Melamine refining and purifying device

Abstract

The utility model belongs to the technical field of melamine purification, and particularly relates to a melamine refining and purifying device which comprises a mixing and dissolving unit, a press filter, an air-cooled crystallization tower, a centrifugal machine and a pulverizer, and the mixing and dissolving unit is used for dissolving and mixing water and melamine; the press filter is used for filtering the dissolved melamine; the air cooling crystallization tower is used for cooling and crystallizing melamine; the centrifugal machine is used for solid-liquid separation of the purified melamine; the crusher is used for crushing large-particle melamine; the mixing and dissolving unit, the press filter, the air-cooled crystallization tower, the centrifugal machine and the crusher are connected in sequence; the air cooling crystallization tower comprises a tower body, a liquid inlet pump, a packing layer, spraying heads and a spraying rod, the tower body is provided with a discharging pipe, an air inlet pipe and an air outlet pipe, the packing layer is connected with the tower body, the spraying rod is rotationally connected with the tower body, the spraying heads are arranged on the spraying rod, and the liquid inlet pump is communicated with the spraying heads through the spraying rod. According to the scheme, the problems of low cooling speed and non-uniform temperature during cooling crystallization of melamine are solved.

Description

Technical Field

[0001] This solution belongs to the field of melamine purification technology, specifically involving a melamine refining and purification device. Background Technology

[0002] According to the technology primarily used in the high-pressure non-catalytic melamine process, the conversion of urea into melamine melt also generates waste gas and numerous byproducts. The waste gas mainly consists of ammonia and carbon dioxide, while the byproducts primarily include OAT (ozone-air-acetylene) and condensation polymers. Carbon dioxide is typically separated before melamine melt purification; the practical purpose of this is to remove these byproducts, unconverted urea, and dissolved ammonia. Purification of the melamine melt is usually carried out through the dissolution of the melamine melt and subsequent crystallization of solid melamine.

[0003] Currently, an existing purification device and method for melamine processing raw materials, with publication number CN117065378A, includes a stripping tank. The top of the stripping tank has a feed pipe for injecting raw materials, and the bottom has a discharge pipe for discharging raw materials. A central inner column is installed at the center of the bottom of the stripping tank, and a steam input pipe is connected to the bottom of the central inner column. A gas collecting device is installed on the top of the stripping tank, and a stirring mechanism to improve the reaction rate is installed on the central inner column. In the purification of melamine, impurities contained in the melamine can be removed through steps such as heating, quenching, dissolving, stripping, and crystallization, thereby purifying the melamine product. Furthermore, the stirring mechanism, which improves the reaction rate during stripping, ensures a more complete reaction.

[0004] However, there is also a problem: melamine has a slow cooling rate and uneven solution temperature during cooling crystallization. Utility Model Content

[0005] This solution provides a melamine refining and purification device to solve the problems of slow cooling rate and uneven temperature during melamine cooling crystallization.

[0006] This solution provides a melamine refining and purification apparatus, including:

[0007] Mixing and dissolving unit: used to dissolve and mix water and melamine;

[0008] Filter press: Used to filter dissolved melamine;

[0009] Air-cooled crystallization tower: used to cool the crystallization of melamine;

[0010] Centrifuge: Used for solid-liquid separation and purification of melamine;

[0011] Crusher: Used to crush large particles of melamine;

[0012] The mixing and dissolving unit, filter press, air-cooled crystallization tower, centrifuge and pulverizer are connected in sequence;

[0013] The air-cooled crystallization tower includes a tower body, a liquid inlet pump, a packing layer, spray heads, and a spray rod. The tower body is equipped with a discharge pipe, an air inlet pipe, and an air outlet pipe. The packing layer is fixedly connected to the tower body, and the spray rod is rotatably connected to the tower body. The spray rod is equipped with multiple spray heads, and the liquid inlet pump is connected to the spray heads through the spray rod.

[0014] The principle of this solution is as follows: the mixing and dissolving unit dissolves and mixes water and melamine. Through heating and stirring, the melamine is fully dissolved in the water. A relatively high temperature needs to be maintained to increase solubility. The dissolved melamine solution is then filtered through a filter press to remove solid impurities and undissolved particles. This improves the purity of the solution, reduces potential impurities during subsequent crystallization, and ensures product quality.

