Carbon thermal reduction recycling method for Fenton iron mud

Abstract

The invention provides a carbon thermal reduction recycling method for Fenton iron mud. The method comprises the following steps: (1) drying the Fenton iron mud; (2) carrying out ball milling and mixing treatment on the dried Fenton iron mud and carbon powder to obtain a ball milling and mixing treatment material; (3) in the presence of protective gas, calcining the ball-milled and mixed material; (4) performing magnetic separation on the calcined material to obtain magnetic powder; and (5) recycling the magnetic powder to the Fenton oxidation pond. According to the method disclosed by the invention, the treatment of the Fenton iron mud is realized, the obtained magnetic powder is recycled to the Fenton oxidation pond, the organic matters in the wastewater can be efficiently removed, the stability of effluent is ensured, and the cyclic utilization of iron resources is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and more specifically, relates to a method for carbon thermal reduction and reuse of Fenton iron sludge. Background Art

[0002] With the acceleration of industrialization, wastewater treatment technology is facing increasingly severe challenges. In particular, for industrial wastewater containing refractory organic matter, traditional water treatment technology often fails to achieve the expected treatment effect. Advanced oxidation technology produces highly oxidizing free radicals to act on pollutants, thereby achieving the advantages of reducing biological toxicity and improving biodegradability.

[0003] Fenton oxidation technology has shown broad application prospects in the field of sewage treatment due to its simple operation, low equipment requirements and good oxidation effect. Fenton oxidation technology combines the characteristics of oxidation and flocculation, and can effectively remove a large number of difficult-to-degrade organic matter. However, after the reaction, a large amount of iron sludge containing toxic and harmful pollutants will be produced. If it is discharged directly, it will pollute the environment and is not conducive to the recycling and development of resources. Summary of the invention

[0004] The purpose of the present invention is to provide a method for carbon thermal reduction and recycling of Fenton iron sludge. The method of the present invention realizes the treatment of Fenton iron sludge, and the obtained magnetic powder is recycled to the Fenton oxidation tank, which can achieve efficient removal of organic matter in wastewater, ensure the stability of effluent, and realize the recycling of iron resources.

[0005] In order to achieve the above object, the present invention provides a method for carbon thermal reduction and recycling of Fenton iron sludge, the method comprising:

[0006] (1) Drying the Fenton iron mud;

[0007] (2) ball-milling the dried Fenton iron mud and carbon powder to obtain a ball-milled mixed material;

[0008] (3) calcining the ball-milled mixed material in the presence of a protective gas;

[0009] (4) subjecting the calcined material to magnetic separation to obtain magnetic powder;

[0010] (5) The magnetic powder is recycled to the Fenton oxidation tank.

[0011] According to the present invention, preferably, in step (1), the drying process is carried out in a rotary dryer.

[0012] According to the present invention, preferably, in step (1), the drying temperature is 60-120°C.

[0013] According to the present invention, preferably, in step (2), ball milling and mixing treatment is carried out in a ball mill.

[0014] According to the present invention, preferably, in step (2), the mass ratio of the Fenton iron mud to the carbon powder is (1-5): 1;

[0015] The particle size of the ball milled mixed material is 100-200 meshes.

[0016] According to the present invention, preferably, in step (3), the calcination treatment is carried out in a rotary kiln.

[0017] According to the present invention, preferably, in step (3), the protective gas is nitrogen, hydrogen or ammonia;

[0018] The calcination treatment is carried out at a temperature of 400-800° C. and for a time of 0.5-2 h.

[0019] According to the present invention, preferably, in step (4), magnetic separation is carried out in a magnetic separation device.

[0020] According to the present invention, preferably, the Fenton iron sludge is a filter cake obtained by plate and frame filtration of the iron sludge produced after Fenton treatment.

[0021] According to the present invention, preferably, the method further comprises: using the carbon powder obtained by the magnetic separation as the carbon powder raw material of step (2).

[0022] In the present invention, the carbon powder obtained by the magnetic separation can be used as the carbon powder raw material of step (2), and added to a ball mill with the Fenton iron mud after the drying treatment according to a certain mass ratio, and then ball milled and mixed in the ball mill.

[0023] The technical solution of the present invention has the following beneficial effects:

[0024] The method of the present invention realizes the treatment of Fenton iron mud, and the obtained magnetic powder is recycled to the Fenton oxidation tank, which can realize the efficient removal of organic matter in wastewater, ensure the stability of effluent, and realize the recycling of iron resources.

[0025] The method of the invention has simple process, easy operation, high automation, low processing cost and is easy to industrialize.

[0026] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0028] Figure 1 A process flow chart of a method for carbon thermal reduction and recycling of Fenton iron sludge according to an embodiment of the present invention is shown.

[0029] Figure 2 A diagram showing the magnetic force of magnetic powder according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0031] The present invention is further described below by examples:

[0032] The Fenton iron mud used in the following examples is a filter cake obtained by plate and frame filtration of iron mud produced by Fenton treatment of industrial wastewater.

[0033] The following determination of chemical oxygen demand (COD) is carried out by rapid digestion spectrophotometry. The detailed test steps can refer to the industry standard HJ / T 399-2007.

