Device and method for recovering ammonia in heavy metal waste liquid and preparing nano-metal material

Abstract

The invention discloses a device for recovering ammonia in heavy metal waste liquid and preparing nano-metal materials, the device comprises an electrolysis chamber, a driving chamber and a recovery chamber which are sequentially arranged from top to bottom, and the interior of the electrolysis chamber is divided into an anode chamber and a cathode chamber; a collection box is arranged on the electrolysis chamber, a first filter screen is arranged in the cathode chamber, and a push plate is embedded in the side wall of one side of the cathode chamber; a water outlet pipe and a second screw are arranged in the driving chamber, the second screw is sleeved with a first gear, a second gear is arranged on the water outlet pipe, and a water wheel for driving the push plate to stretch out and draw back is arranged in the water outlet pipe; a moving pipe capable of moving up and down for aeration is arranged in the recovery chamber; a recovery and preparation method by using the device comprises the following steps: S1, electrolyzing to obtain a nano-metal material; s2, adjusting the pH value of the electrolyzed wastewater, aerating, and recovering to obtain ammonia gas; according to the device disclosed by the invention, precipitation and water are synchronously separated, the aeration effect on wastewater is enhanced in the separation process, and the efficiency of recovering ammonia and preparing a nano-metal material is improved.

Description

Technical Field

[0001] The invention relates to the technical field of ammonia recovery, and in particular to a device and method for recovering ammonia in heavy metal waste liquid and preparing nano metal materials. Background Art

[0002] Wastewater is generated in each production link of the electroplating process. Not only is the amount of wastewater large, but also there are many types of wastewater, including pre-plating degreasing wastewater, organic matter removal wastewater, plated parts rinsing wastewater, tank washing wastewater, waste plating liquid, and test water wastewater. Nitric acid pickling is one of the methods to remove oxides on the surface of workpieces. In addition, copper-containing nitric acid etching liquid is also produced in the electroplating process. At present, the main treatment methods for heavy metal wastewater are mainly chemical methods (neutralization precipitation and sulfide precipitation) and oxidation methods, which produce a large amount of sludge and require additional treatment. Electrocatalytic reduction is an alternative method for treating wastewater by combining electrochemical and catalytic technologies. By applying an electric current to the cathode, nitrate undergoes an electrochemical reduction reaction, converting it into harmless N2 or ammonia (NH3) with economic value.

[0003] Existing equipment for recovering ammonia and nano-metal materials is usually separate. It is necessary to first use electrolysis equipment to recover the nano-metal materials, and then transfer the remaining wastewater to the ammonia recovery equipment. The two equipments operate independently, so the recovery efficiency is low. The present invention proposes an equipment and method for simultaneously recovering ammonia and nano-metal materials, so as to realize the efficient separation and recovery of heavy metals and ammonia resources. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a device and method for recovering ammonia in heavy metal waste liquid and preparing nano-metal materials.

[0005] The technical scheme of the present invention is: a device for recovering ammonia in heavy metal waste liquid and preparing nano-metal materials, comprising an electrolysis chamber, a driving chamber and a recovery chamber arranged in sequence from top to bottom, wherein the interior of the electrolysis chamber is divided into a cathode chamber and an anode chamber by a cation membrane; a collecting box is arranged on the electrolysis chamber, a first filter screen is arranged inside the cathode chamber and is slidably and sealedly connected to the inner wall of the cathode chamber, and a push plate for pushing the sediment on the first filter screen into the collecting box is embedded on the side wall of one side of the cathode chamber, a through hole for docking with the collecting box is arranged on the side wall of the cathode chamber on the other side, and the push plate is connected to a spiral tube arranged in the side wall of the cathode chamber through a first screw;

[0006] The driving chamber is hollow inside and is provided with a water outlet pipe connecting the cathode chamber and the recovery chamber, a second screw that penetrates the first filter screen and is threadedly sleeved with the first filter screen, the second screw is sleeved with a first gear that is rotatably connected to the driving chamber, the water outlet pipe is provided with a second gear for opening or closing the water outlet pipe, the second gear is meshed with the first gear for transmission, a water wheel that rotates by utilizing the waste liquid in the water outlet pipe is provided in the water outlet pipe, one end of the first central axis of the water wheel penetrates the water outlet pipe and is connected to the spiral tube belt transmission; a ratchet and a tooth plate that meshes with the second gear on one side is provided in the driving chamber, a ratchet that meshes with the ratchet on the other side of the tooth plate is provided, a third gear is sleeved on the second central axis of the ratchet, the other end of the first central axis penetrates the water outlet pipe and is provided with a fourth gear that is perpendicular to the third gear and meshes with the transmission; an air inlet pipe, a drain pipe and an ammonia recovery pipe are provided in the recovery chamber.

