A separation and purification system for potassium nitrate production and a method thereof

Abstract

This invention discloses a separation and purification system for potassium nitrate production, comprising a stirred dissolving vessel, a filter, a crystallization and washing machine, a fluidized bed dryer, and a packaging machine connected sequentially. The stirred dissolving vessel consists of an upper crushing chamber and a lower dissolving chamber. A heating jacket is installed outside the dissolving chamber. A stirring shaft is vertically installed inside the stirred dissolving vessel, penetrating from top to bottom through the crushing and dissolving chambers. Stirring wheels are installed on the outer walls of both chambers, and a motor is installed at the downward extension of the stirring shaft. A filter screen is installed at the connection between the upper and lower parts of the crushing and dissolving chambers. This invention, by setting up a crushing and dissolving chamber within the stirred dissolving vessel, crushes lumpy potassium nitrate into powder before dissolving it. Furthermore, the crushing in the crushing chamber and the stirring and thermal dissolution in the dissolving chamber are achieved through the same stirring shaft, integrating crushing and thermal dissolution into one system. This saves on equipment investment costs and improves production efficiency.

Description

Technical Field

[0001] This invention relates to the field of potassium nitrate production technology, and in particular to a separation and purification system and method for potassium nitrate production. Background Technology

[0002] Potassium nitrate is a chemical fertilizer containing 13.8% nitrogen and 46.6% potassium oxide. It is commonly known as potassium nitrate or saltpeter. Its relative molecular mass is 101.10. It is a colorless, transparent orthorhombic or rhombic crystal or white powder, exhibiting minimal hygroscopicity in air and not easily agglomerating. Its relative density is 2.019 (16℃), and its melting point is 334℃. It is readily soluble in water, with solubility increasing rapidly with temperature. It is soluble in liquid ammonia and glycerol, but insoluble in anhydrous ethanol and ether. Potassium nitrate is a chlorine-free nitrogen-potassium compound fertilizer with high solubility. Its active ingredients, nitrogen and potassium, are rapidly absorbed by crops, leaving no chemical residue. It is suitable for application to vegetables, fruits, flowers, and some chlorine-sensitive crops (such as potatoes, strawberries, beans, etc.). Potassium nitrate is a strong oxidizing agent and can cause combustion and explosion upon contact with organic matter. Therefore, potassium nitrate should be stored in a cool, dry place, away from fire and heat sources. Do not store or transport with reducing agents, acids, or flammable materials.

[0003] Existing potassium nitrate purification equipment purifies potassium nitrate with low purity by directly feeding lumpy nitric acid into a dissolving tank for heating and dissolution. This process is time-consuming and inefficient. Furthermore, the lack of a stirring device prevents the stirring of the dissolved potassium nitrate solution. During condensation, a long time is required for the potassium nitrate to cool down and crystallize, wasting considerable time. This method is inefficient for large-scale processing and production, hindering large-scale and batch production.

[0004] Therefore, in view of this, the inventor has studied and improved the existing structure and its shortcomings, and provided a separation and purification system and method for potassium nitrate production, in order to achieve a more practical purpose. Summary of the Invention

[0005] To address the problems mentioned in the background section, this invention provides a separation and purification system and method for potassium nitrate production.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A separation and purification system for potassium nitrate production includes a stirred dissolving vessel, a filter, a crystallization and washing machine, a fluidized bed dryer, and a packaging machine connected in sequence. The stirred dissolving vessel consists of a crushing chamber located at the top and a dissolving chamber located at the bottom. A heating jacket is provided outside the dissolving chamber. A stirring shaft is vertically arranged inside the stirred dissolving vessel, passing through the crushing chamber and the dissolving chamber from top to bottom. Stirring wheels are provided on the outer walls of the crushing chamber and the dissolving chamber. A motor is provided at the downward extension end of the stirring shaft. A filter screen is provided at the connection between the upper and lower parts of the crushing chamber and the dissolving chamber.

[0008] The crushing chamber has a feed inlet on one side of the upper end, and the bottom of the dissolving chamber has a downward concave structure on both sides to facilitate the discharge of potassium nitrate solution.

