Radioactive slurry treatment system and treatment method

Abstract

The invention discloses a radioactive slurry treatment system and method, and the system comprises a receiving device which is used for receiving radioactive slurry; the filtering and drying device is connected with the receiving device, the filtering and drying device comprises a filter and a dryer arranged on the filter, the radioactive slurry is filtered through the filter, and filter residues obtained through filtering in the filter are dried through the dryer; the first collecting device is connected with a filtrate outlet of the filter, and the first collecting device is used for collecting filtrate obtained by filtering; the second collecting device is connected with a discharging valve of the filter, and the second collecting device is used for collecting dry mud obtained after filtering and drying treatment; the filtering and drying device is arranged in the hot chamber, and the receiving device, the first collecting device and the second collecting device are arranged outside the hot chamber. The solid content in the liquid is reduced through solid-liquid separation, and the cement is solidified after the waste liquid is concentrated; compared with a mud-water mixed state, the water content of a filtered filter cake is reduced, and the mud treatment efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of radioactive waste treatment, and in particular relates to a treatment system and a treatment method for radioactive mud. Background Art

[0002] When nuclear facilities are decommissioned, radioactive mud is deposited at the bottom of large radioactive waste liquid storage tanks. Compared with the waste liquid in the upper layer of the tank, the radioactivity of the bottom mud is 5-10 times or even higher. During the mud retrieval and transportation process, the solid content is generally controlled at 5-20vt%. Existing mud treatment methods include cement solidification and vacuum drying. If the retrieved mud is directly cemented, a large amount of waste will be generated to ensure that the radioactivity of the cement solidified body does not exceed the standard, which does not meet the waste minimization requirements of radioactive waste treatment; if the retrieved mud is sent to vacuum drying, due to the low efficiency of vacuum drying treatment, it cannot meet the treatment of a large amount of mud. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a radioactive mud treatment system and method in view of the above-mentioned deficiencies in the prior art. According to the distribution characteristics of radioactive nuclides in the upper clear liquid and the bottom mud, a solid-liquid separation and drying method is selected to minimize waste and improve the mud treatment efficiency.

[0004] The technical solution adopted to solve the technical problem of the present invention is to provide a radioactive mud treatment system, comprising:

[0005] a receiving device for receiving radioactive slurry;

[0006] A filtering and drying device is connected to the receiving device, and includes a filter and a dryer disposed on the filter. The radioactive mud is filtered through the filter, and the filter residue obtained by filtering in the filter is dried through the dryer.

[0007] A first collecting device, connected to the filtrate outlet of the filter, and used to collect the filtrate obtained by filtration;

[0008] A second collecting device is connected to the discharge valve of the filter, and is used to collect the dry mud obtained after filtering and drying;

[0009] The filtering and drying device is arranged in the hot room, and the receiving device, the first collecting device and the second collecting device are arranged outside the hot room.

[0010] Preferably, the receiving device comprises: a mud receiving tank, a first pipeline, and a feed valve. The mud receiving tank is connected to the filter through the first pipeline, and the feed valve is arranged on the first pipeline.

[0011] Preferably, the radioactive mud treatment system further comprises:

[0012] A liquid level detection device, a material level detection device, and a control unit. The liquid level detection device and the material level detection device are arranged in the filter. The liquid level detection device is used to send the detected liquid level in the filter to the control unit. The control unit controls the opening of the feed valve so that the liquid level does not exceed a preset limit. The material level detection device is used to send the detected material level of the filter residue in the filter (3) to the control unit. When the filter cake formed by the filter residue reaches the preset filter cake height, the control unit controls the feed valve (2) to close and no longer feeds.

[0013] Preferably, the radioactive mud treatment system further comprises:

[0014] The flushing pipeline is connected to the first pipeline, and the connection point is arranged on the first pipeline between the feed valve and the filter. The flushing pipeline is used to pass flushing water to flush the first pipeline.

[0015] Preferably, the radioactive mud treatment system further comprises:

[0016] The compressed air device is connected to the filter and is used to provide compressed air to the filter. The compressed air device is arranged outside the hot room.

[0017] Preferably, the compressed air device comprises: a second pipeline, a first valve, a third pipeline, a second valve,

[0018] The second pipeline is connected to the feed port of the filter, the first valve is arranged on the second pipeline, and the second pipeline is used to introduce compressed air;

[0019] The third pipeline is connected with the filtrate outlet of the filter, the second valve is arranged on the third pipeline, and the third pipeline is used for introducing compressed air.

[0020] Preferably, the radioactive mud treatment system further comprises:

[0021] The vacuum device is connected to the first collecting device and is used for vacuuming. The vacuum device is arranged outside the hot room.

[0022] Preferably, the vacuum device comprises: a fourth pipeline, an air extraction valve,

[0023] The fourth pipeline is connected to the first collecting device, the air extraction valve is arranged on the fourth pipeline, and the fourth pipeline is used for vacuuming.

[0024] Preferably, the radioactive mud treatment system further comprises:

[0025] The condensation collection device is connected to the fourth pipeline. The condensation collection device is used to condense the steam discharged from the residue drying and collect the condensate. The condensation collection device is arranged outside the hot room.

[0026] Preferably, the first collecting device comprises: a waste liquid collecting tank, a fifth pipeline, a drain valve, a sixth pipeline, and a liquid outlet valve.

[0027] The fifth pipeline is connected with the waste liquid collection tank, the drain valve is arranged on the fifth pipeline, the fifth pipeline is used to discharge the filtrate, the waste liquid collection tank is connected with the filter through the sixth pipeline, and the liquid outlet valve is arranged on the sixth pipeline.

