A mixing device for repairing saline-alkali soil based on fly ash and a repairing method thereof

Abstract

The application provides a mixing device for repairing saline-alkali soil based on fly ash and a repairing method thereof, and relates to the field of repairing saline-alkali soil based on fly ash. The mixing device for repairing saline-alkali soil based on fly ash and the repairing method thereof comprise a support and a mixing barrel mounted on the support, one end of the mixing barrel is rotatably mounted with a rotating piece, the rotating piece is fixedly mounted with a stirring barrel inside, the bottom end of the stirring barrel is provided with a plurality of screening holes, the stirring barrel is provided with cavities A, B and C and a stirring zone, the stirring barrel is provided with cavities A, B and C and a stirring zone, the cavity A is used for loading chemical modifiers, the mixing device for repairing saline-alkali soil based on fly ash and the repairing method thereof can break and disperse materials before mixing, improve the mixing effect, add three kinds of materials in a certain order in sequence, further improve the mixing efficiency through the double-spiral mixing mechanism, shorten the mixing time, and clean the mixing barrel after the mixing is completed and the materials are discharged.

Description

Technical Field

[0001] The invention relates to the field of fly ash restoration of saline-alkali land, and in particular to a mixing device and a restoration method thereof based on fly ash for restoration of saline-alkali land. Background Art

[0002] Saline-alkali land is a widespread type of land that seriously restricts agricultural production and ecological environment improvement. Its soil contains high concentrations of salt, such as sodium chloride, sodium sulfate, etc., as well as alkaline substances such as sodium carbonate, sodium bicarbonate, etc. These substances lead to the deterioration of the physical, chemical and biological properties of the soil. The high osmotic pressure of saline-alkali land makes it difficult for plants to absorb water and nutrients in the soil. The soil is compacted, has poor ventilation and water permeability, and has low microbial activity, which greatly restricts the growth of vegetation and the sustainable development of agriculture. Fly ash is a solid waste generated after burning coal in coal-fired power plants. Its output is huge and increases year by year. Fly ash contains silicon, aluminum, iron, calcium and other nutrients required for plant growth. Its particles have certain adsorption properties and can improve soil structure. The application of fly ash in saline-alkali land restoration has many advantages: on the one hand, the components such as silicates in fly ash can undergo ion exchange reactions with the salt in the soil, reduce the content of harmful salts such as sodium ions in the soil, and improve the chemical properties of the soil; on the other hand, the fine particles of fly ash can fill the soil pores, improve the air permeability and aggregate structure of the soil, and are conducive to microbial activity and plant root growth; the improvement of saline-alkali land is of great significance to improving land utilization, ensuring the sustainable development of agriculture and improving the ecological environment. Among the many saline-alkali land improvement methods, mixing fly ash with organic materials (such as compost, green manure, etc.) and chemical amendments (such as gypsum, sulfur, etc.) is a more effective way.

[0003] The traditional mixing device for mixing fly ash and organic materials is a simple stirring mixer. When working, the stirring shaft is driven by a motor to rotate, and the stirring blades rotate accordingly, thereby stirring and mixing the fly ash and organic materials placed in the mixing barrel. Since the fly ash particles are small and light in texture, and the organic materials are often irregular in shape, different in size and have a certain degree of fibrousness, during the stirring process, due to the relatively simple stirring method of the stirring blades, more time is required to quickly and fully mix these materials with huge differences in physical properties, resulting in a longer mixing time, which affects the subsequent work process. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention provides a mixing device and a repair method for saline-alkali land repair based on fly ash, which solves the problems raised in the above background technology.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a mixing device based on fly ash for repairing saline-alkali land and its repair method, including a bracket and a mixing barrel installed on the bracket, one end of the mixing barrel is rotatably installed with a rotating part, a stirring barrel is fixedly installed in the rotating part, the bottom end of the stirring barrel is provided with a plurality of sieve holes, the stirring barrel is provided with cavity A, cavity B, cavity C and a stirring zone, cavity A is used to load chemical modifiers, the stirring zone is used to add fly ash and organic materials, and a stirring mechanism for stirring is installed in the stirring zone.

[0006] A double-helix mixing mechanism for mixing and stirring is installed in the mixing barrel. The double-helix mixing mechanism includes two inclined spiral shafts and two spiral blades with opposite spiral directions. The length of one spiral shaft is greater than that of the other spiral shaft. Channels A are provided inside the two spiral shafts. The outer surface of one of the spiral shafts is connected to several one-way valve nozzles for discharging the gas in one of the channels A, and a one-way valve A is installed at the bottom end of the other spiral shaft.

