Double-rake alternating type agricultural magnetic repair material recycling process method

Abstract

The invention discloses a double-rake alternating type agricultural magnetic remediation material recovery treatment process method which comprises the following steps: S1, irrigating and stirring an area where to-be-remedied soil is located to form flowable slurry; s2, putting a magnetic repairing material into the slurry, stirring to uniformly mix the slurry and the material, standing for 8-12 hours, and uniformly stirring the slurry again; s3, the front rake is completely immersed in the slurry and moves in a Z shape to adsorb magnetic substances in the slurry; the rear rake hovers; a double-channel partition plate of the collecting device is located at the neutral position, and a discharging opening is closed; s4, when the thickness sensor detects that the thickness of the adsorption layer of the front rake is larger than or equal to 15 mm, the front rake is automatically triggered for discharging, and the rear rake is synchronously started and immersed in mud for adsorption; s5, similarly, when it is detected that the thickness of the adsorption layer of the rear rake is larger than or equal to 15 mm, the rear rake unloads materials, and the front rake works again; and S6, the collected magnetic repair materials are collected into a collecting device through the double rakes, and centralized treatment is facilitated. The method is suitable for the farmland mud environment containing impurities, and low-cost cyclic utilization of the magnetic repairing material can be achieved.

Description

Technical Field

[0001] The present invention relates to the field of solid waste resource utilization, and particularly to a dual-rake alternating agricultural magnetic remediation material recovery and treatment process method. Background Art

[0002] At present, the soil environmental problems in China still need to be solved by means of advanced technologies, especially the heavy metal pollution problem. In the polluted soil, heavy metals accumulate and are enriched in plants, and will enter the human body through the food chain, affecting human health and also causing damage to the ecological environment. There are various applications of magnetic soil remediation materials, but there is a lack of technology for adsorbing magnetic materials in the soil for recycling. Therefore, there is an urgent need for a method that can achieve continuous operation and efficiently collect magnetic substances. Summary of the Invention

[0003] The purpose of the present invention is to provide a soil heavy metal treatment process method based on magnetic remediation materials suitable for wetlands, so as to be suitable for use in wetlands.

[0004] To this end, the present invention provides a dual-rake alternating agricultural magnetic remediation material recovery and treatment process method, including: S1. Irrigate and stir the area where the soil to be remediated is located to form flowing slurry; S2. Put magnetic remediation materials into the slurry, stir to make the slurry and the materials evenly mixed, let it stand for 8 - 12 hours, and then stir the slurry evenly again; S3. Completely immerse the front rake into the slurry and move in a "Z" shape to adsorb magnetic substances in the slurry; the rear rake hovers; the double-channel partition of the collection device is in the neutral position and the discharge port is closed; S4. When the thickness of the adsorption layer of the front rake detected by the infrared thickness sensor is ≥ 15 mm, automatically trigger the front rake to discharge materials, and the rear rake is synchronously started and immersed in the slurry for adsorption; S5. Similarly, when the thickness of the adsorption layer of the rear rake is detected to be ≥ 15 mm, the rear rake discharges materials and the front rake resumes work; S6. The dual rakes collect the magnetic remediation materials collected into the collection device for centralized treatment.

[0005] Compared with the prior art, the present invention has the following technical features / advantages:

[0006] (1) Adopt an asymmetric dual-rake layout, with a magnetic pole spacing of 8 mm for the front rake and 5 mm for the rear rake, and the spatial trajectories of the dual rakes are staggered to achieve continuous operation;

[0007] (2) Can automatically switch modes and automatically trigger alternating discharging based on the infrared thickness sensor;

[0008] (3) Low manufacturing cost, support for rapid on-site repair, and environmental friendliness.

[0009] In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the accompanying

[0011] In the drawings:

[0012] Figure 1 is the process flow chart of the present invention;

[0013] Figure 2 is the schematic diagram of the special equipment used in the treatment process method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] The present invention will be described in detail below with reference to the drawings and in combination with embodiments.

