Adsorbent as well as application and preparation method thereof

Abstract

The invention relates to the technical field of water pollution treatment, and discloses an adsorbent and application and a preparation method thereof, and the method specifically comprises the following steps: S1, obtaining, drying and grinding iron tailings and municipal sludge; s2, uniformly mixing the ground iron tailings, municipal sludge and # imgabs0 according to a set mass ratio, and carrying out magnetizing roasting in a closed container; and S3, cooling the roasted product in an oxygen-free atmosphere, carrying out magnetic separation, and drying to obtain the adsorbent. The method solves the problem of insufficient iron resource recovery efficiency in the prior art, and has the characteristics of high economic benefit and efficient utilization of iron tailings.

Description

Technical Field

[0001] The present invention relates to the technical field of water pollution control, and more specifically to an adsorbent and an application and preparation method thereof. Background Art

[0002] Mineral resources are important resources for human survival and development. Most of the energy and raw materials needed for people's lives need to be obtained through the development of mineral resources. However, when ore waste is exposed to oxygen and water, especially sulfur-containing minerals (mainly pyrite, FeS), it will oxidize to produce acid mine drainage (AMD). AMD has the characteristics of strong acidity, high concentration of sulfate and heavy metal / metalloid ions (such as heavy metal ions Fe, Mn, Cu, Zn, Cd, Pb, Cr, As), and it is very easy to enter streams and dams with rainwater, causing serious pollution of groundwater and surface water, causing regional ecological and environmental problems. It has been recognized as the main source of pollution of soil and water environment in mining areas worldwide. At present, water pollution incidents caused by AMD frequently occur in abandoned mines in China, threatening the quality of water environment. To this end, it is urgent to develop low-cost and sustainable treatment technologies to reduce the adverse environmental impacts on receiving water bodies or ecosystems.

[0003] In general, AMD treatment technologies are divided into active and passive treatment. Active treatment generally refers to the continuous addition of alkaline industrial chemicals such as calcium oxide (CaO), sodium hydroxide (NaOH), slaked lime (Ca(OH)2), and limestone (CaCO3) to neutralize acidity and precipitate metals. Passive treatment uses gravity flow to construct limestone beds and wetlands to naturally purify AMD. Passive treatment has relatively low operating costs and maintenance and requires almost no external energy input, while active treatment requires not only a continuous supply of chemicals, but also long-term use of energy and manpower.

[0004] Economic factors play an important role in the feasibility of AMD treatment technology. In the active or passive treatment system of AMD, alkaline agent neutralization remains an indispensable method. However, chemical dosing precipitation method has high operating costs and may cause secondary pollution or require treatment or disposal. In contrast, adsorption method has good development prospects due to its high selectivity, rapid and effective characteristics, especially with the development and application of cheap adsorbent materials, its treatment cost can be greatly reduced. Recently, some researchers have used alkaline industrial byproducts for the treatment of AMD, otherwise these byproducts will be treated as waste, usually landfilled or piled on construction sites. From an environmental point of view, it will be more cost-effective and desirable to reuse these alkaline solid wastes instead of alkaline industrial chemicals. Many natural resources have been used to effectively adsorb heavy metals from aqueous solutions, including lignite, attapulgite, zeolite and bentonite. In addition to their effectiveness, the utilization of these natural resources helps to reduce the cost of AMD treatment. Therefore, the development of low-cost adsorbent materials with suitable adsorption capacity has important application prospects for the treatment of AMD.

[0005] The prior art has a method for preparing a magnetic biochar adsorbent by hydrothermal carbonization of iron tailings and municipal sludge, a product and its application in the treatment of dye-contaminated wastewater. The method includes: step 1, material preparation: placing municipal sludge and iron tailings in a homogenization tank, stirring them fully to homogenize them; step 2, hydrothermal reaction: transferring the homogenized municipal sludge and iron tailings mixture to a hydrothermal reactor for hydrothermal reaction, and setting the hydrothermal reaction temperature to 210-270°C; step 3, solid-liquid separation: after the hydrothermal reaction is completed and cooled, open the hydrothermal reactor, separate the obtained solid-liquid mixed suspension into solid-liquid, and dry the separated solid phase product to obtain a magnetic biochar adsorbent.