[0007] Two fixed tubes are fixedly installed on the outside of the mixing barrel, one end of the two fixed tubes is rotatably connected to the two spiral shafts respectively, and the two fixed tubes are provided with channels B, channel C and channel D which are connected in sequence, the two channels D are connected with the two channels A respectively, and a drainage tube for draining the chemical modifier into one of the channels D is connected between the mixing barrel and one of the fixed tubes, and a gas transmission mechanism for conveying gas to the other channel B is fixedly installed in the mixing barrel, and a piston group A for controlling the opening or closing of the drainage mechanism and a piston group B for controlling the opening or closing of the gas transmission mechanism are respectively installed in the two fixed tubes.

[0008] Preferably, one end of the mixing barrel and the stirring barrel are both conical.

[0009] Preferably, the inner bottom wall of the cavity A is set to be inclined, and a feeding pipe is installed on the upper surface of the mixing barrel, and the feeding pipe is connected to the cavity A.

[0010] Preferably, the stirring mechanism includes a stirring rod, several groups of longitudinally distributed stirring blades, a motor, two gears and a gear ring. The radius of the multiple groups of stirring blades decreases successively. One end of the motor and the stirring rod are both located in the cavity C. The motor is rotatably connected to the stirring barrel, and the motor is fixed to one of the brackets through a fixed frame. The output end of the motor is fixedly connected to one end of the stirring rod. Several stirring blades are fixedly connected to the stirring rod, one of the gears is fixedly connected to the stirring rod, and the other gear is rotatably connected to the stirring barrel through a rotating shaft and is meshed with the gear ring. The gear ring is fixedly connected to the stirring barrel, and the two gears are meshed.

[0011] Preferably, the piston group A includes an integrally formed piston A, a push rod A and a slider. The piston A is slidably connected to the channel D adjacent to it, and the two are in close contact. The slider is slidably connected to the channel C adjacent to it.

[0012] Preferably, the piston group B includes a piston B, a push rod B, a fixed block, a sleeve and a spring. The piston B is slidingly connected to the channel B adjacent to it, and the two are in close contact. One end of the push rod B is fixedly connected to the piston B, and the other end is slidingly connected to the sleeve. The fixed block is fixedly connected to the inner wall of the channel B adjacent to it, the fixed block is fixedly connected to the sleeve, and the two ends of the spring are fixedly connected to the fixed block and the push rod B respectively.

[0013] Preferably, the gas delivery mechanism includes an air delivery pipe A, an air delivery pipe B and an air intake pipe. The air delivery pipe A and the air delivery pipe B are fixedly connected to the mixing barrel, and one end of the air delivery pipe A is connected to one of the channels B, and the other end is rotatably connected to the air intake pipe. The other end of the air intake pipe is used to connect to an external air pump, and the two ends of the air delivery pipe B are respectively connected to the two channels B.

[0014] Preferably, the double-helix mixing mechanism further comprises an annular fixed ring and two grinding wheels, the inner wall of the fixed ring is subjected to anti-slip treatment, and the two grinding wheels are respectively fixedly connected to the two spiral shafts and are in close contact with the fixed ring.

[0015] Preferably, a feed hopper is fixedly connected to the interior of the rotating member, and one end of the feed hopper is connected to the mixing barrel.

[0016] A method for repairing saline-alkali land based on fly ash, comprising the following steps:

[0017] S1: Conduct a comprehensive test of the target saline-alkali land, including soil salt content, pH value, soil texture (such as the ratio of sand, silt, and clay), nutrient status (nitrogen, phosphorus, potassium, and trace element content), and groundwater level parameters. Based on the test results, assess the condition of the saline-alkali land to determine its degree of salinization, fertility level, and major problems.

[0018] S2: Select fly ash from appropriate sources, ensure it meets relevant quality standards, and screen the fly ash to remove large particles of impurities and unburned carbon particles;

[0019] S3: Prepare organic materials, such as well-rotted compost, manure, or green manure. If compost is used, ensure it is fully decomposed to avoid fermentation and the production of harmful gases or the depletion of soil oxygen. Determine the degree of decomposition by measuring the temperature, odor, color, and texture of the compost. Crush the organic materials to a suitable particle size.

