Mining area heavy metal wastewater treatment device

Abstract

The utility model relates to the technical field of mining area heavy metal wastewater treatment, in particular to a mining area heavy metal wastewater treatment device which comprises an advanced oxidation unit, a chemical precipitation unit and a membrane filtration unit, the advanced oxidation unit comprises an advanced oxidation reaction box, a visible light lamp is arranged on the side surface of the middle part in the advanced oxidation reaction box, a water inlet pipeline is arranged at the top of the advanced oxidation reaction box, a sulfuric acid tank, a peroxydisulfate tank and a catalyst tank are arranged above the advanced oxidation reaction box, and the sulfuric acid tank, the peroxydisulfate tank and the catalyst tank are all arranged on a support frame; the sulfuric acid tank is connected with the advanced oxidation reaction box through a first conduit. When the heavy metal wastewater treatment device for the mining area is used, the advanced oxidation unit is added before the chemical precipitation unit is used, so that chelated heavy metal and the like which are difficult to treat by chemical precipitation in the wastewater of the mining area are oxidized, and the heavy metal enters the chemical precipitation unit and easily reacts with a sodium sulfide solution to form precipitate.

Description

Technical Field

[0001] The utility model relates to the technical field of heavy metal wastewater treatment in mining areas, in particular to a heavy metal wastewater treatment device in mining areas. Background Art

[0002] With the growing global demand for industry and mineral resources, industrial activities, especially mining activities, are expanding at an unprecedented rate. With this expansion, the problem of heavy metal wastewater discharge in mining areas has become increasingly prominent. This is not only because it contains a variety of harmful heavy metal ions such as lead (Pb), cadmium (Cd), and mercury (Hg), but also because these ions can exist in the environment for a long time, not only the soil and water bodies are seriously polluted, but also may eventually affect human health through the food chain and cause many diseases. The severity of this environmental problem has prompted people to put forward higher requirements for wastewater treatment technology.

[0003] There are many different technologies currently used for heavy metal wastewater treatment, but each technology has its limitations. For example, although the traditional physical filtration method has simple equipment and is easy to operate, it is relatively ineffective in removing heavy metal ions at the atomic or molecular level; although the chemical precipitation method is effective in some cases, it suffers from low treatment efficiency and is difficult to deal with low-concentration pollution. Although the advanced oxidation process has a significant effect on the treatment of organic matter and can significantly improve the biodegradability of organic pollutants, its direct effect on the treatment of heavy metals is limited. Although the old precipitation method is effective under specific conditions, it is unable to remove complex ions and stabilize heavy metal complexes.

[0004] Therefore, developing an integrated system to effectively remove heavy metals from mining wastewater is an important environmental protection technology challenge at present. The system needs to overcome the shortcomings of current technology, such as improving the efficiency of the entire system and reducing operating costs in order to simplify the treatment process. Utility Model Content

[0005] The purpose of the utility model is to solve the above-mentioned shortcomings in the prior art and to propose a mining area heavy metal wastewater treatment device.

[0006] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme: design a mining area heavy metal wastewater treatment device, including an advanced oxidation unit, a chemical precipitation unit and a membrane filtration unit;

[0007] The advanced oxidation unit includes an advanced oxidation reaction box, a visible light lamp is installed on the middle side of the advanced oxidation reaction box, a water inlet pipe is installed on the top of the advanced oxidation reaction box, a sulfuric acid tank, a peroxydisulfate tank, and a catalyst tank are arranged above the advanced oxidation reaction box, the sulfuric acid tank, the peroxydisulfate tank, and the catalyst tank are all arranged on a support frame, the sulfuric acid tank is connected to the advanced oxidation reaction box through a first conduit, and a sulfuric acid switch valve is installed on the first conduit, the peroxydisulfate tank is connected to the water injection type rotator through a second conduit, and the catalyst tank is also connected to the water injection type rotator through a third conduit, wherein the water injection type rotator is installed inside the advanced oxidation reaction box;