[0028] Preferably, the pore size of the filter plate is 100 to 1000 μm.

[0029] Preferably, the radioactive mud treatment system further comprises:

[0030] The output device includes: a screw conveyor and a motor. The screw conveyor is arranged between the filter and the second collecting device. The inlet of the screw conveyor is connected to the discharge valve of the filter. The discharge interface of the screw conveyor is connected to the second collecting device. The motor is connected to the screw conveyor. The screw conveyor is arranged in the hot chamber, and the motor is arranged outside the hot chamber.

[0031] Preferably, the radioactive mud treatment system further comprises: a first sealing component, a second sealing component,

[0032] The first sealing assembly is arranged between the inlet of the screw conveyor and the filter, and the first sealing assembly is used to seal the connection between the inlet of the screw conveyor and the filter;

[0033] The second sealing component is arranged between the discharge interface of the screw conveyor and the second collecting device, and the second sealing component is used to seal the connection between the discharge interface of the screw conveyor and the second collecting device.

[0034] The present invention also provides a method for treating radioactive mud using the above system, comprising the following steps:

[0035] receiving the radioactive slurry by a receiving device;

[0036] The radioactive mud is transported to the filtering and drying device, and the radioactive mud is filtered through the filter to separate the solid and the liquid, and the solid remains in the filter in the form of filter residue, and the filtrate flows into the first collecting device;

[0037] The dryer is started to dry the filter residue in the filter, and the filter residue is converted into dry mud after drying;

[0038] After drying is completed, the discharge valve of the filter is opened and the dry mud is loaded into the second collecting device.

[0039] Preferably, the method further comprises the following steps:

[0040] During the filtration process or after the filtration is completed, the vacuum device is started to put the first collecting device and the filtering and drying device into a vacuum state.

[0041] Preferably, the method further comprises the following steps:

[0042] When the dry mud is discharged, turn on the compressed air device to back-blow the filter plate of the filter.

[0043] Preferably, when the liquid level detection device detects that the liquid level in the filter reaches a preset liquid level height, the control unit controls the feed valve to close;

[0044] When the level detection device detects that the filter cake formed by the filter residue in the filter reaches the preset filter cake height, the control unit controls the feed valve to close and no more feed is made.

[0045] Preferably, the drying temperature in the dryer is 60 to 120°C.

[0046] Preferably, the step starts the dryer to dry the filter residue in the filter, and the moisture content in the dry mud is controlled to be no more than 1vt% at the drying end point, and whether the drying end point is reached is determined by detecting the exhaust gas humidity.

[0047] Preferably, the processing method further comprises the following steps:

[0048] After the filtration is completed, the filtrate in the first collection device is discharged;

[0049] Condensing the steam discharged during the drying process of the filter residue in the filter, and collecting the condensate;

[0050] The discharged filtrate and collected condensate are evaporated and concentrated, and finally solidified with cement.

[0051] The present invention provides a method and system for treating radioactive mud. According to the situation that radioactive nuclides are mainly concentrated in solid-phase mud and the radioactive characteristics of mud and clear liquid in a large tank, a method for treating the radioactive mud by first separating solid from liquid and then drying is selected. On the one hand, the solid content in the liquid is reduced by solid-liquid separation, and the waste liquid can be further concentrated and then cemented to meet the treatment standard of cement solidified bodies, and the volume of cement solidified bodies is reduced, the amount of waste is reduced, and waste minimization can be achieved; on the other hand, compared with the mud-water mixed state, the water content of the filtered filter cake is greatly reduced, the mud treatment efficiency is improved, and the engineering problem of mud treatment with a high alpha nuclide content can be solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic diagram of the structure of the radioactive mud treatment system in Example 2 of the present invention.

[0053] In the figure: 1-mud receiving tank; 2-feed valve; 3-filter; 4-liquid outlet valve; 5-exhaust valve; 6-first valve; 7-drain valve; 8-second valve; 9-dryer; 10-discharge valve; 11-screw conveyor; 12-discharge interface; 13-first pipeline; 14-second pipeline; 15-third pipeline; 16-fourth pipeline; 17-fifth pipeline; 18-sixth pipeline; 19-hot chamber; 20-waste liquid collection tank; 21-motor; 22-stirring paddle motor; 23-sealed barrel. DETAILED DESCRIPTION

[0054] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0055] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0056] In the description of this patent, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing this patent 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 a limitation on this patent.

[0057] In the description of this patent, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, it can be fixedly connected or set, or it can be detachably connected or set, or connected or set in one piece. For ordinary technicians in this field, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0058] Example 1

[0059] This embodiment provides a radioactive mud treatment system, comprising:

[0060] a receiving device for receiving radioactive slurry;

[0061] A filtering and drying device is connected to the receiving device, and includes a filter and a dryer disposed on the filter. The radioactive mud is filtered through the filter, and the filter residue obtained by filtering in the filter is dried through the dryer.

[0062] A first collecting device, connected to the filtrate outlet of the filter, and used to collect the filtrate obtained by filtration;

[0063] A second collecting device is connected to the discharge valve of the filter, and is used to collect the dry mud obtained after filtering and drying;

[0064] The filtering and drying device is arranged in the hot room, and the receiving device, the first collecting device and the second collecting device are arranged outside the hot room.