[0006] However, the existing technology has the problem of insufficient efficiency in iron resource recovery. Therefore, how to invent an adsorbent that can efficiently recover iron resources is a technical problem that urgently needs to be solved in this technical field. Summary of the invention

[0007] In order to solve the problem of insufficient iron resource recovery efficiency in the prior art, the present invention provides an adsorbent and its application and preparation method, which has the characteristics of high economic benefit and efficient utilization of iron tailings.

[0008] In order to achieve the above-mentioned purpose of the present invention, the technical scheme adopted is as follows: An adsorbent made of iron tailings, municipal sludge, It is made by co-thermal magnetization calcination according to the mass ratio of 10:N1:N2, N1∈(0.5~5), N2∈(0.1~0.6).

[0009] Application of an adsorbent for removing acid mine drainage ion.

[0010] A method for preparing an adsorbent comprises the following steps: S1. Obtain, dry and grind iron tailings and municipal sludge; S2, according to the mass ratio of 10:N1:N2, N1∈(0.5~5), N2∈(0.1~0.6), mixed with ground iron tailings, municipal sludge and Mix well and carry out magnetization roasting in a closed container; S3. Cool the calcined product in an oxygen-free atmosphere, separate it by magnetic separation, and then dry it to obtain an adsorbent. Preferably, in step S1, the iron tailings are fine iron tailings with a particle size of ≤4500µm after crushing, grinding and sorting.

[0011] Furthermore, in the step S1, the iron tailings are ground to any mesh size of 50-80. Furthermore, in step S2, the iron content of the iron tailings is in the range of 29% to 32%.

[0012] Furthermore, in the step S2, the magnetization calcination temperature ranges from 600 to 800°C. Furthermore, in the step S2, the magnetization calcination time ranges from 10 to 50 minutes. Furthermore, in step S3, the magnetic separation adopts wet magnetic separation, and the magnetic induction intensity ranges from 80 to 120 mT.

[0013] Furthermore, the step S3 is specifically as follows: cooling the mixture obtained after roasting in an oxygen-free atmosphere, weighing several grams of the roasted product, adding deionized water, performing a wet magnetic separation, suction filtering, and drying in a blast drying oven to obtain a tailings adsorbent The beneficial effects of the present invention are as follows: The present invention combines organic sludge, difficult-to-select low-grade iron tailings, The co-thermal magnetic roasting treatment is simple to operate and obtains alkaline tailings adsorption material with adsorption effect, which solves the problem of insufficient iron resource recovery efficiency in the prior art and has the characteristics of high economic benefits and efficient utilization of iron tailings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The present invention is a schematic diagram of a process for preparing an adsorbent.

[0015] Figure 2 This is the SEM image of the iron tailings in Example 3.

[0016] Figure 3 This is the SEM image of the tailings adsorption material in Example 3 Figure 4 The Langmuir and Freundlich linear adsorption isotherm equations of the tailings adsorption material in Example 3 are fitted. DETAILED DESCRIPTION The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] Example 1 An adsorbent made of iron tailings, municipal sludge, It is made by co-heating magnetization roasting in a mass ratio of 10:0.5:0.1 and is used to remove acidic mine wastewater. ion.

[0018] The invention mixes iron tailings and organic sludge for magnetization roasting, utilizes reducing gas generated by pyrolysis of organic sludge to react with trivalent iron for magnetization reaction, and adopts The catalysis achieves the clean production goal of treating waste with waste, provides a new technical path for the treatment and disposal of organic sludge and the resource utilization of iron tailings, and the obtained tailings product can be used as an alkaline adsorption material to achieve the clean production goal of full component utilization with a simple process. The adsorbent can operate effectively and stably under acidic conditions, has low production costs, and is more environmentally friendly.

[0019] Example 2 like Figure 1 As shown, a method for preparing an adsorbent comprises the following steps: S1. Obtain, dry and grind iron tailings and municipal sludge; S2, mixed with ground iron tailings, municipal sludge and Mix well and carry out magnetization roasting in a closed container; S3. Cool the calcined product in an oxygen-free atmosphere, separate it by magnetic separation, and then dry it to obtain an adsorbent. In this embodiment, in step S1, the iron tailings are crushed, ground and sorted to a particle size between 178 µm and 297 µm.