[0015] The air-cooled crystallization tower cools and promotes the crystallization of melamine from the solution. The tower body contains the solution and cooling medium. A feed pump pumps the mixed solution into the tower body. The packing layer increases the contact area between the solution and the cooling medium, promoting heat exchange. Spray nozzles and spray bars evenly spray the solution onto the packing layer, increasing the contact area between the solution and air. Inlet and outlet pipes introduce cold air, carrying away heat from the solution and aiding in cooling. The hot solution is evenly dispersed on the packing layer through the spray nozzles, while the introduction of cold air further cools it, causing the melamine to gradually crystallize and precipitate.

[0016] Centrifuges are used for solid-liquid separation of crystallized melamine. This effectively removes the remaining mother liquor after crystallization, yielding relatively pure melamine crystals, reducing moisture content, and facilitating subsequent processing. A pulverizer then breaks down large melamine crystals into fine particles. This results in uniform, fine melamine granules, which are convenient for packaging, transportation, and further processing.

[0017] The beneficial effects of this scheme are: the design of the air-cooled crystallization tower enables the solution to be cooled uniformly, promotes the formation of melamine crystals, and improves crystallization efficiency and quality.

[0018] Furthermore, it also includes a rotating shaft, which is rotatably connected to the tower body. Multiple spray rods are provided, and the multiple spray rods are arranged in a circular pattern on the rotating shaft. The spray head is inclinedly arranged on the spray rod.

[0019] The inlet pump delivers the mixed solution through pipelines to the rotating shaft, from which it is distributed to individual spray bars. Each spray bar has multiple spray heads, which are angled to ensure the solution is sprayed at a specific angle, facilitating coverage of a wider area. The reaction force from the liquid sprayed from the spray heads causes the rotating shaft to rotate, which in turn drives the spray bars to rotate, ensuring the solution is evenly sprayed across the entire packing layer and increasing the contact area between the solution and the packing layer.

[0020] This device uses the reaction force of the spray head to drive the spray bar to rotate, so that the solution can be evenly distributed on the packing layer, avoiding local overheating or overcooling, and ensuring that the entire packing layer can effectively participate in the cooling process.

[0021] Furthermore, it also includes stirring blades, which are fixedly connected to the rotating shaft and located at the bottom of the tower. A feed pump delivers the mixed solution through pipelines to the rotating shaft, and then distributes it from the rotating shaft to each spray bar. Multiple spray heads on each spray bar are angled, and the reaction force from the liquid sprayed from the spray heads causes the rotating shaft to rotate.

[0022] The stirring blades are located at the bottom of the column and rotate together with the shaft, forcibly agitating the solution at the bottom. The rotation of the blades generates shear force and eddies, promoting the circulation of the solution at the bottom of the column and preventing sedimentation or the formation of areas with excessively high concentrations. The rotation of the blades also helps to break down temperature gradients in the solution, resulting in more uniform and efficient heat transfer between the cold air and the solution, preventing crystallization and clumping.

[0023] Furthermore, it also includes a fan connected to an air inlet pipe. The fan draws outside cold air into the tower through the air inlet pipe, providing the cold source required for cooling. The stable flow of cold air provided by the fan ensures that sufficient cooling capacity is always maintained within the tower, significantly improving cooling efficiency.

[0024] Furthermore, it also includes a fixing frame for securing the tower body, which is fixedly connected to the tower body. The fixing frame provides additional support to the tower body, ensuring that the tower body remains vertical and stable under various operating conditions. The fixing frame can absorb and disperse vibrations generated during operation through its structural design, reducing tower body swaying and resonance.

[0025] Furthermore, the system also includes a temperature sensor and a controller. The temperature sensor is located inside the tower body, and the temperature sensor, inlet pump, and fan are all electrically connected to the controller. The temperature sensor is used to collect temperature data at different locations inside the tower body in real time and transmit this data to the controller. The controller receives the data from the temperature sensor and analyzes and processes it according to the set target temperature range. The controller typically employs a PID (Proportional-Integral-Derivative) control algorithm to achieve precise temperature regulation.

[0026] The temperature inside the tower is maintained stable by adjusting the flow rate of the inlet pump and the speed of the fan. When the temperature exceeds the set range, the controller automatically adjusts the flow rate of the inlet pump or the speed of the fan to restore the target temperature. The inlet pump, according to the controller's instructions, adjusts its speed or valve opening to control the flow rate of the solution entering the tower, thus affecting the cooling rate. The fan, according to the controller's instructions, adjusts its speed or air intake to control the flow rate of cold air entering the tower, further affecting the cooling effect.