[0065] This embodiment also provides a method for treating radioactive mud using the above system, comprising the following steps:

[0066] receiving the radioactive slurry by a receiving device;

[0067] The radioactive mud is transported to the filtering and drying device, and the radioactive mud is filtered through the filter to separate the solid and the liquid, and the solid remains in the filter in the form of filter residue, and the filtrate flows into the first collecting device;

[0068] The dryer is started to dry the filter residue in the filter, and the filter residue is converted into dry mud after drying;

[0069] After drying is completed, the discharge valve of the filter is opened and the dry mud is loaded into the second collecting device.

[0070] The present embodiment provides a method and system for treating radioactive mud. According to the situation that radioactive nuclides are mainly concentrated in the solid phase mud and according to the radioactive characteristics of the mud and the clear liquid in the large tank, a method of first solid-liquid separation and then drying is selected for the radioactive mud. On the one hand, the solid content in the liquid is reduced by solid-liquid separation, and the waste liquid can be further concentrated and then cemented to meet the treatment standards of cement solidified bodies, and the volume of cement solidified bodies is reduced, the amount of waste is reduced, and waste minimization can be achieved; on the other hand, compared with the mud-water mixed state, the water content of the filter cake after filtration is greatly reduced, which improves the mud treatment efficiency, thereby solving the engineering problem of mud treatment with a high α nuclide content.

[0071] Example 2

[0072] like Figure 1 As shown, this embodiment provides a radioactive mud processing system, comprising:

[0073] a receiving device for receiving radioactive slurry;

[0074] A filtering and drying device is connected to the receiving device, and comprises a filter 3 and a dryer 9 arranged on the filter 3, wherein the radioactive mud is filtered through the filter 3, and the filter residue obtained by filtering in the filter 3 is dried through the dryer 9;

[0075] A first collecting device, connected to the filtrate outlet of the filter, and used to collect the filtrate obtained by filtration;

[0076] A second collecting device is connected to the discharge valve 10 of the filter 3, and is used to collect the dry mud obtained after filtering and drying;

[0077] The filtering and drying device is arranged in the heat chamber 19 , and the receiving device, the first collecting device and the second collecting device are arranged outside the heat chamber 19 .

[0078] Specifically, the hot chamber 19 in this embodiment is a mud processing hot chamber 19. The filtering and drying device is arranged in the hot chamber, so that the radioactivity of the radioactive mud in the filtering process is effectively shielded.

[0079] Preferably, the receiving device comprises: a mud receiving tank 1 , a first pipeline 13 , and a feed valve 2 . The mud receiving tank 1 is connected to the filter 3 via the first pipeline 13 , and the feed valve 2 is arranged on the first pipeline 13 .

[0080] Specifically, the filter 3 in this embodiment includes a filter body, a filter feed port disposed on the filter body, a filter filtrate outlet, and a filter discharge valve 10. The filter feed port is connected to the first pipeline 13. The filter 3 also includes a stirring paddle and a stirring paddle motor 22, the stirring paddle is connected to the stirring paddle motor 22, the stirring paddle motor 22 is disposed outside the heat chamber 19, and the stirring head of the stirring paddle is disposed in the filter body.

[0081] Preferably, the radioactive mud treatment system further comprises:

[0082] The liquid level detection device, the material level detection device, and the control unit are arranged in the filter 3. The liquid level detection device is used to send the detected liquid level in the filter 3 to the control unit. The control unit controls the opening of the feed valve 2 so that the liquid level does not exceed the preset limit. The material level detection device is used to send the detected material level of the filter residue in the filter 3 to the control unit. When the filter cake formed by the filter residue reaches the preset filter cake height, the control unit controls the feed valve 2 to close and no longer feed.

[0083] Specifically, the level detection device in this embodiment is a level meter.

[0084] Preferably, the radioactive mud treatment system further comprises:

[0085] The flushing pipeline is connected to the first pipeline 13 , and the connection point is arranged on the first pipeline 13 between the feed valve 2 and the filter 3 . The flushing pipeline is used to pass flushing water to flush the first pipeline 13 .

[0086] Preferably, the radioactive mud treatment system further comprises:

[0087] The compressed air device is connected to the filter 3 and is used to provide compressed air to the filter 3 . The compressed air device is arranged outside the heat chamber 19 .

[0088] Preferably, the compressed air device comprises: a second pipeline 14, a first valve 6, a third pipeline 15, a second valve 8,

[0089] The second pipeline 14 is connected to the feed port of the filter 3, the first valve 6 is arranged on the second pipeline 14, and the second pipeline 14 is used to introduce compressed air;

[0090] The third pipeline 15 is connected to the filtrate outlet of the filter, the second valve 8 is arranged on the third pipeline 15, and the third pipeline 15 is used for introducing compressed air.

[0091] Preferably, the radioactive mud treatment system further comprises:

[0092] The vacuum device is connected to the first collecting device and is used for vacuuming. The vacuum device is arranged outside the hot chamber 19 .

[0093] Preferably, the vacuum device comprises: a fourth pipeline 16, an air extraction valve 5,

[0094] The fourth pipeline 16 is connected to the first collecting device, the air extraction valve 5 is arranged on the fourth pipeline 16, and the fourth pipeline 16 is used for vacuuming.

[0095] Preferably, the radioactive mud treatment system further comprises:

[0096] The condensation collection device is connected to the fourth pipeline 16 . The condensation collection device is used to condense the steam discharged from the residue drying and collect the condensate. The condensation collection device is arranged outside the heat chamber 19 .

