A mine leaching pollution buffer zone and its application

Abstract

A mine leaching pollution buffer zone and its application belong to the field of mine pollution prevention and control technology, and overcome the defects of the existing technology that it is not applicable to mines under mining, steep slopes and the like, and cannot prevent the continuous pollution of surrounding soil and water bodies during the mining process or the accumulation of leaching water. The mine leaching pollution buffer zone of the present invention includes a water storage zone, a deceleration pretreatment zone, a non-metallic adsorption precipitation zone and a heavy metal ion enhanced adsorption zone arranged in sequence. The present invention adopts a multi-layer pollution blocking zone construction method, which can achieve simultaneous blocking of metal pollutants and non-metallic pollutants, while improving the pH of the leaching water, killing acidophilic bacteria, filtering divalent iron ions, and avoiding the terminal regeneration of acidic leaching water.

Description

Technical Field

[0001] The present invention belongs to the technical field of mine pollution prevention and control, and in particular relates to a mine leaching pollution buffer zone and application thereof. Background Art

[0002] The development of mineral resources has created a large number of exposed mountains and abandoned land such as tailings ponds, bringing about a series of ecological and environmental problems. In particular, some sulfur-containing metal mines, coal mines, phosphate mines, etc. will dissolve a large amount of heavy metals, acidic substances, phosphorus and other pollutants under the long-term erosion of rainwater, seriously polluting the surrounding fields and water bodies, and the subsequent treatment is difficult and costly.

[0003] In the existing governance system, in order to control mine washout pollution, the following two aspects are mainly taken into account: (1) Source control, that is, physical isolation of pollution sources such as exposed mountains or tailings ponds (such as covering the surface with soil and then regreening) to prevent rainwater from washing away. Although this method can greatly reduce the dissolution of pollutants, it is not applicable to mines under mining and steep slopes and waste rock piles formed by mining. (2) End-of-pipe treatment, that is, abandoning the early prevention and control of leaching pollution and only treating the wastewater in the mine pit or tailings dam after mining. Although this method is low-cost and widely used, it cannot prevent the continuous pollution of surrounding soil and water bodies during the mining process or the accumulation of leaching water, and still falls into the category of first pollute and then treat. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the existing technology that it is not applicable to mines under mining, steep slopes and the like, and cannot prevent the continuous pollution of the surrounding soil and water bodies during the mining process or the accumulation of leaching water, thereby providing a mine leaching pollution buffer zone and its application.

[0005] To this end, the present invention provides the following technical solutions.

[0006] In a first aspect, the present invention provides a mine leaching pollution buffer zone, comprising a water storage zone, a deceleration pretreatment zone, a non-metallic adsorption precipitation zone and a heavy metal ion enhanced adsorption zone arranged in sequence.

[0007] Furthermore, the water storage belt includes a tunnel, and waste rock is provided on a side of the tunnel close to the deceleration pretreatment belt.

[0008] Waste rock has strong water permeability, and the water storage belt can also serve as a fixed deceleration pretreatment belt.

[0009] Preferably, the waste rock is mining waste rock;

[0010] Preferably, the waste rock particle size is between 3 and 5 cm;

[0011] Preferably, the waste rock is limestone;

[0012] Preferably, the waste rock does not contain metal minerals and sulfides.

[0013] Furthermore, the deceleration pretreatment zone comprises, by mass, 40 to 60 parts of anaerobic digestion residue, 10 to 20 parts of composite biochar and 3 to 7 parts of foaming agent.

[0014] Furthermore, the non-metallic adsorption precipitation belt comprises, by mass, 30 to 50 parts of dried water sludge, 20 to 40 parts of steel slag A, 10 to 20 parts of alkaline buffer, 3 to 5 parts of guar gum, and 3 to 5 parts of borax.

[0015] Furthermore, the heavy metal ion enhanced adsorption belt comprises, by mass, 20 to 30 parts of biochar B, 20 to 40 parts of steel slag B, and 10 to 20 parts of cement.

[0016] Furthermore, the composite biochar is prepared from sulfate-reducing bacteria and biochar A in a mass ratio of 1-2:10-15;

[0017] Preferably, the particle size of biochar A is 0.3-0.5 cm, and the specific surface area is between 600-1500 m 2 / g;

[0018] Further, the foaming agent includes at least one of calcium carbonate or magnesium carbonate;

[0019] Furthermore, the particle size of the foaming agent is less than 0.1 mm;

[0020] Furthermore, the deceleration pretreatment zone has a saturated moisture content greater than 95%, a pH value of 7 to 8, and a water penetration rate less than 3×10 -4 cm / s;

[0021] Furthermore, after the raw materials of the deceleration pretreatment belt are mixed, a film covering and curing process is performed for 5 to 10 days;

[0022] Anaerobic digestion residue is the product of anaerobic digestion and dehydration of sludge. This residue is rich in anaerobic microorganisms. Furthermore, the residue has a moisture content of 30% to 50% by weight, a particle size of less than 1 cm, a pH of 6 to 8, an organic matter content of 15% to 30% by weight, and a saturated moisture content greater than 80% by weight.

