System and method for dewatering and solidification of sand-containing slurry and resource utilization

Abstract

The present application relates to the technical field of environmental engineering, and discloses a sand-containing slurry dewatering and solidifying and resource utilization system and method, the sand-containing slurry dewatering and solidifying and resource utilization system comprising a sedimentation unit, a fine sand removal unit, a slurry dewatering and resource utilization unit and a tail water treatment unit. The scheme solves the problem that high sand-containing slurry is difficult to flocculate and dewater, is intensive and efficient, and greatly reduces the dewatering cost.

Description

Technical Field

[0001] This invention relates to the field of environmental engineering technology, specifically to a system and method for dewatering, solidifying, and resource-utilizing sand-containing slurry. Background Technology

[0002] In the process of treating water pollution sources, dredging is the most mature and effective measure. Traditional mud dewatering and solidification processes can achieve mud dewatering and forming mud cakes through measures such as initial sedimentation, chemical homogenization, and dewatering filtration, which are convenient for off-site disposal. However, in engineering practice, some river dredging slurries have a high sand content. Traditional slurry dewatering processes, whether plate and frame filter presses, belt filter presses, or the less commonly used centrifugal dewatering process, are difficult to achieve rapid dewatering and solidification of high sand content. The main problems are: ① The slurry has a high specific gravity, and long-distance transportation requires reducing the slurry concentration, resulting in a large amount of dredging tailwater that needs to be treated. Furthermore, low slurry concentration leads to low sedimentation efficiency, requiring large-capacity primary sedimentation tanks and tailwater sedimentation tanks, which poses a significant land occupation problem; ② High sand content makes long-distance pipeline transportation difficult. The slurry concentration must be reduced to below 8% to ensure normal transportation, resulting in a tailwater volume increase of about 10-12 times; In addition, during the flocculation and chemical dosing process, traditional plate and frame or belt filter presses require a large amount of flocculant and solidifying agent to ensure the dewatering effect. However, fine sand will greatly affect the flocculant effect, leading to excessive dosing. The amount of flocculant and solidifying agent used is greatly increased and the effect is poor. The dewatering filter bags or filter membranes wear out quickly and have high losses, resulting in low efficiency and high cost.

[0003] Geotextile strip dewatering technology can be applied to some extent to dewatering high-sand-content dredging slurry, but its dewatering efficiency is low, it occupies a large area, and has a long dewatering cycle, making it difficult to apply to urban dredging slurry dewatering projects. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned problems existing in the prior art and to provide a system and method for dewatering, solidifying and resource utilization of sand-containing slurry. This solution solves the problem of difficult flocculation and dewatering of high-sand-content slurry, is intensive and efficient, and greatly reduces the dewatering cost.

[0005] To achieve the above objectives, the present invention provides a system for dewatering, solidifying, and utilizing sand-containing slurry, which includes a sedimentation unit, a fine sand removal unit, a slurry dewatering and resource utilization unit, and a tailwater treatment unit.

[0006] The sedimentation unit is used to separate sand-containing mud to obtain slurry and mud, and to precipitate the mud to obtain concentrated mud and supernatant.

[0007] The fine sand removal unit is connected to the sedimentation unit, and the fine sand removal unit is used to perform solid-liquid separation on the slurry from the sedimentation unit to obtain fine sand.

[0008] The mud dewatering and resource utilization unit is connected to the sedimentation unit. The mud dewatering and resource utilization unit is used to flocculate and precipitate the concentrated mud from the sedimentation unit to obtain precipitated mud. Then, the water in the precipitated mud is removed to prepare greening soil.

[0009] The wastewater treatment unit is connected to the sedimentation unit, and the wastewater treatment unit is used to treat the supernatant from the sedimentation unit as wastewater.

[0010] The present invention has the following outstanding advantages: (1) By setting up a sedimentation unit, a coarse sand removal unit, and a fine sand removal unit, sand particles are quickly removed, and the hydraulic characteristics of mortar are fully considered, resulting in low cost and high efficiency; (2) After the mud dewatering and resource utilization unit removes most of the mortar, the amount of reagent used is greatly reduced while the flocculation and sedimentation effect is improved, and the wear of the filter press equipment is reduced; (3) By adding planting soil and bentonite, the moisture content requirement of the filter press cake is relaxed while the landscaping characteristics of the cake are improved, and it can be used as planting soil for park landscaping to achieve resource utilization; (4) The removed sand particles are relatively simple in composition and can be used for the resource utilization of building raw materials; (5) The combination of three-stage sedimentation and tailwater purification is efficient and intensive, and can solve a large amount of dredging tailwater problems. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of the sand-containing mud dewatering, solidification, and resource utilization system of the present invention;

[0012] Figure 2 This is a schematic diagram of the precipitation unit of the present invention;

[0013] Figure 3 This is a schematic diagram of the coarse sand removal unit of the present invention;

[0014] Figure 4 This is a schematic diagram of the structure of the fine sand removal unit of the present invention;

[0015] Figure 5 This is a schematic diagram of the structure of the mud dewatering and resource utilization unit of the present invention;

[0016] Figure 6 This is a schematic diagram of the wastewater treatment unit of the present invention.