[0097] Preferably, the first collecting device comprises: a waste liquid collecting tank 20, a fifth pipeline 17, a drain valve 7, a sixth pipeline 18, and a liquid outlet valve 4.

[0098] The fifth pipeline 17 is connected to the waste liquid collection tank 20 , the drain valve 7 is arranged on the fifth pipeline 17 , the fifth pipeline 17 is used to discharge the filtrate, the waste liquid collection tank 20 is connected to the filter 3 through the sixth pipeline 18 , and the liquid outlet valve 4 is arranged on the sixth pipeline 18 .

[0099] Preferably, the pore size of the filter plate of the filter 3 is 100 to 1000 μm.

[0100] Specifically, the pore size of the filter plate in this embodiment is 500 μm.

[0101] Preferably, the radioactive mud treatment system further comprises:

[0102] The output device includes: a screw conveyor 11 and a motor 21. The screw conveyor 11 is arranged between the filter 3 and the second collecting device. The inlet of the screw conveyor 11 is connected to the discharge valve 10 of the filter 3. The discharge interface 12 of the screw conveyor 11 is connected to the second collecting device. The motor 21 is connected to the screw conveyor 11. The screw conveyor 11 is arranged in the hot chamber 19, and the motor 21 is arranged outside the hot chamber 19.

[0103] Specifically, the second collecting device in this embodiment is a sealing barrel 23 .

[0104] Preferably, the radioactive mud treatment system further comprises: a first sealing component, a second sealing component,

[0105] The first sealing assembly is disposed between the inlet of the screw conveyor 11 and the filter 3, and the first sealing assembly is used to seal the connection between the inlet of the screw conveyor 11 and the filter 3;

[0106] The second sealing component is disposed between the discharge interface of the screw conveyor 11 and the second collecting device, and is used to seal the connection between the discharge interface 12 of the screw conveyor 11 and the second collecting device.

[0107] When the dry mud is discharged, the connection between the filter 3 and the screw conveyor 11, the screw conveyor 11, the discharge interface 12 of the screw conveyor 11, etc. are sealed to avoid the diffusion of dry mud dust; after the dry mud is discharged, the compressed air device can be turned on to back-blow the filter plate to reduce the blockage ratio of the holes on the filter plate;

[0108] This embodiment also provides a method for treating radioactive mud using the above system, comprising the following steps:

[0109] receiving the radioactive slurry by a receiving device;

[0110] The radioactive mud is transported to the filtering and drying device, and the radioactive mud is filtered through the filter 3 to separate the solid and the liquid, and the solid remains in the filter 3 in the form of filter residue, and the filtrate flows into the first collecting device;

[0111] The dryer 9 is started to dry the filter residue in the filter 3, and the filter residue is converted into dry mud after drying;

[0112] After drying is completed, the discharge valve 10 of the filter 3 is opened and the dry mud is loaded into the second collecting device.

[0113] Preferably, the method further comprises the following steps:

[0114] During the filtration process or after the filtration is completed, the vacuum device is started to put the first collecting device and the filtering and drying device into a vacuum state.

[0115] Preferably, the method further comprises the following steps:

[0116] When the dry mud is discharged, the compressed air device is turned on to back-blow the filter plate of the filter 3.

[0117] Preferably, when the liquid level detection device detects that the liquid level in the filter 3 reaches a preset liquid level height, the control unit controls the feed valve 2 to close;

[0118] During continuous feeding, when the level detection device detects that the filter cake formed by the filter residue in the filter 3 reaches the preset filter cake height, the control unit controls the feed valve 2 to close and no more feeding is performed.

[0119] Preferably, the drying temperature in the dryer 9 is 60 to 120°C.

[0120] Preferably, the step starts the dryer 9 to dry the filter residue in the filter 3, and the moisture content in the dry mud is controlled to be no more than 1vt% at the drying end point, and whether the drying end point is reached is determined by detecting the exhaust gas humidity.

[0121] Preferably, the processing method further comprises the following steps:

[0122] After the filtration is completed, the filtrate in the first collection device is discharged;

[0123] Condensing the steam discharged during the drying process of the filter residue in the filter 3, and collecting the condensate;

[0124] The discharged filtrate and collected condensate are evaporated and concentrated, and finally solidified with cement.

[0125] This method is applicable to the treatment of all solid-liquid mixed radioactive liquids.

[0126] The present embodiment provides a method and system for treating radioactive mud. According to the situation that radioactive nuclides are mainly concentrated in the solid phase mud and according to the radioactive characteristics of the mud and the clear liquid in the large tank, a method of first solid-liquid separation and then drying is selected for the radioactive mud. On the one hand, the solid content in the liquid is reduced by solid-liquid separation, and the waste liquid can be further concentrated and then cemented to meet the treatment standards of cement solidified bodies, and the volume of cement solidified bodies is reduced, the amount of waste is reduced, and waste minimization can be achieved; on the other hand, compared with the mud-water mixed state, the water content of the filter cake after filtration is greatly reduced, which improves the mud treatment efficiency, thereby solving the engineering problem of mud treatment with a high α nuclide content.

[0127] The operation process relies on the filtration and drying device to perform solid-liquid separation and vacuum drying of the radioactive mud, and the dry mud and liquid are temporarily stored and cemented respectively, which can greatly reduce the amount of waste treatment, solve the problem of waste minimization in radioactive mud treatment, and provide reference and value for the treatment of radioactive mud in other domestic projects.