[0007] Furthermore, both ends of the air intake pipe are fixedly connected to the side walls of the recovery chamber, one end of the second center axis passes through the upper wall of the air intake pipe, and the side wall of the second center axis is provided with a plurality of oblique grooves connected end to end, a movable tube threadedly connected thereto is longitudinally provided on the air intake pipe, a connecting plate longitudinally slidably connected to the inner wall of the air intake pipe is provided on the top of the movable tube, the movable tube is rotatably connected to the connecting plate, and a circular hole for the second center axis to pass through is provided on the connecting plate, at least one sliding block slidably connected to the oblique groove is provided on the circular hole, and a stirring blade is provided at the bottom of the movable tube.

[0008] Description: By utilizing the rotation of the second central axis, the movable tube can move up and down during the aeration process, so as to aerate the wastewater at multiple depths. In addition, the rotation generated during the up and down movement makes the wastewater aeration more uniform, thereby enhancing the aeration effect and improving the ammonia recovery efficiency.

[0009] Furthermore, second filter screens with gradually decreasing particle sizes are arranged in sequence from top to bottom in the collecting box, one side of the second filter screen passes through the outer wall of the cathode chamber, a plurality of vibration blocks for colliding with the second filter screen are arranged inside the side wall of the cathode chamber, the vibration blocks are fixedly connected to the side wall of the collecting box by springs, and a plurality of cams corresponding to the vibration blocks are arranged at the other end of the second center axis.

[0010] Description: By utilizing the rotation of the second central axis, the cam drives the vibration block to displace multiple times, which rebounds under the action of the spring and collides with the second filter screen to make it vibrate, thereby dispersing the nano-metal material precipitate on the second filter screen and improving the particle size screening efficiency.

[0011] Furthermore, a fan for introducing air into the air intake pipe is rotatably provided on the side wall of the recovery chamber, and the third central axis of the fan is connected to the first central axis by a belt transmission.

[0012] Description: The rotation of the first central axis is used as the driving source of the fan to introduce air into the recovery chamber for aeration, thereby reducing the use of electronic control components and saving resources.

[0013] Furthermore, an ammonia recovery chamber connected to an ammonia recovery pipe is provided on one side of the recovery chamber, and a solution for absorbing ammonia is contained in the ammonia recovery chamber, wherein the solution is any one of an aqueous solution, a sulfuric acid solution or a phosphoric acid solution.

[0014] Note: Setting up an ammonia recovery room can directly absorb and store ammonia to prevent leakage.

[0015] Furthermore, a sealing plate for opening or closing the through hole is slidably provided in the side wall of the electrolysis chamber, and the sealing plate is fixedly connected to the tooth plate through a connecting rod.

[0016] Note: By opening or closing the through hole through the sealing plate, it is possible to prevent the wastewater from splashing into the collection box and affecting the nano-metal material during the process of passing the wastewater.

[0017] Furthermore, the water outlet pipe is composed of a first branch pipe, a rotating plate, a positioning plate and a second branch pipe which are arranged in sequence from top to bottom. The two ends of the rotating plate are respectively rotatably sealed with the first branch pipe and the positioning plate, the positioning plate is fixedly connected to the second branch pipe, a water outlet hole is provided on the rotating plate, and the rotating plate is fixedly sleeved with the second gear, and a docking hole is provided on the positioning plate for rotatably docking with the water outlet hole.

[0018] Note: The docking hole and the water outlet hole are made to face each other by the rotation of the second gear, so that the opening and closing periods of the water outlet pipe can be controlled by controlling the rotation speed.

