Shield slag zero-emission treatment system and method

Abstract

This invention relates to a zero-discharge treatment system and method for tunnel boring machine (TBM) excavation. The system includes a vibrating screen with a hopper at the bottom, the hopper's outlet connected to a first pipe; a spiral sand washer located below the first pipe, with an overflow pipe connected to a wastewater tank; a coarse sand conveyor with its inlet below the spiral sand washer's outlet; a hydrocyclone separator with its inlet connected to the wastewater tank; a fine sand recovery machine located below the hydrocyclone separator's underflow outlet; a fine sand conveyor with its inlet below the fine sand recovery machine's outlet; a clean water spraying device with its outlet above the vibrating screen; a clean water conveying device with its outlet above the sand washer; a flocculation purification tank connected to the hydrocyclone separator; and an automatic dosing device and a filter press, each connected to the flocculation purification tank. This invention provides on-site treatment of TBM excavation, separating it into gravel and sand for recycling, and achieving zero wastewater discharge.

Description

Technical Field

[0001] The invention belongs to the technical field of slag treatment, and relates to shield slag treatment technology, and specifically, to a shield slag zero-emission treatment system and method. Background Art

[0002] In the process of rapid social development, urban tunnels and subways are being built in large quantities as part of social infrastructure construction. The shield construction method is used in urban tunnel and subway construction due to its safety, high construction efficiency, low cost and wide applicability. A large amount of shield debris is generated during the shield construction process. How to deal with the shield debris generated by shield construction is an important issue.

[0003] At present, the treatment method for shield slag is to directly transport it out for landfill and stacking. This treatment method will form a construction slag treatment and disposal area. Plants are difficult to grow in the construction slag treatment and disposal area, which not only occupies land, but also causes serious environmental pollution. For example, due to the unstable accumulation of water-containing slag, landslides and collapses are prone to occur, which is one of the main sources of sand and dust pollution; the liquid leaching of slag will cause serious pollution to the water source near the construction slag treatment and disposal area. In addition, due to the characteristics of high mud content and high water content of shield slag, it is inevitable that it will leak during transportation, causing pollution to the road environment. Summary of the invention

[0004] In view of the above-mentioned problems existing in the existing shield slag treatment process, the present invention provides a shield slag zero-emission treatment system and method, which is used for on-site treatment of shield slag generated during the construction of urban tunnels, subways, etc., so that the shield slag can be separated into gravel and sand for recycling, and zero sewage discharge can be achieved.

[0005] In order to achieve the above object, the present invention provides a shield slag zero-discharge treatment system, comprising:

[0006] A vibrating screening machine, wherein the discharge port of the vibrating screening machine is arranged above the stone bin, a hopper is arranged at the lower part of the vibrating screening machine, and the discharge port of the hopper is connected to a first pipeline;

[0007] A spiral sand washing machine, wherein the sand washing tank of the spiral sand washing machine is located below the first pipeline, and the spiral sand washing machine is provided with an overflow pipeline connected to the sewage tank;

[0008] Coarse sand belt conveyor, the feeding port of the coarse sand belt conveyor is located below the discharging port of the spiral sand washing machine, and the discharging port of the coarse sand belt conveyor is located above the coarse sand silo;

[0009] A cyclone separator, wherein the feed port of the cyclone separator is connected to the sewage tank;

[0010] A fine sand recovery machine is located below the underflow port of the cyclone separator;

[0011] Fine sand belt conveyor, the feed port of the fine sand belt conveyor is located below the discharge port of the fine sand recovery machine, and the discharge port of the fine sand belt conveyor is located above the fine sand silo;

[0012] A clean water spray device is connected to the clean water tank, and a water outlet of the clean water spray device is arranged above the vibrating screening machine;

[0013] A clean water conveying device is connected to the clean water tank, and a water outlet of the clean water conveying device is arranged above the sand washing tank;

[0014] A flocculation purification tank is connected to the overflow port of the cyclone separator;

[0015] and an automatic dosing device and a filter press which are respectively connected to the flocculation purification tank.

[0016] Furthermore, it also includes a feeding device, which is arranged on the feeding side of the vibrating screening machine.

