A method for treating mine sewage

Abstract

This invention belongs to the field of environmental management technology and provides a method for treating mine wastewater. The method involves mixing the mine wastewater with an adsorption system for adsorption to produce intermediate wastewater; then mixing the intermediate wastewater with modified volcanic rock for adsorption to produce mixed wastewater; and finally, filtering the mixed wastewater with a flocculant to complete the treatment. The method uses an alkaline solution of coconut shell powder to adsorb metal ions from the wastewater. Discarded coconut shells are directly mixed with the alkaline solution. The alkaline action loosens the coconut shell lignin, increasing its micropores and specific surface area, reducing the repulsive force between the metal ions and the coconut shell, enabling direct adsorption of metal elements in the water. The volcanic rock is then composited with hydroxyapatite under high-temperature calcination. The porous volcanic rock loaded with hydroxyapatite effectively adsorbs metal ions from the water. Finally, a flocculant is added to further treat the water, thereby removing metal ions and solid matter from the water.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental governance, and in particular to a method for treating mine sewage. Background Art

[0002] Mine wastewater is wastewater generated during underground mining operations. Water is used to maintain normal operations, and underground water resources, due to changes in osmotic pressure, enter the mine, generating a large amount of wastewater. This wastewater needs to be promptly transported to the surface, which not only impacts construction but, more importantly, the safety of underground workers. However, mine wastewater contains a large number of metal ions, primarily iron and manganese. Direct release of these metals into the environment can cause irreversible damage to the ecological environment. Therefore, mining operations often require wastewater treatment. Existing treatment methods, including precipitation, oxidation, and electrochemical treatment, can reduce metal ion levels in water, but they require extensive supporting facilities and increase costs. Furthermore, removal efficiency decreases significantly over time. Therefore, new methods for treating mine wastewater are urgently needed. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects in the prior art and provide a method for treating mine sewage.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for treating mine wastewater, comprising the following steps:

[0006] (1) Mixing mine wastewater and an adsorption system for adsorption to obtain intermediate wastewater;

[0007] (2) mixing the intermediate sewage and the modified volcanic rock for adsorption to obtain mixed sewage;

[0008] (3) The mixed sewage and flocculant are mixed and filtered to complete the treatment.

[0009] Preferably, the adsorption system in step (1) is a coconut shell powder solution;

[0010] The preparation method of the coconut shell powder solution comprises the following steps:

[0011] Mixing coconut shell powder and alkaline solution and ultrasonicating to obtain coconut shell powder solution;

[0012] The particle size of the coconut shell powder is 1 to 2 mm, and the mass concentration of the alkaline solution is 18 to 23%;

[0013] The base is sodium hydroxide and / or potassium hydroxide;

[0014] The mass volume ratio of the coconut shell powder and the alkaline solution is 1g:2-3mL.

[0015] Preferably, the frequency of the ultrasound is 30 to 35 kHz, and the duration is 1 to 1.5 hours.

[0016] Preferably, the volume ratio of the mine wastewater to the adsorption system in step (1) is 1:0.05-0.08;

[0017] The adsorption time in step (1) is 0.5 to 1 h.

[0018] Preferably, the method for preparing the modified volcanic rock comprises the following steps:

[0019] The modified volcanic rock is obtained by ball-milling the volcanic rock and the hydroxyapatite and then calcining the volcanic rock;

[0020] The mass ratio of the volcanic rock to the hydroxyapatite is 1:0.6-0.8;

[0021] The ball milling has a rotation speed of 500 to 700 rpm and a time of 0.3 to 0.7 h.

[0022] Preferably, the calcination temperature is 700-800° C. and the calcination time is 1-2 hours.

[0023] Preferably, the mass volume ratio of the modified volcanic rock in step (2) to the mine wastewater in step (1) is 40-60 g:1 L;

[0024] The adsorption time in step (2) is 0.5 to 1 h.

[0025] Preferably, the flocculant in step (3) is polyacrylamide;

[0026] The mass volume ratio of the flocculant in step (3) to the mine sewage in step (1) is 20-30 g:1 L.

[0027] Preferably, the mixing time in step (3) is 1 to 1.5 hours.