[0023] Furthermore, the non-metallic adsorption precipitation belt satisfies at least one of the following conditions:

[0024] (1) The dried water supply sludge has a total content of aluminum salts and iron salts greater than 20 wt%, a moisture content less than 30 wt%, and an organic matter content less than 10 wt%; the dried water supply sludge refers to the sludge produced in the water supply plant;

[0025] (2) The particle size of the steel slag A is less than 1 mm;

[0026] (3) The alkaline buffer is powdered calcium carbonate or magnesium carbonate;

[0027] (4) The particle size of the alkaline buffer is less than 0.5 mm.

[0028] Furthermore, the heavy metal ion enhanced adsorption belt satisfies at least one of the following conditions:

[0029] (1) The particle size of the biochar B is 0.1-0.3 mm, and the specific surface area is between 600-1500 m 2 / g;

[0030] (2) The particle size of the steel slag B is 1-3 mm.

[0031] Furthermore, the height of the water storage belt is 25-40 cm;

[0032] Furthermore, the width of the water storage belt is 40~70cm; the width of the water storage belt can be set according to the length of the slope and the local regular daily rainfall.

[0033] Furthermore, the deceleration pretreatment belt is laid at a height of 30 to 45 cm. Preferably, the bottom of the deceleration pretreatment belt is 5 to 10 cm lower than the bottom of the water storage belt.

[0034] Furthermore, the deceleration pretreatment zone has a width of 20 to 40 cm;

[0035] Furthermore, the non-metallic adsorption precipitation belt is laid at a height of 25 to 40 cm. Preferably, the bottom of the non-metallic adsorption precipitation belt is 5 to 10 cm lower than the bottom of the deceleration pretreatment belt.

[0036] Furthermore, the width of the non-metallic adsorption precipitation zone is 30-40 cm;

[0037] Furthermore, the heavy metal ion enhanced adsorption belt is laid at a height of 25 to 40 cm. Preferably, the bottom of the heavy metal ion enhanced adsorption belt is 5 to 10 cm lower than the bottom of the deceleration pretreatment belt.

[0038] Furthermore, the width of the heavy metal ion enhanced adsorption zone is 40 to 60 cm;

[0039] The width of each band in the present invention refers to Figure 1 The length of the horizontal setting; the height of each belt refers to the distance from the top to the bottom of the corresponding belt.

[0040] Furthermore, the deceleration pretreatment zone, the non-metallic adsorption precipitation zone and the heavy metal ion enhanced adsorption zone are distributed in a stepped manner along the water flow direction; preferably, the tops of two adjacent zones are lowered by 5 to 10 cm in sequence, and the raised parts are fixed with waste rocks.

[0041] In the second aspect, the present invention provides an application of the mine leaching pollution buffer zone in a mine, wherein the water storage zone, deceleration pretreatment zone, non-metallic adsorption precipitation zone and heavy metal ion enhanced adsorption zone in the mine leaching pollution buffer zone are arranged in sequence along the water flow direction of the sewage to be purified.

[0042] The steel slag A comes from the smelting waste of the smelter, is an alkaline slag, and has a particle size of <1 mm. The total mass of CaO, iron and iron-aluminum oxides accounts for >30% of the mass content of the steel slag A.

[0043] Steel slag B comes from smelting waste of the smelter. It is an alkaline slag with a particle size of 1~3mm. The total mass of silicate minerals and iron oxide accounts for more than 50% of the mass content of steel slag B, and the structure is loose and porous.

[0044] After film covering and curing, the oxygen content is <5% and the amount of sulfate-reducing bacteria is >150 million / g.

[0045] Preferably, the surface of the deceleration pretreatment belt is covered with a waterproof membrane to prevent rainwater that does not need to be treated from entering during rainfall.

[0046] The mine leaching pollution buffer zone is set at the foot of the mine, the bottom of the mine slope, or between the mine and the surrounding fields and water bodies, and treats the sewage before it flows into the fields and water bodies.