[0017] Preferably, the fine sand recovery machine is provided with a lower water tank, which is connected to the sewage pool through a sewage conveying device, the feed port of the cyclone separator is connected to the sewage pool through a first conveying device, and the feed port of the cyclone separator is connected to the lower water tank through a second conveying device.

[0018] Preferably, the sewage conveying device includes a sewage pump arranged in the sewage pool and a sewage pipe connecting the lower water tank and the sewage pump; the first conveying device includes a first slurry pump arranged in the sewage pool and a first conveying pipe connecting the first slurry pump and the feed port of the cyclone separator; the second conveying device includes a second slurry pump arranged in the lower water tank and a second conveying pipe connecting the second slurry pump and the feed port of the cyclone separator.

[0019] Preferably, it also includes a transfer tank, which is connected to the overflow port of the cyclone separator through a second pipe, and the transfer tank is connected to the flocculation purification tank through a third conveying device, and the third conveying device includes a third slurry pump arranged in the transfer tank and a third conveying pipe connecting the third slurry pump and the flocculation purification tank.

[0020] Preferably, the sewage tank and the transfer tank are both provided with liquid level float switches.

[0021] Preferably, the automatic dosing device includes a dosing container for injecting liquid medicine, a metering pump arranged in the dosing container, a dosing pipeline connected to the metering pump, and a control module, the metering pump is electrically connected to the control module, the dosing pipeline is directly connected to the flocculation purification tank, and the control module is electrically connected to a flow meter arranged on the third conveying pipeline.

[0022] Preferably, the clean water spray device includes a first clean water pump arranged in the clean water tank and a spray water pipe connected to the first clean water pump, and the water outlet of the clean water spray device is arranged on the spray water pipe; the clean water conveying device includes a second clean water pump arranged in the clean water tank and a clean water pipe connected to the second clean water pump, and the water outlet of the clean water conveying device is arranged on the clean water pipe.

[0023] Preferably, the flocculation purification tank is provided with a first clean water outlet, which is connected to the clean water tank through a third pipe, and the flocculation purification tank is connected to the filter press through a fourth conveying device; the fourth conveying device includes a fourth slurry pump arranged in the flocculation purification tank and a fourth conveying pipe connecting the fourth slurry pump and the filter press; the filter press is provided with a second clean water outlet, and the second clean water outlet is located above the clean water tank.

[0024] In order to achieve the above object, the present invention also provides a shield slag zero-emission treatment method, comprising the following steps:

[0025] The slag generated by shield construction is sent to the vibrating screen, which is sprayed with clean water during operation. The large-particle stone with a particle size of >6mm is screened into the stone bin by the vibrating screen, and the mud water screened by the vibrating screen is sent to the spiral fine sand machine;

[0026] The high-pressure clean water is transported to the spiral fine sand machine. After the mud water is washed by the high-pressure clean water and the spiral mixing and washing of the spiral fine sand machine, the coarse sand with a particle size of ≤6mm and >2.3mm falls into the coarse sand belt conveyor and is transported to the coarse sand silo by the coarse sand belt conveyor, and the mud sewage enters the sewage pool;

[0027] The muddy sewage in the sewage pool is directly sent to the cyclone separator, or first sent to the lower water tank and then sent to the cyclone separator from the lower water tank; the muddy sewage is separated by the cyclone separator, the fine sand mud produced enters the fine sand recovery machine, and the overflow sewage enters the flocculation purification tank;

[0028] The fine sand recovery machine dehydrates and screens the fine sand slurry from the cyclone separator, and sends the fine sand with a particle size of ≤2.3mm and ≥0.5mm to the fine sand belt conveyor, which then sends it to the fine sand silo. The screened material enters the lower water tank, which then sends it to the cyclone separator and to the fine sand recovery machine for cyclic washing.

[0029] The flocculation purification tank flocculates the overflow sewage from the cyclone separator. At the same time, the automatic dosing device automatically adds flocculation agents to the flocculation purification tank to accelerate the flocculation process. The upper clear liquid of the flocculation purification tank flows into the clear water tank, and the flocculated mud in the flocculation purification tank is sent to the filter press.