[0020] In a specific embodiment, in the step S1, the iron tailings are ground to 50 mesh. In a specific embodiment, in step S2, the iron content of the iron tailings is 29%. In a specific embodiment, in step S2, the mass ratio of iron tailings, municipal sludge and NaCO3 is 10:5:0.6. In a specific embodiment, in step S2, the magnetization calcination temperature is 600°C. In a specific embodiment, in step S2, the magnetization calcination time is 10 minutes. In a specific embodiment, in step S3, the magnetic separation adopts wet magnetic separation, and the magnetic induction intensity is 80mT.

[0021] In this embodiment, the iron tailings are recycled, and the weakly magnetic minerals such as hematite and limonite that are difficult to select in the iron tailings are reduced to strong magnetic magnetite ( ), and then magnetic separation can recover magnetite concentrate with an iron grade of ≥60%, which meets the industrial standard (GB / T 36704-2018); the sludge is harmless and valuable. The organic components in municipal sludge (such as printing and dyeing sludge, papermaking sludge) are pyrolyzed at high temperature to produce reducing gases such as CO and H2, which not only replace traditional fossil fuels to reduce energy consumption, but also promote the reduction reaction of iron oxides. At the same time, the iron element in the sludge can be recovered simultaneously; the tailings are comprehensively utilized: the tailings after magnetic separation can be used as building materials (such as cement admixtures) or adsorption materials because the organic pollutants are fully pyrolyzed, realizing "waste treatment with waste", In this embodiment, the present invention uses sludge to replace fossil fuels as a reducing agent, combined with the catalytic effect of Na2CO3, to obtain an alkaline tailings adsorption material with adsorption effect, and its adsorption effect on Fe3+ in AMD can reach more than 97%. In addition, the present invention effectively utilizes the volatile components in municipal sludge, reduces the iron resources in the iron tailings, achieves high-grade recovery of iron resources in the iron tailings, achieves the clean production goal of treating waste with waste, has significant economic benefits, realizes more efficient utilization of iron tailings, and indirectly reduces carbon emissions and pollutant emissions. It provides a new technical path for the treatment and disposal of organic sludge and the resource utilization of iron tailings.

[0022] Example 3 A method for preparing an adsorbent comprises the following steps: S1. Obtain, dry and grind iron tailings and municipal sludge; S2, mixed with ground iron tailings, municipal sludge and Mix well and carry out magnetization roasting in a closed container; S3. Cool the calcined product in an oxygen-free atmosphere, separate it by magnetic separation, and then dry it to obtain an adsorbent. In this embodiment, in step S1, the iron tailings are crushed, ground and sorted to a particle size of 2500µm to 3500µm.

[0023] In a specific embodiment, in the step S1, the iron tailings are ground to 80 mesh. In a specific embodiment, in step S2, the iron content of the iron tailings is 32%. In a specific embodiment, in step S2, the mass ratio of iron tailings, municipal sludge and NaCO3 is 10:0.5:0.1. In a specific embodiment, in step S2, the magnetization calcination temperature is 800°C. In a specific embodiment, in the step S2, the magnetization calcination time is 50 minutes. In a specific embodiment, in step S3, the magnetic separation adopts wet magnetic separation, and the magnetic induction intensity is 120mT.

[0024] Example 4 A method for preparing an adsorbent comprises the following steps: S1. Crush the dried iron tailings and municipal sludge, mix them evenly with Na2CO3 and place them in the same porcelain boat. When the reactor temperature rises to the specified temperature, place the porcelain boat in the reactor for magnetization roasting. The iron content of the iron tailings is 29%~32%; the mass ratio of the iron tailings to municipal sludge is 10:2:; the amount of Na2CO3 added is 5%; the iron tailings are crushed to a particle size of 50-80 mesh; the magnetization roasting temperature is 750℃; the magnetization roasting time is 30min; S2. After cooling the mixture obtained after calcination in an oxygen-free atmosphere, 5 g of the calcined product was weighed, 500 mL of deionized water was added, and wet magnetic separation was performed at a magnetic induction intensity of 120 mT, and then filtered and dried in a blast drying oven at 60 ° C for 24 h to obtain tailings material, the SEM image of which is shown as follows: Figure 2 , Figure 3 shown.