[0008] The catalyst tank is filled with a mixed catalyst of 20 mg FePc / CN-6: 20 ml water, wherein FePc / CN-6 is iron phthalocyanine / carbon nitride and the mass percentage of iron phthalocyanine to carbon nitride is 6%;

[0009] The chemical precipitation unit comprises a primary chemical precipitation reaction box and a secondary chemical precipitation reaction box, the primary chemical precipitation reaction box and the secondary chemical precipitation reaction box are arranged side by side on the side of the advanced oxidation reaction box, a fourth conduit is arranged on the top of the primary chemical precipitation reaction box, the other end of the fourth conduit is connected to the bottom of the advanced oxidation reaction box, and a fifth conduit is arranged between the primary chemical precipitation reaction box and the secondary chemical precipitation reaction box, one end of the fifth conduit is fixed to the bottom of the primary chemical precipitation reaction box and the other end is fixed to the top of the secondary chemical precipitation reaction box;

[0010] The chemical precipitation unit also includes a water tank, a sodium sulfide tank, and a liquid alkali tank. The water tank, the sodium sulfide tank, and the liquid alkali tank are arranged above the secondary chemical precipitation reaction box, and the water tank, the sodium sulfide tank, and the liquid alkali tank are all arranged on a support frame. A seventh conduit is installed at the bottom of the water tank, the other end of the seventh conduit is connected to the secondary chemical precipitation reaction box, and a second shunt pipe is installed on the seventh conduit, and the other end of the second shunt pipe is connected to the primary chemical precipitation reaction box. The sodium sulfide tank is filled with 2g / l of sodium sulfide, and the sodium sulfide tank is connected to the secondary chemical precipitation reaction box through a sixth conduit. The sixth conduit is also provided with a first shunt pipe connected to the primary chemical precipitation reaction box, and the liquid alkali tank is connected to the secondary chemical precipitation reaction box through an eighth conduit, and a third shunt pipe connected to the primary chemical precipitation reaction box is installed on the eighth conduit;

[0011] The outlet end of the first shunt pipe and the outlet end of the second shunt pipe are combined into the same and installed in the primary chemical precipitation reaction box for connection, and the outlet end of the sixth conduit and the outlet end of the seventh conduit are combined into the same and installed in the secondary chemical precipitation reaction box for connection;

[0012] The membrane filtration unit includes a membrane filtration box, which is arranged on the side of the secondary chemical precipitation reaction box, and is connected to a ninth conduit at the bottom of the membrane filtration box, the other end of the ninth conduit is connected to the bottom of the secondary chemical precipitation reaction box, and a nanofiltration membrane device is arranged in the membrane filtration box. The membrane material of the nanofiltration membrane device is a polyamide membrane, and its membrane flux is 10-30LMH. The top of the nanofiltration membrane device is connected to a drainage pipe, which passes through the membrane filtration box and extends to the outside of the membrane filtration box, wherein the sulfuric acid tank is connected to the top of the membrane filtration box through the tenth conduit.

[0013] Preferably, a persulfate switch valve is installed on the second conduit, and a catalyst switch valve is installed on the third conduit.

[0014] Preferably, the water injection rotator includes a rotating rod arranged in the advanced oxidation reaction box, the top of the rotating rod is connected to the top of the advanced oxidation reaction box, and a water injection head is installed at the bottom of the rotating rod, the second conduit and the third conduit are both rotatably connected to the rotating rod, and the rotating rod is connected to the water injection head.

[0015] Preferably, a first pH probe is installed on one side of the top of the advanced oxidation reaction tank, the first pH probe extends to the interior of the advanced oxidation reaction tank, a first agitator is arranged inside the first-level chemical precipitation reaction tank, and a second agitator is arranged inside the second-level chemical precipitation reaction tank, and a second pH probe extending to the interior of the first-level chemical precipitation reaction tank is also arranged on the first-level chemical precipitation reaction tank, and a third pH probe extending to the interior of the second-level chemical precipitation reaction tank is also arranged on the second-level chemical precipitation reaction tank.