[0030] The filter press dries and dehydrates the mud from the flocculation purification tank. The dried mud cake is discharged and the liquid after filtration flows into the clean water tank.

[0031] Compared with the prior art, the advantages and positive effects of the present invention are:

[0032] (1) The present invention has a reasonable structure and compact layout, occupies less space for shield slag treatment, and can perform on-site screening, sand washing, cyclone separation, flocculation and filter press treatment on shield slag, thereby achieving graded solid-liquid separation of sand and gravel of different particle sizes and water in shield slag, turning waste into treasure, and reusing inorganic raw materials and water resources of slag. While saving social resources, it generates huge economic benefits. The transportation volume of treated shield slag is greatly reduced, effectively reducing transportation costs.

[0033] (2) The present invention treats shield construction waste at the shield construction site in an environmentally friendly manner, and separates the shield construction waste into gravel, coarse sand, fine sand and dried mud cake. The separated gravel, coarse sand and fine sand can be used for on-site shield construction. Since the dried mud cake has a low water content, there is no leakage problem during transportation, thus avoiding the leakage pollution of the road environment caused by direct external transportation, the need for a storage yard to waste a large amount of land resources, and the leachate pollution of the environment.

[0034] (3) The present invention performs circulating cyclone separation and fine sand recovery on mud water, which can effectively buffer and reduce mud blockage, improve the processing efficiency of the equipment and the quality of sand and gravel.

[0035] (4) The clean water in the clean water tank of the present invention is screened, sprayed and spirally finely sanded, and then flows back into the clean water tank after flocculation and pressure filtration, thereby realizing the recycling of clean water and reducing the amount of circulating water required by the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a simplified structural diagram of a shield slag zero-discharge treatment system according to an embodiment of the present invention;

[0037] Figure 2 The present invention is a flow chart of the shield tunneling slag zero-emission treatment method.

[0038] In the figure, 1, vibrating screening machine, 101, discharge port of vibrating screening machine, 102, hopper, 103, first pipeline, 2, stone silo, 3, spiral sand washing machine, 301, sand washing trough, 302, overflow pipeline, 303, discharge port of spiral sand washing machine, 4, sewage pool, 5, coarse sand belt conveyor, 6, coarse sand silo, 7, cyclone separator, 701, feed port of cyclone separator, 702, bottom flow port of cyclone separator, 703, overflow port of cyclone separator, 704, second pipeline, 8, fine sand recovery machine, 801, discharge port of fine sand recovery machine, 802, lower water tank, 9, fine sand belt conveyor, 901, discharge port of fine sand belt conveyor, 10, fine sand silo, 11, clean water spraying device, 12, clean water conveying device, 13, flocculation purification tank, 1301, first clean water outlet, 1302, third pipeline, 14, automatic dosing device, 1401, dosing pipeline, 15, filter press, 1501, second clean water outlet, 16, clean water tank, 17, feeding device, 18, sewage conveying device, 19, first conveying device, 20, second conveying device, 21, transfer tank, 22, third conveying device. DETAILED DESCRIPTION

[0039] The present invention is described in detail below by way of exemplary embodiments. However, it should be understood that elements, structures, and features in one embodiment may also be beneficially combined in other embodiments without further description.

[0040] In the description of the present invention, it should be noted that the terms "upper", "lower", "top", "bottom", etc., indicating the orientation or positional relationship, are based on the positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0041] See also Figure 1 In one embodiment of the present invention, a shield slag zero-emission treatment system is provided, comprising:

[0042] A vibrating screening machine 1, wherein a discharge port 101 of the vibrating screening machine is arranged above the stone bin 2, a hopper 102 is arranged at the lower part of the vibrating screening machine 1, and a first pipe 103 is connected to the discharge port of the hopper;

[0043] A spiral sand washer 3, wherein a sand washing tank 301 of the spiral sand washer 3 is located below the first pipeline 103, and the spiral sand washer 3 is provided with an overflow pipeline 302 connected to the sewage tank 4;

[0044] A coarse sand belt conveyor 5, wherein the feed port of the coarse sand belt conveyor 5 is located below the discharge port 303 of the spiral sand washing machine, and the discharge port 501 of the coarse sand belt conveyor is located above the coarse sand silo 6;