[0009] Preferably, the integrated crystallization and washing machine includes an upper cavity and a lower cavity, with a partition plate in the middle and a material discharge port on the inner wall of the partition plate;

[0010] The crystallization washing machine has a crystallization cylinder vertically installed inside, which passes through a partition plate. A drive shaft is vertically installed inside the crystallization cylinder, which passes through the upper and lower walls of the crystallization washing machine.

[0011] Preferably, the drive shaft is provided with first connecting pipes horizontally on the outer walls of the upper and lower cavities, respectively. A first scraper is provided vertically on one end of the first connecting pipe near the inner wall of the upper cavity, and a second scraper is provided vertically on the side of the first connecting pipe near the outer wall of the crystallizing cylinder.

[0012] Preferably, multiple sets of first scrapers are vertically arranged on the side of the first scraper close to the inner wall of the crystallization washing machine, and a first nozzle is arranged between adjacent first scrapers;

[0013] The second scraper has multiple sets of second scrapers vertically arranged on one side of the inner wall of the crystallization washing machine, and a second nozzle is arranged between adjacent second scrapers.

[0014] Preferably, the top inner wall of the crystallization cylinder is provided with a first channel, and the upper end face of the first channel is connected to a main inlet pipe through a bearing. The upper ends of the main inlet pipe are respectively connected to a cooling water pipe and a first deionized water pipe.

[0015] The bottom inner wall of the crystallizing cylinder is provided with a second channel, and the lower end face of the second channel is connected to a second main inlet pipe through a bearing. The lower ends of the second main inlet pipe are respectively connected to a second deionized water pipe and a cooling water circulation pipe.

[0016] The first channel and the second channel are not connected to each other and are semi-closed structures. The bottom side of the first channel has a liquid inlet hole, which is located on the upper side of the drive shaft and inside the crystallization cylinder.

[0017] The second channel has a liquid outlet hole on one side of the top. The liquid outlet hole is located on the lower side of the drive shaft and inside the crystallization cylinder.

[0018] Preferably, a first solenoid valve is provided on the second deionized water pipeline, and a second solenoid valve is provided on the cooling water circulation pipeline;

[0019] A third solenoid valve is provided on one side of the second channel, and a fourth solenoid valve is provided on the pipeline of the first connecting pipe located in the lower cavity.

[0020] The cooling water pipeline is equipped with a seventh solenoid valve, and the first deionized water pipeline is equipped with an eighth solenoid valve.

[0021] A sixth solenoid valve is provided on one side of the first channel, and a fifth solenoid valve is provided on the pipeline of the first connecting pipe located in the upper cavity.

[0022] Preferably, the outer wall of the lower cavity is provided with a first cooling jacket, the outer wall of the upper cavity is provided with a second cooling jacket, the bottom side of the first cooling jacket is connected to a first jacket inlet, and the upper side is connected to a first jacket outlet.

[0023] The partition plate has an inlet and an outlet on its two side walls, respectively. The partition plate has a hollow structure inside to facilitate the flow of cooling water.

[0024] The second cooling jacket has a second jacket inlet connected to one side of its bottom and a second jacket outlet connected to one side of its top. The second jacket outlet is connected to a cooling water pipe.

[0025] The first jacket inlet is connected to the cooling water circulation pipe, and the first jacket inlet, the first jacket outlet, the partition plate inlet, the partition plate outlet, the second jacket inlet, and the second jacket outlet are connected in sequence.

[0026] Preferably, the inner wall of the crystallizing cylinder and the outer wall of the drive shaft are provided with multiple sets of baffles at equal intervals.

[0027] Preferably, a connecting rod is fixed between the first scraper and the second scraper.

[0028] The drive shaft extends through the outer wall of the upward-extending end of the crystallization washing machine and is fitted with a first drive wheel. The first drive wheel is connected to a second drive wheel via a drive belt, and the second drive wheel is connected to a motor via a rotating shaft.

[0029] A separation and purification method for potassium nitrate production includes the following steps:

[0030] S1. Put the lumpy crude potassium nitrate into the crushing chamber of the stirred dissolving vessel and start the motor at the bottom to crush it. The crushed powdered potassium nitrate is filtered through the middle filter screen and then enters the dissolving chamber.