[0047] The mines being treated are pyrite mines, coal mines, phosphate mines, and other mines that may produce acidic leaching water, heavy metals, phosphates, sulfates and other pollutants; the pH value of acidic wastewater is <4.5, and the types of heavy metals include: Cu, Pb, Zn, Cd, Mn, etc.

[0048] After the leachate water passed through the deceleration pretreatment zone, the pH value was significantly increased to between 4.5 and 6, and the contents of Acidithiobacillus and sulfate decreased by >70% and >40%, respectively.

[0049] Non-metallic adsorption and precipitation tapes can be used to adsorb and precipitate non-metallic pollutants such as sulfide and phosphate, with adsorption efficiencies >70% and >40%, respectively. Guar gum and borax crosslink to form a reversible gel, which is used to control the rate of acidic water (pH < 5.5). Under acidic conditions, the permeation rate can be reduced by over 30%, improving reaction time.

[0050] The heavy metal ion enhanced adsorption belt can effectively prevent acidic solution erosion. After passing through the heavy metal ion enhanced adsorption belt, the final removal efficiency of heavy metal pollutants such as Cu, Pb, Zn, Cd, and Mn is >90%, and the final removal rate of Fe is >75%. The pH value of the leaching water is between 6-7.

[0051] The technical solution of the present invention has the following advantages:

[0052] 1. The mine leaching pollution buffer zone of the present invention comprises a water storage zone, a deceleration pretreatment zone, a non-metallic adsorption precipitation zone and a heavy metal ion enhanced adsorption zone which are arranged in sequence.

[0053] The present invention is different from the conventional source control or end-of-pipe soil / water treatment methods of mine management. It starts from process management and is more suitable for pollution prevention and control in mines under development or abandoned land with large slopes. By reducing pollutants, the risk of soil and water pollution is greatly reduced, and the end-of-pipe treatment cost is reduced. The present invention adopts a multi-layer pollution blocking belt construction method, which can achieve simultaneous blocking of metal pollutants and non-metallic pollutants, while improving the pH value of leaching water, killing acidophilic bacteria, filtering divalent iron ions, and avoiding end-of-pipe regeneration of acidic leaching water.

[0054] 2. The leaching pollution blocking materials used in the present invention are mostly solid wastes, including anaerobic digestion residue of sludge, steel slag, dried water sludge, etc. Combining them with mine pollution control can greatly improve the utilization rate of solid waste resources, achieve "waste treatment with waste", and reduce the cost of solid waste treatment and disposal and mine governance costs.

[0055] 3. The working principle and specific effects of the deceleration pretreatment zone are as follows: (1) Using sludge anaerobic digestion residue as the main material, taking advantage of its extremely high water saturation rate and low permeability, it acts as a deceleration zone to increase the overall residence time of the leaching water in the buffer zone and allow it to fully react with various materials; in addition, the sludge residue is rich in anaerobic microorganisms and ammonium ions, and is in a deep reduction state, which can inhibit the oxidation of divalent iron and sulfur ions and inhibit the growth of acidophilic bacteria; (2) Using biochar compounded with sulfate-reducing bacteria, on the one hand, it uses the protective effect of biochar to reduce the toxic effects of dissolved oxygen and heavy metals in the leaching water on acidophilic thiobacillus; on the other hand, it can serve as a growth matrix for sulfate-reducing bacteria, accelerate their growth and reproduction, and decompose sulfate ions to the greatest extent and inhibit acidophilic bacteria. (3) Using an appropriate amount of calcium carbonate or magnesium carbonate as a foaming agent, on the one hand, it can react with the leaching water, increase the pH value, and drive away oxygen; on the other hand, it can form tiny non-connected cavities in the sludge residue, increase the saturation content of the leaching water, and further increase the retention time.

[0056] 4. The working principle and specific effects of the non-metallic adsorption precipitation belt are as follows: (1) The dried water sludge contains a large amount of iron and aluminum coagulants, which have a strong flocculation and precipitation effect on pollutants such as phosphate, sulfide, sulfate, and ammonia nitrogen under weak alkaline conditions; (2) The fine-grained steel slag after screening contains a large amount of CaO and reducing iron. Combined with alkaline buffers, it can create a weak alkaline environment for the leaching water at this stage, further increase the pH value, and can undergo adsorption and precipitation reactions with sulfide ions to reduce the sulfide ion concentration.

