Mixing device for repairing saline-alkali soil based on fly ash and repairing method thereof

Abstract

The invention 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 by fly ash. The mixing device for repairing the saline-alkali soil based on the fly ash comprises a support and a mixing barrel installed on the support, a rotating part is rotatably installed at one end of the mixing barrel, a stirring barrel is fixedly installed in the rotating part, a plurality of screening holes are formed in the bottom end of the stirring barrel, and a cavity A, a cavity B, a cavity C and a stirring area are formed in the stirring barrel; a cavity A, a cavity B, a cavity C and a stirring area are formed in the stirring barrel, and the cavity A is used for containing a chemical modifier. According to the mixing device for repairing the saline-alkali soil based on the fly ash and the repairing method thereof, before being mixed, the materials can be smashed and dispersed, the mixing effect is improved, and the three materials are sequentially added according to a certain sequence; the mixing efficiency can be further improved, the mixing time can be shortened, and the mixing barrel can be cleaned after materials are discharged after mixing is completed.

Description

Technical Field

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

[0002] Saline-alkali land is a type of land that widely exists and severely restricts agricultural production and the improvement of the ecological environment. Its soil contains high concentrations of salts such as sodium chloride and sodium sulfate, as well as alkaline substances such as sodium carbonate and sodium bicarbonate. These substances cause the physical, chemical, and biological properties of the soil to deteriorate. 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 air and water permeability, and low microbial activity, which greatly limits 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 and other facilities. Its output is huge and increasing year by year. Fly ash contains various nutrient elements required for plant growth, such as silicon, aluminum, iron, and calcium. Its particles have a certain adsorption capacity and the ability to improve soil structure. Applying fly ash to the repair of saline-alkali land has many advantages: on the one hand, components such as silicate in fly ash can undergo ion exchange reactions with salts in the soil, reducing the content of harmful salts such as sodium ions in the soil and improving the chemical properties of the soil; on the other hand, the fine particles of fly ash can fill soil pores, improving the air and water permeability and aggregate structure of the soil, which is beneficial to microbial activities and the growth of plant roots. The improvement of saline-alkali land is of great significance for improving land utilization efficiency, ensuring the sustainable development of agriculture, and improving the ecological environment. Among many saline-alkali land improvement methods, mixing fly ash with organic materials (such as compost, green manure, etc.) and chemical modifiers (such as gypsum, sulfur, etc.) is a relatively effective approach.

[0003] The traditional mixing device for mixing fly ash and organic materials is a simple stirring mixer. During operation, the motor drives the stirring shaft to rotate, and the stirring blades rotate accordingly, thereby stirring and mixing the fly ash and organic materials placed in the stirring barrel. Since fly ash particles are fine and light in texture, and organic materials often have irregular shapes, different sizes, and certain fibrous properties, during the stirring process, due to the relatively single stirring method of the stirring blades, it takes more time to quickly and fully mix these materials with greatly different physical properties, resulting in a longer mixing time and affecting the subsequent work process. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a mixing device and a repairing method for repairing saline-alkali land based on fly ash, which solve the problems raised in the above background art.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: A mixing device for repairing saline-alkali soil based on fly ash 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 member, and a stirring barrel is fixedly installed inside the rotating member. A plurality of screening holes are provided at the bottom end of the stirring barrel. Inside the stirring barrel, there are cavity A, cavity B, cavity C and a stirring area. Cavity A is used to load chemical modifiers, and fly ash and organic materials are added to the stirring area. A stirring mechanism for stirring is installed in the stirring area.

[0006] A double-helix mixing mechanism for mixing and stirring is installed inside 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 of the two spiral shafts. A plurality of one-way valve jet heads for discharging the gas inside one of the channels A are communicated with the outer surface of one of the spiral shafts. A one-way valve A is installed at the bottom end of the other spiral shaft.

[0007] Two fixed pipes are fixedly installed on the outer side of the stirring barrel. One end of each of the two fixed pipes is rotatably connected to the two spiral shafts respectively. Inside both of the two fixed pipes, there are sequentially communicated channels B, C and D. The two channels D are respectively communicated with the two channels A. A drain pipe for guiding the chemical modifier to one of the channels D is communicated between the stirring barrel and one of the fixed pipes. An air delivery mechanism for delivering gas to the other channel B is fixedly installed inside the stirring barrel. Inside the two fixed pipes, 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 air delivery mechanism are respectively installed.

