Slurry flocculation filter-press dehydration treatment device and dehydration method

Abstract

The invention discloses a mud flocculation filter-press dehydration treatment device and a dehydration method, the treatment device is formed by sequentially connecting a vibration screening device, a flocculation stirring cavity and a filter-press dehydration device, and the flocculation stirring cavity is connected with a flocculant grouting device through a grouting pipe; according to the dehydration method, the coagulation filter-press dehydration treatment device is adopted, the slurry can be subjected to suction filtration and screening, meanwhile, the requirement of a flocculant is effectively controlled, the stirring speed is controlled to achieve sufficient stirring, and under the action of a water suction pump, the slurry subjected to sufficient flocculation and stirring can be conveyed to a filter-press integrated space to be subjected to efficient filter-press dehydration to form a mud cake to be conveyed out of a site; the method has the advantages of high efficiency, convenience, high controllability and the like.

Description

Technical Field

[0001] The invention relates to a mud flocculation filter pressing dehydration treatment device and also relates to a dehydration method using the device. Background Art

[0002] Mud is an indispensable engineering material in engineering construction. It is mainly made of water, bentonite and admixtures. Its water content is generally 70-80%. It is widely used in bored pile and shield tunneling construction, playing the role of wall protection, slag removal, cooling and hole cleaning. Its physical and chemical properties meet the requirements of relevant regulations in the early stage of use. During use, due to the mixing of construction waste slag, drilling slag and other materials, the properties of the mud gradually deteriorate. When it does not meet the use requirements, it will be properly treated or discarded and become waste mud. With the rapid advancement of engineering construction in my country, a large amount of waste mud is generated. According to statistics, the annual output of waste mud in my country has exceeded 80 million tons. Improper treatment of waste mud will pollute water sources, compact soil, and cause huge environmental pollution problems. Its treatment faces severe challenges.

[0003] Commonly used mud dehydration methods include natural sedimentation, mechanical filter press, ultrasonic dehydration, hot water dehydration, exposure dehydration, electrodialysis dehydration, etc. However, these methods are affected by many factors and have negative effects on dehydration effect and economic benefits, such as low dehydration efficiency, long dehydration time, harsh conditions, and cumbersome dehydration methods. The flocculation method, on the other hand, aggregates mud particles into agglomerates by adding external additives, removes internal water, and then quickly precipitates. It has excellent mud-water separation effect, and after the use of organic-inorganic flocculants, it not only improves the flocculation effect but also significantly improves the economy, becoming one of the most widely used dehydration methods. On the other hand, when the flocculation method is used for mud dehydration, flocculants need to be added to the mud inside the flocculation reaction cylinder, and the mud and flocculants are stirred by a stirring device. The existing stirring device cannot efficiently and fully stir the flocculants and mud; the addition of flocculants is mainly done manually, which is troublesome; at the same time, after the mud is naturally dehydrated, the water content is still 70-80%, and the free water content in the waste mud is relatively high;

[0004] At present, there are still some problems with the existing mud dewatering treatment devices: for example, the patent with announcement number CN115093101A discloses a waste mud dewatering device based on flocculation method, which does not consider how to better separate mud and water during flocculation dewatering, and it is difficult to meet the needs of rapid dehydration in actual engineering applications; the patent with announcement number CN117339287A discloses a mud dewatering device for mud sewage treatment, which uses a pure filter press method to compress and filter the mud. Although the construction cost is lower than the additive method, the actual filter press dewatering effect is poor, the drainage effect is poor, and the mud cake is loose, which is not conducive to recovery. Therefore, it is necessary to provide a new construction mud dewatering device based on flocculation method to solve the above technical problems. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a sludge flocculation filter press dewatering treatment device with high coordination and convenience, and also to provide a dewatering method using the above device.