[0027] Our organization ensures that the temperature inside the tower remains within the optimal range through real-time monitoring and feedback control, thus avoiding the impact of temperature fluctuations on the crystallization process.

[0028] Furthermore, the mixing and dissolving unit includes a mixing tank, a dissolving tank, a dissolving heater, a dissolving aid, and a dissolving pump. The mixing tank is used for heating and mixing with the mother liquor; the dissolving tank is used for dissolving melamine; the dissolving pump pressurizes the liquid in the dissolving tank; the dissolving heater is used for heating the melamine; and the dissolving aid is used for fully dissolving the melamine. The mixing tank, dissolving tank, dissolving heater, and dissolving aid are connected in sequence.

[0029] The mixing tank first provides initial heating and mixing of the mother liquor and melamine to ensure the melamine begins to dissolve. After entering the dissolving tank, the solution is further heated and stirred to ensure complete dissolution of the melamine. The dissolved solution is then pressurized and pumped to the dissolving heater. In the dissolving heater, the solution is further heated to ensure the optimal dissolution temperature is reached. Finally, the solution enters the solvent aid, where it further promotes the dissolution of the melamine during its residence time, ensuring complete dissolution.

[0030] Our organization ensures complete dissolution of melamine in the solution by gradually increasing the temperature, vigorous stirring, and maintaining a reasonable residence time, thereby improving dissolution efficiency. This ensures uniform solution composition, avoiding localized supersaturation or the presence of undissolved particles, thus improving the quality and consistency of the final product.

[0031] Furthermore, the outlet temperature of the dissolution heater is 95-98℃. Controlling the outlet temperature of the dissolution heater at 95-98℃, close to the boiling point of water (100℃), can maximize the solubility of melamine and ensure its complete dissolution. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of an air-cooled crystallization tower for melamine refining and purification.

[0033] Figure 2 This is a flowchart of a melamine refining and purification apparatus.

[0034] The reference numerals in the accompanying drawings include: 1. Tower body; 2. Air outlet pipe; 3. Material outlet pipe; 4. Air inlet pipe; 5. Liquid inlet pump; 6. Spray bar; 7. Spray head; 8. Packing layer; 9. Rotating shaft; 10. Agitator blade; 11. Fixing frame; 12. Fan. Detailed Implementation

[0035] The basics are as follows: Figure 1 As shown:

[0036] This solution provides a melamine refining and purification device, including a mixing and dissolving unit, a filter press, an air-cooled crystallization tower, a centrifuge, and a pulverizer. The air-cooled crystallization tower includes a tower body 1, a liquid inlet pump 5, a packing layer 8, a rotating shaft 9, a fan 12, stirring blades 10, a spray head 7, and a spray bar 6. An air outlet pipe 2 is located at the top of the tower body 1, and a liquid inlet pipe is located inside the rotating shaft. The liquid inlet pipe is rotatably connected to the liquid inlet pump 5 via a rotary joint, and the liquid inlet pump 5 is fixed to the top of the tower body 1. An air inlet pipe 4 is located in the lower part of the tower body 1 and is connected to the fan 12. A fixing frame 11 is also provided at the bottom of the tower body 1 to fix the tower body 1 and prevent it from shaking. A discharge pipe 3 is located at the very bottom of the tower body 1.

[0037] The rotating shaft 9 is rotatably connected to the tower body 1 via bearings. The upper part of the rotating shaft 9 has four circumferentially distributed spray bars 6, each with an equally spaced spray head 7. The liquid inlet pipe is connected to these spray heads 7. All spray heads 7 are located on the same side of the spray bars 6 and are tilted downwards. When the spray heads 7 spray, the reaction force causes the spray bars 6 to rotate, thus causing the rotating shaft 9 to rotate. The bottom of the rotating shaft 9 has a stirring blade 10 for stirring the liquid. When the rotating shaft 9 rotates, it drives the stirring blade 10 to rotate.

[0038] The packing layer 8 is located in the middle of the tower body 1 and below the spray bar 6. The packing layer 8 is made of corrosion-resistant metals such as stainless steel and copper alloy. The metal packing structure is sturdy and not easily deformed or damaged, making it suitable for high-pressure and high-speed operating environments.