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

[0009] Preferably, the inner bottom wall of cavity A is inclined. A feed pipe is installed on the upper surface of the stirring barrel, and the feed pipe is communicated with cavity A.

[0010] Preferably, the stirring mechanism includes a stirring rod, several groups of longitudinally distributed stirring blades, a motor, two gears and a toothed ring. The radii of the multiple groups of stirring blades decrease in sequence. One end of both the motor and the stirring rod is located inside cavity C. The motor is rotatably connected to the stirring barrel, and the motor is fixed to one of the brackets through a fixing frame. The output end of the motor is fixedly connected to one end of the stirring rod. A plurality of stirring blades are all fixedly connected to the stirring rod. One of the gears is fixedly connected to the stirring rod. The other gear is rotatably connected to the stirring barrel through a rotating shaft and is meshed with the toothed ring. The toothed ring is fixedly connected to the stirring barrel, and the two gears are meshed with each other.

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

[0012] Preferably, the piston group B includes a piston B, a push rod B, a fixing block, a sleeve, and a spring. The piston B is slidably connected to the adjacent channel B, 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 fixing block is fixedly connected to the inner wall of the adjacent channel B, the fixing block is fixedly connected to the sleeve, and the two ends of the spring are respectively fixedly connected to the fixing block and the push rod B.

[0013] Preferably, the air delivery mechanism includes an air delivery pipe A, an air delivery pipe B, and an air inlet pipe. The air delivery pipe A and the air delivery pipe B are both fixedly connected to the stirring barrel. One end of the air delivery pipe A is communicated with one of the channels B, and the other end is rotatably connected to the air inlet pipe. The other end of the air inlet pipe is used to be connected to an external air pump. The two ends of the air delivery pipe B are respectively communicated with the two channels B.

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

[0015] Preferably, a feed hopper is fixedly connected inside the rotating member, and one end of the feed hopper is communicated with the stirring barrel.

[0016] A restoration method for saline - alkali land based on fly ash includes the following steps:

[0017] S1: Conduct a comprehensive detection of the target saline - alkali land, including parameters such as soil salt content, pH value, soil texture (such as the proportion of sand, silt, and clay particles), nutrient status (nitrogen, phosphorus, potassium, and trace element content), and groundwater level. Evaluate the condition of the saline - alkali land according to the detection results to determine its salinization degree, fertility level, and the main existing problems.

[0018] S2: Select fly ash from a suitable source to ensure it meets relevant quality standards, and screen the fly ash to remove large - particle impurities and unburned carbon particles.

[0019] S3: Prepare organic materials, such as well - decomposed compost, manure, or green manure. If it is compost, ensure it is fully decomposed to avoid generating harmful gases or consuming soil oxygen during fermentation in the soil. Judge its decomposition degree by detecting indicators such as the temperature, smell, color, and texture of the compost, and crush the organic materials to make their particle sizes appropriate.

[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 improvers 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 and the restoration method based on fly ash for restoring saline-alkali land, through the provided stirring mechanism, can break 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 improvers; through the provided double-helix mixing mechanism, the mixing efficiency can be further improved, and the mixing time can be shortened; 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 improver can be automatically added; and after the mixing is completed and the materials are discharged, the mixing barrel can also be fully 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 enlargement in the middle;

[0027] Figure 5 For the present invention Figure 3 A magnified schematic diagram of the structure at 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] Wherein: 1. Support; 2. Mixing barrel; 3. Rotating member; 4. Stirring barrel; 401. Cavity A; 402. Cavity B; 403. Cavity C; 404. Stirring area; 5. Screening hole; 6. Stirring mechanism; 601. Stirring rod; 602. Stirring blade; 603. Gear; 604. Tooth ring; 7. Double - helix mixing mechanism; 701. Spiral shaft; 702. Channel A; 703. Spiral blade; 704. Fixed ring; 705. Grinding wheel; 8. One - way valve jet head; 9. Fixed pipe; 901. Channel B; 902. Channel C; 903. Channel D; 10. Drainage pipe; 11. Gas - conveying mechanism; 111. Gas - conveying pipe A; 112. Gas - conveying pipe B; 113. Inlet pipe; 12. Piston group A; 121. Piston A; 122. Push rod A; 123. Slide block; 13. Piston group B; 131. Piston B; 132. Push rod B; 133. Fixed block; 134. Sleeve; 14. Feed hopper. Detailed implementation mode