[0016] Preferably, a fourth pH probe extending into the interior of the membrane filtration box is installed on the top of the membrane filtration box, and a third agitator is also provided in the membrane filtration box.

[0017] Preferably, a first row of mud switch plate is installed at the bottom of the primary chemical precipitation reaction box, a second row of mud switch plate is installed at the bottom of the secondary chemical precipitation reaction box, and a third row of mud switch plate is installed at the bottom of the membrane filtration box.

[0018] Preferably, a first lifting pump is installed on the fourth conduit, a second lifting pump is installed on the fifth conduit, a first sodium sulfide switch valve is installed on the first diversion pipe, a second sodium sulfide switch valve is installed on the sixth conduit, a first water tank switch valve is installed on the second diversion pipe, a second water tank switch valve is installed on the seventh conduit, a first liquid alkali lifting pump is installed on the third diversion pipe, a second liquid alkali lifting pump is installed on the eighth conduit, a third lifting pump is installed on the ninth conduit, a fourth lifting pump is installed on the tenth conduit, and a fifth lifting pump is installed on the drainage pipe.

[0019] Preferably, the flow rate range of the first sodium sulfide switch valve and the second sodium sulfide switch valve is set between 5ml / h-8l / h, and the flow rate range of the first water tank switch valve and the second water tank switch valve is set between 0-0.8l / h.

[0020] The utility model proposes a mining area heavy metal wastewater treatment device, which has the following beneficial effects:

[0021] 1. The heavy metal wastewater treatment device in the mining area adds an advanced oxidation unit before using the chemical precipitation unit, and adds FePc / CN-6 to the advanced oxidation reaction box to activate peroxydisulfate, thereby generating persulfate ions under visible light to oxidize the chelated heavy metals in the mining area wastewater that are difficult to treat with chemical precipitation, so that the heavy metals enter the chemical precipitation unit and easily react with the sodium sulfide solution to form a precipitate.

[0022] 2. The heavy metal wastewater treatment device in the mining area treats the wastewater through three methods: advanced oxidation treatment, chemical precipitation treatment, and membrane treatment. The heavy metal concentration is almost close to or lower than 1ug / L. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structure of a mining area heavy metal wastewater treatment device of the utility model;

[0024] Figure 2 It is a schematic diagram of the water injection type rotator of the utility model.

[0025] In the figure: 1, water inlet pipe; 2, advanced oxidation reaction box; 3, visible light lamp; 4, first pH detector; 5, sulfuric acid tank; 6, first conduit; 7, sulfuric acid switch valve; 8, peroxydisulfate tank; 9, catalyst tank; 10, second conduit; 11, third conduit; 12, water injection rotator; 13, peroxydisulfate switch valve; 14, catalyst switch valve; 15, fourth conduit; 16, primary chemical precipitation reaction box; 17, secondary chemical precipitation reaction box; 18, fifth conduit; 19, first mud discharge switch board; 20, second mud discharge switch board; 21, first agitator; 22, second agitator; 23, second pH detector; 24, third pH detector; 25, sodium sulfide tank; 26, liquid alkali tank; 27, water tank; 28, The first shunt pipe; 29, the sixth conduit; 30, the second shunt pipe; 31, the seventh conduit; 32, the third shunt pipe; 33, the eighth conduit; 34, the first lifting pump; 35, the second lifting pump; 36, the first sodium sulfide switch valve; 37, the second sodium sulfide switch valve; 38, the first water tank switch valve; 39, the second water tank switch valve; 40, the first liquid alkali lifting pump; 41, the second liquid alkali lifting pump; 42, the ninth conduit; 43, the membrane filter box; 44, the third mud discharge switch board; 45, the fourth pH detector; 46, the third agitator; 47, the nanofiltration membrane device; 48, the drainage pipe; 49, the tenth conduit; 50, the third lifting pump; 51, the fourth lifting pump; 52, the rotating lever; 53, the water injection head; 54, the fifth lifting pump. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0027] Reference Figure 1-Figure 2 , a mining area heavy metal wastewater treatment device, including an advanced oxidation unit, a chemical precipitation unit and a membrane filtration unit, allowing the wastewater to pass through the advanced oxidation unit, the chemical precipitation unit and the membrane filtration unit in sequence for treatment operations;