[0031] S2. First, open the deionized water storage tank. The deionized water enters the dissolution chamber to dissolve the powdered potassium nitrate. At the same time, turn on the heating jacket to heat and stir the dissolution. Then, open the flocculant storage tank. The industrial inorganic flocculant (aluminum chloride) in the flocculant storage tank enters the dissolution chamber to precipitate impurity ions.

[0032] S3. After being kept warm and allowed to stand, the liquid enters the filter for filtration. After filtration, it enters the integrated crystallization and washing machine for cooling and crystallization. The liquid enters the integrated crystallization and washing machine through the upper chamber. At this time, the first cooling jacket, the second cooling jacket, the partition plate and the crystallization cylinder are filled with coolant and circulate under the action of the booster pump. At this time, the third solenoid valve and the second solenoid valve are opened, and the first solenoid valve and the fourth solenoid valve are closed.

[0033] The seventh and sixth solenoid valves are open, while the eighth and fifth solenoid valves are closed. The coolant passes sequentially through the first cooling jacket, the partition plate, and the second cooling jacket, then enters the first channel through the cooling water pipe, and then enters the crystallizing cylinder through the liquid inlet on one side of the bottom. When the crystallizing cylinder is full of coolant, it enters the second channel through the liquid outlet and then flows back to the circulation tank between the cooling water circulation pipe and the inlet of the first jacket. Thus, the coolant forms a cooling circulation system in the first cooling jacket, the partition plate, the second cooling jacket, and the crystallizing cylinder, causing a large amount of crystals to precipitate.

[0034] S4. When a large amount of crystals precipitate out, some of them will adhere to the outer wall of the crystallization cylinder and the inner wall of the crystallization washing machine. At this time, it is necessary to start the motor and drive the drive shaft to rotate, thereby driving the first scraper and the second scraper to scrape off the attached crystals.

[0035] S5. At this time, the third and second solenoid valves are closed, and the first and fourth solenoid valves are opened. Deionized water enters the first connecting pipe of the lower cavity through the second deionized water pipe, and then washes the attached crystals through the first and second nozzles. This not only speeds up the removal of crystals, but also washes the crystals repeatedly, thereby obtaining relatively pure potassium nitrate.

[0036] The seventh and sixth solenoid valves are opened, and the eighth and fifth solenoid valves are closed. Deionized water enters the first connecting pipe of the lower cavity through the first deionized water pipe, and then washes the attached crystals through the first and second nozzles. This not only speeds up the removal of crystals, but also washes the crystals repeatedly, thereby obtaining relatively pure potassium nitrate.

[0037] S6. After repeated washing, potassium nitrate enters a fluidized bed dryer for drying, and then is packaged by an integrated packaging machine.

[0038] Compared with the prior art, the beneficial effects of the present invention are:

[0039] 1. This invention sets up a crushing chamber and a dissolving chamber in a stirred dissolving vessel to crush lumpy potassium nitrate into powder before dissolving it. Furthermore, the crushing in the crushing chamber and the stirring and hot dissolving in the dissolving chamber are achieved through the same stirring shaft, integrating crushing and hot dissolving into one unit. This not only saves on equipment investment costs but also improves production and processing efficiency.

[0040] 2. In this invention, by setting a crystallization cylinder inside the integrated crystallization and washing machine, the crystallization area of ​​potassium nitrate is increased, thereby improving the overall crystallization efficiency. It also achieves two major functions: cooling circulation crystallization and crystal spray washing. This solves the problem of crystals accumulating and adhering to the inner wall of the integrated crystallization and washing machine, which can greatly improve the overall purification efficiency and quality of potassium nitrate. It has high social use value and application prospects. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the system structure of the present invention;

[0043] Figure 2 This is a schematic diagram of the stirred dissolving vessel structure of the present invention;

[0044] Figure 3 This is a schematic diagram of the integrated crystallization and washing machine of the present invention;

[0045] Figure 4 This is an enlarged schematic diagram of structure A of the present invention;

[0046] Figure 5 This is an enlarged schematic diagram of structure B of the present invention;

[0047] Figure 6 This is a side view of the first scraper of the present invention;

[0048] Figure 7 This is a top view of the first scraper of the present invention;

[0049] Figure 8 This is a top view of the second scraper of the present invention.