[0039] Multiple temperature sensors are installed within the tower body 1. The controller receives data from these sensors and analyzes and processes it according to the set target temperature range. The controller typically employs a PID (Proportional-Integral-Derivative) control algorithm to achieve precise temperature regulation. The temperature within the tower body 1 is kept stable by adjusting the flow rate of the inlet pump 5 and the speed of the fan 12. When the temperature exceeds the set range, the controller automatically adjusts the flow rate of the inlet pump 5 or the speed of the fan 12 to restore the target temperature. The inlet pump 5, according to the controller's instructions, adjusts its speed or valve opening to control the flow rate of the solution entering the tower body 1, thereby affecting the cooling rate. The fan 12, according to the controller's instructions, adjusts its speed or air intake to control the flow rate of cold air entering the tower body 1, further influencing the cooling effect.

[0040] As attached Figure 2 As shown:

[0041] The mixing tank is used for initial mixing and heating of the mother liquor and melamine. A built-in heating device (such as a steam coil or electric heater) maintains the temperature within the mixing tank within a suitable range (e.g., 75-85°C) to promote the initial dissolution of melamine. A mechanical stirrer is provided to ensure thorough and uniform mixing of the materials within the tank. This initial dissolution of some melamine reduces the workload on subsequent dissolution tanks. Heating and stirring further increase the dissolution rate of melamine.

[0042] The dissolving tank ensures complete dissolution of melamine in the solution. The solution is heated with steam to maintain a suitable dissolution temperature. Equipped with a high-efficiency stirrer, it ensures that the melamine particles in the solution have sufficient contact with the solvent, accelerating the dissolution process. Precise temperature control and vigorous stirring ensure that melamine achieves maximum solubility in the solution.

[0043] Dissolving pump: Pressurizes the solution in the dissolving tank and transports it through pipelines to downstream equipment (such as dissolving heaters and dissolving aids). Pressure regulation by the pump ensures stable flow of the solution in the pipeline and overcomes the resistance of downstream equipment. This ensures a continuous and stable flow of the solution to subsequent processing steps, improving production efficiency.

[0044] The dissolution heater provides secondary heating to the solution delivered from the dissolution tank, ensuring the solution reaches the optimal dissolution temperature. Heating is achieved using steam or other heat sources, typically shell-and-tube or plate heat exchangers, to ensure uniform heat transfer. Equipped with a temperature sensor and control system, it monitors and adjusts the solution temperature in real time, maintaining it within a set range (e.g., 95-98°C). This improves the dissolution rate: further heating ensures complete dissolution of melamine in the solution, increasing the purity of the final product. It also ensures stable solution temperature throughout the entire process, preventing incomplete dissolution due to temperature fluctuations.

[0045] The solvent aid utilizes the fluid's own flow and agitation to further promote the dissolution of melamine during the residence time, ensuring complete dissolution. A reasonably designed residence time (e.g., approximately 10 minutes) ensures sufficient time for heat exchange and dissolution reactions in the solution. The solution's own flow characteristics create natural circulation, further promoting the dissolution process. Uniform dissolution ensures that melamine particles in the solution are fully dispersed and dissolved, improving the quality of the final product. Prolonged residence time and natural circulation prevent melamine particles from clumping in the solution, improving crystallization quality. The temperature is maintained at approximately 95℃.

[0046] A filter press filters the dissolved melamine solution to remove solid impurities and undissolved particles. A pump forces the solution through a filter screen or cloth; solid impurities are trapped, while the liquid flows out through the screen. This improves the purity of the solution, reduces potential impurities during subsequent crystallization, and ensures product quality.

[0047] Centrifuges are used to separate the solid and liquid components of crystallized melamine. The centrifugal force generated by high-speed rotation separates the solid particles from the solution. This effectively removes the remaining mother liquor after crystallization, yielding relatively pure melamine crystals, reducing moisture content, and facilitating subsequent processing.

[0048] A pulverizer breaks down large melamine crystals into fine particles. Large crystals are crushed into the desired particle size using mechanical force (such as impact or shearing). This results in uniform, fine melamine granules, which are easier to package, transport, and process for further use.

[0049] As attached Figure 1 , Figure 2 As shown:

[0050] Substandard melamine is dissolved in water at around 100℃. By controlling the appropriate material-to-water ratio, the substandard melamine is completely dissolved. Then, acetic acid is used to adjust the pH value to around 6.5-7.5 to minimize the solubility of amide byproducts. Activated carbon is added for decolorization as needed. After precision filtration, cooling and recrystallization, solid-liquid separation, drying and pulverization, qualified melamine is obtained. It is then pneumatically conveyed to the packaging process for bagging and quantitative packaging, thus completing the purification of substandard melamine into superior melamine.