[0028] The present invention provides a method for treating mine wastewater. The method involves mixing the mine wastewater with an adsorption system for adsorption to produce intermediate wastewater; then mixing the intermediate wastewater with modified volcanic rock for adsorption to produce mixed wastewater; and finally, filtering the mixed wastewater with a flocculant to complete the treatment. The present invention provides a specific adsorption system that uses an alkaline solution of coconut shell powder to adsorb metal ions from the wastewater. This method eliminates the use of biochar and directly mixes discarded coconut shells with the alkaline solution. The alkaline action loosens the coconut shell lignin, increasing its micropores and specific surface area, reducing the repulsive force between the metal ions and the coconut shell, enabling direct adsorption of metal elements in the water. The volcanic rock is then composited with hydroxyapatite under high-temperature calcination. The porous volcanic rock loaded with hydroxyapatite effectively adsorbs metal ions from the water. Finally, a flocculant is added to further treat the water, thereby removing both metal ions and solid matter from the water. The present invention adopts the principle of adsorption, and on the basis of greatly reducing costs and process requirements, effectively removes metal ions in mine sewage, greatly improves the treatment mode of mine sewage, and has wide applicability. DETAILED DESCRIPTION

[0029] The present invention provides a method for treating mine wastewater, comprising the following steps:

[0030] (1) Mixing mine wastewater and an adsorption system for adsorption to obtain intermediate wastewater;

[0031] (2) mixing the intermediate sewage and the modified volcanic rock for adsorption to obtain mixed sewage;

[0032] (3) The mixed sewage and flocculant are mixed and filtered to complete the treatment.

[0033] In the present invention, the adsorption system in step (1) is preferably a coconut shell powder solution.

[0034] In the present invention, the preparation method of the coconut shell powder solution comprises the following steps:

[0035] The coconut shell powder and the alkaline solution are mixed and ultrasonicated to obtain a coconut shell powder solution.

[0036] In the present invention, the particle size of the coconut shell powder is preferably 1-2 mm, more preferably 1.2-1.8 mm, and more preferably 1.4-1.6 mm; the mass concentration of the alkaline solution is preferably 18-23%, more preferably 19-22%, and more preferably 20-21%.

[0037] In the present invention, the base is sodium hydroxide and / or potassium hydroxide.

[0038] In the present invention, the mass volume ratio of the coconut shell powder to the alkaline solution is preferably 1 g: 2-3 mL, more preferably 1 g: 2.2-2.8 mL, and more preferably 1 g: 2.4-2.6 mL.

[0039] In the present invention, the frequency of the ultrasound is preferably 30 to 35 kHz, more preferably 31 to 34 kHz, and more preferably 32 to 33 kHz; the time is preferably 1 to 1.5 h, more preferably 1.1 to 1.4 h, and more preferably 1.2 to 1.3 h.

[0040] In the present invention, the volume ratio of the mine sewage to the adsorption system in step (1) is preferably 1:0.05-0.08, more preferably 1:0.055-0.075, and even more preferably 1:0.06-0.07.

[0041] In the present invention, the adsorption time in step (1) is preferably 0.5 to 1 h, more preferably 0.6 to 0.9 h, more preferably 0.7 to 0.8 h; the stirring rate is preferably 100 to 150 rpm, more preferably 110 to 140 rpm, more preferably 120 to 130 rpm.

[0042] In the present invention, the method for preparing the modified volcanic rock comprises the following steps:

[0043] The modified volcanic rock is obtained by ball-milling volcanic rock and hydroxyapatite and then calcining the mixture.

[0044] In the present invention, the mass ratio of the volcanic rock to the hydroxyapatite is preferably 1:0.6-0.8, more preferably 1:0.65-0.75, and even more preferably 1:0.68-0.72.

[0045] In the present invention, the rotation speed of the ball mill is preferably 500-700 rpm, more preferably 550-650 rpm, and more preferably 580-620 rpm; the time is preferably 0.3-0.7 h, more preferably 0.4-0.6 h, and more preferably 0.45-0.55 h.

[0046] In the present invention, the calcination temperature is preferably 700-800° C., more preferably 720-780° C., and more preferably 740-760° C.; the calcination time is preferably 1-2 h, more preferably 1.2-1.8 h, and more preferably 1.4-1.6 h.

[0047] In the present invention, the mass volume ratio of the modified volcanic rock in step (2) to the mine sewage in step (1) is preferably 40-60 g:1 L, more preferably 45-55 g:1 L, and even more preferably 48-52 g:1 L.