[0045] A cyclone separator 7, wherein a feed port 701 of the cyclone separator is connected to the sewage tank 4;

[0046] The fine sand recovery machine 8 is located below the bottom flow outlet 702 of the cyclone separator;

[0047] A fine sand belt conveyor 9, the feed port of the fine sand belt conveyor 9 is located below the discharge port 801 of the fine sand recovery machine, and the discharge port 901 of the fine sand belt conveyor is located above the fine sand silo 10;

[0048] A clean water spray device 11 is connected to the clean water tank 16, and a water outlet of the clean water spray device 11 is arranged above the vibrating screening machine 1;

[0049] The clean water conveying device 12 is connected to the clean water tank 16, and the water outlet of the clean water conveying device 12 is arranged above the sand washing tank 301;

[0050] The flocculation purification tank 13 is connected to the overflow port of the cyclone separator 7;

[0051] And an automatic dosing device 14 and a filter press 15 which are respectively connected to the flocculation purification tank 12.

[0052] The above-mentioned processing system of the present invention has devices that are closely connected and complement each other, have low operation and maintenance costs, save resources, and have the advantages of simple structure, stable operation, small footprint, and strong operability. It can make up for the shortcomings of small shield construction site area and inability to store shield slag, and the processed gravel, coarse sand, and fine sand can be used in on-site shield construction, and has high application value.

[0053] Continue to see Figure 1 In order to facilitate the feeding of shield slag into the vibrating screening machine and improve the processing efficiency. In a preferred implementation of the above embodiment, the above processing system also includes a feeding device 17, and the feeding device 17 is arranged on the feeding side of the vibrating screening machine 1. Specifically, the feeding device is an excavator, and other feeding devices with lifting functions can also be used.

[0054] For details, see Figure 1The fine sand recovery machine 8 is provided with a lower water tank 802, which is connected to the sewage pool 4 through a sewage conveying device 18, and the feed port 701 of the cyclone separator is connected to the sewage pool 4 through a first conveying device 19, and the feed port 701 of the cyclone separator is connected to the lower water tank 802 through a second conveying device 20. Sewage can enter the cyclone separator directly from the sewage pool through the first conveying device, or it can be first sent to the lower water tank through the sewage conveying device, and then sent from the lower water tank to the cyclone separator by the second conveying device. The cyclone separator separates the fine sand slurry and water in the sewage, and the fine sand slurry enters the fine sand recovery machine for dehydration and screening. The fine sand is sent to the fine sand belt conveyor by the recovery screen of the fine sand recovery machine, and then sent to the fine sand silo. The screened material enters the lower water tank and is sent to the cyclone separator again through the second conveying device to separate the fine sand slurry and water, and then to the fine sand recovery machine for cyclic washing, which can effectively buffer and reduce mud blockage, improve equipment efficiency and sand and gravel quality.

[0055] Specifically, see Figure 1 The sewage conveying device 18 includes a sewage pump arranged in the sewage pool and a sewage pipe connecting the lower water tank 802 and the sewage pump; the first conveying device 19 includes a first slurry pump arranged in the sewage pool and a first conveying pipe connecting the first slurry pump and the feed port 701 of the cyclone separator; the second conveying device 20 includes a second slurry pump arranged in the lower water tank 802 and a second conveying pipe connecting the second slurry pump and the feed port 701 of the cyclone separator.

[0056] Continue to see Figure 1 In a preferred implementation of the above embodiment, the above treatment system further includes a transfer tank 21, the transfer tank 21 is connected to the overflow port 703 of the cyclone separator through a second pipe 704, the transfer tank 21 is connected to the flocculation purification tank 13 through a third conveying device 22, and the third conveying device 22 includes a third slurry pump arranged in the transfer tank and a third conveying pipe connecting the third slurry pump and the flocculation purification tank. Since the excessive overflow sewage generated in the cyclone separator is directly transported to the flocculation purification tank for flocculation treatment, the flocculation of a large amount of sewage cannot be completed due to the limited volume of the flocculation purification tank. Therefore, the overflow sewage generated by the cyclone separator is first overflowed to the transfer tank for storage, and then the sewage is transported from the transfer tank to the flocculation purification tank through the third conveying device for flocculation treatment according to the treatment situation of the flocculation purification tank.