[0017] Explanation of reference numerals in the attached figures

[0018] 1. Slag Removal Unit; 2. Sedimentation Unit: 21. Mortar Sedimentation Tank; 22. Slurry Sedimentation Tank; 23. Mortar Pump; 24. Slurry Pump; 25. First Densitometer; 26. Motor Drive Track; 27. Geotextile; 28. Second Densitometer; 3. Coarse Sand Removal Unit: 31. Coarse Sand Filter; 32. Sand Pit; 33. Third Densitometer; 34. First Three-Way Solenoid Valve; 35. Removable Baffle; 36. Drainage Ditch; 4. Fine Sand Removal Unit: 41. Fine Sand Transfer Tank; 42. Hydrocyclone Separator; 43. Vibration... 44. Screen; 45. First transfer pump; 5. First conveyor belt; 5. Sludge dewatering and resource utilization unit: 51. Sludge transfer tank; 52. Flocculation dosing equipment; 53. Sludge dewatering filter press equipment; 54. Soil holding silo; 55. Mixer; 56. Second conveyor belt; 57. Third conveyor belt; 58. Second transfer pump; 6. Tailwater treatment unit: 61. Tailwater sedimentation tank; 62. Three-stage tailwater sedimentation tank; 63. Tailwater purification equipment; 64. Third transfer pump; 65. Turbidity meter; 66. Second three-way solenoid valve. Detailed Implementation

[0019] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0020] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0021] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0022] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions provided in the various embodiments of this invention can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] The present invention will be described in detail below through embodiments.

[0024] Example 1

[0025] like Figure 1 The sand-containing sludge dewatering, solidification, and resource utilization system shown includes a sedimentation unit 2, a fine sand removal unit 4, a sludge dewatering and resource utilization unit 5, and a tailwater treatment unit 6.

[0026] The sedimentation unit 2 is used to separate sand-containing mud to obtain slurry and mud, and to precipitate the mud to obtain concentrated mud and supernatant.

[0027] The fine sand removal unit 4 is connected to the sedimentation unit 2. The fine sand removal unit 4 is used to perform solid-liquid separation on the mortar from the sedimentation unit 2 to obtain fine sand.

[0028] The mud dewatering and resource utilization unit 5 is connected to the sedimentation unit 2. The mud dewatering and resource utilization unit 5 is used to flocculate and precipitate the concentrated mud from the sedimentation unit 2 to obtain precipitated mud. Then, the water in the precipitated mud is removed to prepare greening soil.

[0029] The tailwater treatment unit 6 is connected to the sedimentation unit 2, and the tailwater treatment unit 6 is used to treat the supernatant from the sedimentation unit 2 as tailwater.

[0030] The sand-containing slurry used in this invention is a high-sand-content slurry, which contains coarse sand, fine sand, and slurry, and comes from river dredging. Since the sand-containing slurry obtained from river dredging usually contains impurities such as stones, garbage, and slag, in order to remove these impurities for subsequent processing, the sand-containing slurry dewatering, solidification, and resource utilization system of this invention is also equipped with a slag removal unit 1 connected to the outlet of the dredging slurry pipeline. The slag removal unit 1 is connected to the sedimentation unit 2. The slag removal unit 1 is used to remove slag from the sand-containing slurry obtained from river dredging (preliminarily removing stones, garbage, slag, and other impurities from the sand-containing slurry), and then the slag-removed sand-containing slurry is transported to the sedimentation unit 2 for preliminary separation.

[0031] In this embodiment, the slag removal unit used is a bar screen slag remover.

[0032] In this invention, such as Figure 1 and Figure 2 As shown, the sedimentation unit 2 includes a sedimentation tank and a geotextile 27. The geotextile 27 is movably installed in the sedimentation tank via a motor-driven track 26, and divides the sedimentation tank into a mortar sedimentation tank 21 and a mud sedimentation tank 22. The geotextile 27 has an opening that connects the mortar sedimentation tank 21 and the mud sedimentation tank 22.