[0025] S3. Use the tailings adsorption material to remove Fe3+ in AMD, such as Figure 3 As shown in the figure, the removal rate can reach up to 98% in 180 minutes.

[0026] The adsorption experimental conditions were: pH = 2.4-2.6, temperature = 25°C, adsorbent dosage = 2 g; concentration = 606 mg / L; contact time = 180 min.

[0027] The drying conditions of S1 and S2 are as follows: the iron tailings and municipal sludge are placed in an oven at 105 °C and dried for 24 hours respectively.

[0028] Example 5 In this example, the adsorbent of the present invention in Example 4 is combined with a Fe 3+ A comparative experiment was conducted with the adsorbent X1, and the only difference between X1 and the adsorbent of the present invention in Example 4 was that no Na2CO3 was added.

[0029] The conditions of the comparative experiment are as follows: At room temperature, add H2O2 to AMD to convert Fe2+ into Fe3+. The added amount is 1.3 ml / L and the reaction is stirred for 5 minutes.

[0030] Take 2g of the adsorbent of the present invention and the adsorbent of X1, respectively, and put them into 100ml of AMD (C0=606mg / L) for full reaction for 3h, then measure the Fe3+ concentration C1 in the solution, and calculate the Fe3+ removal rate according to the formula, Fe3+ removal rate (%) = ×100%, The experimental results are shown in Table 1: Table 1 Removal effect of Fe3+ in AMD

[0031] As can be seen from Table 1, the Fe3+ removal effect of the adsorbent of the present invention is much better than that of X1. Therefore, the present invention not only solves the disposal problem of two large solid wastes through the coordinated treatment of iron tailings and municipal sludge, combined with the catalytic effect of Na2CO3, but also realizes the efficient recovery of iron resources and the high-value utilization of tailings. Its creativity is reflected in process innovation, resource synergy and low-carbon design, providing sustainable solutions for the fields of metallurgy and environmental protection.

[0032] Embodiment 6-8 The difference between Examples 5 to 7 and Example 2 is that the parameters of the preparation method are different, as shown in Table 2: Table 2

[0033] Obviously, the above embodiments of the present invention are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. An adsorbent, characterized in that: From iron tailings, municipal sludge, It is made by co-thermal magnetization calcination according to the mass ratio of 10:N1:N2, N1∈(0.5~5), N2∈(0.1~0.6).

2. Use of the adsorbent according to claim 1, characterized in that: For the removal of acid mine drainage ion.

3. A method for preparing the adsorbent according to claim 1, characterized in that: The following steps are involved: S1. Obtain, dry and grind iron tailings and municipal sludge; S2, according to the mass ratio of 10:N1:N2, N1∈(0.5~5), N2∈(0.1~0.6), mixed with ground iron tailings, municipal sludge and Mix well and carry out magnetization roasting in a closed container; S3. Cool the calcined product in an oxygen-free atmosphere, separate it by magnetic separation, and then dry it to obtain an adsorbent.

4. The preparation method according to claim 3, characterized in that: In the step S1, the iron tailings are fine iron tailings with a particle size of ≤4500µm after crushing, grinding and sorting.

5. The preparation method according to claim 3, characterized in that: In the step S1, the iron tailings are ground to any mesh size of 50-80.

6. The preparation method according to claim 3, characterized in that In the step S1, the iron content of the iron tailings is in the range of 29% to 32%.

7. The preparation method according to claim 3, characterized in that: In the step S2, the magnetization calcination temperature ranges from 600 to 800°C.

8. The preparation method according to claim 3, characterized in that: In the step S2, the magnetization calcination time ranges from 10 to 50 minutes.

9. The preparation method according to claim 3, characterized in that: In the step S3, the magnetic separation adopts wet magnetic separation, and the magnetic induction intensity ranges from 80 to 120 mT.

10. The preparation method according to claim 9, characterized in that: The step S3 is specifically as follows: cooling the mixture obtained after calcination in an oxygen-free atmosphere, weighing several grams of the calcined product, adding deionized water, performing a wet magnetic separation, filtering, and drying in a blast drying oven to obtain a tailings adsorbent.

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