[0050] In the diagram: 1. Stirred dissolving vessel; 101. Deionized water storage tank; 102. Flocculant storage tank; 103. Dissolving chamber; 104. Crushing chamber; 105. Heating jacket; 106. Filter screen; 2. Filter machine.

[0051] Crystallization washing integrated machine 3, crystallization cylinder 31, drive shaft 32, first cooling jacket 33, second cooling jacket 34, first scraper 35, first scraper blade 351, first nozzle 352;

[0052] Second scraper 36, second scraper blade 361, second nozzle 362;

[0053] First base plate 37, partition plate 38, material discharge port 39, baffle plate 310, first jacket inlet 311, first jacket outlet 312, partition plate inlet 313, partition plate outlet 314, second jacket inlet 315, second jacket outlet 316, cooling water pipe 317, first deionized water pipe 318, main inlet pipe 319, second deionized water pipe 320, cooling water circulation pipe 321, second main inlet pipe 322, first solenoid valve 323, second solenoid valve 324, third solenoid valve 325, fourth solenoid valve 326, fifth solenoid valve 327, sixth solenoid valve 328, first channel 329, liquid inlet hole 330, first connecting pipe 331, second channel 332, liquid outlet hole 333, second base plate 334, seventh solenoid valve 335, eighth solenoid valve 336, first drive wheel 337, drive belt 338, second drive wheel 339;

[0054] 4. Fluidized bed dryer; 5. Fan; 6. Packaging machine. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] Example 1

[0057] Reference Figure 1-2A separation and purification system for potassium nitrate production includes a stirred dissolving vessel 1, a filter 2, a crystallization and washing integrated machine 3, a fluidized bed dryer 4, and a packaging integrated machine 6 connected end to end. The stirred dissolving vessel 1 consists of a crushing chamber 104 located at the top and a dissolving chamber 103 located at the bottom. A heating jacket 105 is provided on the outside of the dissolving chamber 103. A stirring shaft is vertically arranged inside the stirred dissolving vessel 1, passing through the crushing chamber 104 and the dissolving chamber 103 from top to bottom. A stirring wheel is provided on the outer wall of the crushing chamber 104 and the dissolving chamber 103. A motor is provided at the downward extension end of the stirring shaft. A filter screen 106 is provided at the upper connection of the crushing chamber 104 and the dissolving chamber 103. A feed inlet is opened on one side of the upper end of the crushing chamber 104. The bottom two sides of the dissolving chamber 103 have a downward concave structure to facilitate the discharge of potassium nitrate solution.

[0058] Example 2

[0059] Reference Figure 1-8 The difference between this embodiment and embodiment 1 is that the crystallization washing machine 3 includes an upper cavity and a lower cavity, with a partition plate 38 in the middle. The inner wall of the partition plate 38 is provided with a discharge port 39, which facilitates the crystals in the upper cavity to be scraped off and fall into the lower cavity.

[0060] The crystallization washing machine 3 has a crystallization cylinder 31 vertically arranged inside, which passes through the partition plate 38. The crystallization cylinder 31 has a drive shaft 32 vertically arranged inside, which passes through the upper and lower walls of the crystallization washing machine 3.

[0061] The drive shaft 32 is horizontally provided with first connecting pipes 331 on the outer walls of the upper and lower cavities respectively. A first scraper 35 is vertically provided at one end of the first connecting pipe 331 near the inner wall of the upper cavity. A second scraper 36 is vertically provided on the side of the first connecting pipe 331 near the outer wall of the crystallization cylinder 31. A first base plate 37 is horizontally fixed at the bottom of the first scraper 35 and the second scraper 36 in the upper cavity. The first base plate 37 is close to the upper end face of the partition plate 38, which facilitates the scraping of crystals on the upper end face of the partition plate 38.

[0062] A second base plate 334 is horizontally fixed at the bottom of the first connecting pipe 331 located in the lower cavity. The second base plate 334 is close to the bottom wall of the crystallization washing machine 3, which facilitates the scraping of crystals on the bottom wall of the crystallization washing machine 3 and conveying them to the fluidized bed dryer 4 through the bottom discharge port for drying.