[0033] In this invention, the sand-containing slurry after slag removal is transported to the mortar settling tank 21. Taking advantage of the fact that mortar has a higher specific gravity and settles faster than mud, the mortar will preferentially settle in the mortar settling tank 21, while the less dense mud will enter the mud settling tank 22 through the opening on the geotextile 27 and undergo further sedimentation in the mud settling tank 22 to obtain concentrated mud and supernatant.

[0034] Furthermore, to better separate the mortar and mud, the geotextile used has a density of 600-1000 g / m³. 2 Furthermore, in this embodiment, the geotextile used has a density of 800 g / m³. 2 .

[0035] The size of the mortar sedimentation tank 21 and the mud sedimentation tank 22 can be controlled by adjusting the position of the geotextile 27 according to the actual situation. A first density meter 25 is installed at the opening of the geotextile 27 to measure the density of the slurry at the opening in real time. The calculation formulas for the position of the geotextile 27 are shown in Equations (1) and (2):

[0036]

[0037]

[0038] In equations (1) and (2), x is the distance between the geotextile 27 and its initial position (when x is positive, it means that the geotextile 27 needs to move in the direction of reducing the volume of the mortar sedimentation tank 21, and the distance moved is x, that is, the length of the mortar sedimentation tank 21 becomes smaller; conversely, when x is negative, it means that the geotextile 27 needs to move in the direction of increasing the volume of the mortar sedimentation tank 21, and the distance moved is x, that is, the length of the mortar sedimentation tank 21 becomes larger); B is the width of the mortar sedimentation tank 21 (the width of the mortar sedimentation tank 21 is the same as that of the mud sedimentation tank 22 and the sedimentation tank), h is the depth of the slurry in the mortar sedimentation tank 21, and V s0 V is the volume of the mortar settling tank 21 when the geotextile 27 is in its initial position. n0 ρ is the volume of the mud settling tank 22 when the geotextile 27 is in its initial position. s ρ is the average density of the slurry in mortar sedimentation tank 21. n The average density (ρ) of the slurry in mud sedimentation tank 22 s and ρ n (All values ​​were obtained through calibration tests), ρ t For the real-time density measurement of the first density meter 25, V s V represents the volume of the mortar settling tank 21 after the geotextile 27 is adjusted. n The volume of the mud sedimentation tank 22 after the adjustment of the geotextile 27.

[0039] A mortar pump 23 is installed in the mortar sedimentation tank 21 to pump out the mortar in the mortar sedimentation tank 21; a mud pump 24 is installed in the mud sedimentation tank 22 to pump out the concentrated mud in the mud sedimentation tank 22 and transport it to the mud dewatering and resource utilization unit 5.

[0040] Furthermore, a second density meter 28 is also installed in the mud sedimentation tank 22 to detect the density of the supernatant in the mud sedimentation tank 22. When the second density meter 28 detects that the average density of the supernatant over a period of 0.5 hours or more is ≥1.1 g / cm³, the density of the supernatant is determined to be within the specified range. 3 When the supernatant contains a large amount of mud, the mud sedimentation tank 22 is already at full capacity. At this time, it is necessary to shut down the slag removal unit 1 and stop conveying the slag-removed sand-containing mud into the sedimentation unit 2.

[0041] The sand-containing slurry dewatering, solidification, and resource utilization system of the present invention also includes a coarse sand removal unit 3, such as... Figure 1 and Figure 3 As shown, the coarse sand removal unit 3 includes a coarse sand filter tank 31, with a sand pile 32 at the inlet end of the coarse sand filter tank 31, and a detachable baffle 35 on the side wall of the end of the coarse sand filter tank 31 away from the sand pile 32.

[0042] The coarse sand removal unit 3 also includes a first three-way solenoid valve 34. The mortar sedimentation tank 21 of the sedimentation unit 2 is connected to the inlet of the first three-way solenoid valve 34. The first outlet of the first three-way solenoid valve 34 is connected to the fine sand removal unit 4. The second outlet of the first three-way solenoid valve 34 is connected to the coarse sand filter tank 31. The coarse sand removal unit 3 is also connected to the fine sand removal unit 4.

[0043] In this invention, a third density meter 33 is also provided at the inlet of the first three-way solenoid valve 34 for measuring the density of mortar from the mortar settling tank 21. The mortar's average density is ≤1.5 g / cm³ over a period of 0.5 hours or more. 3 When the coarse sand content in the mortar is low, the mortar is directly transported to the fine sand removal unit 4 for solid-liquid separation by regulating the first three-way solenoid valve 34 to obtain fine sand; when the average density of the mortar is >1.5 g / cm³ for 0.5 h or more. 3 When the surface mortar has a high coarse sand content, it is necessary to adjust the first three-way solenoid valve 34 to transport the mortar to the coarse sand filter tank 31 to further remove the coarse sand. Then, the mortar after removing the coarse sand is transported to the fine sand removal unit 4 for solid-liquid separation to obtain fine sand.