[0028] Wastewater enters the advanced oxidation reaction box 2 from the water inlet pipe 1. The first pH detector 4 in the advanced oxidation reaction box 2 detects the pH of the wastewater. If the detected pH is greater than 4, the sulfuric acid switch valve 7 is opened. At this time, since the sulfuric acid tank 5 is located above the advanced oxidation reaction box 2, the sulfuric acid in the sulfuric acid tank 5 will enter the advanced oxidation reaction box 2 along the first conduit 6 under the action of gravity, thereby reducing the pH of the wastewater in the advanced oxidation reaction box 2 to below 3. Then, the visible light lamp 3 is turned on to irradiate the wastewater, and the second conduit 10 is turned on. The disulfate switch valve 13 and the catalyst switch valve 14 on the third conduit 11, under the action of gravity, the persulfate in the persulfate tank 8 and the mixed catalyst of 20mgFePc / CN-6:20ml water in the catalyst tank 9 are sent into the advanced oxidation reaction box 2 through the water injection type rotator 12 arranged in the advanced oxidation reaction box 2. Under the irradiation of visible light, FePc / CN-6 activates the disulfate to produce persulfate, and oxidizes the chelated heavy metals and other precipitates that are difficult to treat in the wastewater;

[0029] The water injection rotator 12 is composed of a rotating rod 52 disposed at the top of the advanced oxidation reaction box 2 and a water injection head 53 installed at the bottom of the rotating rod 52. The rotating rod 52 drives the water injection head 53 to rotate. The second conduit 10 and the third conduit 11 are both rotatably connected to the rotating rod 52, and the rotating rod 52 is connected to the water injection head 53, so that the water injection head 53 can discharge a mixed catalyst of persulfate and 20mgFePc / CN-6:20ml water while rotating.

[0030] After the initial sedimentation of the wastewater in the advanced oxidation reaction box 2 is completed, the first lifting pump 34 on the fourth conduit 15 is started to pump the wastewater in the advanced oxidation reaction box 2 into the primary chemical precipitation reaction box 16. At this time, the second pH detector 23 in the primary chemical precipitation reaction box 16 will detect the wastewater entering the primary chemical precipitation reaction box 16. If its pH is less than 8.5, the first liquid alkali lifting pump 40 is turned on to send the liquid alkali in the liquid alkali tank 26 to the primary chemical precipitation reaction box 16 through the third branch pipe 32 to increase the pH of its wastewater to above 9.5, and then the first sodium sulfide switch valve 36 on the first branch pipe 28 is opened. At this time, 2g / l of sodium sulfide in the sodium sulfide tank 25 flows into the primary chemical precipitation reaction box 16 and reacts. After the heavy metals in the wastewater react with the sodium sulfide, the heavy metals with lower solubility will precipitate in the primary chemical precipitation when the pH is between 8-10. The bottom of the precipitation reaction box 16, then the second lifting pump 35 on the fifth conduit 18 is turned on to send the unreacted wastewater in the primary chemical precipitation reaction box 16 to the secondary chemical precipitation reaction box 17. At this time, the third pH detector 24 will detect the pH of the wastewater in the secondary chemical precipitation reaction box 17. If the pH is less than 10.5, the second liquid alkali lifting pump 41 will be turned on to send the liquid alkali in the liquid alkali tank 26 to the secondary chemical precipitation reaction box 17 through the eighth conduit 33, so that the pH of the wastewater in the secondary chemical precipitation reaction box 17 is increased to above 11.5, and then the second sodium sulfide switch valve 37 of the sixth conduit 29 is opened to allow 2g / l of sodium sulfide in the sodium sulfide tank 25 to flow into the secondary chemical precipitation reaction box 17 and react. After the heavy metals in the wastewater react with the sodium sulfide, the heavy metals with low solubility will sink to the bottom of the secondary chemical precipitation reaction box 17 when the pH is between 10-12;

