A treatment process for mining sludge and sewage

Abstract

The present invention relates to a treatment process for mining sludge and sewage, and belongs to the technical field of mining sludge and sewage treatment. A treatment process for mining sludge and sewage treats mining sludge and sewage through a treatment system, wherein the treatment system comprises a water distribution tank, a reaction tank and a sedimentation tank connected in sequence, the reaction tank is used to add a flocculant for flocculation reaction, wherein the flocculant is made of activated carbon as a raw material, metal oxides are generated on its surface to form composite particles, and then modified with cardanol and aminothiophenol. The treatment system for mining sludge and sewage of the present invention comprises a water distribution tank, a reaction tank and a sedimentation tank, which helps to improve the treatment efficiency, and also helps to protect the environment and ensure the stable operation of the mine water treatment system. The flocculant prepared by the scheme of the present invention adsorbs perfluorinated compounds through hydrophobic effect, hydrogen bond, ion exchange and electrostatic interaction, and has an excellent removal effect on them.

Description

Technical Field

[0001] The invention belongs to the technical field of mining sludge and sewage treatment, and relates to a mining sludge and sewage treatment process. Background Art

[0002] Fluoride-containing mine water belongs to a special type of polluted mine water, and its formation is mainly due to the high content of fluoride in the soil and strata of the mining area. The destruction of underground aquifers during coal mining causes groundwater to seep into the tunnels through coal mining cracks. Under the action of physical, chemical and microorganisms, fluoride-containing minerals in fluorine-rich rocks (such as fluorite, apatite, etc.) are dissolved under the scouring of groundwater, causing fluoride ions to enter the groundwater and eventually migrate to the mine water to form fluoride-containing mine water. At the same time, the mine water in most mining areas is alkaline. When the hydroxide ion content is high, it is easy to replace the fluoride ions in the fluoride-containing minerals, resulting in an increase in the fluoride ion concentration in the mine water.

[0003] Excessive fluorine content poses a major challenge to the resource utilization and recycling of mine water in my country. Directly discharging mine water with excessive fluorine content not only wastes water resources, but also pollutes the groundwater system and poses a serious threat to the safety of domestic water for residents in the mining area.

[0004] Activated carbon is a specially treated carbon. Organic raw materials (fruit shells, coal, wood, etc.) are heated in an airtight condition to reduce non-carbon components, and then react with gas to erode the surface and produce a well-developed microporous structure. Activated carbon has become a widely used adsorption material in the treatment of fluorine-containing mine water due to its large specific surface area, well-developed pore structure and low cost. However, unmodified activated carbon has poor adsorption effect on fluorine. Summary of the invention

[0005] The object of the present invention is to provide a treatment process for mining sludge and sewage. The treatment system for mining sludge and sewage of the present invention comprises a water distribution tank, a reaction tank and a sedimentation tank, which is helpful to improve the treatment efficiency, protect the environment and ensure the stable operation of the mine water treatment system. The flocculant prepared by the scheme of the present invention adsorbs perfluorinated compounds through hydrophobic effect, hydrogen bond, ion exchange and electrostatic interaction, and has an excellent removal effect on perfluorinated compounds.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A treatment process for mining sludge and sewage, wherein the treatment process treats the mining sludge and sewage through a treatment system, wherein the treatment system comprises a water distribution tank, a reaction tank and a sedimentation tank which are connected in sequence, wherein the water distribution tank mainly adjusts the water content and pH value of the mine sludge and sewage and filters large particle impurities, the reaction tank is used to add a flocculant for flocculation reaction, and the sedimentation tank allows the solid particles in the flocculated mine water to settle to the bottom by gravity, thereby realizing solid-liquid separation; wherein the flocculant is obtained by using activated carbon as a raw material, generating metal oxides on its surface to form composite particles, and then modifying it with cardanol and aminothiophenol.

[0008] As a preferred technical solution of the present invention, in the water distribution tank, the water content of the mine sludge sewage is adjusted to more than 60% and the pH value is adjusted to 7.