[0044] The reason for providing a sand pile 32 at the inlet end of the coarse sand filter tank 31 is that when the slurry enters the coarse sand filter tank 31, it will flow through the sand pile 32. Under the dispersion and buffering effect of the sand pile 32, the slurry flow rate can be quickly reduced, thereby reducing the sand carrying capacity and achieving the purpose of rapid sedimentation of coarse sand.

[0045] Furthermore, a detachable baffle 35 is provided on the side wall of the coarse sand filter tank 31 at the end away from the sand pile 32. This is to facilitate the loader to enter and transfer the coarse sand obtained from sedimentation. In addition, a drainage ditch 36 is provided on the outside of the detachable baffle 35 to collect the mortar that overflows and leaks from the detachable baffle 35 and prevent pollution.

[0046] In this invention, the first densitometer 25 and the second densitometer 28 used are both insertion-type mud densitometers, while the third densitometer 33 used is a pipe-type mud densitometer.

[0047] Furthermore, such as Figure 1 and Figure 4 As shown, the fine sand removal unit 4 includes a fine sand transfer tank 41 and a cyclone separator 42 connected to the fine sand transfer tank 41. A first transfer pump 44 is provided in the fine sand transfer tank 41.

[0048] The first outlet of the first three-way solenoid valve 34 is connected to the fine sand transfer tank 41, and the coarse sand filter tank 31 is also connected to the fine sand transfer tank 41. The slurry from the slurry sedimentation tank 21 and the slurry after removing coarse sand from the coarse sand filter tank 31 are homogenized in the fine sand transfer tank 41. Then, the material obtained after homogenization in the fine sand transfer tank 41 is transported to the hydrocyclone separator 42 for hydrocyclone separation to obtain fine sand slurry. At the same time, the fine sand removal unit 4 also includes a vibrating screen 43, which is used to screen the fine sand slurry from the hydrocyclone separator 42. The material on the screen is fine sand.

[0049] The hydrocyclone separator 42 used in this invention is a hydrocyclone separator. The diameter of the hydrocyclone separator is determined by the fine sand content and the processing flow rate, and the outlet size is adjusted by comprehensively considering the processing efficiency and fine sand removal rate. The vibrating screen 43 used is a vibrating screen with a dense mesh, and the mesh is denser to a aperture of 0.4-0.8 mm. In this embodiment, the mesh aperture of the vibrating screen 43 is 0.5 mm, which can better separate fine sand.

[0050] The fine sand removal unit 4 also includes a first conveyor belt 45. The fine sand screened by the vibrating screen 43 is conveyed to the stockpile via the first conveyor belt 45 and then transported off-site for disposal.

[0051] Furthermore, the drainage ditch 36 is also connected to the fine sand transfer tank 41, and the mortar collected by the drainage ditch 36 is also transported to the fine sand transfer tank 41 for homogenization.

[0052] In this invention, the method for removing water from the precipitated sludge can be filter pressing. The filter cake obtained from the filter pressing is mixed with planting soil and bentonite to obtain soil for landscaping. Therefore, as... Figure 1 and Figure 5 As shown, the mud dewatering and resource utilization unit 5 includes a mud transfer tank 51, a flocculation dosing device 52, and a mud dewatering filter press 53 connected in sequence along the material direction; wherein the mud sedimentation tank 22 is connected to the mud transfer tank 51, and the concentrated mud from the mud sedimentation tank 22 is homogenized in the mud transfer tank 51.

[0053] The hydrocyclone separator 42 is also connected to the mud transfer tank 51, and the vibrating screen 43 is also connected to the mud transfer tank 51. Since the material obtained after homogenization in the fine sand transfer tank 41 contains a small amount of mud that has not been completely separated, after being separated by the hydrocyclone separator 42, fine sand slurry and upper material are obtained. The fine sand slurry separated by the hydrocyclone will be transported to the vibrating screen 43 for further screening, while the upper material will enter the mud transfer tank 51 for homogenization. The undersize material obtained by the vibrating screen 43 will also enter the mud transfer tank 51 for homogenization in order to fully collect the mud.