[0063] Two sets of first scrapers 351 are vertically arranged on the side of the first scraper 35 close to the inner wall of the crystallization washing machine 3. A set of first wide-edge scrapers 353 is arranged between the two sets of first scrapers 351. The distance between the tip and the tail of the first wide-edge scraper 353 is a, and the distance between the tip and the tail of the first scraper 351 is b. A is greater than b, so that it can better fit the inner wall of the crystallization washing machine 3.

[0064] A first nozzle 352 is provided between adjacent first scrapers 351 and first wide-edge scrapers 353;

[0065] The second scraper 36 has two sets of second scrapers 361 vertically arranged on one side of the inner wall of the crystallization washing machine 3. A set of second narrow-edge scrapers 363 is arranged between the two sets of second scrapers 361. The distance between the tip and the tail of the second narrow-edge scraper 363 is d, and the distance between the tip and the tail of the second scraper 361 is c. d is less than c, so that it can better fit the outer wall of the crystallization cylinder 31.

[0066] A second nozzle 362 is provided between the adjacent second scraper 361 and the second narrow-edge scraper 363.

[0067] Example 3

[0068] Reference Figure 1-8 The difference between this embodiment and embodiment 2 is that: a first channel 329 is provided on the top inner wall of the crystallization cylinder 31, and a main inlet pipe 319 is inserted into the upper end face of the first channel 329 through a bearing. Cooling water pipe 317 and a first deionized water pipe 318 are respectively connected to the upper two sides of the main inlet pipe 319.

[0069] The bottom inner wall of the crystallization cylinder 31 is provided with a second channel 332. The lower end face of the second channel 332 is connected to a second main inlet pipe 322 through a bearing. The lower ends of the second main inlet pipe 322 are respectively connected to a second deionized water pipe 320 and a cooling water circulation pipe 321.

[0070] The first channel 329 and the second channel 332 are not connected to each other and are semi-closed structures. The bottom side of the first channel 329 is provided with a liquid inlet hole 330, which is located on the upper side of the drive shaft 32 and inside the crystallizing cylinder 31.

[0071] The second channel 332 has a liquid outlet hole 333 on one side of the top. The liquid outlet hole 333 is located on one side of the lower end of the drive shaft 32 and inside the crystallization cylinder 31.

[0072] The second deionized water pipe 320 is equipped with a first solenoid valve 323, and the cooling water circulation pipe 321 is equipped with a second solenoid valve 324.

[0073] A third solenoid valve 325 is provided on one side of the second channel 332, and a fourth solenoid valve 326 is provided on the pipeline of the first connecting pipe 331 located in the lower cavity.

[0074] A seventh solenoid valve 335 is installed on the cooling water pipe 317, and an eighth solenoid valve 336 is installed on the first deionized water pipe 318.

[0075] A sixth solenoid valve 328 is provided on one side of the first channel 329, and a fifth solenoid valve 327 is provided on the first connecting pipe 331 located in the upper cavity.

[0076] The outer wall of the lower cavity is provided with a first cooling jacket 33, and the outer wall of the upper cavity is provided with a second cooling jacket 34. The bottom side of the first cooling jacket 33 is connected to a first jacket inlet 311, and the upper side is connected to a first jacket outlet 312.

[0077] The partition plate 38 has a partition plate inlet 313 and a partition plate outlet 314 connected to its two side walls respectively. The partition plate 38 has a hollow structure inside to facilitate the flow of cooling water.

[0078] The second cooling jacket 34 has a second jacket inlet 315 connected to one side of its bottom and a second jacket outlet 316 connected to one side of its upper end. The second jacket outlet 316 is connected to the cooling water pipe 317.

[0079] The first jacket inlet 311 is connected to the cooling water circulation pipe 321. The first jacket inlet 311, the first jacket outlet 312, the partition plate inlet 313, the partition plate outlet 314, the second jacket inlet 315, and the second jacket outlet 316 are connected in sequence. A coolant circulation tank is installed on the pipeline between the cooling water circulation pipe 321 and the first jacket inlet 311. The coolant is pressurized by a booster pump to achieve cooling circulation crystallization.

[0080] Multiple sets of baffles 310 are equidistantly and alternately distributed on the inner wall of the crystallizing cylinder 31 and the outer wall of the drive shaft 32, which can slow down the flow rate of the coolant in the crystallizing cylinder 31, thereby gradually causing potassium nitrate crystals to precipitate.