[0009] As a preferred technical solution of the present invention, the method for preparing the flocculant comprises the following steps:

[0010] Step 1: Stirring and mixing nitrate and deionized water to obtain a mixed solution;

[0011] Step 2: slowly drop the mixed solution and alkaline solution into the activated carbon, let it stand after the dropwise addition is completed, wash the solid, dry it, and then calcine it to obtain composite particles;

[0012] Step 3: Place the composite particles in anhydrous ethanol and perform ultrasonic mixing, add cardanol and an initiator, heat and mix, slowly add aminothiophenol and continue stirring, centrifuge to obtain the solid, wash and dry, and obtain a flocculant.

[0013] As a preferred technical solution of the present invention, in step 1, the stirring and mixing is stirring at a temperature of 30-35° C. for 45-60 minutes; the mass ratio of the nitrate to deionized water is 1.0-1.3:5.5-6.0.

[0014] As a preferred technical solution of the present invention, in step 1, the nitrate is composed of aluminum nitrate and zirconium nitrate in a mass ratio of 3.0-3.4:1.0-1.2.

[0015] As a preferred technical solution of the present invention, in step 2, the standing time is 24 hours; and the washing is performed by using deionized water until the surface of the solid is neutral.

[0016] As a preferred technical solution of the present invention, in step 2, the drying is performed at a temperature of 80° C. to a constant weight.

[0017] As a preferred technical solution of the present invention, in step 2, the calcination is performed at a temperature of 500-520° C. for 2-3 hours.

[0018] As a preferred technical solution of the present invention, in step 2, the mass ratio of the mixed solution, the alkaline solution and the activated carbon is 1.2-1.5:3-4:9-10; the alkaline solution is a 25% by mass sodium hydroxide aqueous solution.

[0019] As a preferred technical solution of the present invention, in step three, the ultrasonic mixing is performed at a frequency of 120-150W for 5-8 minutes.

[0020] As a preferred technical solution of the present invention, in step three, the heating and mixing is stirring at a temperature of 40-45° C. for 10-15 minutes.

[0021] As a preferred technical solution of the present invention, in step three, the continued stirring is to raise the temperature to 60-68° C. and stir for 4-5 hours.

[0022] As a preferred technical solution of the present invention, in step three, the washing is performed by washing with anhydrous ethanol; and the drying is performed by placing in an oven at 80° C. to dry to constant weight.

[0023] As a preferred technical solution of the present invention, in step three, the mass ratio of the composite particles, anhydrous ethanol, cardanol, aminothiophenol and initiator is 10-11:40-45:2.0-2.5:4.2-4.4:0.10-0.12; the aminothiophenol is 4-aminothiophenol.

[0024] As a preferred technical solution of the present invention, in step three, the initiator is one or more of azobisisobutyronitrile, azobisisoheptanenitrile and dimethyl azobisisobutyrate.

[0025] Beneficial effects of the present invention:

[0026] The mining sludge and sewage treatment system of the present invention comprises a water distribution tank, a reaction tank and a sedimentation tank, which is helpful to improve the treatment efficiency, protect the environment and ensure the stable operation of the mine water treatment system. The flocculant prepared by the scheme of the present invention adsorbs perfluorinated compounds through hydrophobic effect, hydrogen bond, ion exchange and electrostatic interaction, and has an excellent removal effect on perfluorinated compounds. DETAILED DESCRIPTION

[0027] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with embodiments.

[0028] A treatment process for mining sludge and sewage, wherein the treatment process treats the mining sludge and sewage through a treatment system, wherein the treatment system comprises a water distribution tank, a reaction tank and a sedimentation tank which are connected in sequence, wherein the water distribution tank mainly adjusts the water content of the mine sludge and sewage to more than 60%, the pH value to 7 and filters large particle impurities, the reaction tank is used to add flocculants for flocculation reaction, and the sedimentation tank allows the solid particles in the flocculated mine water to settle to the bottom by gravity, thereby realizing solid-liquid separation; wherein the flocculant is obtained by using activated carbon as a raw material, generating metal oxides on its surface to form composite particles, and then modifying it with cardanol and aminothiophenol.