[0020] S4: Select appropriate chemical improvers based on the test results of saline-alkali land. If the soil is too alkaline, gypsum (calcium sulfate) improver can be used to neutralize the alkalinity. For some special cases, such as when the soil contains too many heavy metal ions, corresponding chelating agents can be selected for treatment.

[0021] S5: Determine the mixing ratio of fly ash, organic materials and chemical modifiers according to the specific conditions of saline-alkali land.

[0022] Compared with the prior art, the present invention has the following beneficial effects: the mixing device based on fly ash for repairing saline-alkali land and the repair method thereof, through the provided stirring mechanism, can crush and disperse the materials before mixing, thereby improving the mixing effect; during the mixing process, the three materials are not added at once, but are added in sequence in a certain order, with fly ash being added first, followed by organic materials, and finally chemical modifiers; the provided double-helix mixing mechanism can further improve the mixing efficiency and shorten the mixing time; when fly ash and organic materials are mixed, a one-way valve nozzle is required to spray to increase the contact area and promote their full mixing; when the one-way valve nozzle stops working, the chemical modifier can be automatically added; and after the mixing is completed and the materials are discharged, the mixing barrel can also be thoroughly cleaned. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 A cross-sectional view of the front view of the mixing barrel of the present invention;

[0025] Figure 3 It is a cross-sectional view of the front view of the double-helix mixing mechanism of the present invention;

[0026] Figure 4 For the present invention Figure 3 A schematic diagram of the structure at center A;

[0027] Figure 5 For the present invention Figure 3 A magnified schematic diagram of the structure at point B in the middle;

[0028] Figure 6 It is a cross-sectional view of the front view of the mixing barrel of the present invention;

[0029] Figure 7 It is a cross-sectional view of the front view of the stirring mechanism of the present invention;

[0030] Figure 8 A sectional view of a side view of a mixing barrel of the present invention;

[0031] Figure 9 It is a top view of the gear and gear ring of the present invention.

[0032] Among them: 1. Bracket; 2. Mixing barrel; 3. Rotating part; 4. Mixing barrel; 401. Cavity A; 402. Cavity B; 403. Cavity C; 404. Mixing zone; 5. Screen hole; 6. Mixing mechanism; 601. Mixing rod; 602. Mixing blade; 603. Gear; 604. Gear ring; 7. Double helix mixing mechanism; 701. Helical shaft; 702. Channel A; 703. Helical blade; 704. Fixed ring; 705. Grinding wheel; 8. One-way valve nozzle; 9. Fixed pipe; 901. Channel B; 902. Channel C; 903. Channel D; 10. Drainage pipe; 11. Gas delivery mechanism; 111. Gas delivery pipe A; 112. Gas delivery pipe B; 113. Inlet pipe; 12. Piston group A; 121. Piston A; 122. Push rod A; 123. Slider; 13. Piston group B; 131. Piston B; 132. Push rod B; 133. Fixed block; 134. Sleeve; 14. Feed hopper. DETAILED DESCRIPTION

[0033] like Figures 1-9As shown, a mixing device for repairing saline-alkali land based on fly ash and a repair method thereof, comprising a bracket 1 and a mixing barrel 2 mounted on the bracket 1, the mixing barrel 2 is fixedly connected to the bracket 1, and the bottom end of the mixing barrel 2 is installed with a barrel bottom cover that can be opened and closed, characterized in that: a rotating part 3 is rotatably installed at one end of the mixing barrel 2, a stirring barrel 4 is fixedly installed inside the rotating part 3, one end of the mixing barrel 2 and the stirring barrel 4 are both conical, a feed hopper 14 is fixedly connected to the inside of the rotating part 3, one end of the feed hopper 14 is communicated with the stirring barrel 4, and fly ash is fed into the mixing barrel 4 through the feed hopper 14. The organic materials are fed into the stirring zone 404. The bottom end of the stirring barrel 4 is provided with a plurality of sieve holes 5. The stirring barrel 4 is provided with a cavity A401, a cavity B402, a cavity C403 and a stirring zone 404. The cavity C403 is connected to the stirring zone 404. The outer surface of the stirring barrel 4 and the inner bottom wall of the cavity A401 are set to be inclined. The upper surface of the stirring barrel 4 is provided with a feeding pipe, which is connected to the cavity A401. The chemical modifier is injected into the cavity A401 through the feeding pipe. The cavity A401 is used to load the chemical modifier. The stirring zone 404 is filled with the chemical modifier. When fly ash and organic materials are added, a stirring mechanism 6 for stirring is installed in the stirring zone 404. The stirring mechanism 6 includes a stirring rod 601, several groups of longitudinally distributed stirring blades 602, a motor, two gears 603 and a gear ring 604. The radius of the multiple groups of stirring blades 602 decreases in sequence. One end of the motor and the stirring rod 601 are both located in the cavity C403. The motor is rotatably connected to the stirring barrel 4, and the motor is fixed to one of the brackets 1 through a fixing frame. The output end of the motor is fixedly connected to one end of the stirring rod 601. Several stirring blades are connected to the stirring barrel 4. The rod 601 is fixedly connected, one of the gears 603 is fixedly connected to the stirring rod 601, and the other gear 603 is rotatably connected to the stirring barrel 4 through a rotating shaft, and is meshed with a gear ring 604. The gear ring 604 is fixedly connected to the stirring barrel 4, and the two gears 603 are meshed. The stirring rod 601 is driven to rotate by a motor, and the stirring rod 601 can drive several groups of stirring blades 602 to rotate to crush fly ash and organic materials. The stirring rod 601 can drive the stirring barrel 4 to rotate through the gear 603 and the gear ring 604, thereby improving the mixing efficiency.

