtration test results, and other quality indicators. Secondly, it effectively prevents high-humidity air from fully contacting high-temperature materials, effectively solving the problem of product moisture absorption and clumping caused by full contact between high-temperature materials and high-humidity coolers, improving product finishing quality and reducing the risk of customer complaints. Thirdly, it reduces the amount of exhaust gas to be treated in the later stages of sodium monofluorophosphate production, which is of great significance for improving the plant's environmental protection.

[0056] A process for producing high-purity sodium monofluorophosphate includes the following steps:

[0057] Step 1: Place the raw materials into the feeding hopper 1, open the valve of the discharge port of the feeding hopper 1, and transport the raw materials to the mixer 2 for mixing. The mixed raw materials are then transported to the distribution hopper 3 for temporary storage through the transfer mechanism.

[0058] Step 2: Open the valve at the discharge port at the lower end of the distribution bin 3 to convey the material to the feed inlet of the feed auger 4. The feed auger 4 conveys and crushes the material and then conveys it to the graphite reactor 5 for heating and reaction.

[0059] Step 3: After the material reaction in graphite reactor 5 is completed, it is discharged to cooling equipment 6 for cooling. The cooled material product is discharged to material temporary storage bin 7 for temporary storage.

[0060] Step 4: The material in the material temporary storage bin 7 is conveyed to the crusher 8 for crushing. The crushed material is then conveyed to the bag filter 9 for filtration. The filtered material is then conveyed to the finished product bin 10 for storage. The material in the finished product bin 10 is then conveyed to the automatic packaging conveyor line for packaging.

[0061] In practical use, after crushing, the product is screened by a vibrating screen and then conveyed to the finished product silo 10 to improve the quality of the finished product.

[0062] Before packaging, the finished products in the finished product warehouse 10 are transported to the iron remover for iron removal before being repackaged to prevent iron impurities from appearing in the products and further improve product quality.

Claims

1. A high-purity sodium monofluorophosphate production system, comprising a feeding silo (1), the discharge port of the feeding silo (1) conveying raw materials to a mixer (2), the mixer (2) conveying the materials to a distribution silo (3) via a transfer mechanism, and the distribution silo (3) conveying the materials to a graphite reactor (5) via a feeding auger (4), characterized in that, The graphite reactor (5) has an insulation sleeve (501) on the outside of the furnace body, and a spiral groove (502) on the inside of the insulation sleeve (501). The heating wire (503) is installed in the spiral groove (502) and is close to the furnace body of the graphite reactor (5). The material after the graphite reactor (5) reaction is sequentially conveyed to the cooling equipment (6), the material storage bin (7), the crusher (8), the bag filter (9), and the finished product bin (10). The finished product bin (10) discharges the material to the automatic packaging conveyor line for packaging. The heating wire (503) is set in two sets, and the two sets of heating wire (503) are respectively set in the upper and lower parts of the graphite reactor (5) and are divided into two groups. The graphite reactor (5) is equipped with a temperature sensor at the feed inlet. The blades of the feed auger (4) consist of three parts: a positive spiral blade (401), a negative spiral blade (402), and a crushing blade (403). The crushing blade (403) is located below the feed inlet of the feed auger (4) and is arranged in multiple groups along the circumference of the feed auger (4). Each group of crushing blades (403) consists of multiple pieces and is distributed along the length of the feed auger (4). The crushing blades (403) are arranged at an angle. The positive spiral blade (401) and the negative spiral blade (402) convey the material towards the discharge port of the feed auger (4).

2. The high-purity sodium monofluorophosphate production system according to claim 1, characterized in that, The graphite reactor (5) has a furnace body with dimensions of φ160mm×900mm and an effective volume of 15.5~16.5L.

3. The high-purity sodium monofluorophosphate production system according to claim 1, characterized in that, The cooling device (6) includes a cooling chamber (601), with a cooling inlet (602) at the upper end and a cooling outlet (603) at the bottom. A cooling drum (604) is provided inside the cooling chamber (601). The shaft of the cooling drum (604) is rotatably mounted on the side wall of the cooling chamber (601) via a bearing. The cooling drum (604) is a hollow structure. A water inlet pipe (605) and a water outlet pipe (606) are provided at both ends of the shaft of the cooling drum (604). A scraper (607) is provided above the cooling outlet (603) and is set close to the cooling drum (604).

4. The high-purity sodium monofluorophosphate production system according to claim 3, characterized in that, An anti-overflow roller (608) is provided diagonally above the cooling roller (604), and the anti-overflow roller (608) is set in close contact with the cooling roller (604).

5. The high-purity sodium monofluorophosphate production system according to claim 1, characterized in that, The pulverizer (8) is equipped with an air inlet, which is connected to the air outlet of the air filter (11) through a pipe. The upper end of the bag filter (9) is connected to the exhaust fan (12) through a pipe, and the air outlet of the exhaust fan (12) is connected to the air inlet of the air filter (11).

6. The high-purity sodium monofluorophosphate production system according to claim 1, characterized in that, The transfer mechanism includes an RGV trolley (13) located below the discharge port of the mixer (2). The RGV trolley (13) is equipped with a transfer tank (14). The RGV trolley (13) moves along the first track (15) to the lifting platform of the elevator (16). A second track (17) is provided above the distribution bin (3). The RGV trolley (13) moves along the second track (17) to the top of the distribution bin (3).

7. A process for producing high-purity sodium monofluorophosphate, using the high-purity sodium monofluorophosphate production system described in any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Put the raw materials into the feeding bin (1), open the valve of the discharge port of the feeding bin (1), and transport the raw materials to the mixer (2) for mixing. The mixed raw materials are then transported to the distribution bin (3) for temporary storage through the transfer mechanism. Step 2: Open the valve at the discharge port at the lower end of the distribution bin (3) to transport the material to the feed inlet of the feed auger (4). The feed auger (4) transports and crushes the material and then transports it to the graphite reactor (5) for heating and reaction. Step 3: After the material reaction in the graphite reactor (5) is completed, it is discharged into the cooling equipment (6) for cooling. The cooled material product is discharged into the material temporary storage bin (7) for temporary storage. Step 4: The material in the material storage bin (7) is transported to the crusher (8) for crushing. The crushed material is then transported to the bag filter (9) for filtration. The filtered material is then transported to the finished product bin (10) for storage. The material in the finished product bin (10) is then transported to the automatic packaging conveyor line for packaging.

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