[0015] Referring to Figure 1 , the soil heavy metal treatment process method based on magnetic repair materials of the present invention includes the following steps:

[0016] S1. Irrigate and stir the area where the soil to be repaired is located to form a flowing slurry;

[0017] S2. Put magnetic repair materials into the slurry, stir to mix the slurry and the materials evenly, and stir the slurry evenly again after standing for 8 - 12 hours;

[0018] S3. Initial state: The front rake is completely immersed in the slurry, moves in a "Z" shape at a speed of 0.5 m / s to adsorb magnetic substances in the slurry; the rear rake hovers 50 mm above the slurry, and the magnet is in a standby state (maintaining this state with a weak magnetic field); the double-channel partition of the collection device is in a neutral position, and the discharge port is closed;

[0019] S4. When the thickness of the adsorption layer of the front rake detected by the infrared thickness sensor is ≥ 15 mm, the front rake is automatically triggered to discharge; the speed of the front rake is reduced to 0.2 m / s, the magnet activation state is maintained, and the rear rake is synchronously started to immerse in the slurry at a speed of 0.5 m / s for adsorption;

[0020] S5. The rear rake replaces the front rake to work. Similarly, when the thickness of the adsorption layer of the rear rake is detected to be ≥ 15 mm, the speed of the rear rake is reduced to 0.2 m / s after discharging, and the front rake is synchronously started to immerse in the slurry at a speed of 0.5 m / s to work, so as to realize the synchronous work and alternating discharging of the front and rear rakes;

[0021] S6. The double rakes collect the magnetic repair materials collected into the collection device for centralized treatment.

[0022] The addition amount of the magnetic remediation material is 2% of the plough layer soil quality. The magnetic remediation material is specifically magnetic modified fly ash, and its specific surface area has increased by 13.4 times compared with ordinary fly ash. The magnetic modified fly ash is put into the heavy metal contaminated soil to fix the active metal in the soil on the surface. Under the action of an external magnetic field, the magnetic modified fly ash is removed, and the active heavy metals on the surface of the magnetic modified fly ash are removed through desorption, finally reducing the activity of heavy metals in the soil and reducing the total amount of heavy metals.

[0023] The raw materials of the magnetic remediation material include: 10 g of fly ash that has passed through a 100-mesh sieve and is dried, 3.3019 g of FeCl3·6H2O, 150 mL of deionized water, 1 g of citric acid, 5 mL of polyethylene glycol, 1.6981 g of FeSO4·7H2O, and 2 mol / L of NaOH.

[0024] A preparation method of a magnetic modified fly ash (MFA2:1) material includes the following steps:

[0025] The fly ash (FA) passes through a 100-mesh sieve and is placed in a drying oven to be dried at 100 °C for 2 h. Add 10 g of fly ash that has passed through a 100-mesh sieve, 3.3019 g of FeC13·6H2O, 1 g of citric acid, then add 5 mL of polyethylene glycol and 150 mL of deionized water to a self-made container. Then, mechanically stir for 5 min to dissolve FeC13·6H2O. Pass nitrogen into the mixed solution to expel oxygen for 30 min, and then add 1.6981 g of FeSO4·7H2O to make it evenly mixed. Let it stand for adsorption for 2 h, then heat the water bath to 70 °C, and quickly add 2 mo1 / L of NaOH as a precipitant under high-speed stirring to adjust the solution to pH≥12.5. Stop stirring after 10 min and keep the constant temperature. The product is cured at 70 °C for 2 h, and then cooled to room temperature. Separate and collect with a magnet and then wash with deionized water until pH = 6.5. Dry in an oven at 40 °C to obtain magnetic fly ash MFA2:1, and pass through a 100-mesh sieve for standby.

[0026] The treatment equipment according to this method can be composed of integrating a double harrow, a collection device, a hydraulic cylinder, a translation motor and an infrared thickness sensor on the body of a rotary tiller. A partition is distributed in the collection device, which opens / closes corresponding to the lifting of the front / rear harrow bodies.

[0027] The moving paths of the double harrows do not cross. The magnetic pole spacing of the front harrow is 8 mm, the magnetic pole spacing of the rear harrow is 5 mm, and the front harrow maintains a vertical spacing of 200 mm from the rear harrow after lifting, so that the double harrows will not collide.

[0028] When the unloading of one side harrow body starts, the other side harrow body has recovered adsorption for at least 30 s to ensure the continuous operation of the harrow body.

[0029] The collection device includes a double-channel baffle. The front-channel baffle is opened during the unloading of the front rake, and the rear-channel baffle is opened during the unloading of the rear rake.