[0034] A double-helix mixing mechanism 7 for mixing and stirring is installed in the mixing barrel 2. The double-helix mixing mechanism 7 includes two inclined spiral shafts 701 and two spiral blades 703 with opposite spiral directions. The length of one spiral shaft 701 is greater than that of the other spiral shaft 701. A channel A702 is provided inside the two spiral shafts 701. The outer surface of one of the spiral shafts 701 is connected to a plurality of one-way valve nozzles 8 for discharging the gas in one of the channels A702. A one-way valve A is installed at the bottom end of the other spiral shaft 701. The double-helix mixing mechanism 7 also includes an annular fixed ring 704 and two grinding wheels 705. The inner wall of the fixed ring 704 is anti-slip treated. The two grinding wheels 705 are fixedly connected to the two spiral shafts 701 respectively and are in close contact with the fixed ring 704. The two spiral shafts 701 make circular motion around the central axis of the mixing barrel 4 and rotate by the friction between the two grinding wheels 705 and the fixed ring 704.

[0035] Two fixed pipes 9 are fixedly installed on the outside of the mixing barrel 4, and one end of the two fixed pipes 9 is rotatably connected to the two spiral shafts 701 respectively. The two fixed pipes 9 are provided with channels B901, channel C902 and channel D903 which are connected in sequence. The two channels D903 are connected to the two channels A702 respectively. A drainage pipe 10 for draining the chemical modifier into one of the channels D903 is connected between the mixing barrel 4 and one of the fixed pipes 9. A gas delivery mechanism 11 for delivering gas to the other channel B901 is fixedly installed in the mixing barrel 4. The gas delivery mechanism 11 includes a gas delivery pipe A111, a gas delivery pipe B112 and an air inlet pipe 113. The gas delivery pipes A111 and B112 are both It is fixedly connected to the mixing barrel 4, and one end of the air supply pipe A111 is connected to one of the channels B901, and the other end is rotatably connected to the air inlet pipe 113. The other end of the air inlet pipe 113 is used to connect to an external air pump. The two ends of the air supply pipe B112 are respectively connected to the two channels B901. The air inlet pipe 113 is inflated by the air pump, so that the gas enters the air supply pipes A111 and B112, thereby moving the pistons A121 and B131. The air inlet pipe 113 is evacuated by the air pump, and the pistons A121 and B131 are reset. The two fixed tubes 9 are respectively installed with a piston group A12 for controlling the opening or closing of the drainage mechanism and an active member A12 for controlling the opening or closing of the air supply mechanism 11. Plug group B13, piston group A12 includes an integrally formed piston A121, a push rod A122 and a slider 123. The piston A121 is slidably connected to the channel D903 adjacent to it, and the two are in close contact. The slider 123 is slidably connected to the channel C902 adjacent to it. When the slider 123 contacts one of the inner side walls of the channel C902, the piston A121 can prevent the chemical modifier in the drainage tube 10 from entering the channel D903. When the slider 123 moves to contact the other inner side wall of the channel C902, the piston A121 can move accordingly and allow the chemical modifier in the drainage tube 10 to enter the channel D903. The piston group B13 includes a piston B131, a push rod B1 32. The fixed block 133, the sleeve 134 and the spring, the piston B131 is slidably connected to the channel B901 adjacent to it, and the two are in close contact. One end of the push rod B132 is fixedly connected to the piston B131, and the other end is slidably connected to the sleeve 134. The fixed block 133 is fixedly connected to the inner wall of the channel B901 adjacent to it. The fixed block 133 is fixedly connected to the sleeve 134. The two ends of the spring are fixedly connected to the fixed block 133 and the push rod B132 respectively. When the gas delivery mechanism 11 delivers the gas to the channel B and pushes the piston B131 to move into the channel C902, the gas passes through the channel B901, the channel C902 and the channel D903 in sequence and enters one of the channels A702.