[0029] Example 1

[0030] The preparation method of the flocculant comprises the following steps:

[0031] Step 1: Stirring and mixing nitrate and deionized water to obtain a mixed solution;

[0032] In step 1, the stirring and mixing is performed at a temperature of 30-35° C. for 45-60 minutes; the mass ratio of the nitrate to deionized water is 1.0-1.3:5.5-6.0; the nitrate is composed of aluminum nitrate and zirconium nitrate in a mass ratio of 3.0-3.4:1.0-1.2;

[0033] Step 2: slowly drop the mixed solution and alkaline solution into the activated carbon, let it stand after the dropwise addition is completed, wash the solid, dry it, and then calcine it to obtain composite particles;

[0034] In step 2, the standing time is 24 hours; the washing is performed by using deionized water until the surface of the solid is neutral; the drying is performed at 80°C to constant weight; the calcination is performed at 500-520°C for 2-3 hours; the mass ratio of the mixed solution, the alkaline solution and the activated carbon is 1.2-1.5:3-4:9-10; the alkaline solution is a 25% by mass sodium hydroxide aqueous solution;

[0035] Step 3: placing the composite particles in anhydrous ethanol and ultrasonically mixing them, adding cardanol and an initiator, heating and mixing, slowly adding aminothiophenol and continuing to stir, centrifuging and collecting solids, washing, and drying to obtain a flocculant;

[0036] In step three, the ultrasonic mixing is performed at a frequency of 120-150W for 5-8 minutes; the heated mixing is performed by stirring at a temperature of 40-45°C for 10-15 minutes; the continued stirring is performed by heating to 60-68°C and stirring for 4-5 hours; the washing is performed by washing with anhydrous ethanol; the drying is performed by placing the mixture in an oven at 80°C and drying to constant weight; the mass ratio of the composite particles, anhydrous ethanol, cardanol, aminothiophenol and initiator is 10-11:40-45:2.0-2.5:4.2-4.4:0.10-0.12; and the initiator is azobisisobutyronitrile.

[0037] Example 1

[0038] The preparation method of the flocculant comprises the following steps:

[0039] Step 1: Stirring and mixing nitrate and deionized water to obtain a mixed solution;

[0040] In step 1, the stirring and mixing is performed at a temperature of 30° C. for 45 minutes; the mass ratio of the nitrate to deionized water is 1.0:5.5; the nitrate is composed of aluminum nitrate and zirconium nitrate in a mass ratio of 3.0:1.0;

[0041] Step 2: slowly drop the mixed solution and alkaline solution into the activated carbon, let it stand after the dropwise addition is completed, wash the solid, dry it, and then calcine it to obtain composite particles;

[0042] In step 2, the standing time is 24 hours; the washing is performed by using deionized water until the surface of the solid is neutral; the drying is performed at 80°C to constant weight; the calcination is performed at 500°C for 2 hours; the mass ratio of the mixed solution, the alkaline solution and the activated carbon is 1.2:3:9; the alkaline solution is a 25% by mass sodium hydroxide aqueous solution;

[0043] Step 3: placing the composite particles in anhydrous ethanol and ultrasonically mixing them, adding cardanol and an initiator, heating and mixing, slowly adding aminothiophenol and continuing to stir, centrifuging and collecting solids, washing, and drying to obtain a flocculant;

[0044] In step three, the ultrasonic mixing is performed at a frequency of 120 W for 5 minutes; the heated mixing is performed by stirring at a temperature of 40° C. for 10 minutes; the continued stirring is performed by heating to 60° C. and stirring for 4 hours; the washing is performed by washing with anhydrous ethanol; the drying is performed by placing the mixture in an oven at 80° C. and drying to constant weight; the mass ratio of the composite particles, anhydrous ethanol, cardanol, aminothiophenol and initiator is 10:40:2.0:4.2:0.10; and the initiator is azobisisobutyronitrile.