[0057] 5. The working principle and specific effects of the heavy metal ion enhanced adsorption belt are as follows: (1) Although the deceleration pretreatment belt and the non-metallic adsorption precipitation belt can also adsorb some heavy metals, most of them (>60%) are still in the leaching water. Since the pH of the leaching water has risen to above 6 at this time, they can be easily adsorbed and precipitated by steel slag and biochar. (2) Steel slag and biochar have large specific surface areas and are loose and porous. When combined in proportion, they can efficiently remove various heavy metal ions in the leaching water through physical adsorption and chemical adsorption. DETAILED DESCRIPTION

[0058] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0059] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0060] Example 1

[0061] This embodiment provides a mine leaching pollution buffer zone, such as Figure 1 As shown, it is also applied to the prevention and control of leaching pollution of the slag pile of the Zhaishan acidic pyrite mine, including the following steps:

[0062] (1) After the rain, the maximum penetration depth of the soil on the surface of the mine waste pile was measured to be about 28 cm. The contents of Cu, Pb, and Cd in the leached water at the foot of the slope were high, at 560 μg / L, 410 μg / L, and 12.8 μg / L, respectively. The pH value was 3.3, the content of Acidithiobacillus was 42 million per L, and the total sulfur and phosphorus contents were 4.9 mg / L and 0.3 mg / L, respectively.

[0063] (2) Setting up a water storage belt 2: Since the slope length of the mine slope 1 is relatively low, approximately 45 m, and the local rainfall is moderate, a water storage belt 2 is excavated with a height (i.e., depth) of 30 cm, a width (horizontally) of 50 cm, and a length (perpendicular to the water flow direction) of 10 m. A 15 cm wide layer of waste rock 3 is filled on the side of the water storage belt 2 near the deceleration pretreatment belt 4. The waste rock in this embodiment is limestone.

[0064] (3) Set up the deceleration pretreatment zone 4: the height is 35 cm, the width is 30 cm, and the length is the same as the water storage zone 2. The deceleration pretreatment zone 4 is set next to the water storage zone 2, the top of the deceleration pretreatment zone 4 is flush with the top of the water storage zone 2, and the bottom of the deceleration pretreatment zone 4 is 5 cm lower than the bottom of the water storage zone 2. Take 50 parts of anaerobic digestion residue (water content 35.6%, pH value 6.8, particle size <1 cm, organic matter content 21.4%, saturated moisture content 90wt%), 15 parts of composite biochar (prepared by sulfate-reducing bacteria and biochar A in a mass ratio of 1:10; biochar A particle size of 0.4~0.5 cm, specific surface area between 600~1100m 2 / g), 5 parts of calcite powder (particle size <0.1mm), mixed evenly, filled and lightly compacted. After 7 days of film curing, the pH value of the deceleration pretreatment zone was measured to be 7.3, and the water penetration rate was 1.7×10 -4 cm / s, saturated moisture content 98%, oxygen content 3.9%, and sulfate-reducing bacteria 290 million / g.

[0065] (4) Set up a non-metallic adsorption sedimentation zone 5: 35 cm in height, 30 cm in width, and 10 m in length. The non-metallic adsorption sedimentation zone 5 is set adjacent to the deceleration pretreatment zone 4. The top of the metal adsorption sedimentation zone 5 is 5 cm lower than the top of the deceleration pretreatment zone 4, and the bottom of the metal adsorption sedimentation zone 5 is 5 cm lower than the bottom of the deceleration pretreatment zone 4. Take 30 parts of dried water supply sludge (total content of aluminum salts and iron salts 27.4%, moisture content 25.3%, organic matter content 6.5%), 20 parts of fine-grained steel slag A (particle size <1 mm, total mass proportion of CaO, iron and iron-aluminum oxides 37.2%), 20 parts of calcium carbonate powder (particle size <0.5 mm), 3 parts of guar gum, and 3 parts of borax, mix them well, fill them, and lightly compact them.

[0066] (5) Set up a heavy metal ion enhanced adsorption zone 6: height 35 cm, width 55 cm, length 10 m. The heavy metal ion enhanced adsorption zone 6 is set adjacent to the non-metallic adsorption precipitation zone 5. The top of the heavy metal ion enhanced adsorption zone 6 is 5 cm lower than the top of the non-metallic adsorption precipitation zone 5, and the bottom of the heavy metal ion enhanced adsorption zone 6 is 5 cm lower than the bottom of the non-metallic adsorption precipitation zone 5. Take 25 portions of biochar B (particle size 0.1-0.3 mm, specific surface area between 1000-1500 m 2 / g), 30 parts of coarse-grained steel slag B (particle size 1~3mm, silicate minerals and iron oxide account for 52.7% of the total mass), and 20 parts of cement, mixed evenly and filled, and left to dry and consolidate naturally to form a porosity of about 30%.