[0019] The method for recovering ammonia from heavy metal waste liquid and preparing nano-metal materials according to any of the above-mentioned devices comprises the following steps:

[0020] S1. Pour the heavy metal wastewater containing nitrate into the cathode chamber of the electrolysis chamber, pour the supporting electrolyte into the anode chamber of the electrolysis chamber, start electrolysis, and the current density is 15-25 mA / cm 2 , until the heavy metal hydroxide is mineralized to obtain nano-metal materials with a particle size of ≤500nm, and the nitrate is converted into ammonium ions;

[0021] The second screw is started to rotate to move the first filter up, and at the same time, the second screw drives the second gear on the water outlet pipe to rotate until the first filter moves up to the highest point, and then the water outlet pipe is opened to allow the wastewater containing ammonium ions to enter the recovery chamber, and the first central axis of the water wheel rotates to drive the spiral tube to rotate, and the screw drives the push plate to translate to push the nano-metal material on the first filter into the collection chamber through the through hole;

[0022] After the wastewater containing ammonium ions is discharged, the second screw drives the first filter screen to the bottom of the cathode chamber, and the outlet pipe is closed synchronously. At this time, the second gear drives the toothed plate to return to translation, and the toothed plate drives the ratchet, the third gear and the fourth gear to rotate, so that the first central axis drives the push plate back to the side wall of the cathode chamber in the reverse direction, and the next wave of heavy metal wastewater containing nitrate ions can be introduced to continue electrolysis;

[0023] S2. When the wastewater containing ammonium ions enters the recovery chamber, the pH of the wastewater containing ammonium ions is adjusted to 11-12, and air is introduced into the wastewater containing ammonium ions through an air inlet pipe to aerate the wastewater containing ammonium ions. The ammonium ions in the wastewater containing ammonium ions are converted into ammonia gas after pH adjustment and aeration, and the ammonia gas is discharged and recovered from the ammonia gas recovery pipe.

[0024] Furthermore, in step S1, before electrolysis, a catalyst is first added to the heavy metal wastewater containing nitrate ions in the cathode chamber, the mass ratio of the heavy metal wastewater containing nitrate ions to the catalyst is 1L: 0.2~0.4g, and the catalyst is any one of copper, carbon nanotubes, copper-palladium alloy or metal molecular complex catalyst.

[0025] Description: The above catalyst can convert nitrate into ammonia with high selectivity, high current efficiency, high ammonia selectivity and low by-product nitrite.

[0026] The beneficial effects of the device and method of the present invention are:

[0027] (1) The recovery and preparation device of the present invention improves the separation efficiency by separating the nanometal material from the wastewater after the nanometal material is prepared, and collecting the nanometal material and the wastewater into the recovery chamber simultaneously. In the separation process, the mobile aeration pipe in the recovery chamber is driven to move up and down, and the wastewater is aerated at multiple depths, thereby improving the aeration efficiency. At the same time, the nanometal material is screened by particle size, and the particle size screening effect is enhanced by vibration.

[0028] (2) The recovery and preparation method of the present invention can control the nano-morphology of heavy metal precipitation by applying current to the cathode, regulating the current density and the addition of catalyst, and preparing nano-metal materials of different sizes and morphologies. It also allows nitrates to undergo an electrochemical reduction reaction to convert them into ammonia with economic value, thereby achieving efficient separation and recovery of heavy metals and ammonia resources. The method reduces the treatment cost and environmental risks without the addition of reagents, and the removal rate of heavy metals in heavy metal waste liquid exceeds 99%, and the ammonia recovery rate exceeds 90%. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is the overall appearance diagram of the recovery and preparation equipment of the present invention;

[0030] Figure 2is an internal structural diagram of the recovery and preparation equipment of the present invention;

[0031] Figure 3 1 is a diagram showing the internal structure of a drive chamber of a recovery and preparation device according to an embodiment 1 of the present invention;

[0032] Figure 4 It is a diagram of the internal structure of the water outlet pipe of the recovery and preparation equipment of the present invention;

[0033] Figure 5 is a diagram of the baffle structure of the recovery and preparation equipment of the present invention;