[0054] In this invention, a second transfer pump 58 is also provided in the mud transfer tank 51. The material obtained after homogenization in the mud transfer tank 51 is pumped to the flocculation dosing equipment 52 for flocculation and sedimentation through the second transfer pump 58. The precipitated mud obtained after flocculation and sedimentation is transported to the mud dewatering filter press 53 for filter press to obtain filter cake. The mud dewatering filter press 53 is also connected to the mud transfer tank 51. The filter tail water obtained by the mud dewatering filter press 53 contains a small amount of flocculant, which is transported back to the mud transfer tank 51 for recycling.

[0055] The mud dewatering filter press 53 used in this invention is a belt filter press.

[0056] Furthermore, the mud dewatering and resource utilization unit 5 also includes a mixer 55, a soil holding chamber 54, a second conveyor belt 56, and a third conveyor belt 57. The soil holding chamber 54 is used to hold planting soil and bentonite. The planting soil and bentonite in the soil holding chamber 54 are transported to the mixer 55 via the second conveyor belt 56. The filter cake from the mud dewatering filter press 53 is transported to the mixer 55 via the third conveyor belt 57. In the mixer 55, the filter cake is mixed with the planting soil and bentonite to obtain greening soil, which is then transported to the park for planting soil to achieve resource utilization.

[0057] The moisture content of the filter cake obtained in this invention can be relaxed to 60-65%. The proportion of bentonite and planting soil added takes into account the moisture content of the filter cake and the soil for landscaping, as well as the organic matter content of the filter cake. Furthermore, the weight ratio of filter cake, bentonite and planting soil is 20:1-2:2-4.

[0058] In this invention, such as Figure 1 and Figure 6 As shown, the effluent treatment unit 6 includes an effluent sedimentation tank 61, an effluent tertiary sedimentation tank 62, an effluent purification device 63, and a second three-way solenoid valve 66. The effluent sedimentation tank 61 and the effluent tertiary sedimentation tank 62 are both connected to the inlet of the second three-way solenoid valve 66, and a turbidity meter 65 is installed at the inlet of the second three-way solenoid valve 66. The first outlet of the second three-way solenoid valve 66 is connected to the effluent purification device 63, and the second outlet of the second three-way solenoid valve 66 is connected to the drainage pipeline. A third transfer pump 64 is installed in the effluent tertiary sedimentation tank 62.

[0059] The mud sedimentation tank 22 is connected to the tailwater sedimentation tank 61. The supernatant from the mud sedimentation tank 22 is transported to the tailwater sedimentation tank 61 for further sedimentation. The flocculation dosing device 52 is connected to the tailwater tertiary sedimentation tank 62. The flocculated supernatant obtained from flocculation and sedimentation in the flocculation dosing device 52 is transported to the tailwater tertiary sedimentation tank 62 for sedimentation. Then, the supernatant obtained from sedimentation in the tailwater tertiary sedimentation tank 62 is pumped out by the third transfer pump 64. The supernatant obtained from the tailwater sedimentation tank 61 and the supernatant obtained from the tailwater tertiary sedimentation tank 62 are mixed to obtain a mixed liquid. The concentration of suspended solids in the mixed liquid is monitored in real time by the turbidity meter 65. When the concentration of suspended solids in the mixed liquid exceeds N0 mg / L, the second three-way solenoid valve 66 is controlled to transport the mixed liquid to the tailwater purification device 63 for purification treatment. After reaching the standard, it is discharged. When the concentration of suspended solids in the mixed liquid is ≤ N0 mg / L... When the concentration is mg / L, the mixture is directly delivered to the drainage pipeline for discharge by controlling the second three-way solenoid valve 66.

[0060] Among them, N0 is the standard requirement value for wastewater discharge, which is related to the receiving water body into which it is discharged, and is generally 10; turbidity and suspended solids concentration have a linear relationship, which can be obtained by fitting, or estimated by using 1 mg / L = 0.13 NTU.

[0061] Example 2

[0062] A method for dewatering, solidifying, and utilizing sand-containing slurry, implemented in the sand-containing slurry dewatering, solidifying, and resource utilization system of Example 1, includes the following specific steps:

[0063] S1. The sandy mud obtained from the dredging of the river (the sandy mud is high sandy mud, in which the weight ratio of coarse sand: fine sand: mud is 0.4-5:0.4-2:1, and in this embodiment the weight ratio of coarse sand: fine sand: mud is 3:1:1) is transported from the dredging mud pipe outlet to the slag removal unit 1 for slag removal. Then the slag-removed sandy mud is transported to the mortar sedimentation tank 21. The mortar will preferentially settle in the mortar sedimentation tank 21, while the less dense mud will enter the mortar sedimentation tank 22 through the opening on the geotextile 27 and undergo further sedimentation in the mortar sedimentation tank 22 to obtain concentrated mud and supernatant. At the same time, the density of the slurry at the opening of the geotextile 27 is measured in real time using the first density meter 25, so that the position of the geotextile 27 can be adjusted in time by the motor-driven track 26. The calculation formula for the position of the geotextile 27 is shown in formula (1) and formula (2).