[0048] In the present invention, the adsorption time in step (2) is preferably 0.5 to 1 h, more preferably 0.6 to 0.9 h, more preferably 0.7 to 0.8 h; the stirring rate is preferably 100 to 150 rpm, more preferably 110 to 140 rpm, more preferably 120 to 130 rpm.

[0049] In the present invention, the flocculant in step (3) is preferably polyacrylamide.

[0050] In the present invention, the mass volume ratio of the flocculant in step (3) to the mine sewage in step (1) is preferably 20-30 g:1 L, more preferably 22-28 g:1 L, and even more preferably 24-26 g:1 L.

[0051] In the present invention, the mixing time in step (3) is preferably 1 to 1.5 h, more preferably 1.1 to 1.4 h, and more preferably 1.2 to 1.3 h; the stirring rate is preferably 100 to 150 rpm, more preferably 110 to 140 rpm, and more preferably 120 to 130 rpm.

[0052] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0053] Example 1

[0054] 1.5 mm coconut shell powder was soaked in 20% sodium hydroxide solution, the ratio of coconut shell powder to alkaline solution was controlled to be 1 g:3 mL, and then ultrasonicated at a frequency of 30 kHz for 1 h to obtain a mixed system.

[0055] The volcanic rock and hydroxyapatite were mixed in a mass ratio of 1:0.7, ball-milled at a rotation speed of 600 rpm for 0.5 h, and then calcined at 750° C. for 1 h to obtain the modified volcanic rock.

[0056] The mine sewage and the adsorption system were mixed with the volume ratio of sewage and adsorption system being 1:0.06, and adsorbed at 150rpm for 1h; then modified volcanic rock was added with the ratio of modified volcanic rock and mine sewage being 50g:1L, and adsorbed at 120rpm for 0.8h; then polyacrylamide was added with the ratio of polyacrylamide and mine sewage being 25g:1L, and mixed at 130rpm for 1.5h, precipitated and filtered to complete the treatment.

[0057] Example 2

[0058] 1.3 mm coconut shell powder was soaked in 18% potassium hydroxide solution, the ratio of coconut shell powder to alkaline solution was controlled to be 1 g:2.6 mL, and then ultrasonicated at a frequency of 32 kHz for 1.2 h to obtain a mixed system.

[0059] The volcanic rock and hydroxyapatite were mixed in a mass ratio of 1:0.62, ball-milled at a rotation speed of 550 rpm for 0.6 h, and then calcined at 780° C. for 2 h to obtain the modified volcanic rock.

[0060] The mine sewage and the adsorption system were mixed at a volume ratio of 1:0.055, and adsorbed at 140rpm for 0.7h. Modified volcanic rock was then added at a ratio of 45g:1L to the mine sewage, and adsorbed at 100rpm for 1h. Polyacrylamide was then added at a ratio of 23g:1L to the mine sewage, and mixed at 100rpm for 1.5h. The mixture was precipitated and filtered to complete the treatment.

[0061] Example 3

[0062] 2 mm coconut shell powder was soaked in 22% potassium hydroxide solution, the ratio of coconut shell powder to alkaline solution was controlled to be 1 g:3 mL, and then ultrasonicated at a frequency of 30 kHz for 1 h to obtain a mixed system.

[0063] The volcanic rock and hydroxyapatite were mixed in a mass ratio of 1:0.73, ball-milled at a rotation speed of 680 rpm for 0.3 h, and then calcined at 800° C. for 1 h to obtain the modified volcanic rock.

[0064] The mine sewage and the adsorption system were mixed with the volume ratio of sewage and adsorption system being 1:0.08, and adsorption was carried out at 110rpm for 0.9h. Then, modified volcanic rock was added with the ratio of modified volcanic rock and mine sewage being 54g:1L, and adsorption was carried out at 120rpm for 0.8h. Then, polyacrylamide was added with the ratio of polyacrylamide and mine sewage being 28g:1L, and mixing was carried out at 130rpm for 1.3h. The mixture was precipitated and filtered to complete the treatment.

[0065] Example 4

[0066] 1.7 mm coconut shell powder was soaked in 19% sodium hydroxide solution, the ratio of coconut shell powder to alkaline solution was controlled to be 1 g:2.5 mL, and then ultrasonicated at a frequency of 31 kHz for 1.4 h to obtain a mixed system.