[0034] Figure 6 1 is a diagram showing the internal structure of a recovery chamber of a recovery and preparation device embodiment 1 of the present invention;

[0035] Figure 7 1 is a diagram showing the internal structure of a recovery chamber of a recovery and preparation device according to Embodiment 2 of the present invention;

[0036] Figure 8 is a diagram showing the internal structure of the collection chamber of the recovery and preparation device embodiment 3 of the present invention;

[0037] Among them, 1-electrolysis chamber, 11-cathode chamber, 12-first filter screen, 121-push plate, 122-first screw, 123-screw tube, 124-baffle, 125-through hole, 13-anode chamber, 2-drive chamber, 21-second screw, 211-first gear, 22-water outlet pipe, 221-second gear, 222-water wheel, 223-first central axis, 224-fourth gear, 225-positioning plate, 226-water outlet, 227-docking Hole, 228-rotating plate, 23-tooth plate, 231-connecting plate, 24-ratchet, 241-second center axis, 242-third gear, 243-oblique groove, 244-cam, 3-recovery chamber, 31-moving pipe, 311-connecting rod, 32-ammonia recovery chamber, 33-ammonia recovery pipe, 34-inlet pipe, 341-fan, 342-third center axis, 35-drain pipe, 4-collecting chamber, 41-second filter, 42-vibrating block. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below in conjunction with specific implementation methods to better reflect the advantages of the present invention.

[0039] Example 1: A device for recovering ammonia from heavy metal waste liquid and preparing nano-metal materials, such as Figure 1 and Figure 2As shown, it includes an electrolysis chamber 1, a driving chamber 2 and a recovery chamber 3 which are arranged in sequence from top to bottom, an ammonia recovery chamber 32 which is connected to an ammonia recovery pipe 33 is provided on one side of the recovery chamber 3, and an aqueous solution for absorbing ammonia is contained in the ammonia recovery chamber 32, and the inside of the electrolysis chamber 1 is divided into a cathode chamber 11 and an anode chamber 13 by a cation membrane on the left and right; a collecting box 4 is provided on the electrolysis chamber 1, a first filter screen 12 which is slidably sealed and connected to the inner wall of the cathode chamber 11, and a push plate 121 for pushing the sediment on the first filter screen 12 into the collecting box 4 is embedded on the side wall of one side of the cathode chamber 11, a through hole 125 which is docked with the collecting box 4 is provided on the side wall of the cathode chamber 11 on the other side, and the push plate 121 is connected to a spiral tube 123 arranged in the side wall of the cathode chamber 11 through a first screw 122; a catalyst storage box which is connected to the cathode chamber 11, and a pH regulating box which is connected to both the cathode chamber 11 and the recovery chamber 3 are provided on the electrolysis chamber 1;

[0040] like Figure 3 As shown, the driving chamber 2 is hollow inside and is provided with a water outlet pipe 22 connecting the cathode chamber 11 and the recovery chamber 3, and a second screw 21 that penetrates the first filter screen 12 and is threadedly sleeved with the first filter screen 12. The second screw 21 is driven by a rotating motor arranged in the driving chamber 2. A first gear 211 that is rotatably connected to the driving chamber 2 is sleeved on the second screw 21. A second gear 221 for opening or closing the water outlet pipe 22 is provided on the water outlet pipe 22. The second gear 221 is meshed with the first gear 211 for transmission. The water outlet pipe 22 is provided with a second gear 221 that is used to utilize the water outlet. The water wheel 222 rotates the waste liquid in the water pipe, and one end of the first central axis 223 of the water wheel 222 penetrates the water outlet pipe 22 and is connected to the spiral tube 123 with a transmission; the driving chamber 2 is provided with a ratchet 24 and a toothed plate 23 with one side meshing with the second gear 221, and the other side of the toothed plate 23 is provided with ratchet teeth meshing with the ratchet 24, and the second central axis 241 of the ratchet 24 is sleeved with a third gear 242, and the other end of the first central axis 241 penetrates the water outlet pipe 22 and is provided with a fourth gear 224 that is perpendicular to and meshing with the third gear 242;