[0081] A connecting rod is fixed between the first scraper 35 and the second scraper 36 to strengthen the fixation; the drive shaft 32 passes through the outer wall of the upward extension end of the crystallization washing machine 3 and is sleeved with the first transmission wheel 337. The first transmission wheel 337 is connected to the second transmission wheel 339 through the transmission belt 338. The second transmission wheel 339 is connected to the motor through the rotating shaft.

[0082] Example 4

[0083] A separation and purification method for potassium nitrate production includes the following steps:

[0084] S1. Put the lumpy crude potassium nitrate into the crushing chamber 104 in the stirring dissolving vessel 1, and start the motor at the bottom to crush it. The crushed powdered potassium nitrate is filtered through the middle filter screen 106 and then enters the dissolving chamber 103.

[0085] S2. First, open the deionized water storage tank 101. Deionized water enters the dissolution chamber 103 to dissolve the powdered potassium nitrate. At the same time, turn on the heating jacket 105 to heat and stir the dissolution. Then, open the flocculant storage tank 102. The industrial inorganic flocculant (aluminum chloride) in the flocculant storage tank 102 enters the dissolution chamber 103 to precipitate impurity ions.

[0086] S3. After being kept warm and allowed to stand, the liquid enters the filter 2 for filtration. After filtration, it enters the integrated crystallization and washing machine 3 for cooling and crystallization. The liquid enters the integrated crystallization and washing machine 3 through the upper chamber. At this time, the first cooling jacket 33, the second cooling jacket 34, the partition plate 38 and the crystallization cylinder 31 are filled with coolant and circulate under the action of the booster pump. At this time, the third solenoid valve 325 and the second solenoid valve 324 are opened, and the first solenoid valve 323 and the fourth solenoid valve 326 are closed.

[0087] The seventh solenoid valve 335 and the sixth solenoid valve 328 are opened, while the eighth solenoid valve 336 and the fifth solenoid valve 327 are closed. The coolant passes sequentially through the first cooling jacket 33, the partition plate 38, and the second cooling jacket 34, then enters the first channel 329 through the cooling water pipe 317, and then enters the crystallizing cylinder 31 through the liquid inlet 330 on the bottom side. When the crystallizing cylinder 31 is full of coolant, it enters the second channel 332 through the liquid outlet 333, and then flows back to the coolant circulation tank between the cooling water circulation pipe 321 and the first jacket inlet 311. Thus, the coolant forms a cooling circulation system in the first cooling jacket 33, the partition plate 38, the second cooling jacket 34, and the crystallizing cylinder 31, causing a large amount of crystals to precipitate.

[0088] S4. When a large amount of crystals precipitate out, some of them will adhere to the outer wall of the crystallization cylinder 31 and the inner wall of the crystallization washing machine 3. At this time, it is necessary to start the motor and drive the drive shaft 32 to rotate, thereby driving the first scraper 35 and the second scraper 36 to scrape off the attached crystals.

[0089] S5. At this time, the third solenoid valve 325 and the second solenoid valve 324 are closed, and the first solenoid valve 323 and the fourth solenoid valve 326 are opened. Deionized water enters the first connecting pipe 331 of the lower cavity through the second deionized water pipe 320, and then washes the attached crystals through the first nozzle 352 and the second nozzle 362. This not only speeds up the removal of crystals, but also washes the crystals repeatedly, thereby obtaining relatively pure potassium nitrate.

[0090] The seventh solenoid valve 335 and the sixth solenoid valve 328 are opened, and the eighth solenoid valve 336 and the fifth solenoid valve 327 are closed. Deionized water enters the first connecting pipe 331 of the lower cavity through the first deionized water pipe 318, and then washes the attached crystals through the first nozzle 352 and the second nozzle 362. This not only speeds up the removal of crystals, but also allows for repeated washing of the crystals, thereby obtaining relatively pure potassium nitrate.

[0091] This invention achieves two major functions—cooling and circulating crystallization and crystal spraying and washing—through a single set of equipment, and solves the problem of crystals accumulating and adhering to the inner wall of the integrated crystallization and washing machine 3, which can greatly improve the overall purification efficiency and quality of potassium nitrate.

[0092] S6. After repeated washing, potassium nitrate enters the fluidized bed dryer 4 for drying, and then is packaged by the integrated packaging machine 6.