[0036] A method for repairing saline-alkali land based on fly ash, comprising the following steps:

[0037] S1: Conduct a comprehensive test of the target saline-alkali land, including soil salt content, pH value, soil texture such as the ratio of sand, silt, and clay, nutrient status, nitrogen, phosphorus, potassium, and trace element content, and groundwater level parameters. Professional soil testing instruments and methods can be used, such as a conductivity meter to measure soil salinity, a pH meter to measure pH, and a soil texture analyzer to determine texture type, to obtain accurate data information. Based on the test results, the condition of the saline-alkali land can be assessed to determine its salinization degree, fertility level, and major problems, so as to formulate targeted remediation plans. For example, if the soil salt content is too high and is strongly alkaline, and nutrients are extremely scarce, it is necessary to focus on measures to reduce salinity, adjust pH, and supplement nutrients.

[0038] S2: Select fly ash from an appropriate source and ensure it meets relevant quality standards, such as heavy metal content. Screen the fly ash to remove large impurities and unburned carbon particles. Vibrating screen equipment can be used for screening to make the fly ash particles more uniform and fine, which is conducive to subsequent mixing with other materials and dispersion in the soil.

[0039] S3: Prepare organic materials, such as well-rotted compost, manure, or green manure. If compost is used, ensure it is fully decomposed to avoid fermentation and the production of harmful gases or the depletion of soil oxygen. Determine the degree of decomposition by measuring the temperature, odor, color, and texture of the compost. Crush the organic materials to a suitable particle size.

[0040] S4: Select appropriate chemical modifiers based on the test results of saline-alkali land. If the soil is too alkaline, gypsum calcium sulfate modifier can be used to neutralize the alkalinity. If the sodium ion content in the soil is too high, gypsum can also reduce the alkalinity of the soil through ion exchange. For some special cases, such as excessive heavy metal ions in the soil, corresponding chelating agents can be selected for treatment. At the same time, prepare other chemical reagents that may be needed, such as microbial agents used to regulate the soil microbial environment.

[0041] S5: Determine the mixing ratio of fly ash, organic materials and chemical modifiers according to the specific conditions of saline-alkali land. The amount of fly ash added can account for 30%-50% of the total mixed material, organic materials account for 30%-40%, and chemical modifiers account for 10%-20%.

[0042] When in use, firstly, fly ash is put into the mixing zone 404 of the mixing barrel 4 through the feed hopper 14, and then gas is injected into the air inlet pipe 113 through the air pump. The gas in the air inlet pipe 113 enters the air delivery pipe A111 and the air delivery pipe B112, and the gas in the air delivery pipe B112 enters the channel B901 near the piston group A12. At this time, the air pressure in the channel B901 increases, and the gas pushes the slider 123 to move, thereby moving the piston group A12. When the slider 123 of the piston group A12 moves to the position shown in FIG. Figure 4 When the position is shown, the slider 123 is against one side of the channel C902, so that the piston group A12 no longer moves. At this time, the piston A121 blocks the inlet end of the fixed tube 9 close to it, and then the chemical modifier is injected into the cavity A401 of the mixing barrel 4 through the feed pipe. The chemical modifier can be a gypsum calcium sulfate modifier. It should be noted that the liquid gypsum modifier can be prepared by dissolving gypsum powder in water. The solubility of gypsum in water is relatively low. At 20°C, the solubility of gypsum is about 0.2g / 100mL. In order to increase its solubility, the dissolution efficiency can be improved by heating and stirring. Then, a part of the liquid gypsum modifier will enter To the drainage tube 10, since the piston A121 blocks the inlet end of the fixed tube 9, the chemical modifier will not enter the fixed tube 9 through the inlet end of the fixed tube 9; since the gas in the gas pipe A111 will also enter another channel B901, by increasing the output power of the air pump, the gas can overcome the elastic force of the spring at the fixed block 133, the spring begins to compress, and the piston B131 moves. When the piston B131 moves to the channel C902 close to it, the gas passes through channel B901, channel C902, channel D903, and channel A702 of one of the spiral shafts 701 in turn, and the gas is ejected from several one-way valve nozzles 8.