[0057] Specifically, the sewage pool 4 and the transfer pool 21 are both provided with a liquid level float switch. When the sewage level in the sewage pool and the transfer pool reaches a preset value, the liquid level float switch is turned on, and the sewage in the pool can flow into the next treatment equipment through a pump and a pipeline.

[0058] Specifically, see Figure 1 The automatic dosing device 14 includes a dosing container for injecting liquid medicine, a metering pump arranged in the dosing container, a dosing pipeline 1401 connected to the metering pump, and a control module. The metering pump is electrically connected to the control module. The dosing pipeline 1401 is directly connected to the flocculation purification tank 13. The control module is electrically connected to a flow meter arranged on the third delivery pipeline. The automatic dosing device controls the input flow of the metering pump through the control module to pump the flocculation agent into the flocculation purification tank. The control module adjusts the flow of the flocculation agent pumped into the flocculation purification tank according to the flow detected by the metering meter from the transfer tank into the flocculation purification tank.

[0059] Specifically, the clean water spray device 11 includes a first clean water pump disposed in the clean water tank 16 and a spray water pipe connected to the first clean water pump, and the water outlet of the clean water spray device 11 is disposed on the spray water pipe; the clean water delivery device 12 includes a second clean water pump disposed in the clean water tank 16 and a clean water pipeline connected to the second clean water pump, and the water outlet of the clean water delivery device is disposed on the clean water pipeline. The clean water tank delivers clean water to the vibrating screening machine through the clean water spray device to clean the sludge on the surface of the screened stone, reduce the mud content of the stone, and provide better conditions for the reuse of the stone. The clean water tank delivers high-pressure clean water to the spiral sand washing machine through the clean water delivery device, performs high-pressure washing on the sand and gravel slurry in the sand washing tank, reduces the clay adhering to the sand and gravel, effectively reduces the mud content of the sand and gravel, and provides better conditions for the reuse of sand and gravel resources.

[0060] Specifically, the flocculation purification tank 13 is provided with a first clean water outlet 1301, the first clean water outlet 1301 is connected to the clean water tank 16 through the third pipeline 1302, and the flocculation purification tank is connected to the filter press 15 through the fourth conveying device 23; the fourth conveying device 23 includes a fourth slurry pump arranged in the flocculation purification tank 13 and a fourth conveying pipe connecting the fourth slurry pump and the filter press 15; the filter press 15 is provided with a second clean water outlet 1501, and the second clean water outlet 1501 is located above the clean water tank 16. The clean water generated by the flocculation purification tank flows into the clean water tank through the first clean water outlet and the third pipeline for recycling, and the mud generated by the flocculation purification tank is pumped into the filter press through the fourth conveying device, and is dried and dehydrated by the filter press to form a mud cake for discharge. Similarly, the clean water generated by the filter press flows into the clean water tank through the second clean water outlet for recycling. It effectively improves the utilization rate of resources, saves resources, and is beneficial to environmental protection.

[0061] The process of shield slag treatment by the above-mentioned shield slag zero emission treatment system is as follows:

[0062] The feeding device sends the shield slag into the vibrating screening machine for stone screening. During the operation of the vibrating screening machine, the clear water tank sprays the shield slag through the clear water spray device, and the large-particle stone with a particle size > 6mm is screened into the stone bin by the vibrating screening machine. The mud water screened by the vibrating screening machine flows into the hopper and is transported to the sand washing tank of the spiral fine sand machine through the first pipeline. The clear water tank transports high-pressure clean water to the sand washing tank through the clean water conveying device. After the mud water in the sand washing tank is flushed with high-pressure clean water and washed by the spiral stirring of the spiral fine sand machine, the coarse sand with a particle size ≤ 6mm and > 2.3mm falls into the coarse sand belt conveyor through the discharge port of the spiral fine sand machine, and is transported to the coarse sand silo by the coarse sand belt conveyor. The mud sewage enters the sewage tank through the overflow pipe. The muddy sewage in the sewage pool is sent to the cyclone separator through the first conveying device, or sent to the lower water tank through the sewage conveying device, and then sent to the cyclone separator through the second conveying device; the muddy sewage is separated by the cyclone separator, and the generated fine sand slurry enters the fine sand recovery machine from the bottom flow port of the cyclone separator, and the overflow sewage enters the flocculation purification tank through the overflow port of the cyclone separator; the fine sand recovery machine dehydrates and screens the fine sand slurry from the cyclone separator, and sends the fine sand with a particle size of ≤2.3mm and ≥0.5mm to the fine sand belt conveyor, which is sent to the fine sand silo by the fine sand belt conveyor, and the screened material enters the lower water tank and is sent to the cyclone separator through the second conveying device to the fine sand recovery machine for cyclic washing. The flocculation purification tank flocculates the overflow sewage from the cyclone separator, and the flocculation agent is automatically added to the flocculation purification tank through the automatic dosing device to accelerate the flocculation process. The upper clear liquid of the flocculation purification tank flows into the clear water tank, and the flocculated mud in the flocculation purification tank is sent to the filter press. The filter press dries and dehydrates the mud from the flocculation purification tank, and the dried mud cake after treatment is discharged, and the liquid after filtration flows into the clear water tank.

[0063] The above-mentioned shield slag zero-emission treatment system of the present invention performs screening separation, spiral sand washing separation, cyclone separation and fine sand recovery treatment, flocculation treatment and filter press treatment on the shield slag, thereby realizing the recovery and reuse of stone, coarse sand and fine sand, and recycling water resources. The treated dried mud cake is easy to transport without leakage problems, thus solving the problems of resource waste and environmental pollution caused by shield slag, with a high resource reuse rate and realizing zero-emission treatment.

[0064] Another embodiment of the present invention provides a shield slag zero-emission treatment method, comprising the following steps:

[0065] S1. Send the slag generated by shield construction to the vibrating screening machine, spray it with clean water during the operation of the vibrating screening machine, and screen the large-particle stone with a particle size of >6mm into the stone bin through the vibrating screening machine. The muddy water screened by the vibrating screening machine is transported to the spiral fine sand machine. During the vibrating screening process, the slag is washed with clean water to wash away the sludge on the surface of the stone, so that the separation effect of the stone and the silt and sewage is better, and the separation efficiency is improved.

[0066] S2. High-pressure clean water is delivered to the spiral fine sand machine. After the mud water is washed by high-pressure clean water and the spiral fine sand machine's spiral stirring and washing, the coarse sand with a particle size of ≤6mm and >2.3mm falls into the coarse sand belt conveyor, which is transported to the coarse sand silo by the coarse sand belt conveyor, and the muddy sewage enters the sewage pool. Using high-pressure clean water for flushing during spiral fine sand can reduce the clay adhering to the sand and gravel, effectively reduce the mud content of the sand and gravel, and provide better conditions for the reuse of sand and gravel resources.

[0067] S3. The muddy sewage in the sewage pool is directly sent to the cyclone separator, or first sent to the lower water tank, and then sent to the cyclone separator from the lower water tank; the muddy sewage is separated by the cyclone separator, and the fine sand mud produced enters the fine sand recovery machine through the bottom flow port, and the overflow sewage enters the flocculation purification tank through the overflow port. The method of sending the muddy sewage in the sewage pool to the lower water tank first is mainly to effectively buffer and reduce mud blockage, and improve the separation efficiency of the cyclone separator and the quality of sand and gravel.

[0068] S4, the fine sand recovery machine dehydrates and screens the fine sand slurry from the cyclone separator, and sends the fine sand with a particle size of ≤2.3mm and ≥0.5mm to the fine sand belt conveyor, which is then sent to the fine sand silo. The screened material enters the lower water tank, which is then sent to the cyclone separator and the fine sand recovery machine for cyclic washing. The screened material is subjected to multiple cyclone separations and fine sand recovery, so that as much sand and gravel as possible can be separated, thereby improving the separation quantity and quality of sand and gravel.