[0041] like Figure 5 As shown, a sealing plate 124 for opening or closing the through hole 125 is slidably provided in the side wall of the electrolysis chamber 1, and the sealing plate 124 is fixedly connected to the tooth plate 23 through a connecting rod 231;

[0042] like Figure 4As shown, the water outlet pipe 22 is composed of a first branch pipe, a rotating plate 228, a positioning plate 225 and a second branch pipe arranged in sequence from top to bottom, the two ends of the rotating plate 228 are respectively rotatably sealed with the first branch pipe and the positioning plate 225, the positioning plate 225 is fixedly connected with the second branch pipe, a water outlet hole 226 is provided on the rotating plate 228, and the rotating plate 228 is fixedly sleeved with the second gear 221, and a docking hole 227 is provided on the positioning plate 225 for rotatably docking with the water outlet hole 226;

[0043] like Figure 6 As shown, the recovery chamber 3 is provided with an air intake pipe 34, a drain pipe 35 and an ammonia recovery pipe 33; both ends of the air intake pipe 34 are fixedly connected to the side walls of the recovery chamber 3, one end of the second central axis 241 passes through the upper wall of the air intake pipe 34, and the side wall of the second central axis 241 is provided with a plurality of oblique grooves 243 connected end to end, a movable tube 31 threadedly connected thereto is longitudinally provided on the air intake pipe 34, a connecting plate 311 longitudinally slidably connected to the inner wall of the air intake pipe 34 is provided on the top of the movable tube 31, the movable tube 31 is rotatably connected to the connecting plate 311, and a circular hole for the second central axis 241 to pass through is provided on the connecting plate 311, a sliding block slidably connected to the oblique groove 243 is provided on the circular hole, and two stirring blades are provided at the bottom of the movable tube 31; a one-way valve is provided on the air intake pipe 34, and an air pump can be used to inflate the air intake pipe 34, and both the one-way valve and the air pump can use existing equipment.

[0044] The method for recovering ammonia from heavy metal waste liquid and preparing nano-metal materials by the above device comprises the following steps:

[0045] S1. Pour the heavy metal wastewater containing nitrate into the cathode chamber 11 of the electrolysis chamber 1, and pour the supporting electrolyte (for example, 0.5 mol / L potassium sulfate solution) into the anode chamber 13 of the electrolysis chamber 11. First, add a catalyst to the heavy metal wastewater containing nitrate in the cathode chamber 11. The mass ratio of the heavy metal wastewater containing nitrate to the catalyst is 1L:0.3g. The catalyst is carbon nanotubes. Then, start electrolysis at a current density of 20 mA / cm 2 , until the heavy metal hydroxide is mineralized to obtain nano-metal materials with a particle size of ≤500nm, and the nitrate is converted into ammonium ions;

[0046] The second screw 21 is started to rotate to move the first filter screen 12 upward. At the same time, the second screw 21 drives the second gear 221 on the water outlet pipe 22 to rotate until the first filter screen 12 moves to the highest point. The water outlet pipe 22 is opened to allow the wastewater containing ammonium ions to enter the recovery chamber 3. The first central axis 223 of the water wheel 222 rotates to drive the screw tube 123 to rotate. The screw 122 drives the push plate 121 to translate and push the nano-metal material on the first filter screen 12 into the collection chamber 4 through the through hole 125.

[0047] After the wastewater containing ammonium ions is discharged, the second screw 21 drives the first filter screen 12 to the bottom of the cathode chamber 11, and the outlet pipe 22 is closed synchronously. At this time, the second gear 222 drives the tooth plate 23 to return to translation, and the tooth plate 23 drives the ratchet 24, the third gear 242 and the fourth gear 224 to rotate, so that the first central axis 223 drives the push plate 121 in the reverse direction to return to the side wall of the cathode chamber 11, and then the next wave of heavy metal wastewater containing nitrate ions can be introduced to continue electrolysis;

[0048] S2. When the wastewater containing ammonium ions enters the recovery chamber 3, the pH of the wastewater containing ammonium ions is adjusted to 11.5, and air is introduced into the wastewater containing ammonium ions through the air inlet pipe 34. The second central axis 241 rotates to make the movable tube 31 move up and down through the change of the oblique groove 243, and the movable tube 31 rotates synchronously when moving up and down, so that the wastewater containing ammonium ions is aerated at multiple depths. The ammonium ions in the wastewater containing ammonium ions are converted into ammonia after pH adjustment and aeration, and the ammonia is discharged and recovered from the ammonia recovery pipe 33.