[0006] Technical solution: The present invention discloses a mud flocculation filter press dewatering treatment device, wherein the treatment device is an oscillating screening device, a flocculation stirring chamber and a filter press dewatering device connected in sequence, and the flocculation stirring chamber is connected to a flocculant grouting device through a grouting pipe; the oscillating screening device comprises an externally arranged shock absorbing device and an internally arranged screen; a water pump and a motor are provided on the connecting passage between the oscillating screening device and the flocculation stirring chamber; a stirring fan is provided in the flocculation stirring chamber; the flocculant grouting device comprises a storage bin and a control valve; the filter press dewatering device comprises a drainage device and a hub, and the hub is connected by a transmission track.

[0007] Wherein, the bottom plate of the flocculation stirring chamber is slightly inclined, and the angle is adjusted to 3-6 degrees.

[0008] The engine is provided with control buttons, including a button for controlling the flocculation stirring speed, an integrated device start switch, a water pump speed control switch and an oscillating screening device switch.

[0009] Wherein, a water stop valve is provided on the connection passage between the filter press dehydration device and the flocculation stirring chamber, and the water stop valve is controlled by an upper rotating faucet.

[0010] Wherein, the mesh has a mesh aperture of 0.15 to 1 mm; the shock absorbing device is composed of a shock absorber, a spring, and a buffer block. The shock absorbing device contains a shock absorber, a spring, and a buffer block. The spring can be a coil spring, a leaf spring, or a gas spring, which is located at the core of the shock absorbing device to provide elastic restoring force. The shock absorber is usually installed in parallel with the spring to absorb excess energy generated by vibration. In this device, it is installed at the left and right ends of the spring. The buffer block can be rubber, polyurethane or other highly elastic materials, installed at the extreme position of the shock absorber or spring to absorb large impacts. In this device, it is installed at the upper and lower ends of the spring.

[0011] The flocculant grouting device is connected to the flocculation stirring chamber by two grouting pipes; the flocculant grouting device is provided with two storage bins and two control valves.

[0012] The dehydration method using the above-mentioned mud flocculation filter press dehydration treatment device comprises the following steps:

[0013] S1. Add mud to the oscillating filter device, start the engine, the oscillating filter device and the stirring fan, and the mud enters the flocculation stirring chamber through the screen; start the master control engine, adjust the pumping pump speed button to control the mud pumping speed, and start the mud oscillating filter device switch at the same time, so that the mud suction and filtration devices work together to prevent large particles and stones from entering the mud flocculation stirring space to damage the stirring fan, damage the internal space and affect the rear-end filter press device, and start the stirring fan to stir the mud inside the mud flocculation stirring space at a uniform speed to ensure that its solid phase is evenly dispersed;

[0014] S2. When the mud fills 75-85% of the flocculation stirring chamber, the flocculant grouting device is turned on, and the flocculant is added to the flocculation stirring chamber. The mud and the flocculant in the flocculation stirring chamber are mixed to obtain a mud cake; the type and injection rate of the flocculant are controlled according to the characteristics of the mud (density, pH value, solid content, etc.) to ensure that the waste of the flocculant is reduced and the flocculation and dehydration effect of the mud is improved;

[0015] S3. The flocculated mud cake is subjected to deep filtration, and the waste mud cake after filtration is transported out by the conveyor crawler connected to the hub for loading and transportation. This process only requires manual control of the master control engine to operate the above process once when starting the machine, and the highly coordinated mud flocculation, filtration, pressing and dehydration combined treatment device can continue to work on its own. Subsequently, it is only necessary to regularly check the storage bin of the flocculant grouting device and fill the flocculant until the construction is completed.

[0016] The flocculants are flocculants A and B, wherein flocculants A are composed of one or more of PAC, lime and fly ash; and flocculants B are composed of one or two of NPAM and sodium dodecyl sulfate.

[0017] The flocculants are flocculants A and B, wherein flocculant A is composed of one or more of polyaluminium chloride (PAC), lime and fly ash; and flocculant B is composed of one or two of non-ionic polyacrylamide (NPAM) and sodium dodecyl sulfate.