[0031] Specifically, the chemical precipitation unit further includes a water tank 27, on which a second shunt pipe 30 connected to the first shunt pipe 28 and a seventh pipe 31 connected to the sixth pipe 29 are provided, and the concentration of the sodium sulfide can be adjusted by adding an aqueous solution to the sodium sulfide;

[0032] After the wastewater completes the reaction in the secondary chemical precipitation reaction box 17, the third boost pump 50 is started to pump the wastewater from the secondary chemical precipitation reaction box 17 to the membrane filter box 43 through the ninth conduit 42. At this time, the fourth pH detector 45 will detect the wastewater. If the pH of the wastewater is greater than 8, the fourth boost pump 51 on the tenth conduit 49 is started to pump the sulfuric acid in the sulfuric acid tank 5 to the membrane filter box 43, so that the pH of the wastewater is less than 7. Then the wastewater will be filtered through the nanofiltration membrane device 47 whose membrane material is a polyamide membrane and whose membrane flux is 10-30LMH, and discharged from the drainage pipe 48 under the operation of the fifth boost pump 54.

[0033] Furthermore, mud discharge switch plates are provided at the bottom of the primary chemical precipitation reaction box 16, the bottom of the secondary chemical precipitation reaction box 17, and the bottom of the membrane filtration box 43. When there is a lot of sediment in the primary chemical precipitation reaction box 16, the secondary chemical precipitation reaction box 17, and the membrane filtration box 43, the mud discharge switch plates can be opened to discharge mud.

[0034] Furthermore, agitators are provided in the primary chemical precipitation reaction box 16 , the secondary chemical precipitation reaction box 17 , and the membrane filtration box 43 , which can stir the wastewater, thereby accelerating its reaction rate.

[0035] Embodiment 1

[0036] The utility model is applied to the treatment of heavy metal wastewater in a mining area in Meizhou City. The pH of the wastewater is 6.6, and the excessive heavy metals in the raw water are 3.43mg / L zinc, 64ug / L cadmium, 545ug / L lead, and 0.32mg / L manganese. The utility model is applied to the treatment of heavy metal wastewater according to the following steps.

[0037] The operator connects the wastewater to the water inlet pipe 1, turns on the power supply of all equipment, turns off the mud discharge switch board, turns on the visible light lamp 3, turns on all agitators, all lifting pumps, all switch valves and the nanofiltration membrane device 47 with a membrane flux of 15LMH, sets the flow rate of the sodium sulfide switch valve to 2l / h, and the flow rate of the water tank switch valve to 200ml / h. The mining wastewater enters the advanced oxidation reaction box 2. The first pH detector 4 automatically opens the sulfuric acid switch valve 7 if the wastewater pH is greater than 4, and automatically closes the sulfuric acid switch valve 7 when the pH is less than 3. After oxidation, the wastewater uses the first lifting pump 34 to enter the primary chemical precipitation reaction box 16 from the advanced oxidation reaction box 2 through the fourth conduit 15. At this time, if the pH is less than 8.5, the first liquid alkali lifting pump 40 is automatically opened, and if the pH is greater than 9.5, the first liquid alkali lifting pump 40 is automatically closed. The wastewater removes pH in the primary chemical precipitation reaction box 16. The wastewater is then removed from the secondary chemical precipitation reaction tank 17 through the fifth conduit 18. If the pH is less than 10.5, the second liquid alkali lift pump 41 is automatically opened; if the pH is greater than 11.5, the second liquid alkali lift pump 41 is automatically closed. The wastewater is removed from the secondary chemical precipitation reaction tank 17 through the ninth conduit 42 to the membrane filter box 43 from the secondary chemical precipitation reaction tank 17. If the fourth pH detector 45 detects that the wastewater pH is greater than 8, the fourth lift pump 51 is automatically opened to pump sulfuric acid into the membrane filter box 43. When the pH is less than 7, the sulfuric acid switch valve 7 is automatically closed. At this time, the wastewater is filtered through the nanofiltration membrane 47 and then discharged from the drainage pipe 48. During the reaction, the sludge is discharged regularly through the sludge discharge switch plate.