[0049] Embodiment 2: This embodiment differs from Embodiment 1 in that Figure 7 As shown, a fan 341 for introducing air into the air inlet pipe 34 is rotatably provided on the side wall of the recovery chamber 3, and the third central axis 342 of the fan 341 is connected to the first central axis 223 with a belt transmission.

[0050] The recovery and preparation method of this embodiment is different from that of Embodiment 1 in that when the first central axis 223 rotates in the forward direction, that is, when the water outlet pipe 22 drains water, water gradually enters the recovery chamber 3, and at the same time, the fan 341 rotates to introduce air into the air inlet pipe 34, automatically starting the aeration of the wastewater; when the first central axis 223 rotates in the reverse direction, that is, all the wastewater enters the recovery chamber 3, the fan 341 still rotates to guide air, and continues to aerate the wastewater, thereby enhancing the aeration efficiency.

[0051] Embodiment 3: This embodiment differs from Embodiment 1 in that Figure 8 As shown, the collecting box 4 is provided with second filter screens 41 with gradually decreasing particle sizes from top to bottom, and the particle sizes of the second filter screens 41 are 400nm, 200nm, and 50nm from top to bottom, respectively. One side of the second filter screen 41 penetrates the outer wall of the cathode chamber 11, and three vibration blocks 42 for colliding with the second filter screen 41 are provided inside the side wall of the cathode chamber 11. The vibration blocks 42 are fixedly connected to the side walls of the collecting box 4 through springs, and the other end of the second central axis 241 is provided with three cams 244 that contact the vibration blocks 42 one by one.

[0052] The recovery and preparation method of this embodiment is different from that of Embodiment 1 in that when the nano-metal material enters the collection box 4, it will first accumulate in a partial area of ​​the top second filter screen 41, and when the first central axis 223 rotates in the opposite direction, the cam 244 will rotate to drive the vibration block 42 to slide, and after the cam 244 is separated from the vibration block 42, the vibration block 42 recovers under the action of the spring and hits the second filter screen 41, so that the accumulated nano-metal material is dispersed and passes through multiple second filter screens 41 to complete automatic screening.

[0053] Example 4: This example is different from Example 1 in that in step S1, the current density is 15 mA / cm 2 .

[0054] Example 5: This example is different from Example 1 in that in step S1, the current density is 25 mA / cm 2 .

[0055] Example 6: This example is different from Example 1 in that, in step S1, a catalyst is added to the heavy metal wastewater containing nitrate ions in the cathode chamber 11, and the mass ratio of the heavy metal wastewater containing nitrate ions to the catalyst is 1L:0.2g.

[0056] Example 7: This example is different from Example 1 in that, in step S1, a catalyst is added to the heavy metal wastewater containing nitrate in the cathode chamber 11, and the mass ratio of the heavy metal wastewater containing nitrate to the catalyst is 1L:0.4g.

[0057] Example 8: This example is different from Example 1 in that, in step S2, the pH of the wastewater containing ammonium ions is adjusted to 11.

[0058] Example 9: This example is different from Example 1 in that, in step S2, the pH of the wastewater containing ammonium ions is adjusted to 12.

[0059] Application Examples

[0060] The effects of various parameters of the method for recovering ammonia and preparing nano-metal materials using the device of the present invention on the ammonia recovery rate and heavy metal removal rate were explored.

[0061] Table 1 Ammonia recovery rate and heavy metal removal rate in Examples 1, 4 to 9

[0062]

[0063]

[0064] It can be seen from the results in Table 1 that too small or too large current density, too small catalyst addition, and too small or too large pH will reduce the ammonia recovery rate and heavy metal removal rate. In Example 7, the ammonia recovery is the same as that in Example 1 and the heavy metal removal rate is relatively higher, but the amount of catalyst added is also increased. However, the increase in the heavy metal removal rate is less than the increase in the amount of catalyst added. Therefore, from an economic point of view, the parameter effect of Example 1 is relatively better.