[0067] (6) Water inlets A, B and C are respectively left at the contact surface between the deceleration pretreatment zone 4 and the non-metallic adsorption precipitation zone 5, the contact surface between the non-metallic adsorption precipitation zone 5 and the heavy metal ion enhanced adsorption zone 6, and behind the heavy metal ion enhanced adsorption zone 6, with a length and width of 5 cm.

[0068] (7) After the rain, the leaching water in intake A contained 452 μg / L, 347 μg / L, and 10 μg / L of Cu, Pb, and Cd, respectively. The pH was 4.8, the Acidithiobacillus count was 16 million cells / L, and the total sulfur and phosphorus contents were 4.5 mg / L and 0.5 mg / L, respectively. The leaching water in intake B contained 292 μg / L, 231 μg / L, and 7.6 μg / L of Cu, Pb, and Cd, respectively. The pH was 6.4, the Acidithiobacillus count was 6 million cells / L, and the total sulfur and phosphorus contents were 1.3 mg / L and 0.2 mg / L, respectively. The leached water from intake C contained 37.9 μg / L of Cu, 21.4 μg / L of Pb, and 2.3 μg / L of Cd, respectively; the pH was 6.6; the Acidithiobacillus count was 5 million per liter; and the total sulfur and phosphorus contents were 1.0 mg / L and 0.2 mg / L, respectively. The effluent quality has been significantly improved.

[0069] Example 2

[0070] This embodiment provides a mine leaching pollution buffer zone, such as Figure 1 As shown, the mine leaching pollution buffer zone of this embodiment is applied to the foot of the phosphate mine slope, including the following steps:

[0071] (1) After the rain, the maximum penetration depth of the surface soil at the foot of the mine slope was measured to be about 31 cm. The contents of total phosphorus, total sulfur and heavy metal Zn in the leached water at the foot of the slope were high, at 179 mg / L, 47.5 mg / L and 177 μg / L, respectively. The pH value was 3.6, and the content of Acidithiobacillus was 29 million / L.

[0072] (2) Setting up a water storage belt 2: Since the slope is relatively low, about 35 m long, and the local rainfall is high, a water storage belt 2 is excavated with a height of 30 cm, a width of 60 cm, and a length of 7 m. The side of the water storage belt 2 near the deceleration pretreatment belt 4 is filled with 15 cm wide waste rock 3. The waste rock in this embodiment is crushed limestone.

[0073] (3) Set up the deceleration pretreatment zone 4: the height is 35 cm, the width is 35 cm, and the length is the same as the water storage zone 2. The deceleration pretreatment zone 4 is set next to the water storage zone 2, the top of the deceleration pretreatment zone 4 is flush with the top of the water storage zone 2, and the bottom of the deceleration pretreatment zone 4 is 5 cm lower than the bottom of the water storage zone 2. Take 60 parts of anaerobic digestion residue (water content 41.3%, pH value 7.1, particle size <1 cm, organic matter content 17.5%, saturated moisture content 89 wt%), 10 parts of composite biochar (prepared by sulfate-reducing bacteria and biochar A in a mass ratio of 1:15; the particle size of biochar A is 0.3~0.5 cm, and the specific surface area is between 500~900 m 2 / g), 6 parts of calcite powder (particle size <0.1mm), mixed evenly, filled and lightly compacted. After 5 days of film curing, the pH value of the deceleration pretreatment zone was measured to be 7.4, and the water penetration rate was 7.9×10 -5 cm / s, saturated moisture content 97%, oxygen content 3.5%, and sulfate-reducing bacteria 240 million / g.

[0074] (4) Set up a non-metallic adsorption sedimentation zone 5: 35 cm in height, 40 cm in width, and 7 m in length. The non-metallic adsorption sedimentation zone 5 is set adjacent to the deceleration pretreatment zone 4. The top of the metal adsorption sedimentation zone 5 is 5 cm lower than the top of the deceleration pretreatment zone 4, and the bottom of the metal adsorption sedimentation zone 5 is 5 cm lower than the bottom of the deceleration pretreatment zone 4. Take 40 parts of dried water supply sludge (total content of aluminum salts and iron salts 29%, moisture content 23%, organic matter content 5.1%), 30 parts of fine-grained steel slag A (particle size <1 mm, total mass proportion of CaO, iron and iron-aluminum oxides 34.8%), 15 parts of calcium carbonate powder (particle size <0.5 mm), 4 parts of guar gum, and 4 parts of borax, mix them well, fill them, and lightly compact them.