[0045] Example 2

[0046] The preparation method of the flocculant comprises the following steps:

[0047] Step 1: Stirring and mixing nitrate and deionized water to obtain a mixed solution;

[0048] In step 1, the stirring and mixing is stirring at a temperature of 32° C. for 50 minutes; the mass ratio of the nitrate to deionized water is 1.1:5.6; the nitrate is composed of aluminum nitrate and zirconium nitrate in a mass ratio of 3.1:1.1;

[0049] Step 2: slowly drop the mixed solution and alkaline solution into the activated carbon, let it stand after the dropwise addition is completed, wash the solid, dry it, and then calcine it to obtain composite particles;

[0050] In step 2, the standing time is 24 hours; the washing is performed by washing with deionized water until the surface of the solid is neutral; the drying is performed at 80°C to constant weight; the calcination is performed at 510°C for 2.5 hours; the mass ratio of the mixed solution, the alkaline solution and the activated carbon is 1.3:3.3:9.3; the alkaline solution is a 25% by mass aqueous sodium hydroxide solution;

[0051] Step 3: placing the composite particles in anhydrous ethanol and ultrasonically mixing them, adding cardanol and an initiator, heating and mixing, slowly adding aminothiophenol and continuing to stir, centrifuging and collecting solids, washing, and drying to obtain a flocculant;

[0052] In step three, the ultrasonic mixing is performed at a frequency of 130 W for 6 minutes; the heated mixing is performed by stirring at a temperature of 42° C. for 12 minutes; the continued stirring is performed by heating to 63° C. and stirring for 4.5 hours; the washing is performed by washing with anhydrous ethanol; the drying is performed by placing the mixture in an oven at 80° C. and drying to constant weight; the mass ratio of the composite particles, anhydrous ethanol, cardanol, aminothiophenol and initiator is 10.5:42:2.2:4.3:0.11; and the initiator is azobisisobutyronitrile.

[0053] Example 3

[0054] The preparation method of the flocculant comprises the following steps:

[0055] Step 1: Stirring and mixing nitrate and deionized water to obtain a mixed solution;

[0056] In step 1, the stirring and mixing is performed at a temperature of 33° C. for 55 minutes; the mass ratio of the nitrate to deionized water is 1.2:5.8; the nitrate is composed of aluminum nitrate and zirconium nitrate in a mass ratio of 3.3:1.2;

[0057] Step 2: slowly drop the mixed solution and alkaline solution into the activated carbon, let it stand after the dropwise addition is completed, wash the solid, dry it, and then calcine it to obtain composite particles;

[0058] In step 2, the standing time is 24 hours; the washing is performed by washing with deionized water until the surface of the solid is neutral; the drying is performed at 80°C to constant weight; the calcination is performed at 515°C for 2.5 hours; the mass ratio of the mixed solution, the alkaline solution and the activated carbon is 1.4:3.6:9.6; the alkaline solution is a 25% by mass aqueous sodium hydroxide solution;

[0059] Step 3: placing the composite particles in anhydrous ethanol and ultrasonically mixing them, adding cardanol and an initiator, heating and mixing, slowly adding aminothiophenol and continuing to stir, centrifuging and collecting solids, washing, and drying to obtain a flocculant;

[0060] In step three, the ultrasonic mixing is performed at a frequency of 140 W for 7 minutes; the heated mixing is performed by stirring at a temperature of 43° C. for 13 minutes; the continued stirring is performed by heating to 65° C. and stirring for 4.5 hours; the washing is performed by washing with anhydrous ethanol; the drying is performed by placing the mixture in an oven at 80° C. and drying to constant weight; the mass ratio of the composite particles, anhydrous ethanol, cardanol, aminothiophenol and initiator is 10.5:43:2.3:4.3:0.11; and the initiator is azobisisobutyronitrile.