[0038] After being treated by the utility model, the pH value of the heavy metal wastewater is 7.5, the concentration of zinc is 1ug / L, the concentration of cadmium is 0.8ug / L, the concentration of lead is 0.9ug / L, and the concentration of manganese is 0.8ug / L.

[0039] Embodiment 2

[0040] The utility model is applied to the treatment of heavy metal wastewater in a mining area in Zhongshan City. The pH of the raw water is 6.3, and the heavy metals exceeding the standard in the raw water include zinc 19.1mg / L, cadmium 322ug / L, lead 909ug / L, beryllium 2.1ug / L, and manganese 2.4mg / L. The utility model is applied to the treatment of heavy metal wastewater according to the following steps.

[0041] The operator connects the wastewater to the water inlet pipe 1, turns on the power supply of all equipment, turns off the mud discharge switch board, turns on the visible light lamp 3, turns on all agitators, all lifting pumps, all switch valves and the nanofiltration membrane device 47 with a membrane flux of 25LMH, sets the flow rate of the sodium sulfide switch valve to 6l / h, and the flow rate of the water tank switch valve to 100ml / h. The mining wastewater enters the advanced oxidation reaction box 2. The first pH detector 4 automatically opens the sulfuric acid switch valve 7 if the wastewater pH is greater than 4, and automatically closes the sulfuric acid switch valve 7 when the pH is less than 3. After oxidation, the wastewater uses the first lifting pump 34 to enter the primary chemical precipitation reaction box 16 from the advanced oxidation reaction box 2 through the fourth conduit 15. At this time, if the pH is less than 8.5, the first liquid alkali lifting pump 40 is automatically opened, and if the pH is greater than 9.5, the first liquid alkali lifting pump 40 is automatically closed. The wastewater removes pH in the primary chemical precipitation reaction box 16. The wastewater is then removed from the secondary chemical precipitation reaction tank 17 through the fifth conduit 18. If the pH is less than 10.5, the second liquid alkali lift pump 41 is automatically opened; if the pH is greater than 11.5, the second liquid alkali lift pump 41 is automatically closed. The wastewater is removed from the secondary chemical precipitation reaction tank 17 through the ninth conduit 42 to the membrane filter box 43 from the secondary chemical precipitation reaction tank 17. If the fourth pH detector 45 detects that the wastewater pH is greater than 8, the fourth lift pump 51 is automatically opened to pump sulfuric acid into the membrane filter box 43. When the pH is less than 7, the sulfuric acid switch valve 7 is automatically closed. At this time, the wastewater is filtered through the nanofiltration membrane 47 and then discharged from the drainage pipe 48. During the reaction, the sludge is discharged regularly through the sludge discharge switch plate.

[0042] After being treated by the utility model, the pH of the heavy metal wastewater is 7.2, the concentration of zinc is 0.9ug / L, the concentration of cadmium is 0.8ug / L, the concentration of lead is 0.9ug / L, the concentration of beryllium is 0.08ug / L, and the concentration of manganese is 1ug / L.