[0075] (5) Set up the heavy metal ion enhanced adsorption zone 6: the height is 35 cm, the width is 40 cm, and the length is the same as the non-metal adsorption precipitation zone 5. The heavy metal ion enhanced adsorption zone 6 is set adjacent to the non-metal adsorption precipitation zone 5. The top of the heavy metal ion enhanced adsorption zone 6 is 5 cm lower than the top of the non-metal adsorption precipitation zone 5, and the bottom of the heavy metal ion enhanced adsorption zone 6 is 5 cm lower than the bottom of the non-metal adsorption precipitation zone 5. Take 20 portions of biochar B (particle size 0.1~0.3 mm, specific surface area between 800~1300 m 2 / g), 40 parts of coarse-grained steel slag B (particle size 1-3 mm, silicate minerals and iron oxide account for 46.6% of the total mass), and 15 parts of cement are mixed evenly and filled, and formed after drying and consolidation, with a porosity of about 26%.

[0076] (6) Water inlets A, B and C are respectively left at the contact surface between the deceleration pretreatment zone 4 and the non-metallic adsorption precipitation zone 5, the contact surface between the non-metallic adsorption precipitation zone 5 and the heavy metal ion enhanced adsorption zone 6, and behind the heavy metal ion enhanced adsorption zone 6, with a length and width of 5 cm.

[0077] (7) After the rain, the total phosphorus, total sulfur, and heavy metal Zn contents of the leached water at intake A were measured to be 162 mg / L, 9.3 mg / L, and 151 μg / L, respectively. The pH value was 5.1, and the Acidithiobacillus content was 9 million cells / L. The total phosphorus, total sulfur, and heavy metal Zn contents of the leached water at intake B were 21.1 mg / L, 1.8 mg / L, and 113 μg / L, respectively. The pH value was 6.5, and the Acidithiobacillus content was 5 million cells / L. The total phosphorus, total sulfur, and heavy metal Zn contents of the leached water at intake C were 12.3 mg / L, 1.1 mg / L, and 26.0 μg / L, respectively. The pH value was 6.8, and the Acidithiobacillus content was 3 million cells / L. The effluent quality was significantly improved.

[0078] Example 3

[0079] This embodiment provides a mine leaching pollution buffer zone, such as Figure 1 As shown, the mine leaching pollution buffer zone of this embodiment is applied to the prevention and control of leaching pollution on the slope of the Xiaonanshan acidic pyrite mine, including the following steps:

[0080] (1) After the rain, the maximum penetration depth of the soil at the bottom of the slope was measured to be about 25 cm. The contents of Mn, Pb, and S in the leached water at the foot of the slope were high, at 709 μg / L, 351 μg / L, and 5.8 mg / L, respectively. The pH value was 3.9, and the content of Acidithiobacillus was 59 million per liter.

[0081] (2) Setting up a water storage belt 2: Since the slope is relatively low, about 15 m long, and the local rainfall is moderate, a water storage belt with a height of 28 cm, a width of 40 cm, and a length of 6 m is excavated, and a 10 cm wide waste rock 3 is filled near the outer side. The waste rock in this embodiment is crushed limestone waste rock.

[0082] (3) Set up the deceleration pretreatment zone 4: the height is 33 cm, the width is 25 cm, and the length is the same as the water storage zone 2. The deceleration pretreatment zone 4 is set next to the water storage zone 2, the top of the deceleration pretreatment zone 4 is flush with the top of the water storage zone 2, and the bottom of the deceleration pretreatment zone 4 is 5 cm lower than the bottom of the water storage zone 2. Take 50 parts of anaerobic digestion residue (water content 43%, pH value 6.7, particle size <1 cm, organic matter content 19%, saturated moisture content 86 wt%), 20 parts of composite biochar (prepared by sulfate-reducing bacteria and biochar A in a mass ratio of 1:7; biochar A particle size is 0.4~0.5 cm, and the specific surface area is between 600~1100 m 2 / g), 10 parts of calcite powder (particle size <0.1mm), mixed evenly, filled and lightly compacted. After 5 days of film curing, the pH value of the deceleration pretreatment zone was measured to be 7.1, and the water penetration rate was 2.9×10 -4 cm / s, saturated moisture content 96%, oxygen content 3.1%, and sulfate-reducing bacteria 350 million / g.