[0067] The volcanic rock and hydroxyapatite were mixed in a mass ratio of 1:0.65, ball-milled at a rotation speed of 620 rpm for 0.6 h, and then calcined at 730° C. for 1.8 h to obtain the modified volcanic rock.

[0068] The mine sewage and the adsorption system were mixed at a volume ratio of 1:0.06, and adsorbed at 140rpm for 1h. Then, modified volcanic rock was added at a ratio of 48g:1L to the mine sewage, and adsorbed at 110rpm for 1h. Then, polyacrylamide was added at a ratio of 30g:1L to the mine sewage, and mixed at 100rpm for 1h. The mixture was precipitated and filtered to complete the treatment.

[0069] The treatment results of Examples 1 to 4 are recorded in Table 1.

[0070] Table 1 Processing results

[0071]

[0072]

[0073] As can be seen from the above examples, the present invention provides a method for treating mine wastewater. The method involves mixing mine wastewater with an adsorption system for adsorption to produce intermediate wastewater; then mixing the intermediate wastewater with modified volcanic rock for adsorption to produce mixed wastewater; and finally, filtering the mixed wastewater with a flocculant to complete the treatment. The present invention provides a specific adsorption system that utilizes an alkaline solution of coconut shell powder to adsorb metal ions from wastewater. This method eliminates the use of biochar and directly mixes discarded coconut shells with the alkaline solution. The alkaline action loosens the coconut shell lignin, increasing its micropores and specific surface area, reducing the repulsive force between the coconut shell and the metal ions, enabling direct adsorption of metal elements from the water. The volcanic rock is then composited with hydroxyapatite under high-temperature calcination. The porous volcanic rock loaded with hydroxyapatite effectively adsorbs metal ions from the water. Finally, a flocculant is added to further treat the water, thereby removing both metal ions and solid matter from the water. According to the results of the examples, the treatment method provided by the present application has a total iron removal rate of 99.78% and a manganese removal rate of 98.69%, and has an excellent metal removal effect.

[0074] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for treating mine wastewater, characterized in that: It includes the following steps: (1) Mixing mine wastewater and an adsorption system for adsorption to obtain intermediate wastewater; (2) mixing the intermediate sewage and the modified volcanic rock for adsorption to obtain mixed sewage; (3) Mixing the mixed sewage and flocculant and filtering to complete the treatment; The adsorption system described in step (1) is coconut shell powder solution; The preparation method of the coconut shell powder solution comprises the following steps: Mixing coconut shell powder and alkaline solution and ultrasonicating to obtain coconut shell powder solution; The particle size of the coconut shell powder is 1 to 2 mm, and the mass concentration of the alkaline solution is 18 to 23%; The base is sodium hydroxide and / or potassium hydroxide; The mass volume ratio of the coconut shell powder and the alkaline solution is 1g:2-3mL; The preparation method of the modified volcanic rock comprises the following steps: The modified volcanic rock is obtained by ball-milling the volcanic rock and the hydroxyapatite and then calcining the volcanic rock; The mass ratio of the volcanic rock to the hydroxyapatite is 1:0.6-0.8; The ball milling has a rotation speed of 500 to 700 rpm and a time of 0.3 to 0.7 h.

2. The processing method according to claim 1, characterized in that The frequency of the ultrasound is 30 to 35 kHz, and the duration is 1 to 1.5 hours.

3. The processing method according to claim 2, characterized in that The volume ratio of the mine wastewater to the adsorption system in step (1) is 1:0.05-0.08; The adsorption time in step (1) is 0.5 to 1 h.

4. The processing method according to claim 3, characterized in that The calcination temperature is 700-800° C. and the calcination time is 1-2 hours.

5. The processing method according to claim 4, characterized in that The mass volume ratio of the modified volcanic rock in step (2) to the mine wastewater in step (1) is 40-60 g:1 L; The adsorption time in step (2) is 0.5 to 1 h.

6. The processing method according to claim 5, characterized in that The flocculant in step (3) is polyacrylamide; The mass volume ratio of the flocculant in step (3) to the mine sewage in step (1) is 20-30 g:1 L.

7. The processing method according to claim 6, characterized in that The mixing time in step (3) is 1 to 1.5 hours.

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