[0128] Example 3

[0129] This embodiment provides a method for treating radioactive mud using the radioactive mud treatment system in Embodiment 2, which differs from Embodiment 2 in that it includes the following steps:

[0130] Step 1): The recovered radioactive mud is transported to the mud receiving tank 11 through the first pipeline 13;

[0131] Step 2): Open the feed valve 2 to transport the radioactive mud in the mud receiving tank 11 into the filter 3 at a preset solid content;

[0132] Step 3): The radioactive mud is subjected to solid-liquid separation under negative pressure in the filter 3, the filtrate flows into the waste liquid collection tank 20, and the filter residue remains in the filter 3;

[0133] Step 4): After the wet mud filter cake accumulates to a certain amount, the feeding is stopped, and after the filtration is completed, the filtrate in the waste liquid collection tank 20 is discharged;

[0134] Step 5): Start the vacuum device, evacuate the filter 3 to maintain a preset vacuum degree, and put the waste liquid collection tank 20 and the filter 3 in a vacuum state;

[0135] Step 6): After the vacuum filtration of the radioactive mud is completed, the dryer 9 of the filter drying device is started, and its heating function is turned on to vacuum dry the wet filter cake, and further dry it in the filter 3. The water vapor generated by the drying is discharged through the vacuum device, and the water vapor discharged during the drying process is condensed by the condensation collection device, and the condensate is collected. The tail gas is purified by the filtration system and then discharged;

[0136] Step 7): After reaching the drying end point, that is, after the drying is completed, the discharge port of the filter 3 is opened, and the dry mud is discharged from the discharge port of the filter 3 and temporarily stored in the sealed barrel 23 through the discharge interface 12 of the screw conveyor 11. The sealed barrel 23 is then sent to the temporary storage warehouse; the filtering, drying and discharging system of the radioactive mud is arranged in the mud treatment hot chamber 19, which can achieve the containment of radioactivity during the filtering, drying and loading processes.

[0137] Step 8): The filtrate discharged from step 4) and the condensate collected during the drying process of step 6) are collected and evaporated and concentrated as needed, and finally solidified with cement.

[0138] Repeat steps 1) to 8) until the radioactive mud has completely completed the solid-liquid separation, drying and waste liquid cement solidification process.

[0139] Specifically, when the radioactive mud is fed in step 2) of this embodiment, the level meter on the filter 3 is interlocked with the feed valve 2, so that the feed amount of the radioactive mud can be controlled, and the feeding and solid-liquid separation can be performed intermittently and repeated multiple times until the preset filter cake volume is reached.

[0140] Step 3) During the solid-liquid separation of the radioactive mud, the vacuum device or the compressed air device can be used alone or in combination to separate the radioactive mud into solid and liquid.

[0141] The present embodiment provides a method and system for treating radioactive mud. According to the situation that radioactive nuclides are mainly concentrated in the solid phase mud and according to the radioactive characteristics of the mud and the clear liquid in the large tank, a method of first solid-liquid separation and then drying is selected for the radioactive mud. On the one hand, the solid content in the liquid is reduced by solid-liquid separation, and the waste liquid can be further concentrated and then cemented to meet the treatment standards of cement solidified bodies, and the volume of cement solidified bodies is reduced, the amount of waste is reduced, and waste minimization can be achieved; on the other hand, compared with the mud-water mixed state, the water content of the filter cake after filtration is greatly reduced, which improves the mud treatment efficiency, thereby solving the engineering problem of mud treatment with a high α nuclide content.

[0142] The operation process relies on the filtration and drying device to perform solid-liquid separation and vacuum drying of the radioactive mud, and the dry mud and liquid are temporarily stored and cemented respectively, which can greatly reduce the amount of waste treatment, solve the problem of waste minimization in radioactive mud treatment, and provide reference and value for the treatment of radioactive mud in other domestic projects.

[0143] Example 4

[0144] This embodiment provides a method for treating radioactive mud using the radioactive mud treatment system in Embodiment 2, which differs from Embodiment 2 in that it includes the following steps:

[0145] Step 1): Radioactive slurry feeding and filtration

[0146] When feeding, the feed valve 2 is opened, and the radioactive mud enters the filter 3. The radioactive mud is transported from the mud receiving tank 1 to the filter 3 of the mud treatment hot chamber 19 through the first pipeline 13. The feed valve 2 is interlocked with the level meter on the filter 3. When the mud in the filter 3 reaches a certain liquid level, the feed valve 2 can be interlocked with the level meter to complete the feeding of the radioactive mud.

[0147] After the feeding is completed, the feeding valve 2 is closed, the liquid outlet valve 4 is opened, the air extraction valve 5 is opened, and the vacuum device is started. The radioactive mud is separated into solid and liquid under negative pressure, and the liquid flows into the waste liquid collection tank 20, and the solid filter cake remains in the filter 3.

[0148] The mud feeding and filtering are repeated intermittently until the filter cake thickness reaches a predetermined filter cake height, and then flushing water is introduced to flush the first pipe 13. After the flushing water is filtered, the radioactive mud feeding and filtering process is completed.

[0149] Step 2): Filter cake drying

[0150] After the radioactive mud is filtered, the filtrate in the waste liquid collection tank 20 is discharged, and then the vacuum device is started to put the waste liquid collection tank 20 and the filter 3 in a vacuum state; the dryer 9 on the filter 3 is started to dry the wet filter cake;

[0151] During the drying process, steam is extracted from the filter 3 through the waste liquid collection tank 20 by the vacuum device, condensed by the condensation collection device and collected. During the drying period, the stirring paddle in the filter 3 can be started to stir the filter cake to improve the drying efficiency.