[0093] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0094] In this invention, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," "link," and "fix" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0095] The control method of this invention is automatic control through a controller. The control circuit of the controller can be implemented by simple programming by those skilled in the art. The power supply is also common knowledge in the art. Furthermore, since this invention is mainly used to protect mechanical devices, the control method and circuit connection will not be explained in detail here.

[0096] 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. A separation and purification system for potassium nitrate production, comprising a stirred dissolving vessel (1), a filter (2), a crystallization and washing integrated machine (3), a fluidized bed dryer (4), and a packaging integrated machine (6) connected sequentially end to end, characterized in that: The stirred dissolving vessel (1) consists of a crushing chamber (104) located at the top and a dissolving chamber (103) located at the bottom. A heating jacket (105) is provided on the outside of the dissolving chamber (103). A stirring shaft is vertically arranged inside the stirred dissolving vessel (1). The stirring shaft runs through the crushing chamber (104) and the dissolving chamber (103) from top to bottom. A stirring wheel is provided on the outer wall of the stirring shaft located on the crushing chamber (104) and the dissolving chamber (103). A motor is provided at the downward extension end of the stirring shaft. A filter screen (106) is provided at the upper and lower connection between the crushing chamber (104) and the dissolving chamber (103). The crystallization washing machine (3) includes an upper cavity and a lower cavity, with a partition plate (38) in the middle and a material discharge port (39) on the inner wall of the partition plate (38). The crystallization washing machine (3) has a crystallization cylinder (31) vertically arranged inside, the crystallization cylinder (31) passes through the partition plate (38), and the crystallization cylinder (31) has a drive shaft (32) vertically arranged inside, the drive shaft (32) passes through the upper and lower walls of the crystallization washing machine (3). The crystallization cylinder (31) has a first channel (329) on its top inner wall. The upper end of the first channel (329) is connected to a main inlet pipe (319) via a bearing. The upper ends of the main inlet pipe (319) are connected to a cooling water pipe (317) and a first deionized water pipe (318) respectively. The bottom inner wall of the crystallization cylinder (31) is provided with a second channel (332). The lower end face of the second channel (332) is connected to a second main inlet pipe (322) through a bearing. The lower ends of the second main inlet pipe (322) are respectively connected to a second deionized water pipe (320) and a cooling water circulation pipe (321).

2. The separation and purification system for potassium nitrate production according to claim 1, characterized in that: The drive shaft (32) is horizontally provided with a first connecting pipe (331) on the outer wall of the upper cavity and the lower cavity respectively. The first connecting pipe (331) is vertically provided with a first scraper (35) on one end near the inner wall of the upper cavity, and a second scraper (36) is vertically provided on the side of the first connecting pipe (331) near the outer wall of the crystallizing cylinder (31).

3. The separation and purification system for potassium nitrate production according to claim 2, characterized in that: The first channel (329) and the second channel (332) are not connected to each other and are semi-closed structures. The bottom side of the first channel (329) is provided with a liquid inlet hole (330), which is located on the upper side of the drive shaft (32) and inside the crystallizing cylinder (31). The second channel (332) has a liquid outlet hole (333) on one side of the top. The liquid outlet hole (333) is located on one side of the lower end of the drive shaft (32) and inside the crystallizing cylinder (31).

4. The separation and purification system for potassium nitrate production according to claim 3, characterized in that: The outer wall of the lower cavity is provided with a first cooling jacket (33), and the outer wall of the upper cavity is provided with a second cooling jacket (34). The bottom side of the first cooling jacket (33) is connected to a first jacket inlet (311), and the upper side is connected to a first jacket outlet (312). The partition plate (38) has a partition plate inlet (313) and a partition plate outlet (314) connected to its two side walls respectively. The partition plate (38) has a hollow structure inside, which facilitates the flow of cooling water.