[0069] S5. The flocculation purification tank flocculates the overflow sewage from the cyclone separator, and the flocculation agent is automatically added to the flocculation purification tank through the automatic dosing device to accelerate the flocculation process. The upper part of the clear liquid in the flocculation purification tank flows into the clear water tank, and the flocculated mud in the flocculation purification tank is sent to the filter press. The clear liquid produced by flocculation flows into the clear water tank for recycling, which can be recycled, saves energy, and is beneficial to environmental protection.

[0070] S6. The filter press dries and dehydrates the mud from the flocculation purification tank. The dried mud cake is discharged and the liquid after filtration flows into the clean water tank. The liquid produced by filtration flows into the clean water tank for recycling, which can be recycled, further saving energy and benefiting environmental protection.

[0071] In one embodiment of the above method, in step S3, when excess overflow sewage is generated in the cyclone separator, if it is directly transported to the flocculation purification tank for flocculation treatment, due to the limited volume of the flocculation purification tank, it is impossible to complete the flocculation of a large amount of sewage. Therefore, the overflow sewage generated by the cyclone separator can first overflow into the transfer tank for storage, and then according to the treatment situation of the flocculation purification tank, the sewage is transported from the transfer tank to the flocculation purification tank through a third conveying device for flocculation treatment.

[0072] The zero-emission treatment method for shield slag of the present invention performs screening separation, spiral sand washing separation, cyclone separation and fine sand recovery treatment, flocculation treatment and filter press treatment on the shield slag, thereby realizing the recovery and reuse of stone, coarse sand and fine sand, and recycling of water resources. The treated dried mud cake is easy to transport without leakage problems, thus solving the problems of resource waste and environmental pollution caused by shield slag, achieving a high resource reuse rate and realizing zero-emission treatment.

[0073] The above embodiments are used to explain the present invention rather than to limit the present invention. Any modification and change made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A shield slag zero-emission treatment system, characterized in that: include: A vibrating screening machine, the discharge port of which is arranged above the stone bin, a hopper is arranged at the bottom of the vibrating screening machine, the discharge port of which is connected with a first pipeline, and the vibrating screening machine is used to separate large-particle stones with a particle size of more than 6 mm; A spiral sand washing machine, wherein the sand washing tank of the spiral sand washing machine is located below the first pipeline, the spiral sand washing machine is provided with an overflow pipeline connected to the sewage tank, and the spiral sand washing machine is used to separate coarse sand with a particle size of ≤6mm and >2.3mm; a coarse sand belt conveyor, wherein the feed port of the coarse sand belt conveyor is located below the discharge port of the spiral sand washing machine, and the discharge port of the coarse sand belt conveyor is located above the coarse sand silo; A cyclone separator, wherein the feed port of the cyclone separator is connected to the sewage tank; The fine sand recovery machine is located below the bottom flow port of the cyclone separator. The fine sand recovery machine is connected to the feed port of the cyclone separator. The fine sand recovery machine dehydrates and screens the fine sand slurry from the cyclone separator to separate fine sand with a particle size of ≤2.3mm and ≥0.5mm. The separated undersize is sent to the cyclone separator to the fine sand recovery machine for cyclic washing. Fine sand belt conveyor, the feed port of the fine sand belt conveyor is located below the discharge port of the fine sand recovery machine, and the discharge port of the fine sand belt conveyor is located above the fine sand silo; A clean water spray device is connected to the clean water tank, and the water outlet of the clean water spray device is arranged above the vibrating screening machine; a clean water conveying device is connected to the clean water tank, and the water outlet of the clean water conveying device is arranged above the sand washing tank; a flocculation purification tank is connected to the overflow port of the cyclone separator, and the flocculation purification tank is provided with a first clean water outlet, and the first clean water outlet is connected to the clean water tank through a third pipeline; and an automatic dosing device and a filter press which are respectively connected with the flocculation purification tank; the filter press is provided with a second clean water outlet which is located above the clean water tank.

2. The shield slag zero-discharge treatment system according to claim 1, characterized in that: It also includes a feeding device, which is arranged on the feeding side of the vibration screening machine.

3. The shield slag zero-discharge treatment system according to claim 1 or 2, characterized in that: The fine sand recovery machine is provided with a lower water tank, which is connected to the sewage pool through a sewage conveying device, the feed port of the cyclone separator is connected to the sewage pool through a first conveying device, and the feed port of the cyclone separator is connected to the lower water tank through a second conveying device.