[0152] After drying for a certain period of time, the humidity detector on the fourth pipeline 16 is used to determine whether the filter cake is dried. After drying, the heater on the filter 3 is turned off, and after the dry mud cools to a certain temperature, the air extraction valve 5 on the fourth pipeline 16 is closed, and the vacuum device is turned off to restore the filter 3 to normal pressure.

[0153] Step 3): Dry mud discharge

[0154] After the filter cake is dried, the discharge valve 10 of the filter 3 is opened, and the dry mud is discharged from the filter 3, and after being transported by the screw conveyor 11, it enters the sealed barrel 23 through the discharge interface 12 of the screw conveyor 11. After the sealed barrel 23 is loaded, it leaves and is transported to the waste temporary storage by a transport vehicle;

[0155] Step 4): Liquid cement solidifies

[0156] The radioactive waste liquid (filtrate, condensate) collected during the filtration and drying process of the radioactive mud is uniformly sent to the radioactive wastewater treatment center, and the wastewater is concentrated and then cemented.

[0157] Specifically, the pore size of the filter plate in this embodiment is 1000 μm.

[0158] The present embodiment provides a method and system for treating radioactive mud. According to the situation that radioactive nuclides are mainly concentrated in the solid phase mud and according to the radioactive characteristics of the mud and the clear liquid in the large tank, a method of first solid-liquid separation and then drying is selected for the radioactive mud. On the one hand, the solid content in the liquid is reduced by solid-liquid separation, and the waste liquid can be further concentrated and then cemented to meet the treatment standards of cement solidified bodies, and the volume of cement solidified bodies is reduced, the amount of waste is reduced, and waste minimization can be achieved; on the other hand, compared with the mud-water mixed state, the water content of the filter cake after filtration is greatly reduced, which improves the mud treatment efficiency, thereby solving the engineering problem of mud treatment with a high α nuclide content.

[0159] The operation process relies on the filtration and drying device to perform solid-liquid separation and vacuum drying of the radioactive mud, and the dry mud and liquid are temporarily stored and cemented respectively, which can greatly reduce the amount of waste treatment, solve the problem of waste minimization in radioactive mud treatment, and provide reference and value for the treatment of radioactive mud in other domestic projects.

[0160] Example 5

[0161] This embodiment provides a method for treating radioactive mud using the radioactive mud treatment system in Embodiment 2, which differs from Embodiment 2 in that it includes the following steps:

[0162] Step 1): After the radioactive mud is retrieved from the waste liquid tank, it is sent to the mud receiving tank 1, and the feed valve 2 is opened. The radioactive mud enters the filter 3 from the mud receiving tank 1. The feed valve 2 is interlocked with the level meter in the filter 3. When the liquid level reaches the preset liquid level height in the filter 3, the interlock control feed valve 2 is closed.

[0163] Step 2): Open the liquid outlet valve 4 and the air extraction valve 5, start the vacuum device, reduce the air pressure below the filter plate 3, and achieve solid-liquid separation of the slurry above the filter plate under a certain pressure difference, and the filtrate enters the waste liquid collection tank 20;

[0164] Step 3): Repeat steps 1) and 2) and feed in batches for multiple times until the slurry in the filter 3 reaches a preset liquid level.

[0165] Step 4): After the solid-liquid separation is completed, the vacuum device is turned off, and after the waste liquid collection tank 20 returns to normal pressure, the drain valve 7 is opened to discharge the filtrate in the waste liquid collection tank 20, and the drain valve 7 is closed;

[0166] Step 5): Open the liquid outlet valve 4, open the air extraction valve 5, start the vacuum device, and put the waste liquid collection tank 20 and the filter 3 into a vacuum state;

[0167] Step 6): Start the dryer 9 on the filter 3 to dry the wet filter cake; the steam generated during the drying process is extracted by a vacuum device, condensed and cooled by a condensation collection device, and then collected and sent to a low-level wastewater treatment facility, and the remaining tail gas is discharged after purification;

[0168] Step 7): When the drying end point is reached, the dryer 9 on the filter 3 is closed, and after the temperature in the filter 3 drops to 30-50° C., the vacuum device is closed, and the first valve 6 is opened to restore the pressure in the filter 3 to normal, and the drying process is completed;

[0169] Step 8): After drying, the discharge valve 10 of the filter 3 is opened, and the dry mud in the filter 3 is sent to the discharge interface 12 of the screw conveyor 11 by the bolt conveyor 11 through the discharge valve 10 of the filter 3, and the dry mud is loaded into the sealed barrel 23, and the sealed barrel 23 is sent to the waste temporary storage by the transport vehicle.

[0170] Step 9): Repeat steps 1) to 8) until all the radioactive mud is filtered, dried, packaged and temporarily stored.

[0171] Step 10): The radioactive waste liquid (filtrate, condensate) collected during the filtration and drying process is temporarily stored and then sent to a wastewater treatment facility for treatment.