[0043] Then, the motor is started to drive the stirring rod 601 to rotate, and the stirring rod 601 drives several groups of stirring blades 602 to rotate. The stirring blades 602 break up the fly ash, and the small particles of fly ash will fall into the mixing barrel 2 through the several sieve holes 5 at the bottom of the stirring barrel 4. The large particles and agglomerated fly ash remain in the stirring barrel 4 to continue to be broken or broken up, and then the organic material is put into the stirring zone 404 through the feed hopper 14 for breaking. The organic material can be decomposed compost, manure or green manure. Similarly, small particles of organic material will enter the mixing barrel 2 through the sieve holes 5. It should be noted that fly ash is easy to agglomerate in its natural state. This is because the fly ash particles are very fine and have a large specific surface area. There is a strong van der Waals force between the particles, which makes them attract each other and gather into agglomerates. Moreover, in During the production and storage process, fly ash may absorb moisture in the air, further aggravating the agglomeration phenomenon. The presence of these agglomerates will affect the performance of fly ash in saline-alkali land remediation. When used for saline-alkali land remediation, fly ash needs to be fully mixed with organic materials and chemical modifiers. If the fly ash is in an agglomerated state, it will lead to uneven mixing. For example, when mixed with organic materials, the agglomerated fly ash may not be well dispersed in the organic materials, resulting in too much fly ash in some areas and too little in other areas, requiring more time for mixing and stirring. Similarly, by breaking up and crushing the fly ash and organic materials, the mixing rate can be increased and the time required for mixing can be reduced. Moreover, the fly ash is evenly distributed in the soil, thereby improving the physical properties of the soil and creating good conditions for plant growth.

[0044] Next, when the stirring rod 601 rotates, it drives one of the gears 603 to rotate, and one of the gears 603 drives the other gear 603 to rotate. Since the gear 603 is engaged with the gear ring 604, the gear ring 604 can also rotate, and the gear ring 604 drives the stirring barrel 4 to rotate. During the rotation of the stirring barrel 4, since the inner bottom wall of the cavity A401 is inclined, the liquid improver inside it can be shaken during the rotation, thereby achieving the purpose of shaking and stirring, making it more uniform, which is conducive to subsequent uniform mixing, and the rotation process During the mixing process, centrifugal force is generated to accelerate the discharge of the material in the mixing barrel 4. At the same time, when the mixing barrel 4 rotates, it can drive the two fixed pipes 9 to rotate with the mixing barrel 4 as the center. The two fixed pipes 9 respectively drive the two spiral shafts 701 to move in a circular motion to fully mix and stir the materials. The two spiral shafts 701 can respectively drive the two grinding wheels 705 to rotate along the fixed ring 704 during the circular motion. The friction between the two grinding wheels 705 and the fixed ring 704 is used to make the two grinding wheels 705 rotate in the process of the circular motion, thereby making the two spiral shafts 701 move in a circular motion. As the rotating shaft 701 rotates, the two spiral shafts 701 respectively drive the two spiral blades 703 to rotate. Since the spiral directions of the two spiral blades 703 are opposite and they are arranged at an angle, on the one hand, the mixing area is more closely aligned with the mixing barrel 2. On the other hand, the two spiral shafts 701 generate axial driving forces in different directions on the material during rotation. When the two spiral shafts 701 work simultaneously, the material is forced to circulate up and down in the mixing barrel 2 under the action of two opposite axial forces. The longer spiral blades 703, due to their wider coverage, can more effectively transport the material at the bottom upward, while the shorter spiral blades 703 assist in pushing the material within a relatively shorter area, forming a more complex path for the material during the up and down circulation process. This up and down circulation flow can effectively prevent the material from accumulating at the bottom of the mixing barrel 2, ensuring that the material is fully mixed in the entire space, thereby shortening the mixing time. In addition, during the rotation of the spiral shaft 701, it also drives the rotation of several one-way valve nozzles 8. The gas ejected by the one-way valve nozzles 8 can blow away the fly ash, preventing the fly ash from agglomerating again in the mixing barrel 2, thereby further shortening the mixing time.