[0018] Among them, 2.0g-3.0g of polyaluminium chloride (PAC), 0.5g-1.5g of lime and 1.0g-2.0g of fly ash composed of flocculant A and 0.25g-1.25g of non-ionic polyacrylamide (NPAM) and 0.25-0.75g of sodium dodecyl sulfate are added to the 1000mL of mud respectively; further preferably, 2.5g of PAC, 1g of lime and 1.5g of fly ash composed of flocculant A and 0.75g of NPAM and 0.5g of sodium dodecyl sulfate are added to the 1000mL of mud respectively.

[0019] Among them, the injection rate of flocculant A is 5mL / s-10mL / s, and the injection rate of flocculant B is 7.5mL / s-15mL / s.

[0020] The pumping speed of the mud is 50mL / s-100mL / s; the pH of the flocculation-conditioned mud is 8-10; and the water content of the mud is 100%-300%.

[0021] Principle of the invention: The mud flocculation filter pressing and dehydration treatment device of the present invention is highly coordinated and convenient, and meets the integrated operation advantages of mud extraction, screening, flocculation and filter pressing into mud cake, and can quickly separate mud and water from the mud. It has the advantages of fully automatic and convenient operation, as well as excellent flocculation effect and good dehydration effect.

[0022] Specifically: the device of the present invention is equipped with a water pump and a filter at the front end, which can directly extract and filter the discharged construction waste mud. At the same time, it is provided with a master control engine, which can control the extraction speed of the mud and the stirring speed of the mixing bin, and the filter can filter larger stones during the extraction of the mud to prevent the stones from entering the mixing bin and the filter press bin and damaging the mixing fan, crawler and wheel hub; it can be used directly at the construction site, which is extremely convenient. The device is provided with a flocculation stirring chamber at the middle end, and the flocculation stirring chamber is connected to the flocculant grouting device through two grouting pipes. The flocculant grouting device is provided with a grouting control button and a storage bin. A highly targeted flocculant can be added according to the physical and chemical characteristics of the mud, and the grouting speed of the mud can be controlled by controlling the grouting button. It is only necessary to load the material when the material in the bin is below the scale line. The loading process is simple, and the flocculant can be injected quantitatively and at a constant speed, which is more intelligent and saves labor costs. After the slurry is flocculated and conditioned by the flocculant, it forms large-particle mud debris, which settles at the bottom of the flocculation stirring chamber due to its own weight and flocculation. The pump pumps the slurry, and the flocculated mud accumulates inside the flocculation stirring chamber. Due to the slight inclination of the stirring chamber bottom plate and the negative pressure formed after accumulation, and the continuous pumping and pushing, the flocculated mud-water mixture is squeezed into the filter press dehydration device. The end of the device of the present invention is connected to the filter press dehydration device composed of multiple hubs and a transmission crawler, which performs deep filter pressing on the flocculated mud cake and compresses the moisture content of the mud cake to 10-20%. The water in the filter press can be directly discharged, and the mud cake is transferred out by the crawler and accumulated for subsequent excavation and reuse.

[0023] Among them, the specific mechanism of action of the flocculant is as follows: PAC dissolves in the mud to produce a large amount of positive charge, which has a strong electrical neutralization effect with the negative charge on the surface of the mud colloidal particles; the hydrolysis product has an excellent bridging adsorption effect on suspended matter in water; aluminum salt hydrolysis forms a large amount of hydrated metal oxide precipitation with a three-dimensional structure. When these hydrated metal oxides shrink and settle, they capture and sweep the colloidal particles and suspended particles in the water. After lime is dissolved in the mud, it will further increase the pH value of the mud and release a large amount of heat, while further consuming the water inside the mud; significantly improve the shape of the mud, improve storage and transportation conditions, and avoid secondary fly ash and filtrate leakage. After using fly ash to partially replace lime for mud conditioning, the mud pH gradually decreases and approaches neutrality, and its secondary pollution to the natural environment is reduced; fly ash particles are easy to form a porous structure inside, with strong adsorption capacity. After mixing with mud, it can adsorb mud flocs, form a skeleton structure with its particles as the center, reduce the compressibility of the mud, and build a water filtration channel between the filter cakes. NPAM is first dissolved in water to prepare a solution with a concentration of 0.1%. Its molecular chain contains a certain amount of polar genes that can adsorb solid particles suspended in the water, bridging the particles to form large floccules. The hydrophobic components of sodium dodecyl sulfate associate with each other, playing a bridging and netting role, re-flocculating the suspended mud particles to form larger mud flocs. The re-flocculated mud flocs have a loose structure, and free water can pass quickly, thereby greatly improving the filtration speed. The composite flocculant combines the characteristics of the above-mentioned flocculants, fully utilizes the characteristics of the flocculants and the mud characteristics, quickly stirs the flocculants and mud, and aggregates the colloidal particles in the mud into agglomerates through the long-chain molecules in the flocculants. Due to their large dead weight, they naturally precipitate, achieving rapid flocculation and dehydration.