[0061] Example 4

[0062] The preparation method of the flocculant comprises the following steps:

[0063] Step 1: Stirring and mixing nitrate and deionized water to obtain a mixed solution;

[0064] In step 1, the stirring and mixing is stirring at 35° C. for 60 minutes; the mass ratio of the nitrate to deionized water is 1.3:6.0; the nitrate is composed of aluminum nitrate and zirconium nitrate in a mass ratio of 3.4:1.2;

[0065] Step 2: slowly drop the mixed solution and alkaline solution into the activated carbon, let it stand after the dropwise addition is completed, wash the solid, dry it, and then calcine it to obtain composite particles;

[0066] In step 2, the standing time is 24 hours; the washing is performed by washing with deionized water until the surface of the solid is neutral; the drying is performed at 80°C to constant weight; the calcination is performed at 520°C for 3 hours; the mass ratio of the mixed solution, the alkaline solution and the activated carbon is 1.5:4:10; the alkaline solution is a 25% by mass aqueous sodium hydroxide solution;

[0067] Step 3: placing the composite particles in anhydrous ethanol and ultrasonically mixing them, adding cardanol and an initiator, heating and mixing, slowly adding aminothiophenol and continuing to stir, centrifuging and collecting solids, washing, and drying to obtain a flocculant;

[0068] In step three, the ultrasonic mixing is performed at a frequency of 150 W for 8 minutes; the heated mixing is performed by stirring at a temperature of 45° C. for 15 minutes; the continued stirring is performed by heating to 68° C. and stirring for 5 hours; the washing is performed by washing with anhydrous ethanol; the drying is performed by placing the mixture in an oven at 80° C. and drying to constant weight; the mass ratio of the composite particles, anhydrous ethanol, cardanol, aminothiophenol and initiator is 11:45:2.5:4.4:0.12; and the initiator is azobisisobutyronitrile.

[0069] Comparative Example 1

[0070] Compared with Example 2, the difference in Comparative Example 1 is that an equal amount of zirconium nitrate is used to replace aluminum nitrate, and the other components, preparation steps and parameters are the same.

[0071] Comparative Example 2

[0072] Compared with Example 2, the difference in Comparative Example 2 is that an equal amount of aluminum nitrate is used instead of zirconium nitrate, and the other components, preparation steps and parameters are the same.

[0073] Comparative Example 3

[0074] Compared with Example 2, the difference in Comparative Example 3 is that an equal amount of activated carbon is used to replace the composite particles, and the other components, preparation steps and parameters are the same.

[0075] Comparative Example 4

[0076] Compared with Example 2, Comparative Example 4 is different in that aminothiophenol is not used, and the remaining components, preparation steps and parameters are the same.

[0077] Comparative Example 5

[0078] Compared with Example 2, the difference in Comparative Example 5 is that cardanol is not used, and the other components, preparation steps and parameters are the same.

[0079] The flocculants prepared in Examples 1-4 and Comparative Examples 1-5 were subjected to the following adsorption tests, and the test results are shown in Table 1.

[0080] Perfluorinated compound removal test: Perfluorinated compounds with different chain lengths, including perfluorooctanoic acid and perfluorooctane sulfonic acid, were mixed with ultrapure water and prepared into perfluorooctanoic acid wastewater solution and perfluorooctane sulfonic acid wastewater solution with a concentration of 250 μg / L, and the concentrations were determined by liquid chromatography-mass spectrometry. The removal effect of perfluorinated compounds was expressed as removal rate (%), wherein the dosage of flocculant was 10 mg / L.

[0081] Perfluorinated compound removal rate = (C0-C t ) / C0×100%; C0 is the initial concentration of perfluorinated compounds, C t is the concentration of perfluorinated compounds after 180 minutes.