[0034] Example 1

[0035] like Figure 1 As shown, this embodiment provides a method for carbon thermal reduction and recycling of Fenton iron sludge, which specifically includes the following steps:

[0036] (1) Drying the Fenton iron mud in a rotary dryer at a temperature of 100° C. for 2 h;

[0037] (2) adding the dried Fenton iron mud and carbon powder into a ball mill at a mass ratio of 1:1, and then performing ball milling and mixing in the ball mill to obtain a ball milled mixed material with a particle size of 100-200 mesh;

[0038] (3) placing the obtained ball-milled mixed processed material in a rotary kiln, introducing nitrogen protective gas, and performing programmed temperature calcination, heating the temperature to 600° C. at a heating rate of 5° C. / min, calcining at 600° C. for 1 h, and naturally cooling to room temperature after the calcination;

[0039] (4) Separating the calcined material into magnetic powder and carbon powder by magnetic separation in a magnetic separation device to obtain magnetic powder and carbon powder.

[0040] (5) recycling the magnetic powder to the Fenton oxidation tank; using the obtained carbon powder as the carbon powder raw material of step (2), adding it and the dried Fenton iron mud into a ball mill according to the feed ratio, and then performing ball milling and mixing treatment in the ball mill.

[0041] Example 2

[0042] The difference between this embodiment and embodiment 1 is that the mass ratio of the dried Fenton iron mud to the carbon powder is changed from 1:1 to 3:1, and the rest is the same as embodiment 1.

[0043] Example 3

[0044] The difference between this embodiment and embodiment 1 is that the mass ratio of the dried Fenton iron mud to the carbon powder is changed from 1:1 to 5:1, and the rest is the same as embodiment 1.

[0045] Example 4

[0046] The difference between this embodiment and embodiment 1 is only that the nitrogen protective gas is replaced by hydrogen protective gas, and the rest is the same as embodiment 1.

[0047] Example 5

[0048] The only difference between this embodiment and embodiment 2 is that the nitrogen protective gas is replaced by ammonia protective gas, and the rest is the same as embodiment 2.

[0049] Example 6

[0050] The difference between this embodiment and embodiment 3 is only that the nitrogen protective gas is replaced by ammonia protective gas, and the rest is the same as embodiment 3.

[0051] Test Example 1

[0052] 500 ml of influent water (COD=1260 mg / L) from a certain enterprise's Fenton oxidation pond was taken into a beaker, and the pH value of the solution was adjusted to 3 using concentrated H2SO4. 2 g of the magnetic powder prepared in the above embodiment was added and stirred evenly, and then 1.8 ml of H2O2 water with a mass concentration of 30% was added to start the Fenton reaction. After reacting for 2 hours, NaOH aqueous solution was added to adjust the pH value to neutral, and the COD content of the supernatant was detected. The specific test results are shown in Table 1.

[0053] Traditional Fenton experimental method: Take 500 ml of the same Fenton oxidation pond influent (COD = 1260 mg / L) as above and place it in a beaker, use concentrated H2SO4 to adjust the pH of the solution to 3, add 1.7 g Fe2SO4·7H2O and stir evenly, then add 1.8 ml of H2O2 water with a mass concentration of 30% to start the Fenton reaction, add NaOH aqueous solution after 2 hours of reaction to adjust the pH to neutral, and detect the COD content of the supernatant. The specific test results are shown in Table 1.

[0054] Table 1

[0055] project COD after 2h reaction (mg / L) COD removal rate (%) <![CDATA[Traditional Fenton (Fe2SO4·7H2O)]]> 482 61.75％ Example 1 Magnetic Powder 663 47.38％ Example 2 Magnetic Powder 497 60.56％ Example 3 Magnetic Powder 613 51.35％ Example 4 Magnetic Powder 561 55.48％ Example 5 Magnetic Powder 419 66.75％ Example 6 Magnetic Powder 556 55.87％

[0056] Test Example 2

[0057] The magnetic powder prepared in Example 1 was placed in a beaker filled with deionized water and its magnetic force was tested with a magnet. The specific test results are as follows: Figure 2 shown.

[0058] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for carbon thermal reduction and recycling of Fenton iron sludge, characterized in that: The method includes: (1) Drying the Fenton iron mud; (2) ball-milling the dried Fenton iron mud and carbon powder to obtain a ball-milled mixed material; (3) calcining the ball-milled mixed material in the presence of a protective gas; (4) subjecting the calcined material to magnetic separation to obtain magnetic powder; (5) The magnetic powder is recycled to the Fenton oxidation tank.

2. The method according to claim 1, wherein: In step (1), drying is performed in a rotary dryer.

3. The method according to claim 1, wherein: In step (1), the drying temperature is 60-120°C.

4. The method according to claim 1, wherein: In step (2), ball milling and mixing treatment is performed in a ball mill.

5. The method according to claim 1, wherein: In step (2), the mass ratio of the Fenton iron mud to the carbon powder is (1-5): 1; The particle size of the ball milled mixed material is 100-200 meshes.

6. The method according to claim 1, wherein: In step (3), calcination is carried out in a rotary kiln.

7. The method according to claim 1, wherein: In step (3), the protective gas is nitrogen, hydrogen or ammonia; The calcination treatment is carried out at a temperature of 400-800° C. and for a time of 0.5-2 h.

8. The method according to claim 1, wherein: In step (4), magnetic separation is carried out in a magnetic separation device.

9. The method according to claim 1, wherein: The Fenton iron mud is a filter cake obtained by plate and frame filtration of the iron mud produced after Fenton treatment.

10. The method according to claim 1, wherein: The method further comprises: using the carbon powder obtained through the magnetic separation as the carbon powder raw material of step (2).

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