4. The shield slag zero-discharge treatment system according to claim 3, characterized in that: The sewage conveying device includes a sewage pump arranged in the sewage pool and a sewage pipe connecting the lower water tank and the sewage pump; the first conveying device includes a first slurry pump arranged in the sewage pool and a first conveying pipe connecting the first slurry pump and the feed port of the cyclone separator; the second conveying device includes a second slurry pump arranged in the lower water tank and a second conveying pipe connecting the second slurry pump and the feed port of the cyclone separator.

5. The shield slag zero-discharge treatment system according to claim 4, characterized in that: It also includes a transfer tank, which is connected to the overflow port of the cyclone separator through a second pipeline. The transfer tank is connected to the flocculation purification tank through a third conveying device. The third conveying device includes a third slurry pump arranged in the transfer tank and a third conveying pipe connecting the third slurry pump and the flocculation purification tank.

6. The shield slag zero-discharge treatment system according to claim 5, characterized in that: The sewage tank and the transfer tank are both provided with liquid level float switches.

7. The shield slag zero-discharge treatment system according to claim 5 or 6, characterized in that: The automatic dosing device includes a dosing container for injecting liquid medicine, a metering pump arranged in the dosing container, a dosing pipeline connected to the metering pump, and a control module. The metering pump is electrically connected to the control module, the dosing pipeline is directly connected to the flocculation purification tank, and the control module is electrically connected to a flow meter arranged on a third delivery pipeline.

8. The shield slag zero-discharge treatment system according to claim 7, characterized in that: The clean water spray device includes a first clean water pump arranged in the clean water tank and a spray water pipe connected to the first clean water pump, and the water outlet of the clean water spray device is arranged on the spray water pipe; the clean water conveying device includes a second clean water pump arranged in the clean water tank and a clean water pipeline connected to the second clean water pump, and the water outlet of the clean water conveying device is arranged on the clean water pipeline.

9. The shield slag zero-discharge treatment system according to claim 7, characterized in that: The flocculation purification tank is connected to the filter press through a fourth conveying device; the fourth conveying device includes a fourth slurry pump arranged in the flocculation purification tank and a fourth conveying pipe connecting the fourth slurry pump and the filter press.

10. A shield slag zero-emission treatment method, using the shield slag zero-emission treatment system according to any one of claims 3 to 9, characterized in that: Contains the following steps: The slag generated by shield construction is sent to the vibrating screen, which is sprayed with clean water during operation. The large-particle stone with a particle size of >6mm is screened into the stone bin by the vibrating screen, and the mud water screened by the vibrating screen is sent to the spiral fine sand machine; The high-pressure clean water is transported to the spiral fine sand machine. After the mud water is washed by the high-pressure clean water and the spiral mixing and washing of the spiral fine sand machine, the coarse sand with a particle size of ≤6mm and >2.3mm falls into the coarse sand belt conveyor and is transported to the coarse sand silo by the coarse sand belt conveyor, and the mud sewage enters the sewage pool; The muddy sewage in the sewage pool is directly sent to the cyclone separator, or first sent to the lower water tank and then sent to the cyclone separator from the lower water tank; the muddy sewage is separated by the cyclone separator, the fine sand mud produced enters the fine sand recovery machine, and the overflow sewage enters the flocculation purification tank; The fine sand recovery machine dehydrates and screens the fine sand slurry from the cyclone separator, and sends the fine sand with a particle size of ≤2.3mm and ≥0.5mm to the fine sand belt conveyor, which then sends it to the fine sand silo. The screened material enters the lower water tank, which then sends it to the cyclone separator and to the fine sand recovery machine for cyclic washing. The flocculation purification tank flocculates the overflow sewage from the cyclone separator. At the same time, the automatic dosing device automatically adds flocculation agents to the flocculation purification tank to accelerate the flocculation process. The upper clear liquid of the flocculation purification tank flows into the clear water tank, and the flocculated mud in the flocculation purification tank is sent to the filter press. The filter press dries and dehydrates the mud from the flocculation purification tank. The dried mud cake is discharged and the liquid after filtration flows into the clean water tank.

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