[0033] Such as Figures 1-9As shown in the figure, a mixing device for repairing saline-alkali land based on fly ash and its repair method include a bracket 1 and a mixing barrel 2 installed on the bracket 1. The mixing barrel 2 is fixedly connected to the bracket 1. The bottom end of the mixing barrel 2 is provided with a bottom cover that can be opened and closed. It is characterized in that: a rotating member 3 is rotatably installed at one end of the mixing barrel 2, and a stirring barrel 4 is fixedly installed inside the rotating member 3. One end of both the mixing barrel 2 and the stirring barrel 4 is conical. An inlet hopper 14 is fixedly connected inside the rotating member 3. One end of the inlet hopper 14 communicates with the stirring barrel 4. Fly ash and organic materials are fed into the stirring area 404 through the inlet hopper 14. A number of screening holes 5 are provided at the bottom end of the stirring barrel 4. Inside the stirring barrel 4, there are a cavity A401, a cavity B402, a cavity C403 and a stirring area 404. The cavity C403 communicates with the stirring area 404. On the outer surface of the stirring barrel 4, the inner bottom wall of the cavity A401 is inclined. A feed pipe is installed on the upper surface of the stirring barrel 4, and the feed pipe communicates with the cavity A401. Chemical improvers are injected into the cavity A401 through the feed pipe. The cavity A401 is used to hold chemical improvers. The stirring area 404 is used to add fly ash and organic materials. A stirring mechanism 6 for stirring is installed in the stirring area 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 toothed ring 604. The radii of multiple groups of stirring blades 602 decrease in sequence. One end of both the motor and the stirring rod 601 is located inside the cavity C403. The motor is rotatably connected to the stirring barrel 4, and the motor is fixedly connected 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. A number of stirring blades are all fixedly connected to the stirring rod 601. One of the gears 603 is fixedly connected to the stirring rod 601. The other gear 603 is rotatably connected to the stirring barrel 4 through a rotating shaft and is meshed with the toothed ring 604. The toothed ring 604 is fixedly connected to the stirring barrel 4. The two gears 603 are meshed with each other. By driving the stirring rod 601 to rotate through the motor, the stirring rod 601 can drive several groups of stirring blades 602 to rotate, smashing the fly ash and organic materials. The stirring rod 601 can also drive the stirring barrel 4 to rotate through the gears 603 and the toothed ring 604, improving the mixing and stirring 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 screw shafts 701 and two screw blades 703 with opposite screw directions. The length of one screw shaft 701 is greater than that of the other screw shaft 701. Channels A702 are provided inside both screw shafts 701. A number of one - way valve jet heads 8 for discharging the gas in one of the channels A702 are connected to the outer surface of one of the screw shafts 701. A one - way valve A is installed at the bottom of the other screw shaft 701. The double - helix mixing mechanism 7 also includes an annular fixing ring 704 and two grinding wheels 705. The inner wall of the fixing ring 704 is treated with anti - slip. The two grinding wheels 705 are respectively fixedly connected to the two screw shafts 701 and are in close contact with the fixing ring 704. The two screw shafts 701 move in a circular motion around the central axis of the mixing barrel 4 and achieve self - rotation through the frictional force between the two grinding wheels 705 and the fixing ring 704;