[0024] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The mud flocculation filter press dewatering treatment device of the present invention can filter and screen the mud, and at the same time effectively control the flocculant demand and the stirring speed to achieve sufficient stirring. Under the action of the water pump, the fully flocculated and mixed mud can be transported to the integrated filter press space for efficient filter press dehydration to form a mud cake for transportation out of the door, and the moisture content of the lower mud cake can be reduced to below 50%. It has the advantages of high efficiency, convenience, and high controllability. (2) The dehydration method of the present invention makes full use of the characteristics of the flocculant and the mud characteristics. The composite flocculant will not pollute the mud, creating conditions for the recycling of the clear liquid, solid waste treatment or landfill after the solid-liquid separation of the mud. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a front view of the mud flocculation filter pressing and dehydration treatment device of the present invention;

[0026] Figure 2Schematic diagram of the composite flocculant in the treatment method of the present invention, wherein the flocculants are doped with lime (A), PAC (B), fly ash (C), APAM (D), and sodium dodecyl sulfate (E);

[0027] Figure 3 It is a schematic diagram of the dehydration rate curve of the composite flocculant in the treatment method of the present invention;

[0028] Among them: 1. Flocculation stirring chamber; 2. Filter press dehydration device; 3. Water pump; 4. Engine; 5. Button for controlling flocculation stirring speed; 6. Integrated device start switch; 7. Water pump speed control switch; 8. Mud vibration screening device switch; 9. Vibration screening device; 10. Shock absorber; 11. Screen; 12. Flocculation stirring fan; 13. Flocculant grouting device; 14. Grouting pipe; 15. Storage bin; 16. Control valve; 17. Drainage device; 18. Wheel hub; 19. Conveyor track; 20. Water stop valve; 21. Rotating faucet control. DETAILED DESCRIPTION

[0029] The technical scheme of the present invention is further described below in conjunction with the examples. The test materials used in the examples can all be purchased through conventional channels.

[0030] Example 1

[0031] like Figure 1 As shown, the mud flocculation filter press dehydration treatment device of the present invention comprises a flocculation stirring chamber 1 and a filter press dehydration device 2, wherein a water pump 3 is installed at the front end of the flocculation stirring chamber 1; a master control engine 4 of the device is installed at the port of the water pump 3; the master control engine 4 comprises a flocculation stirring speed control button 5, an integrated device start switch 6, a water pump speed control switch 7 and a mud vibration screening device switch 8 at the front end of the master control engine; the mud vibration screening device 9 comprises a shock absorbing device 10 at both ends of the mechanical arm and a middle screen 11; the screen mesh aperture of the screen is 1 mm;

[0032] The flocculation stirring chamber 1 includes a high-speed flocculation stirring fan 12; the angle between the bottom plate of the flocculation stirring chamber 1 and the horizontal plane is 5°; the flocculant grouting device 13 is connected to the flocculation stirring chamber by two grouting pipes 14, and mainly includes two storage bins 15 and two grouting control valves 16;

[0033] There is a water stop valve 20 between the filter press dehydration device 2 and the flocculation stirring chamber 1, and the water stop valve 20 is controlled by an upper rotating faucet 21. The filter press dehydration device 2 includes a drainage device 17 and multiple groups of mud cake hubs 18 arranged on the side; the multiple groups of mud cake hubs are connected by a transmission crawler 19.