[0083] (4) Setting up non-metallic adsorption sedimentation zone 5: The non-metallic adsorption sedimentation zone 5 is 33 cm high, 30 cm wide, and 6 m long. The non-metallic adsorption sedimentation zone 5 is set adjacent to the deceleration pretreatment zone 4. The top of the metal adsorption sedimentation zone 5 is 5 cm lower than the top of the deceleration pretreatment zone 4, and the bottom of the metal adsorption sedimentation zone 5 is 5 cm lower than the bottom of the deceleration pretreatment zone 4. Take 30 parts of dried water supply sludge (total content of aluminum salts and iron salts 27.8%, moisture content 25.9%, organic matter content 6.7%), 20 parts of fine-grained steel slag A (particle size <1 mm, total mass proportion of CaO, iron and iron-aluminum oxides 37.9%), 20 parts of calcium carbonate powder (particle size <0.5 mm), 3 parts of guar gum, and 3 parts of borax, mix them well, fill them, and lightly compact them.

[0084] (5) Set up a heavy metal ion enhanced adsorption zone 6: height 33 cm, width 40 cm, length 6 m. The heavy metal ion enhanced adsorption zone 6 is set adjacent to the non-metallic adsorption precipitation zone 5. The top of the heavy metal ion enhanced adsorption zone 6 is 5 cm lower than the top of the non-metallic adsorption precipitation zone 5, and the bottom of the heavy metal ion enhanced adsorption zone 6 is 5 cm lower than the bottom of the non-metallic adsorption precipitation zone 5. Take 30 portions of biochar B (particle size 0.1~0.3 mm, specific surface area between 1000~1500 m 2 / g), 30 parts of coarse-grained steel slag B (particle size 1-3 mm, silicate minerals and iron oxide account for 51.2% of the total mass), and 15 parts of cement are mixed evenly and filled, and the porosity is about 35% after drying and consolidation.

[0085] (6) Water inlets A, B and C are respectively left at the contact surface between the deceleration pretreatment zone 4 and the non-metallic adsorption precipitation zone 5, the contact surface between the non-metallic adsorption precipitation zone 5 and the heavy metal ion enhanced adsorption zone 6, and behind the heavy metal ion enhanced adsorption zone 6, with a length and width of 5 cm.

[0086] (7) After the rain, the Mn, Pb, and S contents of the leached water at intake A were measured to be 682 μg / L, 327 μg / L, and 5.1 mg / L, respectively. The pH value was 5.9, and the Acidithiobacillus content was 25 million cells / L. The Mn, Pb, and S contents of the leached water at intake B were 566 μg / L, 241 μg / L, and 1.4 mg / L, respectively. The pH value was 6.2, and the Acidithiobacillus content was 11 million cells / L. The Mn, Pb, and S contents of the leached water at intake C were 66.3 μg / L, 28.6 μg / L, and 0.9 mg / L, respectively. The pH value was 6.5, and the Acidithiobacillus content was 3 million cells / L. The effluent quality was significantly improved.

[0087] Comparative Example 1

[0088] In this comparative example, the non-metallic adsorption precipitation belt and the heavy metal ion enhanced adsorption belt are combined into one (the raw materials of the non-metallic adsorption precipitation belt and the heavy metal ion enhanced adsorption belt are mixed), the width is 70 cm, and the other steps are consistent with Example 1. The final leaching water Cu, Pb, and Cd contents are measured to be 72.3 μg / L, 65.6 μg / L, and 4.1 μg / L, respectively, the pH value is 6.1, the Acidithiobacillus content is 50 million / L, and the total sulfur and phosphorus contents are 1.5 mg / L and 0.3 mg / L, respectively.

[0089] Comparative Example 2

[0090] In this comparative example, the deceleration pretreatment zone, the non-metallic adsorption precipitation zone and the heavy metal ion enhanced adsorption zone are combined into one (the raw materials of the three are mixed), with a width of 100 cm. The other steps are consistent with Example 1. The final leaching water Cu, Pb, and Cd contents are measured to be 79.9 μg / L, 72.0 μg / L, and 4.4 μg / L, respectively, the pH value is 5.9, the acidthiobacillus content is 27 million / L, and the total sulfur and phosphorus contents are 2.8 mg / L and 0.3 mg / L, respectively.