[0082] Table 1 Perfluorinated compound removal test results

[0083]

[0084] From the test results in Table 1, it can be seen that compared with Comparative Examples 1-5, the flocculants prepared in the present invention have significantly better removal effects on perfluorinated compounds than the flocculants in Comparative Examples 1-5. This is because the flocculants prepared in the present invention adsorb perfluorinated compounds through hydrophobic effect, hydrogen bonding, ion exchange and electrostatic interaction, and have excellent removal effects on them. Specifically, by in-situ generation of aluminum oxide and zirconium oxide on the surface of activated carbon, aluminum / zirconium exist at the same time, reducing the agglomeration of metal oxides themselves, and more evenly distributing them on the surface of activated carbon, so that aluminum and zirconium elements are evenly loaded on the surface of activated carbon, forming adsorption, ion exchange and coordination effects, followed by hydrogen bonding between cardanol and composite particles, so that it is loaded, and chemical bonds are formed between cardanol and aminothiophenol, so that the flocculant contains a large number of hydrophobic benzene rings and carbon long chains, forming a rigid hydrophobic structure, while modifying dense amino groups, using the hydrophobic effect of the flocculant, the electrostatic effect of the protonated amino group, and the coordination of metal elements to synergistically adsorb perfluorinated compounds, significantly improving the adsorption selectivity, and solving the problem of slow adsorption rate of commonly used flocculants.

[0085] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A process for treating mining sludge and sewage, characterized in that: The treatment process treats mining sludge and sewage through a treatment system, and the treatment system includes a water distribution tank, a reaction tank and a sedimentation tank which are connected in sequence. The water distribution tank mainly adjusts the water content and pH value of the mine sludge and sewage and filters large particle impurities. The reaction tank is used to add flocculants for flocculation reaction. The sedimentation tank allows the solid particles in the flocculated mine water to settle to the bottom by gravity, thereby achieving solid-liquid separation; wherein the flocculant is made of activated carbon as a raw material, metal oxides are generated on its surface to form composite particles, and then modified with cardanol and aminothiophenol; Wherein, the preparation method of the flocculant comprises the following steps: Step 1: Stirring and mixing nitrate and deionized water to obtain a mixed solution; the mass ratio of the nitrate and deionized water is 1.0-1.3:5.5-6.0; the nitrate is composed of aluminum nitrate and zirconium nitrate in a mass ratio of 3.0-3.4:1.0-1.2; Step 2: slowly drop the mixed solution and the alkaline solution into the activated carbon, after the dropwise addition is completed, let it stand, wash the solid, dry it and then roast it to obtain composite particles; the mass ratio of the mixed solution, the alkaline solution and the activated carbon is 1.2-1.5:3-4:9-10; the roasting is performed at a temperature of 500-520°C for 2-3h; Step three: placing the composite particles in anhydrous ethanol for ultrasonic mixing, adding cardanol and an initiator, heating and mixing, slowly adding aminothiophenol and continuing to stir, centrifuging to obtain the solid, washing, and drying to obtain a flocculant; the mass ratio of the composite particles, anhydrous ethanol, cardanol, aminothiophenol and initiator is 10-11:40-45:2.0-2.5:4.2-4.4:0.10-0.12; the heating and mixing is stirring at a temperature of 40-45°C for 10-15min; the continued stirring is heating to 60-68°C and stirring for 4-5h.

2. A mining sludge and sewage treatment process according to claim 1, characterized in that: In the water distribution tank, the water content of the mine sludge sewage is adjusted to above 60% and the pH value is adjusted to 7.

3. The process for treating mining sludge and sewage according to claim 1, characterized in that: In step 1, the stirring and mixing is performed at a temperature of 30-35° C. for 45-60 min.

4. A mining sludge and sewage treatment process according to claim 1, characterized in that: In step 2, the standing time is 24 hours; the washing is performed by using deionized water until the surface of the solid is neutral; and the drying is performed at 80° C. to a constant weight.

5. The process for treating mining sludge and sewage according to claim 1, characterized in that: In step 2, the alkaline solution is a 25% by mass sodium hydroxide aqueous solution.

6. A mining sludge and sewage treatment process according to claim 1, characterized in that: In step three, the washing is performed by using anhydrous ethanol; and the drying is performed by placing the mixture in an oven at 80° C. to a constant weight.

7. A mining sludge and sewage treatment process according to claim 1, characterized in that: In step three, the initiator is one or more of azobisisobutyronitrile, azobisisoheptanenitrile and dimethyl azobisisobutyrate.

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