[0035] Two fixed pipes 9 are fixedly installed on the outer side of the stirring barrel 4. One end of each of the two fixed pipes 9 is rotatably connected to two screw shafts 701 respectively. In each of the two fixed pipes 9, there are successively connected channels B901, channels C902 and channels D903. The two channels D903 are respectively connected to the two channels A702. A drainage pipe 10 for draining the chemical improver into one of the channels D903 is connected between the stirring barrel 4 and one of the fixed pipes 9. An air delivery mechanism 11 for delivering gas into the other channel B901 is fixedly installed in the stirring barrel 4. The air delivery mechanism 11 includes an air delivery pipe A111, an air delivery pipe B112 and an air inlet pipe 113. The air delivery pipe A111 and the air delivery pipe B112 are both fixedly connected to the stirring barrel 4. One end of the air delivery 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 be connected to an external air pump. The two ends of the air delivery pipe B112 are respectively connected to the two channels B901. By inflating the air inlet pipe 113 with an air pump, gas enters the air delivery pipe A111 and the air delivery pipe B112, so that the piston A121 and the piston B131 move. By pumping air from the air inlet pipe 113 with an air pump, the piston A121 and the piston B131 are reset. In the two fixed pipes 9, a piston group A12 for controlling the opening or closing of the drainage mechanism and a piston group B13 for controlling the opening or closing of the air delivery mechanism 11 are respectively installed. The 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 close to it, and the two are in close contact. The slider 123 is slidably connected to the channel C902 close to it. When the slider 123 contacts one inner side wall of the channel C902, the piston A121 can prevent the chemical improver in the drainage pipe 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 the chemical improver in the drainage pipe 10 enters the channel D903. The piston group B13 includes a piston B131, a push rod B132, a fixed block 133, a sleeve 134 and a spring. The piston B131 is slidably connected to the channel B901 close 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 close to it. The fixed block 133 is fixedly connected to the sleeve 134. The two ends of the spring are respectively fixedly connected to the fixed block 133 and the push rod B132. When the air delivery mechanism 11 delivers gas into the passage B and pushes the piston B131 to move into the channel C902, the gas successively passes through the channel B901, the channel C902 and the channel D903 and enters one of the channels A702.

[0036] A remediation method for remediating saline-alkali land based on fly ash includes the following steps:

[0037] S1: Conduct a comprehensive detection of the target saline-alkali land, including parameters such as soil salt content, pH value, soil texture (such as the proportion of sand, silt, and clay particles), nutrient status (nitrogen, phosphorus, potassium, and trace element content), and groundwater level. Professional soil detection instruments and methods can be used. For example, an electrical conductivity meter can be used to measure soil salt content, a pH meter to measure pH value, and a soil texture analyzer to determine the texture type to obtain accurate data information. Evaluate the condition of the saline-alkali land based on the detection results to determine its salinization degree, fertility level, and main existing problems, so as to formulate a targeted restoration plan. For example, if the soil salt content is too high and strongly alkaline, and the nutrients are extremely scarce, measures to reduce salt, adjust pH value, and supplement nutrients need to be considered emphatically;

[0038] S2: Select fly ash from a suitable source to ensure that it meets relevant quality standards, such as non-exceeding heavy metal content, and screen the fly ash to remove large particle impurities and unburned carbon particles. A vibrating screen device can be used for screening to make the fly ash particles more uniform and delicate, which is beneficial for 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 it is compost, ensure that it is fully rotted to avoid generating harmful gases or consuming soil oxygen during fermentation in the soil. Judge the degree of rotting by detecting indicators such as the temperature, smell, color, and texture of the compost, and crush the organic materials to make their particle sizes appropriate;

[0040] S4: Select a suitable chemical modifier according to the detection results of the saline-alkali land. If the soil is too alkaline, gypsum (calcium sulfate) modifier can be selected 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 situations, such as the soil containing excessive heavy metal ions, corresponding chelating agents can be selected for treatment. At the same time, prepare other chemical reagents that may be needed, such as microbial agents for adjusting the soil microbial environment.

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

[0042] In use, first, fly ash is put into the stirring area 404 of the stirring barrel 4 through the feed hopper 14. Then, gas is injected into the intake pipe 113 through an air pump. The gas in the intake pipe 113 enters the gas transmission pipe A111 and the gas transmission pipe B112. The gas in the gas transmission pipe B112 enters the passage B901 near the piston group A12. At this time, the air pressure in the passage B901 increases, and the gas pushes the slider 123 to move, thereby causing the piston group A12 to move. When the slider 123 of the piston group A12 moves to the position as shown in Figure 4 When it reaches the position shown, the slider 123 abuts against one side surface of the passage C902, so that the piston group A12 stops moving. At this time, the piston A121 blocks the inlet end of the fixed pipe 9 close to it. Then, the chemical modifier is injected into the cavity A401 of the stirring 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 0.2 g / 100 mL. To increase its solubility, the dissolution efficiency can be improved by heating and stirring. Then, a part of the liquid gypsum modifier will enter the drainage pipe 10. Since the piston A121 blocks the inlet end of the fixed pipe 9, the chemical modifier will not enter the fixed pipe 9 through the inlet end of the fixed pipe 9. Since the gas in the gas transmission pipe A111 will also enter another passage 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 starts to compress, and the piston B131 moves. When the piston B131 moves into the passage C902 close to it, the gas passes through the passage B901, the passage C902, the passage D903, and the passage A702 of one of the spiral shafts 701 in sequence, and gas is ejected from several one-way valve jet heads 8.