[0064] S2. The mortar obtained in the mortar settling tank 21 is pumped out through the mortar pump 23, and the density of the mortar from the mortar settling tank 21 is measured using the third density meter 33; when the average density of the mortar within 0.5 hours is ≤1.5 g / cm³. 3(Setting the sampling and monitoring interval of the third density meter 33 to 10 minutes, and continuously monitoring three times within 0.5 hours, taking the average value, which is the average density of the mortar within 0.5 hours), the first three-way solenoid valve 34 is adjusted to transport the mortar through the first outlet of the first three-way solenoid valve 34 to the fine sand transfer tank 41 for homogenization; when the average density of the mortar within 0.5 hours is > 1.5 g / cm³. 3 At the same time, the first three-way solenoid valve 34 is regulated, and the mortar is transported to the coarse sand filter tank 31 through the second outlet of the first three-way solenoid valve 34. The mortar flows through the sand pile 32 in the coarse sand filter tank 31, causing the coarse sand contained in the mortar to settle. The mortar after removing the coarse sand is transported to the fine sand transfer tank 41 for homogenization. The loader enters the coarse sand filter tank 31 through the detachable baffle 35 to transfer the settled coarse sand. The mortar that overflows and leaks from the detachable baffle 35 is collected through the drainage ditch 36 and transported to the fine sand transfer tank 41 for homogenization. The material obtained after homogenization in the fine sand transfer tank 41 is transported to the hydrocyclone separator 42 for hydrocyclone separation to obtain fine sand slurry. The fine sand slurry is then transported to the vibrating screen 43 for screening. The screened fine sand is transported to the stockpile through the first conveyor belt 45 and then transported off-site for disposal.

[0065] S3. The concentrated slurry obtained from the slurry sedimentation tank 22 is pumped out by the slurry pump 24 and transported to the slurry transfer tank 51 for homogenization (the upper layer material obtained after hydrocyclone separation by the hydrocyclone separator 42 is also transported to the slurry transfer tank 51 for homogenization, and the undersize material obtained from the vibrating screen 43 is also sent to the slurry transfer tank 51 for homogenization). The material obtained after homogenization in the slurry transfer tank 51 is pumped by the second transfer pump 58 to the flocculation dosing equipment 52 for flocculation and sedimentation. The precipitated slurry obtained after flocculation and sedimentation is transported to the slurry dewatering filter press 53 for filter pressing. The filter cake is obtained (the filter tailwater obtained from the slurry dewatering filter press 53 is transported back to the slurry transfer tank 51 for recycling). Then, the planting soil and bentonite in the soil holding bin 54 are transported to the mixing machine 55 via the second conveyor belt 56. The filter cake is then transported to the mixing machine 55 via the third conveyor belt 57. In the mixing machine 55, the filter cake is mixed with the planting soil and bentonite to obtain greening soil, which is then transported to the park for planting soil to achieve resource utilization. The moisture content of the filter cake is 60%, and the weight ratio of the filter cake, bentonite and planting soil is 20:1:2.

[0066] S4. The supernatant from the mud sedimentation tank 22 is transferred to the tailwater sedimentation tank 61 for further sedimentation (when the average density of the supernatant detected by the second density meter 28 in the mud sedimentation tank 22 within 0.5 hours is ≥1.1 g / cm³). 3At this time (sampling and monitoring interval of 10 minutes is set for the second density meter 28, and three consecutive monitorings are conducted within 0.5 hours, and the average value is taken as the average density of the supernatant within 0.5 hours), the mud sedimentation tank 22 is already at full load, the slag removal unit 1 is shut down, and the conveying of slag-removed sand-containing mud to the mortar sedimentation tank 21 is stopped), the flocculated supernatant obtained from flocculation and sedimentation in the flocculation dosing equipment 52 is transported to the tertiary sedimentation tank 62 for sedimentation, and then the supernatant obtained from sedimentation in the tertiary sedimentation tank 62 is pumped out through the third transfer pump 64. The supernatant obtained from the tertiary sedimentation tank 61 and the supernatant obtained from the tertiary sedimentation tank 62 are mixed to obtain a mixed liquid. The concentration of suspended solids in the mixed liquid is detected in real time by the turbidity meter 65. When the concentration of suspended solids in the mixed liquid exceeds N0, When the concentration of suspended solids in the mixture is ≤ N0 mg / L, the mixture is transported to the tailwater purification equipment 63 through the first outlet of the second three-way solenoid valve 66 by controlling the second three-way solenoid valve 66 for purification treatment. After reaching the standard, it is discharged. When the concentration of suspended solids in the mixture is ≤ N0 mg / L (N0 is 10), the mixture is directly transported to the drainage pipeline through the second outlet of the second three-way solenoid valve 66 by controlling the second three-way solenoid valve 66 for discharge.