[0051] The specific operation described above involves controlling the material-to-water ratio of crude melamine to 1:30-1:33 based on the outlet flow rate of the dissolving pump and the content of unqualified melamine in the product. The feeding speed is adjusted by the screw feeder SC2001, and the product is added to the mixing tank V2001, which is equipped with an agitator and directly heated by steam.

[0052] The mother liquor is pumped into the mixing tank by mother liquor pump P2004A / B. The liquid level in the mixing tank is automatically controlled at 60-70% by the frequency converter of the mother liquor pump, controlled by LIC2001. The temperature of the mixing tank is manually adjusted by the direct steam valve, controlled by TI2001 to approximately 75-85℃.

[0053] The liquid level in the mixing tank gradually rises and overflows into the dissolving tank, which is equipped with a stirrer and heated by an internal coil.

[0054] The uniformly mixed liquid enters the dissolving pump from the dissolving tank, and is pressurized to 0.3-0.7 MPa by the dissolving pump P2001A / B. The dissolving pump outlet regulating valve is controlled by the electromagnetic flow meter, and the flow rate is displayed by the electromagnetic flow meter FI2001. The flow rate is controlled at 30-35 m³ / h and pumped into the dissolving heater E2001 for heating.

[0055] The outlet temperature of the dissolving heater E2001 is controlled by the heating steam valve TIC2002, which controls the outlet liquid temperature of the dissolving heater TI2002 to 95-98℃.

[0056] The hot mixture enters the solvent aid V2002A / B / C, where it is stirred by its own flow and held for approximately 10 minutes to ensure complete dissolution of the melamine. The outlet temperature of the solvent aid TI2003 is maintained at approximately 95°C by adjusting the temperature of TI2002.

[0057] The molten liquid from the solvent aid enters the filter press FV2001A / B, where it is filtered by a pump at a pressure <0.6 MPa. The filtered melamine solution is then pumped to the air-cooled crystallization tower T2001 via the filtrate-to-tower pump P2002A / B.

[0058] The melamine solution is brought into countercurrent contact with cold air drawn in by fan 12F2001 in the air-cooled crystallization tower, and is cooled to 55-60°C through cooling by cold air and evaporation. The temperature of the crystallization tower bottom is regulated by controlling fan 12 and liquid inlet pump 5 via TIC2006. The melamine solution falls into the bottom of the air-cooled crystallization tower, where melamine crystals precipitate and settle naturally.

[0059] When the inlet pump 5 delivers liquid to the spray bar 6, the reaction force from the liquid sprayed from the spray head 7 causes the rotating shaft 9 to rotate. This rotation of the shaft 9 drives the spray bar 6 to rotate, ensuring the solution is evenly sprayed across the entire packing layer 8, increasing the contact area between the solution and the packing layer 8. The stirring blade 10, located at the bottom of the tower body 1, rotates along with the rotating shaft 9, forcibly stirring the solution at the bottom of the tower. The stirring blade 10 generates shear force and eddies through rotation, promoting the circulation of the solution at the bottom of the tower body 1 and preventing solution deposition or the formation of areas with excessively high local concentrations. The rotation of the stirring blade 10 helps break the temperature gradient in the solution, making heat transfer between the cold air and the solution more uniform and efficient, preventing crystallization and clumping.

[0060] Melamine slurry is fed into the concentration tank V2006 via a pneumatic V-shaped discharge ball valve. The discharge rate of the crystallization tower is controlled to ensure that the slurry concentration is matched with that of the horizontal screw centrifuge.

[0061] Melamine slurry is transported by crystal pump P2006A / B to horizontal screw sedimentation centrifuge C2002 for continuous solid-liquid separation. The wet melamine enters the double-paddle dryer G2001 through the hopper for continuous drying.

[0062] The dried and qualified melamine is conveyed by screw conveyor SC2002 to pulverizer FS2001 for crushing. After crushing, the melamine is separated by cyclone separator XF2001 and enters the finished product silo V2007A / B. The melamine remains in two metering silos and is then conveyed by the bottom feeder of the finished product silo to the feeding pipeline, where it is transported by compressed air to the main melamine unit's large silo, where it is packaged as the finished product. Unqualified melamine is returned to the mixing tank for re-refining, thus completing the purification process.