[0043] Then, start the motor to drive the stirring rod 601 to rotate. The stirring rod 601 drives several groups of stirring blades 602 to rotate. The stirring blades 602 disperse the fly ash. The small-particle fly ash will fall into the mixing barrel 2 through several screening holes 5 at the bottom of the stirring barrel 4. The large-particle and agglomerated fly ash remains in the stirring barrel 4 to be further broken or dispersed. Then, the organic material is put into the stirring area 404 through the feed hopper 14 for crushing. The organic material can be decomposed compost, manure or green manure. Similarly, the small-particle organic material will enter the mixing barrel 2 through the screening holes 5. It should be noted that fly ash is prone to agglomeration in its natural state because the fly ash particles are very fine, with a large specific surface area, and there is a strong van der Waals force between the particles, causing them to attract each other and agglomerate. Moreover, during the production and storage processes, fly ash may absorb moisture in the air, further exacerbating the agglomeration phenomenon. The existence of these agglomerates will affect the performance of fly ash in saline-alkali land restoration. When used for saline-alkali land restoration, it is necessary to fully mix fly ash with organic materials and chemical improvers. If the fly ash is in an agglomerated state, it will lead to uneven mixing. For example, when mixing 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, and more time is required for mixing and stirring. Similarly, by dispersing and crushing fly ash and organic materials, the mixing rate can be increased, the mixing time required can be reduced, and 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 will drive one of the gears 603 to rotate. One of the gears 603 drives the other gear 603 to rotate. Since the gear 603 meshes with the toothed ring 604, the toothed ring 604 can also rotate. The toothed ring 604 drives the mixing barrel 4 to rotate. During the rotation of the mixing barrel 4, since the inner bottom wall of the cavity A401 is inclined, the liquid modifier inside it can shake during the rotation, so as to achieve the purpose of shaking and stirring, making it more uniform, which is beneficial to subsequent uniform mixing. Moreover, during the rotation process, centrifugal force will be generated to accelerate the discharge of the materials 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 around 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. During the circular motion of the two spiral shafts 701, they can respectively drive the two grinding wheels 705 to rotate along the fixed ring 704. By using the frictional force between the two grinding wheels 705 and the fixed ring 704, the two grinding wheels 705 can rotate during the circular motion, and then the two spiral shafts 701 rotate. 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 inclined, on the one hand, it makes the stirring area more conform to the mixing barrel 2, and on the other hand, it makes the two spiral shafts 701 generate axial driving forces in different directions on the materials when rotating. When the two spiral shafts 701 work simultaneously, the materials will be forced to circulate up and down in the mixing barrel 2 under the action of two opposite axial forces. The longer spiral blade 703 can more effectively transport the materials at the bottom upward because it covers a wider range, while the short spiral blade 703 assists in pushing the materials in a relatively shorter area, making the materials form a more complex path during the up and down circulation. This up and down circulating flow can effectively prevent the materials from accumulating at the bottom of the mixing barrel 2, ensuring that the materials are fully mixed in the whole space, shortening the mixing time. Moreover, during the rotation of the spiral shaft 701, it will also drive a number of one-way valve jet heads 8 to rotate. The gas ejected by the one-way valve jet heads 8 can disperse the fly ash, preventing the fly ash from agglomerating again in the mixing barrel 2, thus further shortening the mixing time.