[0043] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A mining area heavy metal wastewater treatment device, characterized in that: Includes advanced oxidation unit, chemical precipitation unit and membrane filtration unit; The advanced oxidation unit comprises an advanced oxidation reaction box (2), a visible light lamp (3) is installed on the middle side of the advanced oxidation reaction box (2), a water inlet pipe (1) is installed on the top of the advanced oxidation reaction box (2), a sulfuric acid tank (5), a peroxydisulfate tank (8), and a catalyst tank (9) are arranged above the advanced oxidation reaction box (2), the sulfuric acid tank (5), the peroxydisulfate tank (8), and the catalyst tank (9) are all arranged on a support frame, the sulfuric acid tank (5) is connected to the advanced oxidation reaction box (2) through a first conduit (6), and a sulfuric acid switch valve (7) is installed on the first conduit (6), the peroxydisulfate tank (8) is connected to a water injection type rotator (12) through a second conduit (10), and the catalyst tank (9) is also connected to the water injection type rotator (12) through a third conduit (11), wherein the water injection type rotator (12) is installed inside the advanced oxidation reaction box (2); The catalyst tank (9) contains a mixed catalyst of 20 mg FePc / CN-6: 20 ml water, wherein FePc / CN-6 is iron phthalocyanine / carbon nitride and the mass percentage of iron phthalocyanine to carbon nitride is 6%; The chemical precipitation unit comprises a primary chemical precipitation reaction box (16) and a secondary chemical precipitation reaction box (17), wherein the primary chemical precipitation reaction box (16) and the secondary chemical precipitation reaction box (17) are arranged side by side on the side of the advanced oxidation reaction box (2), a fourth conduit (15) is arranged on the top of the primary chemical precipitation reaction box (16), the other end of the fourth conduit (15) is connected to the bottom of the advanced oxidation reaction box (2), and a fifth conduit (18) is arranged between the primary chemical precipitation reaction box (16) and the secondary chemical precipitation reaction box (17), one end of the fifth conduit (18) is fixed to the bottom of the primary chemical precipitation reaction box (16) and the other end is fixed to the top of the secondary chemical precipitation reaction box (17); The invention also comprises a water tank (27), a sodium sulfide tank (25), and a liquid alkali tank (26). The water tank (27), the sodium sulfide tank (25), and the liquid alkali tank (26) are arranged above the secondary chemical precipitation reaction box (17), and the water tank (27), the sodium sulfide tank (25), and the liquid alkali tank (26) are all arranged on a support frame. A seventh conduit (31) is installed at the bottom of the water tank (27), and the other end of the seventh conduit (31) is connected to the secondary chemical precipitation reaction box (17). A second shunt pipe (30) is installed on the seventh conduit (31), and the other end of the second shunt pipe (30) is connected to the secondary chemical precipitation reaction box (17). One end is connected to the primary chemical precipitation reaction box (16), the sodium sulfide tank (25) is filled with 2g / l sodium sulfide, the sodium sulfide tank (25) is connected to the secondary chemical precipitation reaction box (17) through a sixth conduit (29), the sixth conduit (29) is also provided with a first shunt pipe (28) connected to the primary chemical precipitation reaction box (16), and the liquid alkali tank (26) is connected to the secondary chemical precipitation reaction box (17) through an eighth conduit (33), and the eighth conduit (33) is provided with a third shunt pipe (32) connected to the primary chemical precipitation reaction box (16); The outlet end of the first shunt pipe (28) and the outlet end of the second shunt pipe (30) are combined and connected to the primary chemical precipitation reaction box (16), and the outlet end of the sixth conduit (29) and the outlet end of the seventh conduit (31) are combined and connected to the secondary chemical precipitation reaction box (17); The membrane filtration unit comprises a membrane filtration box (43), the membrane filtration box (43) is arranged on the side of the secondary chemical precipitation reaction box (17), and a ninth conduit (42) is connected to the bottom of the membrane filtration box (43), the other end of the ninth conduit (42) is connected to the bottom of the secondary chemical precipitation reaction box (17), a nanofiltration membrane device (47) is arranged in the membrane filtration box (43), the membrane material of the nanofiltration membrane device (47) is a polyamide membrane, and its membrane flux is 10-30LMH, the top of the nanofiltration membrane device (47) is connected to a drainage pipe (48), the drainage pipe (48) passes through the membrane filtration box (43) and extends to the outside of the membrane filtration box (43), wherein the sulfuric acid tank (5) is connected to the top of the membrane filtration box (43) through the tenth conduit (49).