Claims

1. A device for recovering ammonia from heavy metal waste liquid and preparing nano-metal materials, characterized in that: The invention comprises an electrolysis chamber (1), a driving chamber (2) and a recovery chamber (3) which are arranged in sequence from top to bottom. The interior of the electrolysis chamber (1) is divided into a cathode chamber (11) and an anode chamber (13) by a cation membrane. A collecting box (4) is provided on the electrolysis chamber (1). A first filter screen (12) is provided inside the cathode chamber (11) and is slidably and hermetically connected to the inner wall of the cathode chamber (11). A push plate (121) for pushing the sediment on the first filter screen (12) into the collecting box (4) is embedded on the side wall of the cathode chamber (11). A through hole (125) is provided on the side wall of the other side of the chamber (11) for docking with the collection box (4); the push plate (121) is connected to a screw tube (123) arranged in the side wall of the cathode chamber (11) through a first screw rod (122); the driving chamber (2) is hollow inside and is provided with a water outlet pipe (22) connecting the cathode chamber (11) and the recovery chamber (3), a second screw rod (21) passing through the first filter screen (12) and threadedly sleeved with the first filter screen (12); the second screw rod (21) is sleeved with a first gear (211) ), the water outlet pipe (22) is provided with a second gear (221) for opening or closing the water outlet pipe (22), the second gear (221) is meshed with the first gear (211) for transmission, the water outlet pipe (22) is provided with a water wheel (222) for rotating by utilizing the waste liquid in the water outlet pipe (22), one end of the first central axis (223) of the water wheel (222) penetrates the water outlet pipe (22) and is connected to the spiral tube (123) by belt transmission; the driving chamber (2) is provided with a ratchet (24) and a first central axis (223) on one side connected to the first central axis (223) on the other side; The toothed plate (23) is meshed with two gears (221) for transmission, the other side of the toothed plate (23) is provided with ratchet teeth meshed with a ratchet wheel (24) for transmission, the second central axis (241) of the ratchet wheel (24) is sleeved with a third gear (242), the other end of the first central axis (241) passes through the water outlet pipe (22) and is provided with a fourth gear (224) which is perpendicular to and meshed with the third gear (242); the recovery chamber (3) is provided with an air inlet pipe (34), a water discharge pipe (35) and an ammonia recovery pipe (33).

2. The device for recovering ammonia from heavy metal waste liquid and preparing nano-metal materials according to claim 1, characterized in that: The two ends of the air inlet pipe (34) are fixedly connected to the side walls of the recovery chamber (3); one end of the second central axis (241) passes through the upper wall of the air inlet pipe (34); and a plurality of oblique grooves (243) connected end to end are provided on the side wall of the second central axis (241); a movable pipe (31) threadedly connected thereto is longitudinally provided on the air inlet pipe (34); a connecting plate (311) longitudinally slidably connected to the inner wall of the air inlet pipe (34) is provided on the top of the movable pipe (31); the movable pipe (31) is rotatably connected to the connecting plate (311); and a circular hole for the second central axis (241) to pass through is provided on the connecting plate (311); and at least one sliding block slidably connected to the oblique groove (243) is provided on the circular hole; and a stirring blade is provided at the bottom of the movable pipe (31).

3. The device for recovering ammonia from heavy metal waste liquid and preparing nano-metal materials according to claim 1, characterized in that: The collecting box (4) is provided with second filter screens (41) with gradually decreasing particle sizes from top to bottom, one side of the second filter screen (41) penetrates the outer wall of the cathode chamber (11), a plurality of vibration blocks (42) for colliding with the second filter screen (41) are provided inside the side wall of the cathode chamber (11), the vibration blocks (42) are fixedly connected to the side wall of the collecting box (4) via springs, and a plurality of cams (244) are provided at the other end of the second central axis (241) for contacting the vibration blocks (42) in a one-to-one correspondence.

4. The device for recovering ammonia from heavy metal waste liquid and preparing nano-metal materials according to claim 1, characterized in that: A fan (341) is rotatably provided on the side wall of the recovery chamber (3) for introducing air into the air intake pipe (34), and a third central axis (342) of the fan (341) is connected to the first central axis (223) by a belt transmission.