5. A separation and purification method for potassium nitrate production, employing the separation and purification system for potassium nitrate production as described in claim 4, characterized in that: Includes the following steps: S1. Put the blocky crude potassium nitrate into the crushing chamber (104) of the stirring dissolving kettle (1) and start the motor at the bottom to crush it. The crushed powdered potassium nitrate is filtered through the middle filter screen (106) and then enters the dissolving chamber (103). S2. First, open the deionized water storage tank (101), and the deionized water enters the dissolution chamber (103) to dissolve the powdered potassium nitrate. At the same time, turn on the heating jacket (105) to heat and stir the dissolution. Then, open the flocculant storage tank (102), and the industrial inorganic flocculant in the flocculant storage tank (102) enters the dissolution chamber (103) to precipitate impurity ions. S3. After being kept warm and allowed to stand, the liquid enters the filter (2) for filtration. After filtration, it enters the integrated crystallization and washing machine (3) for cooling and crystallization. The liquid enters the integrated crystallization and washing machine (3) through the upper cavity. At this time, the first cooling jacket (33), the second cooling jacket (34), the partition plate (38) and the crystallization cylinder (31) are filled with coolant and circulate under the action of the booster pump. At this time, the third solenoid valve (325) and the second solenoid valve (324) are opened, and the first solenoid valve (323) and the fourth solenoid valve (326) are closed. The seventh solenoid valve (335) and the sixth solenoid valve (328) are opened, and the eighth solenoid valve (336) and the fifth solenoid valve (327) are closed. The coolant passes through the first cooling jacket (33), the partition plate (38) and the second cooling jacket (34) in sequence, and then enters the first channel (329) through the cooling water pipe (317), and then enters the crystallizing cylinder (31) through the liquid inlet hole (330) on the bottom side. When the coolant fills the crystallizing cylinder (31), it enters the second channel (332) through the liquid outlet hole (333), and then flows back to the circulation tank between the cooling water circulation pipe (321) and the inlet (311) of the first jacket. For this reason, the coolant forms a cooling circulation system in the first cooling jacket (33), the partition plate (38) and the second cooling jacket (34), as well as in the crystallizing cylinder (31), so that a large amount of crystals are precipitated. S4. When a large amount of crystals are precipitated, some of them will adhere to the outer wall of the crystallization cylinder (31) and the inner wall of the crystallization washing machine (3). At this time, it is necessary to start the motor and drive the drive shaft (32) to rotate, thereby driving the first scraper (35) and the second scraper (36) to scrape off the attached crystals. The first scraper (35) is vertically arranged with multiple sets of first scrapers (351) on one side near the inner wall of the crystallization washing machine (3), and a first nozzle (352) is arranged between adjacent first scrapers (351). The second scraper (36) is vertically arranged with multiple sets of second scrapers (361) on one side close to the inner wall of the crystallization washing machine (3), and a second nozzle (362) is arranged between adjacent second scrapers (361). S5. At this time, the third solenoid valve (325) and the second solenoid valve (324) are closed, and the first solenoid valve (323) and the fourth solenoid valve (326) are opened. Deionized water enters the first connecting pipe (331) of the lower cavity through the second deionized water pipe (320), and then washes the attached crystals through the first nozzle (352) and the second nozzle (362). This not only speeds up the removal of crystals, but also allows for repeated washing of the crystals, thereby obtaining relatively pure potassium nitrate. The seventh solenoid valve (335) and the fifth solenoid valve (327) are opened, and the eighth solenoid valve (336) and the sixth solenoid valve (328) are closed. Deionized water enters the first connecting pipe (331) of the upper cavity through the first deionized water pipe (318), and then washes the attached crystals through the first nozzle (352) and the second nozzle (362). This not only speeds up the removal of crystals, but also allows for repeated washing of the crystals, thereby obtaining relatively pure potassium nitrate. S6. After repeated washing, potassium nitrate enters the fluidized bed dryer (4) for drying and is then packaged by the packaging machine (6). The second deionized water pipe (320) is equipped with a first solenoid valve (323), and the cooling water circulation pipe (321) is equipped with a second solenoid valve (324). A third solenoid valve (325) is provided on one side of the second channel (332), and a fourth solenoid valve (326) is provided on the pipeline of the first connecting pipe (331) located in the lower cavity. The cooling water pipe (317) is equipped with a seventh solenoid valve (335), and the first deionized water pipe (318) is equipped with an eighth solenoid valve (336). A sixth solenoid valve (328) is provided on one side of the first channel (329), and a fifth solenoid valve (327) is provided on the pipeline of the first connecting pipe (331) located in the upper cavity.

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