[0034] Example 2

[0035] Dehydration method using the above-mentioned mud flocculation filter press dehydration treatment device:

[0036] S1. During operation, the flocculant is loaded into the flocculant storage bin 15 for standby use, the power is turned on, the switch 6 of the master control engine 4 is started, the master control engine 4 is controlled by three rotary buttons, the knob 5 controls the speed of the flocculation stirring fan 12, the knob 7 controls the oscillation frequency of the mud oscillation screening device 9, the knob 8 controls the slurry pumping frequency of the front water pump 3, the flocculation stirring fan 12 is started first, then the oscillation screening device 9 is started, and then the water pump 3 is started;

[0037] S2. After the mud enters the flocculation and stirring space 1, the flocculant injection device 13 is started, and the slurry discharge rate of the flocculant in the storage bin 15 is controlled by rotating the control valve 16, and the mud enters the mud flocculation and stirring space 1 through the injection pipe 14, and the mud and water are separated after rapid stirring by the high-speed flocculation and stirring fan 12;

[0038] S3. Finally, open the water stop valve 20 and rotate the tap 21 on the top to drain the mud-water mixture, wherein a large amount of free water is discharged through the lateral drainage device 17, and the mud cake enters the filter press dehydration device 2 through the conveyor track 19, and after being rolled by multiple sets of wheel hubs 18, the water inside the mud cake is squeezed out and discharged.

[0039] The flocculant is a composite flocculant, and the preparation of the composite flocculant is as follows: flocculant A is composed of one or more of PAC, lime and fly ash; flocculant B is composed of one or more of APAM and sodium dodecyl sulfate; 2.5g PAC, 1g lime and 1.5g fly ash composed of flocculant A and 0.75g PAM and 0.5g sodium dodecyl sulfate composed of flocculant B are added to 1000mL of the mud respectively; the composite flocculant composed of the above flocculants A and flocculant B is adjusted according to the control variable method to adjust the content of each component, and the pressure dehydration of the mud is tested:

[0040] Depend on Figure 2It can be seen that the pressure dehydration of the mud first increases and then decreases with the increase of lime dosage. The pressure filter dehydration of the mud reaches the maximum value when the dosage is 1.0g, and the optimal dosage of lime is 1.0g; the dehydration of the mud first increases and then decreases with the increase of PAC dosage. In the test, when the PAC dosage is 2.3g, the pressure filter dehydration of the mud reaches the maximum value, so the optimal dosage of PAC is 2.3g; the dehydration of the mud first increases and then decreases with the increase of fly ash dosage. When the dosage is 1.5g, it reaches the maximum value, so the optimal dosage of fly ash is 1.5g; the dehydration amount of the mud first increases and then decreases with the increase of the APAM dosage, and reaches the maximum value when the dosage is 0.75g, so the optimal APAM dosage is 0.75g; the dehydration amount of the mud first increases and then decreases with the increase of the sodium dodecyl sulfate dosage, and reaches the maximum value when the dosage is 0.5g, so the optimal dosage of sodium dodecyl sulfate is 0.5g.

[0041] The sludge is dehydrated by composite flocculants, with the dehydration rate as the dependent variable and the cumulative dehydration time as the independent variable. The functional relationship between the dehydration rate and the dehydration time is fitted. According to the shape of the filter press dehydration test curve, the filter press dehydration law of the sludge is expressed as follows:

[0042]

[0043] Among them, y is the cumulative dehydration rate of mud;

[0044] x is the dehydration time of the mud;

[0045] A 1 , A 2 as a parameter.