[0172] Preferably, in the steps 1), 2), and 3), the radioactive mud feeding can also be fed in a continuous feeding mode, by opening the feed valve 2, and at the same time opening the liquid outlet valve 4 and the air extraction valve 5, starting the vacuum device, and filtering the radioactive mud by using the vacuum device while feeding the radioactive mud, so as to achieve continuous feeding and improve the feeding and filtering efficiency; during continuous feeding, the feed valve 2 is interlocked with the level meter provided on the filter 3, and when the filter cake height reaches the preset filter cake height value, the feed valve 2 is interlocked and closed;

[0173] Preferably, in the step 1), a flushing pipeline can be provided between the feed valve 2 and the filter 3, and the flushing pipeline is a flushing bypass. After the last feeding and filtering are completed, the flushing pipeline is opened to flush the first pipeline 13, and the flushing water is filtered and collected in the waste liquid collection tank 20;

[0174] Preferably, in step 2), during filtration, the vacuum device provides a maximum relative vacuum degree of not less than -80 KPa, and at the same time, the first valve 6 can be opened to open the air pressure device to increase the pressure difference between the filter plates during filtration and improve the filtration effect;

[0175] Preferably, in step 2), the pore size of the filter plate of the filter 3 is 100 to 1000 μm.

[0176] Specifically, the pore size of the filter plate in this embodiment is 100 μm.

[0177] Preferably, in step 6), the heater on the filter 3 can use hot water, hot oil or electric heating, and the heating temperature can be set to 60-90°C (heat source is hot water) according to the characteristics of the material. When using hot oil or electric heating, the drying temperature can be set to 60-120°C.

[0178] Preferably, in step 7), during drying, the drying endpoint is comprehensively judged by the data of the humidity detection instrument set on the air outlet pipe and the actual drying time. During drying, the air humidity corresponding to the water content in the dry filter cake is less than 1% as the drying endpoint; that is, when the water content in some filter cakes is ≥1%, the drying endpoint is not reached; when the water content in some filter cakes is <1%, the drying endpoint is reached.

[0179] Preferably, in step 8), after the dry mud is discharged, the second valve 8 is opened, the compressed air device is turned on, and the filter plate of the filter 3 is back-blown to reduce the clogging of the filter holes on the filter plate;

[0180] Preferably, the mud filter 3, heater 9, discharge valve 10, screw conveyor 11, and discharge interface 12 are all arranged in the mud treatment hot chamber 19 to achieve radioactive containment of the mud filtering, drying, and loading processes; when the filter 3 is discharging and the dry mud is transported in the screw conveyor 11, the rotating shafts of the filter 3 and the screw conveyor 11 use an extended design, so that the motor 21 is placed outside the mud treatment hot chamber 19, reducing the failure rate of the motor 21 and improving the convenience of maintenance.

[0181] Preferably, the filter plate of the filter 3 is designed to be quick-release, so that the filter plate can be quickly replaced; by changing the filter plate structure, pore size, etc., it can be applied to the filtering and drying of all types of radioactive mud.

[0182] The present embodiment provides a method and system for treating radioactive mud. According to the situation that radioactive nuclides are mainly concentrated in the solid phase mud and according to the radioactive characteristics of the mud and the clear liquid in the large tank, a method of first solid-liquid separation and then drying is selected for the radioactive mud. On the one hand, the solid content in the liquid is reduced by solid-liquid separation, and the waste liquid can be further concentrated and then cemented to meet the treatment standards of cement solidified bodies, and the volume of cement solidified bodies is reduced, the amount of waste is reduced, and waste minimization can be achieved; on the other hand, compared with the mud-water mixed state, the water content of the filter cake after filtration is greatly reduced, which improves the mud treatment efficiency, thereby solving the engineering problem of mud treatment with a high α nuclide content.

[0183] The operation process relies on the filtration and drying device to perform solid-liquid separation and vacuum drying of the radioactive mud, and the dry mud and liquid are temporarily stored and cemented respectively, which can greatly reduce the amount of waste treatment, solve the problem of waste minimization in radioactive mud treatment, and provide reference and value for the treatment of radioactive mud in other domestic projects.

[0184] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A radioactive mud treatment system, characterized in that: include: a receiving device for receiving radioactive slurry; A filtering and drying device is connected to the receiving device, the filtering and drying device comprising a filter (3) and a dryer (9) arranged on the filter (3), the radioactive mud is filtered through the filter (3), and the filter residue obtained by filtering in the filter (3) is dried through the dryer (9); A first collecting device connected to the filtrate outlet of the filter (3), the first collecting device being used to collect the filtrate obtained by filtration; A second collecting device connected to the discharge valve (10) of the filter (3), the second collecting device being used to collect the dry mud obtained after filtering and drying; The filtering and drying device is arranged in the hot chamber (19), and the receiving device, the first collecting device and the second collecting device are arranged outside the hot chamber (19).

2. The radioactive mud treatment system according to claim 1, characterized in that: The receiving device comprises: a mud receiving tank (1), a first pipeline (13), and a feed valve (2); the mud receiving tank (1) is connected to a filter (3) via the first pipeline (13), and the feed valve (2) is arranged on the first pipeline (13).

3. The radioactive mud treatment system according to claim 2, characterized in that: Also includes: A liquid level detection device, a material level detection device, and a control unit. The liquid level detection device and the material level detection device are arranged in the filter (3). The liquid level detection device is used to send the detected liquid level in the filter (3) to the control unit. The control unit controls the opening of the feed valve (2) so that the liquid level does not exceed a preset limit value. The material level detection device is used to send the detected material level of the filter residue in the filter (3) to the control unit. When the filter cake formed by the filter residue reaches the preset filter cake height, the control unit controls the feed valve (2) to close and no longer feeds.

4. The radioactive mud treatment system according to claim 2, characterized in that: Also includes: The flushing pipeline is connected to the first pipeline (13), and the connection point is arranged on the first pipeline (13) between the feed valve (2) and the filter (3). The flushing pipeline is used to pass flushing water to flush the first pipeline (13).