[0030] Before unloading, the rake body is vertically lifted by 300 mm to separate from the slurry. The translation motor drives the rake body to move directly above one side of the collection device. The baffle above the collection device is opened, and the baffle on the other side is closed.

[0031] During unloading, the magnet on the rake body is switched to the reverse pulse demagnetization mode, and then the high-frequency vibration is started to make the magnetically modified fly ash fall off naturally.

[0032] Under nitric acid solutions of different concentrations, heavy metals are easily desorbed from the material, and the desorption rate is above 96%.

[0033] The above are only the embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A double-rake alternating agricultural magnetic repair material recycling and treatment process method, characterized in that, The following steps are involved: S1. Irrigate and stir the area where the soil to be repaired is located to form a fluid slurry; S2. Add magnetic repair material to the mud, stir to make the mud and material evenly mixed, let it stand for 8-12 hours and then stir the mud evenly again; S3, initial state: the front rake is completely immersed in the mud, and moves in a "Z-shape" at a speed of 0.5m / s to absorb the magnetic substances in the mud; the rear rake is suspended 50mm above the mud, and the magnet is in a standby state (maintained by a weak magnetic field); the double-channel partition of the collection device is in a neutral position, and the discharge port is closed; S4. When the infrared thickness sensor detects that the thickness of the front rake adsorption layer is ≥15mm, the front rake is automatically triggered to unload; the front rake speed is reduced to 0.2m / s, the magnet is kept activated, and the rear rake is started synchronously and immersed in the mud at a speed of 0.5m / s for adsorption; S5, the rear harrow replaces the front harrow to work. Similarly, when it is detected that the thickness of the rear harrow adsorption layer is ≥15mm, the speed of the rear harrow is reduced to 0.2m / s after unloading, and the front harrow is started synchronously and immersed in the mud at a speed of 0.5m / s to work, so that the front and rear harrows work synchronously and unload alternately; S6. The double rake collects the collected magnetic repair materials into a collection device for centralized processing.

2. The double-rake alternating agricultural magnetic repair material recycling and treatment process method according to claim 1, characterized in that The magnetic repair material is a fly ash magnetic modified material. Compared with ordinary fly ash, the specific surface area of the material is increased by 13.4 times, and the maximum adsorption capacity of Cu, Cd and Pb is increased by 0.55 to 2.32 times, and it has a good adsorption effect.

3. The double-rake alternating agricultural magnetic repair material recycling and treatment process method according to claim 1, characterized in that, The ratio (molar ratio) of the magnetic modification material is: 1:2 of FeSO4·7H2O and FeCl3·6H2O, fly ash, 150mL deionized water, 1g citric acid, 5mL polyethylene glycol, 2-5mol / LNaOH. The amount of magnetic repair material added is more than 2% of the mass of the cultivated soil.

4. The double-rake alternating type agricultural magnetic repair material recycling and treatment process method according to claim 1, characterized in that, The moving paths of the two rakes do not cross, the magnetic pole spacing of the front rake is 8mm, and the magnetic pole spacing of the rear rake is 5mm. After the front rake is lifted, it maintains a vertical distance of 200mm with the rear rake, and the collision of the two rakes will not occur.

5. The double-rake alternating agricultural magnetic repair material recycling and treatment process method according to claim 1, characterized in that When the unloading of one side of the rake body starts, the other side of the rake body has resumed adsorption for at least 30s to ensure the continuous operation of the rake body.

6. The double-rake alternating type agricultural magnetic repair material recycling and treatment process method according to claim 1, characterized in that, The collecting device includes a double channel partition. The front channel partition is opened when the front rake is unloading, and the rear channel partition is opened when the rear rake is unloading.

7. The double-rake alternating type agricultural magnetic repair material recycling and treatment process method according to claim 1, characterized in that, Before unloading, the rake body is lifted vertically by 300mm to separate from the mud. The translation motor drives the rake body to move to the top of one side of the collecting device. The partition above the collecting device is opened and the partition on the other side is closed.

8. The double-rake alternating agricultural magnetic repair material recycling and treatment process method according to claim 1, characterized in that When unloading, the magnet on the rake body is switched to the reverse pulse demagnetization mode, and then high-frequency vibration is started to make the magnetic modified fly ash fall off naturally.

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