[0046] The dehydration curve of the slurry with the addition of composite flocculants (PAC + lime + fly ash + APAM + sodium dodecyl sulfate) is shown in Figure 2. Figure 3 As shown in the figure, after adding the composite flocculant, the dehydration rate of the mud is significantly improved, which greatly shortens the treatment cycle and can reduce the treatment cost of using polyacrylamide alone. The addition of the above composite flocculant will not cause pollution to the mud. After the solid-liquid separation of the mud, the clear liquid that can be recycled can be discharged from the lateral drainage device, and the solid can be disposed of or landfilled, thus realizing efficient, convenient and controllable mud treatment.

Claims

1. A mud flocculation filter press dehydration treatment device, characterized in that: The processing device is a vibration screening device (9), a flocculation stirring chamber (1) and a filter press dewatering device (2) connected in sequence, and the flocculation stirring chamber (1) is connected to the flocculant grouting device (13) through a grouting pipe (14); the vibration screening device (9) comprises an externally arranged shock absorbing device (10) and an internally arranged screen (11); a water pump (3) and an engine (4) are arranged on the connecting passage between the vibration screening device (9) and the flocculation stirring chamber (1); a stirring fan (12) is arranged in the flocculation stirring chamber (1); the flocculant grouting device (13) comprises a storage bin (15) and a control valve (16); the filter press dewatering device (2) comprises a drainage device (17) and a wheel hub (18), and the wheel hub (18) is connected by a transmission crawler (19).

2. The processing device according to claim 1, characterized in that The engine (4) is provided with control buttons, including a flocculation stirring speed control button (5), an integrated device start switch (6), a water pump speed control switch (7) and an oscillating screening device switch (8).

3. The processing device according to claim 1, characterized in that A water stop valve (20) is provided on the connection passage between the filter press dehydration device (2) and the flocculation stirring chamber (1), and the water stop valve (20) is controlled by an upper rotating faucet (21).

4. The processing device according to claim 1, characterized in that The sieve (11) has a sieve hole diameter of 0.15 to 1 mm; the shock absorbing device (10) is composed of a shock absorber, a spring, and a buffer block.

5. The processing device according to claim 1, characterized in that The flocculant grouting device (13) is connected to the flocculation stirring chamber (1) by two grouting pipes (14); the flocculant grouting device (13) is provided with two storage bins (15) and two control valves (16).

6. A dehydration method using the mud flocculation filter press dehydration treatment device according to claim 1, characterized in that: The dehydration method comprises the following steps: S1. Add mud to the vibration screening device, start the engine, vibration screening device and stirring fan, and the mud enters the flocculation stirring chamber through the screen; S2. When the slurry fills 75-85% of the flocculation stirring chamber, the flocculant grouting device is turned on, and the flocculant is added to the flocculation stirring chamber, and the slurry and the flocculant in the flocculation stirring chamber are mixed to obtain a mud cake; S3. The flocculated mud cake is subjected to deep filter pressing, and the waste mud cake after the filter pressing is transported out by the conveyor crawler connected to the wheel hub for loading and external transportation.

7. The method according to claim 6, characterized in that The flocculants are flocculants A and B, wherein the flocculant A is composed of one or more of polyaluminium chloride, lime and fly ash; and the flocculant B is composed of one or two of non-ionic polyacrylamide and sodium dodecyl sulfate.

8. The method according to claim 7, characterized in that The 1000 mL slurry is respectively added with 2.0 g to 3.0 g of polyaluminium chloride, 0.5 g to 1.5 g of lime and 1.0 g to 2.0 g of fly ash-comprising a flocculant A and 0.25 g to 1.25 g of nonionic polyacrylamide and 0.25 to 0.75 g of sodium dodecyl sulfate-comprising a flocculant B.

9. The method according to claim 7, characterized in that: The injection rate of flocculant A is 5mL / s-10mL / s, and the injection rate of flocculant B is 7.5mL / s-15mL / s.

10. The method according to claim 6, characterized in that The pumping speed of the mud is 50mL / s-100mL / s; the pH of the flocculation-conditioned mud is 8-10; and the water content of the mud is 100%-300%.

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