[0045] Then, after the fly ash and organic materials are mixed, the air inlet pipe 113 is evacuated by an air pump, which can be a dual-purpose pump for inflation and extraction. At this time, since the air pipe A111 and the air pipe B112 are connected, the air pipe A111 and the air pipe B112 are in a negative pressure state, and the elastic force of the spring pushes the push rod B132 and the piston B131 to reset. At this time, the one-way valve nozzle 8 stops working, and when the air pipe B112 is in a negative pressure state, the piston group is reset by the negative pressure. A12 is sucked to its original position, so that the slider 123 abuts against the other inner wall of the channel C902. At this time, the piston A121 opens the inlet end of the fixed pipe 9, so that the chemical improver in the cavity A401 passes through the drainage pipe 10, the channel B901 of the fixed pipe 9, and the channel A702 in sequence. At this time, the one-way valve opens, and the chemical improver flows out from the channel A702 of the shorter spiral shaft 701 and mixes with the fly ash and organic materials. The chemical modifier flows out of the end channel, which can accurately deliver the modifier to a specific area of ​​the mixing barrel 2. This area is usually the part where material mixing is relatively active, because the shorter spiral shaft 701 will also stir the surrounding materials when working. This can ensure that the chemical modifier quickly contacts the materials that are being vigorously mixed after being put in, and avoid the modifier from randomly diffusing in the mixing barrel 2, resulting in local excessive concentration or failure to participate in mixing in time, which is beneficial to improving the mixing efficiency of the chemical modifier with fly ash and organic materials. When the mixing is completed, the materials are discharged by opening the bottom cover of the mixing barrel 2. Since the added chemical modifier is liquid, some materials will adhere to the mixing barrel 2 after mixing. At this time, the one-way valve nozzle 8 sprays gas by inflating the air inlet pipe 113 through the air pump. During its circular rotation and self-rotation, it can clean the inner wall of the mixing barrel 2 and the outer side of the stirring barrel 4.

[0046] Finally, it should be noted that during the mixing process of the three materials, fly ash is added first, followed by organic materials, and finally chemical modifiers. Since fly ash and organic materials are mixed first, the sticky components in the organic materials, such as humus and cellulose, can be used to better aggregate the fly ash particles. The organic materials act as a binder, wrapping or connecting the fly ash particles to form a relatively stable aggregate structure. This aggregate structure helps to increase the porosity of the soil, improve the air permeability and water permeability of the soil, and provide a good physical environment for the subsequent growth of plant roots. Fly ash is prone to generate dust when it exists alone. After mixing with organic materials, its flying tendency will be effectively suppressed. At the same time, the structure of the mixed materials is relatively tight, which can reduce material loss and improve material utilization during transportation, storage and subsequent addition of chemical modifiers. Fly ash is generally alkaline, and organic materials will produce organic acids and other substances during the decomposition process. The mixture between them can buffer the pH to a certain extent. This acid-base buffering effect can make the pH change of the entire system more gradual when chemical modifiers are added later, avoiding the effectiveness of chemical modifiers affected by drastic changes in local pH, and is also conducive to maintaining a relatively stable chemical environment.

[0047] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for repairing saline-alkali land based on fly ash, characterized by: The invention relates to a mixing device for repairing saline-alkali land using fly ash, comprising a bracket and a mixing barrel mounted on the bracket, a rotating member rotatably mounted on one end of the mixing barrel, a stirring barrel fixedly mounted in the rotating member, a plurality of sieve holes provided at the bottom end of the stirring barrel, a cavity A, a cavity B, a cavity C and a stirring zone provided in the stirring barrel, cavity A being used to load a chemical improver, the stirring zone being used to add fly ash and organic materials, and a stirring mechanism being installed in the stirring zone for stirring; A double-helix mixing mechanism for mixing and stirring is installed in the mixing barrel. The double-helix mixing mechanism includes two inclined spiral shafts and two spiral blades with opposite spiral directions. The length of one spiral shaft is greater than that of the other spiral shaft. Channels A are provided inside both spiral shafts. The outer surface of one spiral shaft is connected to a plurality of one-way valve nozzles for discharging the gas in one of the channels A. A one-way valve A is installed at the bottom end of the other spiral shaft. Two fixed tubes are fixedly installed on the outside of the mixing barrel, one end of each of the two fixed tubes being rotatably connected to the two spiral shafts. Channels B, C, and D are sequentially connected in sequence in each of the two fixed tubes. The two channels D are connected to the two channels A respectively. A drainage tube for draining the chemical modifier into one of the channels D is connected between the mixing barrel and one of the fixed tubes. A gas transmission mechanism for conveying gas to the other channel B is fixedly installed in the mixing barrel. A piston group A for controlling the opening or closing of the drainage mechanism and a piston group B for controlling the opening or closing of the gas transmission mechanism are respectively installed in the two fixed tubes. The following steps are also included: S1: Conduct a comprehensive test of the target saline-alkali land, including soil salt content, pH, soil texture, nutrient status, and groundwater level parameters. Based on the test results, assess the condition of the saline-alkali land to determine its degree of salinization, fertility level, and major problems. S2: Select fly ash from appropriate sources, ensure it meets relevant quality standards, and screen the fly ash to remove large particles of impurities and unburned carbon particles; S3: Prepare organic materials, such as well-rotted compost, manure, or green manure. If compost is used, ensure it is fully decomposed to avoid fermentation and the production of harmful gases or the depletion of soil oxygen. Determine the degree of decomposition by measuring the temperature, odor, color, and texture of the compost. Crush the organic materials to a suitable particle size. S4: Select appropriate chemical amendments based on the test results of saline-alkali land. If the soil is too alkaline, choose gypsum amendment to neutralize the alkalinity. For some special cases, such as when the soil contains too many heavy metal ions, choose corresponding chelating agents for treatment; S5: Determine the mixing ratio of fly ash, organic materials and chemical modifiers according to the specific conditions of the saline-alkali land. During the mixing process of the three materials, add fly ash first, then add organic materials, and finally add chemical modifiers.