5. The radioactive mud treatment system according to claim 1, characterized in that: Also includes: A compressed air device is connected to the filter (3), and is used to provide compressed air to the filter (3). The compressed air device is arranged outside the heat chamber (19).

6. The radioactive mud treatment system according to claim 5, characterized in that: The compressed air device comprises: a second pipeline (14), a first valve (6), a third pipeline (15), and a second valve (8). The second pipeline (14) is connected to the feed port of the filter (3), the first valve (6) is arranged on the second pipeline (14), and the second pipeline (14) is used to introduce compressed air; The third pipeline (15) is connected to the filtrate outlet of the filter (3), the second valve (8) is arranged on the third pipeline (15), and the third pipeline (15) is used to introduce compressed air.

7. The radioactive mud treatment system according to claim 1, characterized in that: Also includes: A vacuum device is connected to the first collecting device and is used for vacuuming. The vacuum device is arranged outside the hot chamber (19).

8. The radioactive mud treatment system according to claim 7, characterized in that: The vacuum device comprises: a fourth pipeline (16), an air extraction valve (5), The fourth pipeline (16) is connected to the first collecting device, the air extraction valve (5) is arranged on the fourth pipeline (16), and the fourth pipeline (16) is used for vacuum extraction.

9. The radioactive mud treatment system according to claim 8, characterized in that: Also includes: The condensation collection device is connected to the fourth pipeline (16), and is used to condense the steam discharged from the filter residue drying and collect the condensate. The condensation collection device is arranged outside the hot chamber (19).

10. The radioactive mud treatment system according to claim 1, characterized in that: The first collecting device comprises: a waste liquid collecting tank (20), a fifth pipeline (17), a liquid discharge valve (7), a sixth pipeline (18), and a liquid outlet valve (4). The fifth pipeline (17) is connected to the waste liquid collection tank (20), the liquid discharge valve (7) is arranged on the fifth pipeline (17), the fifth pipeline (17) is used to discharge the filtrate, the waste liquid collection tank (20) is connected to the filter (3) through the sixth pipeline (18), and the liquid outlet valve (4) is arranged on the sixth pipeline (18).

11. The radioactive mud treatment system according to claim 1, characterized in that: The filter plate pore size of the filter (3) is 100 to 1000 μm.

12. The radioactive mud treatment system according to claim 1, characterized in that: Also includes: The output device comprises: a screw conveyor (11) and a motor (21); the screw conveyor (11) is arranged between a filter (3) and a second collecting device; an inlet of the screw conveyor (11) is connected to a discharge valve (10) of the filter (3); a discharge interface (12) of the screw conveyor (11) is connected to the second collecting device; the motor (21) is connected to the screw conveyor (11); the screw conveyor (11) is arranged in a heat chamber (19); and the motor (21) is arranged outside the heat chamber (19).

13. The radioactive mud treatment system according to claim 12, characterized in that: Also includes: a first sealing component, a second sealing component, The first sealing component is arranged between the inlet of the screw conveyor (11) and the filter (3), and the first sealing component is used to seal the connection between the inlet of the screw conveyor (11) and the filter (3); The second sealing component is arranged between the discharge interface (12) of the screw conveyor (11) and the second collecting device, and is used to seal the connection between the discharge interface (12) of the screw conveyor (11) and the second collecting device.

14. A method for treating radioactive mud using the system according to any one of claims 1 to 13, characterized in that: The following steps are involved: receiving the radioactive slurry by a receiving device; The radioactive mud is transported to a filtering and drying device, and the radioactive mud is filtered through a filter (3) to separate the solid and the liquid, and the solid remains in the filter (3) in the form of filter residue, and the filtrate flows into a first collecting device; The dryer (9) is started to dry the filter residue in the filter (3), and the filter residue is converted into dry mud after drying; After drying is completed, the discharge valve (10) of the filter (3) is opened and the dry mud is loaded into the second collecting device.

15. The processing method according to claim 14, characterized in that: Using the system of claim 7 or 8, the method further comprises the following steps: During the filtration process or after the filtration is completed, the vacuum device is started to put the first collecting device and the filtering and drying device into a vacuum state.

16. The processing method according to claim 14, characterized in that: Using the system of claim 5 or 6, the method further comprises the following steps: When the dry mud is discharged, the compressed air device is turned on to back-blow the filter plate of the filter (3).

17. The processing method according to claim 14, characterized in that: Using the system of claim 3, When the liquid level detection device detects that the liquid level in the filter (3) reaches a preset liquid level height, the control unit controls the feed valve (2) to close; When the material level detection device detects that the filter cake formed by the filter residue in the filter (3) reaches a preset filter cake height, the control unit controls the feed valve (2) to close and no more feed is made.

18. The processing method according to claim 14, characterized in that: The drying temperature in the dryer (9) is 60 to 120°C.

19. The processing method according to claim 14, characterized in that: The step starts the dryer (9) to dry the filter residue in the filter (3). The moisture content in the dry mud is controlled to be no more than 1vt% at the drying end point, and whether the drying end point is reached is determined by detecting the exhaust gas humidity.

20. The processing method according to claim 14, characterized in that: Using the system of claim 9, the method further comprises the steps of: After the filtration is completed, the filtrate in the first collection device is discharged; Condensing steam discharged during the drying process of the filter residue in the filter (3), and collecting the condensate; The discharged filtrate and collected condensate are evaporated and concentrated, and finally solidified with cement.

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