5. The device for recovering ammonia from heavy metal waste liquid and preparing nano-metal materials according to claim 1, characterized in that: An ammonia recovery chamber (32) connected to an ammonia recovery pipe (33) is provided on one side of the recovery chamber (3). A solution for absorbing ammonia is contained in the ammonia recovery chamber (32), and the solution is any one of an aqueous solution, a sulfuric acid solution or a phosphoric acid solution.

6. The device for recovering ammonia from heavy metal waste liquid and preparing nano-metal materials according to claim 1, characterized in that: A sealing plate (124) for opening or closing the through hole (125) is slidably disposed in the side wall of the electrolysis chamber (1), and the sealing plate (124) is fixedly connected to the tooth plate (23) via a connecting rod (231).

7. The device for recovering ammonia from heavy metal waste liquid and preparing nano-metal materials according to claim 1, characterized in that: The water outlet pipe (22) is composed of a first branch pipe, a rotating plate (228), a positioning plate (225) and a second branch pipe which are arranged in sequence from top to bottom. The two ends of the rotating plate (228) are respectively connected to the first branch pipe and the positioning plate (225) in a rotatable and sealed manner. The positioning plate (225) is fixedly connected to the second branch pipe. The rotating plate (228) is provided with a water outlet hole (226), and the rotating plate (228) is fixedly sleeved with the second gear (221). The positioning plate (225) is provided with a docking hole (227) which is rotatably docked with the water outlet hole (226).

8. The method for recovering ammonia from heavy metal waste liquid and preparing nano-metal materials according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Pour the heavy metal wastewater containing nitrate into the cathode chamber (11) of the electrolysis chamber (1), pour the supporting electrolyte into the anode chamber (13) of the electrolysis chamber (11), and start electrolysis at a current density of 15 to 25 mA / cm 2 , until the heavy metal hydroxide is mineralized to obtain nano-metal materials with a particle size of ≤500nm, and the nitrate is converted into ammonium ions; The second screw (21) is started to rotate so that the first filter (12) moves upward, and at the same time, the second screw (21) drives the second gear (221) on the water outlet pipe (22) to rotate until the first filter (12) moves upward to the highest point, and then the water outlet pipe (22) is opened to allow wastewater containing ammonium ions to enter the recovery chamber (3), the first central axis (223) of the water wheel (222) rotates to drive the screw tube (123) to rotate, and the first screw (122) drives the push plate (121) to translate to push the nano-metal material on the first filter (12) through the through hole (125) into the collection chamber (4); After the wastewater containing ammonium ions is discharged, the second screw (21) drives the first filter (12) to descend to the bottom of the cathode chamber (11), and the outlet pipe (22) is closed synchronously. At this time, the second gear (222) drives the toothed plate (23) to return to translation, and the toothed plate (23) drives the ratchet (24), the third gear (242) and the fourth gear (222) to rotate, so that the first central axis (223) drives the push plate (121) in the reverse direction to return to the side wall of the cathode chamber (11), and then the next wave of heavy metal wastewater containing nitrate ions can be introduced to continue electrolysis; S2. When the wastewater containing ammonium ions enters the recovery chamber (3), the pH of the wastewater containing ammonium ions is adjusted to 11-12, and air is introduced into the wastewater containing ammonium ions through the air inlet pipe (34) to aerate the wastewater containing ammonium ions. The ammonium ions in the wastewater containing ammonium ions are converted into ammonia gas after pH adjustment and aeration, and the ammonia gas is discharged and recovered from the ammonia gas recovery pipe (33).

9. The method for recovering and preparing ammonia from heavy metal waste liquid by the device for preparing nano-metal materials according to claim 8, characterized in that: In step S1, before electrolysis, a catalyst is first added to the heavy metal wastewater containing nitrate ions in the cathode chamber (11), the mass ratio of the heavy metal wastewater containing nitrate ions to the catalyst is 1L: 0.2-0.4g, and the catalyst is any one of copper, carbon nanotubes, copper-palladium alloy or metal molecular complex catalyst.

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