[0091] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A mine leaching pollution buffer zone, characterized in that: It includes a water storage zone, a deceleration pretreatment zone, a non-metallic adsorption precipitation zone and a heavy metal ion enhanced adsorption zone which are arranged in sequence; The deceleration pretreatment belt comprises, by mass, 40 to 60 parts of anaerobic digestion residue, 10 to 20 parts of composite biochar, and 3 to 7 parts of a foaming agent; The non-metallic adsorption precipitation belt comprises, by weight, 30-50 parts of dried water sludge, 20-40 parts of steel slag A, 10-20 parts of alkaline buffer, 3-5 parts of guar gum, and 3-5 parts of borax; The heavy metal ion enhanced adsorption belt comprises, by weight, 20 to 30 parts of biochar B, 20 to 40 parts of steel slag B, and 10 to 20 parts of cement; The composite biochar is prepared from sulfate-reducing bacteria and biochar A in a mass ratio of 1-2:10-15; The foaming agent includes at least one of calcium carbonate or magnesium carbonate.

2. The mine leaching pollution buffer zone according to claim 1, characterized in that: The water storage belt includes a tunnel, and waste rocks are arranged on a side of the tunnel close to the deceleration pretreatment belt.

3. The mine leaching pollution buffer zone according to claim 1, characterized in that: The deceleration pre-treatment zone meets at least one of the following conditions: (1) The particle size of the foaming agent is less than 0.1 mm; (2) The deceleration pretreatment zone has a saturated moisture content greater than 95%, a pH value of 7 to 8, and a water penetration rate less than 3×10 -4 cm / s; (3) After mixing the raw materials of the deceleration pretreatment belt, perform film covering and curing for 5 to 10 days; (4) The anaerobic digestion residue has a moisture content of 30wt%~50wt%, a particle size of <1cm, a pH value of 6~8, an organic matter content of 15wt%~30wt%, and a saturated moisture content of >80wt%.

4. The mine leaching pollution buffer zone according to claim 3 is characterized in that: The particle size of biochar A is 0.3~0.5cm, and the specific surface area is between 600~1500m 2 / g.

5. The mine leaching pollution buffer zone according to claim 1, characterized in that: The non-metallic adsorption precipitation zone satisfies at least one of the following conditions: (1) In the dried water supply sludge, the total content of aluminum salts and iron salts is greater than 20wt%, the moisture content is less than 30wt%, and the organic matter content is less than 10wt%; (2) The particle size of the steel slag A is less than 1 mm; (3) The alkaline buffer is powdered calcium carbonate or magnesium carbonate; (4) The particle size of the alkaline buffer is less than 0.5 mm.

6. The mine leaching pollution buffer zone according to claim 1, characterized in that: The heavy metal ion enhanced adsorption belt satisfies at least one of the following conditions: (1) The particle size of the biochar B is 0.1-0.3 mm, and the specific surface area is between 600-1500 m 2 / g; (2) The particle size of the steel slag B is 1-3 mm.

7. The mine leaching pollution buffer zone according to any one of claims 1 to 6, characterized in that: At least one of the following conditions is met: (1) The height of the water storage belt is 25~40cm; (2) The width of the water storage belt is 40~70cm; (3) The deceleration pretreatment belt is laid at a height of 30 to 45 cm; (4) The width of the deceleration pretreatment zone is 20 to 40 cm; (5) The non-metallic adsorption precipitation belt is laid at a height of 25 to 40 cm; (6) The width of the non-metallic adsorption precipitation zone is 30-40 cm; (7) The heavy metal ion enhanced adsorption belt is laid at a height of 25 to 40 cm; (8) The width of the heavy metal ion enhanced adsorption zone is 40 to 60 cm; (9) The deceleration pretreatment zone, non-metallic adsorption precipitation zone and heavy metal ion enhanced adsorption zone are distributed in a stepped manner along the direction of water flow.

8. The mine leaching pollution buffer zone according to claim 7, characterized in that: The bottom of the deceleration pretreatment zone is 5 to 10 cm lower than the bottom of the water storage zone.

9. The mine leaching pollution buffer zone according to claim 7, characterized in that: The bottom of the non-metallic adsorption precipitation zone is 5 to 10 cm lower than the bottom of the deceleration pretreatment zone.

10. The mine leaching pollution buffer zone according to claim 7, characterized in that: The bottom of the heavy metal ion enhanced adsorption zone is 5 to 10 cm lower than the bottom of the deceleration pretreatment zone.

11. The mine leaching pollution buffer zone according to claim 7, characterized in that: The tops of the two adjacent belts are lowered by 5 to 10 cm in sequence, and the protruding parts are fixed with waste stones.

12. Use of the mine leaching pollution buffer zone according to any one of claims 1 to 11 in a mine, characterized in that: The water storage zone, deceleration pretreatment zone, non-metallic adsorption precipitation zone and heavy metal ion enhanced adsorption zone in the mine leaching pollution buffer zone are arranged in sequence along the flow direction of the sewage to be purified.

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