2. The method for repairing saline-alkali land using fly ash according to claim 1, characterized in that: One end of the mixing barrel and the stirring barrel are both conical.

3. The method for repairing saline-alkali land using fly ash according to claim 1, characterized in that: The inner bottom wall of the cavity A is set to be inclined, and a feeding pipe is installed on the upper surface of the mixing barrel, and the feeding pipe is connected to the cavity A.

4. The method for repairing saline-alkali land using fly ash according to claim 1, characterized in that: The stirring mechanism includes a stirring rod, several groups of longitudinally distributed stirring blades, a motor, two gears and a gear ring. The radius of the multiple groups of stirring blades decreases successively. One end of the motor and the stirring rod are both located in the cavity C. The motor is rotatably connected to the stirring barrel, and the motor is fixed to one of the brackets through a fixed frame. The output end of the motor is fixedly connected to one end of the stirring rod. Several stirring blades are fixedly connected to the stirring rod, one of the gears is fixedly connected to the stirring rod, and the other gear is rotatably connected to the stirring barrel through a rotating shaft and is meshed with the gear ring. The gear ring is fixedly connected to the stirring barrel, and the two gears are meshed.

5. The method for repairing saline-alkali land using fly ash according to claim 1, characterized in that: The piston assembly A includes an integrally formed piston A, a push rod A and a slider. The piston A is slidably connected to a channel D adjacent to the piston A and the two are in close contact. The slider is slidably connected to a channel C adjacent to the piston A.

6. The method for repairing saline-alkali land using fly ash according to claim 1, characterized in that: The piston group B includes a piston B, a push rod B, a fixed block, a sleeve and a spring. The piston B is slidably connected to the channel B adjacent to it, and the two are in close contact. One end of the push rod B is fixedly connected to the piston B, and the other end is slidably connected to the sleeve. The fixed block is fixedly connected to the inner wall of the channel B adjacent to it, the fixed block is fixedly connected to the sleeve, and the two ends of the spring are fixedly connected to the fixed block and the push rod B respectively.

7. The method for repairing saline-alkali land using fly ash according to claim 1, characterized in that: The gas supply mechanism includes an air supply pipe A, an air supply pipe B and an air intake pipe. The air supply pipe A and the air supply pipe B are both fixedly connected to the mixing barrel, and one end of the air supply pipe A is connected to one of the channels B, and the other end is rotatably connected to the air intake pipe. The other end of the air intake pipe is used to connect to an external air pump, and the two ends of the air supply pipe B are respectively connected to the two channels B.

8. The method for repairing saline-alkali land using fly ash according to claim 1, characterized in that: The double-helix mixing mechanism also includes an annular fixed ring and two grinding wheels. The inner wall of the fixed ring is anti-slip treated. The two grinding wheels are fixedly connected to the two spiral shafts respectively and are in close contact with the fixed ring.

9. The method for repairing saline-alkali land using fly ash according to claim 1, characterized in that: A feed hopper is fixedly connected to the interior of the rotating member, and one end of the feed hopper is communicated with the mixing barrel.

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