[0063] Subsequent processing: The mother liquor from solid-liquid separation and the mother liquor overflowing from the air-cooled crystallization tower flow into the mother liquor pool V2004 through a steam jacket pipe. The mother liquor pool is equipped with a heating coil to maintain the mother liquor temperature TI2006 ≥ 70℃.

[0064] The filter cake from the filter press and the solvent aid are periodically discharged into a stirring cooking tank V2003A / B. After dilution with steam condensate, it is boiled with direct steam for about 10 minutes, stirred evenly, and then the stirring is stopped. The sludge liquid is allowed to settle naturally for a period of time, and the clear liquid is discharged into the mother liquor tank through a grading valve. The remaining sludge liquid that cannot be separated into clear liquid is stirred and pumped into a horizontal screw centrifuge C2001 through a slurry pump P2003A / B. The separated clear liquid is returned to the mother liquor tank, and the sludge is considered waste residue, which is bagged and treated together with the waste residue from the external filter of the melamine main system.

[0065] Steam condensate from the mother liquor tank, dissolving heater, air-cooled crystallizer, and drying processes enters the condensate tank V2005. The condensate is pressurized by condensate pumps P2005A / B and used as centrifuge cleaning water, air-cooled crystallizer rinsing water, mother liquor replenishment water, and slag boiling water. Excess condensate is pumped back to the soft water system.

[0066] The above descriptions are merely embodiments of this utility model, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of this utility model, and these should also be considered within the scope of protection of this utility model. These modifications will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application shall be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A melamine refining purification device, comprising: a mixing and dissolving unit for mixing and dissolving water and melamine; a filter press for filtering the dissolved melamine; an air-cooled crystallization tower for cooling and crystallizing melamine; a centrifuge for separating and purifying the solid-liquid separated melamine; a pulverizer for pulverizing large-particle melamine; the mixing and dissolving unit, filter press, air-cooled crystallization tower, centrifuge and pulverizer are connected in sequence; characterized in that the air-cooled crystallization tower comprises a tower body (1), a liquid inlet pump (5), a filler layer (8), a spray head (7) and a spray rod (6), the tower body (1) is provided with a discharge pipe (3), an air inlet pipe (4) and an air outlet pipe (2), the filler layer (8) is fixedly connected with the tower body (1), the spray rod (6) is rotatably connected with the tower body (1), a plurality of spray heads (7) are arranged on the spray rod (6), and the liquid inlet pump (5) is in communication with the spray head (7) through the spray rod (6).

2. A melamine refining purification apparatus according to claim 1, characterized in that Further comprising a rotating shaft (9), the rotating shaft (9) is rotatably connected with the tower body (1), a plurality of spray rods (6) are arranged on the rotating shaft (9) in a circumferential distribution manner, and the spray heads (7) are arranged on the spray rods (6) in an inclined manner.

3. A melamine refining purification apparatus according to claim 2, characterized in that Further comprising a stirring blade (10), the stirring blade (10) is fixedly connected with the rotating shaft (9), and the stirring blade (10) is located at the bottom of the tower body (1).

4. A melamine refining purification apparatus according to claim 1, characterized in that, Further comprising a fan (12), the fan (12) is in communication with the air inlet pipe (4).

5. A melamine refining purification apparatus according to claim 1, characterized in that, Further comprising a fixing frame (11) for fixing the tower body (1), the fixing frame (11) is fixedly connected with the tower body (1).

6. A melamine refining purification apparatus according to claim 4, characterized in that Further comprising a temperature sensor and a controller, the temperature sensor is arranged in the tower body (1), and the temperature sensor, liquid inlet pump (5) and fan (12) are electrically connected with the controller.

7. A melamine refining purification apparatus according to claim 1, characterized in that, The mixing and dissolving unit comprises a mixing tank, a dissolving tank, a dissolving heater, a dissolving aid and a dissolving pump, the mixing tank is used for mixing with mother liquor; the dissolving tank is used for dissolving melamine, the dissolving pump pressurizes the liquid in the dissolving tank, the dissolving heater is used for heating melamine, the dissolving aid is used for fully dissolving melamine, and the mixing tank, dissolving tank, dissolving heater and dissolving aid are connected in sequence.

8. A melamine refining purification apparatus according to claim 7, characterized in that The outlet temperature of the dissolving heater is 95-98℃.

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