[0067] This invention optimizes traditional mud sedimentation tanks into separate sedimentation systems for mortar and mud without altering the existing facility area. The mortar is sent to a coarse sand sedimentation unit, where a slow-flowing sand pile slows the flow rate and promotes rapid settling of large coarse sand particles. Without increasing energy consumption, only a small coarse sand overflow tank is added, which solves the dewatering problem of coarse sand, which accounts for up to 60% of the total sand. Fine sand slurry further separates the fine sand, and the separated mud enters a mud dewatering and resource utilization unit. By mixing it with planting soil and bentonite, the moisture content is relaxed, reducing the cost of expensive flocculants while ensuring dewatering effect and solving the sludge disposal problem. It achieves the main indicators for greening utilization based on the mud cake principle and can be used as landscaping soil. The tailwater is treated by sedimentation, three-stage sedimentation, and tailwater purification equipment before being discharged in compliance with standards.

[0068] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0069] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A system for dewatering, solidifying, and resource utilization of sand-containing slurry, characterized in that, The system for dewatering, solidifying and utilizing sandy mud includes a sedimentation unit (2), a fine sand removal unit (4), a mud dewatering and resource utilization unit (5), and a tailwater treatment unit (6). The sedimentation unit (2) includes a sedimentation tank and a geotextile (27). The geotextile (27) is movably installed in the sedimentation tank via a motor-driven track (26) and divides the sedimentation tank into a mortar sedimentation tank (21) and a mud sedimentation tank (22). An opening is provided on the geotextile (27) to connect the mortar sedimentation tank (21) and the mud sedimentation tank (22). After slag removal, the sand-containing slurry is transported to the slurry sedimentation tank (21), where the slurry settles. The slurry enters the slurry sedimentation tank (22) through the opening on the geotextile (27) and settles there to obtain concentrated slurry and supernatant. The fine sand removal unit (4) is connected to the sedimentation unit (2). The mud dewatering and resource utilization unit (5) is connected to the sedimentation unit (2). The mud dewatering and resource utilization unit (5) is used to flocculate and precipitate the concentrated mud from the sedimentation unit (2) to obtain precipitated mud. Then, the water in the precipitated mud is removed to prepare greening soil. The tailwater treatment unit (6) is connected to the sedimentation unit (2), and the tailwater treatment unit (6) is used to treat the supernatant from the sedimentation unit (2) as tailwater. A first density meter (25) is installed at the opening of the geotextile (27) to measure the density of the slurry at the opening in real time. The calculation formulas for the position of the geotextile (27) are shown in Equations (1) and (2): （1） （2） In equations (1) and (2), x is the distance between the geotextile (27) and the initial position; B is the width of the mortar settling tank (21), h is the depth of the mortar in the mortar settling tank 21, and V is the depth of the mortar in the mortar settling tank 21. s0 V is the volume of the mortar settling tank (21) when the geotextile (27) is in its initial position. n0 ρ is the volume of the slurry settling tank (22) when the geotextile (27) is in its initial position. s ρ is the average density of the slurry in the mortar settling tank (21). n ρ is the average density of the slurry in the mud settling tank (22). t For the real-time density measurement of the first density meter (25), V s V is the volume of the mortar settling tank (21) after the geotextile (27) is adjusted. n The volume of the mud sedimentation tank (22) after the geotextile (27) is adjusted; The system for dewatering, solidifying and resource utilization of sandy mud also includes a coarse sand removal unit (3). The coarse sand removal unit (3) includes a coarse sand filter (31), the inlet end of the coarse sand filter (31) is provided with a sand pile (32), and the side wall of the coarse sand filter (31) away from the sand pile (32) is provided with a detachable baffle (35). The coarse sand removal unit (3) also includes a first three-way solenoid valve (34). The sedimentation unit (2) is connected to the inlet of the first three-way solenoid valve (34). The first outlet of the first three-way solenoid valve (34) is connected to the fine sand removal unit (4). The second outlet of the first three-way solenoid valve (34) is connected to the coarse sand filter (31). The coarse sand removal unit (3) is also connected to the fine sand removal unit (4). A third density meter (33) is also provided at the inlet of the first three-way solenoid valve (34) to measure the density of mortar from the mortar settling tank (21). The density of the mortar is ≤1.5 g / cm³ over a period of more than 0.5 h. 3 At that time, by regulating the first three-way solenoid valve (34), the mortar is transported to the fine sand removal unit (4) for solid-liquid separation to obtain fine sand; when the average density of the mortar is >1.5g / cm³ for more than 0.5h. 3 At that time, the first three-way solenoid valve (34) is adjusted to transport the slurry to the coarse sand filter tank (31) to remove the coarse sand. Then, the slurry after removing the coarse sand is transported to the fine sand removal unit (4) for solid-liquid separation to obtain fine sand.