[0045] Then, after the fly ash and the organic materials are mixed, the air inlet pipe 113 is evacuated by an air pump, which can be a dual-purpose air inflation and evacuation pump. At this time, since the air delivery pipe A111 and the air delivery pipe B112 are connected, the air delivery pipe A111 and the air delivery pipe B112 are in a negative pressure state. The elastic force of the spring pushes the push rod B132 and the piston B131 to reset. At this time, the one-way valve jet head 8 stops working. When the air delivery pipe B112 is in a negative pressure state, the piston group A12 is sucked back to its original position by using its negative pressure, so that the slider 123 abuts against the other inner side wall of the channel C902. At this time, the piston A121 opens the inlet end of the fixed pipe 9, so that the chemical modifier 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 modifier flows out from the channel A702 of the shorter spiral shaft 701 and is mixed with the fly ash and the organic materials. Since the chemical modifier flows out from the bottom channel of the shorter spiral shaft 701, the modifier can be accurately delivered to a specific area of the mixing barrel 2, which is usually the relatively active part of the material mixing. Because the shorter spiral shaft 701 also agitates the surrounding materials during operation, this can ensure that the chemical modifier quickly contacts the materials that are being vigorously mixed after being put in, avoiding the situation that the modifier diffuses randomly in the mixing barrel 2, resulting in too high local concentration or failure to participate in the mixing in time, which is beneficial to improving the mixing efficiency of the chemical modifier with the fly ash and the 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, after mixing, some materials will adhere to the inside of the mixing barrel 2. At this time, the one-way valve jet head 8 is made to eject gas by inflating the air inlet pipe 113 through the air pump. During its circumferential rotation and self-rotation, the inner wall of the mixing barrel 2 and the outer side surface of the stirring barrel 4 can be cleaned.

[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 the chemical modifier is added; since the prior mixing of fly ash and organic materials can utilize the viscous components in the organic materials, such as humus and cellulose, to make the fly ash particles better agglomerate together. The organic materials act as a binder to wrap or connect the fly ash particles, forming a relatively stable agglomerate structure. This agglomerate 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. When fly ash exists alone, it is prone to generate dust. After being mixed with organic materials, its tendency to fly will be effectively inhibited. At the same time, the structure of this mixed material is relatively compact, and during the processes of transportation, storage, and subsequent addition of the chemical modifier, the loss of materials can be reduced, and the utilization rate of materials can be improved. Fly ash is generally alkaline, while organic materials will produce substances such as organic acids during decomposition. Their mixing can buffer the pH value to a certain extent. This acid-base buffering effect can make the change in the pH value of the entire system more gentle when the chemical modifier is added subsequently, avoiding the influence on the effectiveness of the chemical modifier due to a sharp change in the local pH value, and also being beneficial to maintaining a relatively stable chemical environment.

[0047] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A mixing device for repairing saline-alkali land based on fly ash, comprising a bracket (1) and a mixing barrel (2) installed on the bracket (1), characterized in that: One end of the mixing barrel (2) is rotatably installed with a rotating member (3), and a stirring barrel (4) is fixedly installed inside the rotating member (3). A plurality of screening holes (5) are provided at the bottom end of the stirring barrel (4). Inside the stirring barrel (4), there are a cavity A (401), a cavity B (402), a cavity C (403), and a stirring area (404). The cavity A (401) is used to load chemical modifiers, and fly ash and organic materials are added into the stirring area (404). A stirring mechanism (6) for stirring is installed in the stirring area (404). A double - helix mixing mechanism (7) for mixing and stirring is installed inside 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). Channels A (702) are provided inside both of the two spiral shafts (701). A plurality of one - way valve jet heads (8) for discharging the gas in one of the channels A (702) are communicated with the outer surface of one of the spiral shafts (701), and a one - way valve A is installed at the bottom end of the other spiral shaft (701). Two fixed pipes (9) are fixedly installed on the outer side of the stirring barrel (4). One end of each of the two fixed pipes (9) is rotatably connected to the two spiral shafts (701) respectively. Inside each of the two fixed pipes (9), there are successively communicated channels B (901), channels C (902), and channels D (903). The two channels D (903) are respectively communicated with the two channels A (702). A drainage pipe (10) for guiding the chemical modifier into one of the channels D (903) is communicated between the stirring barrel (4) and one of the fixed pipes (9). An air - conveying mechanism (11) for conveying gas into the other channel B (901) is fixedly installed inside the stirring barrel (4). Piston groups A (12) for controlling the opening or closing of the drainage mechanism and piston groups B (13) for controlling the opening or closing of the air - conveying mechanism (11) are installed inside the two fixed pipes (9) respectively.

2. The hybrid device for repairing saline-alkali soil based on fly ash according to claim 1, characterized in that: One end of both the mixing barrel (2) and the stirring barrel (4) is conical in shape.

3. The hybrid device for repairing saline-alkali land based on fly ash according to claim 1, characterized in that: The inner bottom wall of the cavity A (401) is inclined. A feed pipe is installed on the upper surface of the stirring barrel (4), and the feed pipe is communicated with the cavity A (401).