2. A mining area heavy metal wastewater treatment device according to claim 1, characterized in that: A persulfate switch valve (13) is installed on the second conduit (10), and a catalyst switch valve (14) is installed on the third conduit (11).

3. A mining area heavy metal wastewater treatment device according to claim 1, characterized in that: The water injection type rotator (12) comprises a rotating rod (52) arranged in an advanced oxidation reaction box (2), the top of the rotating rod (52) is connected to the top of the advanced oxidation reaction box (2), and a water injection head (53) is installed at the bottom of the rotating rod (52), the second conduit (10) and the third conduit (11) are both rotatably connected to the rotating rod (52), and the rotating rod (52) is connected to the water injection head (53).

4. A mining area heavy metal wastewater treatment device according to claim 1, characterized in that: A first pH probe (4) is also installed on one side of the top of the advanced oxidation reaction tank (2), and the first pH probe (4) extends into the interior of the advanced oxidation reaction tank (2). A first agitator (21) is arranged inside the primary chemical precipitation reaction tank (16), and a second agitator (22) is arranged inside the secondary chemical precipitation reaction tank (17). In addition, a second pH probe (23) is also arranged on the primary chemical precipitation reaction tank (16) and extends into the interior of the primary chemical precipitation reaction tank (16), and a third pH probe (24) is also arranged on the secondary chemical precipitation reaction tank (17) and extends into the interior of the secondary chemical precipitation reaction tank (17).

5. A mining area heavy metal wastewater treatment device according to claim 1, characterized in that: A fourth pH probe (45) extending into the interior of the membrane filtration box (43) is installed on the top of the membrane filtration box (43), and a third agitator (46) is also provided in the membrane filtration box (43).

6. A mining area heavy metal wastewater treatment device according to claim 1, characterized in that: A first row of mud switch plate (19) is installed at the bottom of the primary chemical precipitation reaction box (16), a second row of mud switch plate (20) is installed at the bottom of the secondary chemical precipitation reaction box (17), and a third row of mud switch plate (44) is installed at the bottom of the membrane filtration box (43).

7. A mining area heavy metal wastewater treatment device according to claim 1, characterized in that: A first lifting pump (34) is installed on the fourth conduit (15), a second lifting pump (35) is installed on the fifth conduit (18), a first sodium sulfide switch valve (36) is installed on the first branch pipe (28), a second sodium sulfide switch valve (37) is installed on the sixth conduit (29), a first water tank switch valve (38) is installed on the second branch pipe (30), a second water tank switch valve (39) is installed on the seventh conduit (31), a first liquid alkali lifting pump (40) is installed on the third branch pipe (32), a second liquid alkali lifting pump (41) is installed on the eighth conduit (33), a third lifting pump (50) is installed on the ninth conduit (42), a fourth lifting pump (51) is installed on the tenth conduit (49), and a fifth lifting pump (54) is installed on the drainage pipe (48).

8. A mining area heavy metal wastewater treatment device according to claim 7, characterized in that: The flow rate ranges of the first sodium sulfide switch valve (36) and the second sodium sulfide switch valve (37) are set between 5 ml / h and 8 l / h, and the flow rate ranges of the first water tank switch valve (38) and the second water tank switch valve (39) are set between 0 and 0.8 l / h.

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