2. The system for dewatering, solidifying, and resource utilization of sand-containing slurry according to claim 1, characterized in that, The sand-containing mud dewatering, solidification and resource utilization system also includes a slag removal unit (1), which is connected to the sedimentation unit (2). The slag removal unit (1) is used to remove slag from the sand-containing mud, and then the slag-removed sand-containing mud is transported to the sedimentation unit (2).

3. The system for dewatering, solidifying, and resource utilization of sand-containing slurry according to claim 1, characterized in that, The fine sand removal unit (4) includes a fine sand transfer tank (41) and a hydrocyclone separator (42) connected to the fine sand transfer tank (41). The mortar from the sedimentation unit (2) is homogenized in the fine sand transfer tank (41) and then transported to the hydrocyclone separator (42) for hydrocyclone separation to obtain fine mortar; The fine sand removal unit (4) further includes a vibrating screen (43) for screening the fine sand slurry from the hydrocyclone separator (42) to obtain fine sand.

4. The system for dewatering, solidifying, and resource utilization of sand-containing slurry according to claim 1, characterized in that, The mud dewatering and resource utilization unit (5) includes a mud transfer tank (51), a flocculation dosing device (52), and a mud dewatering filter press (53) connected sequentially along the material direction. The concentrated slurry from the sedimentation unit (2) is homogenized in the slurry transfer tank (51) and then transported to the flocculation dosing equipment (52) for flocculation and sedimentation. The resulting precipitated slurry is then transported to the slurry dewatering filter press (53) for filter press to obtain filter cake. The mud dewatering and resource utilization unit (5) also includes a mixer (55), in which the filter cake from the mud dewatering filter press (53) is mixed with planting soil and bentonite to obtain soil for landscaping.

5. The system for dewatering, solidifying, and resource utilization of sand-containing slurry according to claim 4, characterized in that, The mud transfer tank (51) is connected to the fine sand removal unit (4).

6. The system for dewatering, solidifying, and resource utilization of sand-containing slurry according to claim 1, characterized in that, The mud dewatering and resource utilization unit (5) is connected to the tailwater treatment unit (6); The tailwater treatment unit (6) includes a tailwater sedimentation tank (61), a tailwater tertiary sedimentation tank (62), a tailwater purification device (63), and a second three-way solenoid valve (66). The tailwater sedimentation tank (61) and the tailwater tertiary sedimentation tank (62) are both connected to the inlet of the second three-way solenoid valve (66). The first outlet of the second three-way solenoid valve (66) is connected to the tailwater purification device (63), and the second outlet of the second three-way solenoid valve (66) is connected to the drainage pipeline.

7. A method for dewatering and solidification of sand-containing slurry and resource utilization, characterized by, The method is implemented in the sand-containing mud dewatering, solidification, and resource utilization system according to any one of claims 1-6, and the method includes: The sand-containing mud is transported to the sedimentation unit (2) for separation to obtain slurry and mud, and the mud is precipitated to obtain concentrated mud and supernatant; The density of the mortar obtained in the sedimentation unit (2) is monitored. When the average density of the mortar obtained in the sedimentation unit (2) is ≤1.5g / cm³ over a period of more than 0.5h, the density is monitored. 3 When the mortar obtained in the sedimentation unit (2) is transported to the fine sand removal unit (4) for solid-liquid separation, fine sand is obtained; when the average density of the mortar obtained in the sedimentation unit (2) is >1.5 g / cm³ for more than 0.5 h. 3 At that time, the mortar obtained in the sedimentation unit (2) is transported to the coarse sand removal unit (3) to remove the coarse sand, and then the mortar after removing the coarse sand is transported to the fine sand removal unit (4) for solid-liquid separation to obtain fine sand; The concentrated mud obtained in the sedimentation unit (2) is transported to the mud dewatering and resource utilization unit (5) for flocculation and sedimentation to obtain sedimented mud. Then, the water in the sedimented mud is removed to prepare greening soil. The supernatant obtained in the sedimentation unit (2) is transported to the tailwater treatment unit (6) for tailwater treatment.

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