4. A mixing device for repairing saline-alkali land based on fly ash according to claim 1, characterized in that: The stirring mechanism (6) includes a stirring rod (601), several groups of longitudinally distributed stirring blades (602), a motor, two gears (603) and a toothed ring (604). The radii of multiple groups of stirring blades (602) decrease in sequence. One end of the motor and the stirring rod (601) are both located in the cavity C (403). The motor is rotationally 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 all fixedly connected to the stirring rod (601). One of the gears (603) is fixedly connected to the stirring rod (601), and the other gear (603) is rotationally connected to the stirring barrel (4) through a rotating shaft and is meshed with the toothed ring (604). The toothed ring (604) is fixedly connected to the stirring barrel (4). The two gears (603) are meshed with each other.

5. The mixing device for repairing saline-alkali land based on fly ash according to claim 1, wherein: The piston group A (12) includes a piston A (121), a push rod A (122) and a slider (123) which are integrally formed. The piston A (121) is slidably connected to the adjacent channel D (903), and they are in close contact. The slider (123) is slidably connected to the adjacent channel C (902).

6. The hybrid device for repairing saline-alkali land based on fly ash according to claim 1, characterized in that: The piston group B (13) includes a piston B (131), a push rod B (132), a fixed block (133), a sleeve (134) and a spring. The piston B (131) is slidably connected to the adjacent channel B (901), and they are in close contact. One end of the push rod B (132) is fixedly connected to the piston B (131), and the other end is slidably connected to the sleeve (134). The fixed block (133) is fixedly connected to the inner wall of the adjacent channel B (901). The fixed block (133) is fixedly connected to the sleeve (134). The two ends of the spring are respectively fixedly connected to the fixed block (133) and the push rod B (132).

7. A mixing device for repairing saline-alkali land based on fly ash according to claim 1, characterized in that: The air delivery mechanism (11) includes an air delivery pipe A (111), an air delivery pipe B (112) and an air inlet pipe (113). The air delivery pipe A (111) and the air delivery pipe B (112) are both fixedly connected to the stirring barrel (4). One end of the air delivery pipe A (111) is communicated with one of the channels B (901), and the other end is rotationally connected to the air inlet pipe (113). The other end of the air inlet pipe (113) is used for connecting to an external air pump. The two ends of the air delivery pipe B (112) are respectively communicated with two channels B (901).

8. The mixing device for repairing saline-alkali land based on fly ash according to claim 1, characterized in that: The double - helix mixing mechanism (7) further includes an annular fixed ring (704) and two grinding wheels (705). The inner wall of the fixed ring (704) is treated with anti - slip. The two grinding wheels (705) are respectively fixedly connected to the two spiral shafts (701) and are both in close contact with the fixed ring (704).

9. A mixing device for repairing saline-alkali land based on fly ash according to claim 1, characterized in that: The inside of the rotating member (3) is fixedly connected with a feed hopper (14). One end of the feed hopper (14) is communicated with the stirring barrel (4).

10. A remediation method for saline-alkali soil based on fly ash according to claim 1, characterized in that: Including the mixing device for repairing saline - alkali land based on fly ash according to any one of claims 1 - 9, comprising the following steps: S1: Conduct a comprehensive detection of the target saline-alkali land, including parameters such as soil salt content, pH value, soil texture (such as the proportion of sand, silt, and clay particles), nutrient status (nitrogen, phosphorus, potassium, and trace element content), and groundwater level. Evaluate the condition of the saline-alkali land based on the detection results to determine its salinization degree, fertility level, and the main existing problems; S2: Select fly ash from a suitable source to ensure it meets the relevant quality standards, and screen the fly ash to remove large particle impurities and unburned carbon particles; S3: Prepare organic materials, such as well-rotted compost, manure, or green manure. If it is compost, ensure it is fully rotted to avoid generating harmful gases or consuming soil oxygen during fermentation in the soil. Judge its degree of rotting by detecting indicators such as the temperature, smell, color, and texture of the compost, and crush the organic materials to make their particle size appropriate; S4: Select a suitable chemical modifier according to the detection results of the saline-alkali land. If the soil alkalinity is too strong, gypsum (calcium sulfate) modifier can be selected to neutralize the alkalinity. For some special cases, such as excessive heavy metal ions in the soil, corresponding chelating agents can be selected 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.

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